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Sample records for mdea methyldiethanolamine piperazine

  1. A study on equilibrium solubility for carbon dioxide in methyldiethanolamine-piperazine-water solution

    SciTech Connect

    Liu, H.B.; Zhang, C.F.; Xu, G.W.

    1999-10-01

    Activated methyldiethanolamine (MDEA) technology has been frequently applied for the removal of acidic gases such as CO{sub 2} and H{sub 2}S from gas streams. Solubilities of CO{sub 2} in aqueous mixtures of methyldiethanolamine (MDEA) and piperazine (PZ) have been measured for temperatures and CO{sub 2} partial pressures ranging from 30 to 90 C and 13.16 to 935.3 kPa, respectively. A modified Deshmukh-Mather thermodynamic model is used to correlate the experimental data with the average deviation of 9.8%, in which the effect of salts on Henry's constant is taken into consideration. The results also indicate that the second-order dissociation reaction for piperazine can be neglected. A simple model is also given with the average deviation of 11.6%.

  2. Gas-liquid equilibrium in a CO{sub 2}-MDEA-H{sub 2}O system and the effect of piperazine on it

    SciTech Connect

    Xu, G.W.; Zhang, C.F.; Qin, S.J.; Gao, W.H.; Liu, H.B.

    1998-04-01

    Aqueous N-methyldiethanolamine (MDEA) solutions are widely used for removal of the acid gas (H{sub 2}S and CO{sub 2}) from natural gas synthesis and refinery gas streams. Solubility data of CO{sub 2} and vapor pressure of water in 3.04--4.28 kmol/m{sup 3} aqueous N-methyldiethanolamine (MDEA) solutions were obtained at temperatures ranging from 40 to 100 C and CO{sub 2} partial pressures ranging from 0.876 to 1,013 kPa. A thermodynamic model was proposed and used for predicting CO{sub 2} solubility and water vapor pressure. An enthalpy change of absorption of CO{sub 2} in 4.28 kmol/m{sup 3} MDEA solution was estimated. The effect of piperazine (PZ) concentration on CO{sub 2} loading in MDEA solutions was determined at piperazine concentration ranging from 0 to 0.515 kmol/m{sup 3}. The results show that piperazine is beneficial to the CO{sub 2} loading. The equilibrium partial pressure of piperazine in the PZ-MDEA-H{sub 2}O system was measured in an Ellis Cell. Results show that the PZ-MDEA-H{sub 2}O system is a typical negative deviation system, with the strength of deviation decreasing with MDEA solutions.

  3. Effect of chlorides on solution corrosivity of methyldiethanolamine (MDEA) solutions

    SciTech Connect

    Rooney, P.C.; Bacon, T.R.; DuPart, M.S.; Willbanks, K.D.

    1997-08-01

    Solution corrosivity of MDEA/water solutions containing added HCl or NaCl have been measured by weight loss coupons at 250 F and by linear polarization resistance (LPR) at 208 F using carbon steel, 304SS, 316SS and 410SS. General corrosion as well as pitting or crevice corrosion tendencies were recorded for each species. Based on these results, recommendations are made for chlorides in MDEA that minimizes corrosion in gas treating operations.

  4. Desorption of CO{sub 2} from MDEA and activated MDEA solutions

    SciTech Connect

    Xu, G.W.; Zhang, C.F.; Qin, S.J.; Zhu, B.C.

    1995-03-01

    A packed column was used for investigating the desorption rate of CO{sub 2} from aqueous methyldiethanolamine (MDEA) and activated MDEA solutions. Experiments were conducted within the temperature range 30--70 C, the concentration of MDEA was 4.28 kmol/m{sup 3}, and the concentration of piperazine (PZ) was 0.10 kmol/m{sup 3} for aqueous activated MDEA solutions. Experimental data confirmed that the kinetics model of absorption CO{sub 2} into aqueous MDEA and activated MDEA solutions can be applicable to the situations in which desorption occurs, and the desorption rate of model predictions agree well with that of experimental determination.

  5. Aerobic biodegradability of methyldiethanolamine (MDEA) used in natural gas sweetening plants in batch tests and continuous flow experiments.

    PubMed

    Fürhacker, M; Pressl, A; Allabashi, R

    2003-09-01

    Mixtures of different amines including tertiary amines (methyldiethanolamine, MDEA) are commonly used for the removal of CO2 from gas mixtures or in gas sweetening processes for the extraction of CO2 and H2S. The absorber solutions used can be released into the industrial waste water due to continuous substitution of degraded MDEA, periodically cleaning processes or an accidental spill. In this study, the aerobic biodegradability of MDEA was investigated in a standardised batch test and a continuous flow experiment (40 l/d). The results of the batch test indicated that the MDEA-solution was non-biodegradable during the test period of 28 days, whereas the continuous flow experiments showed biodegradation of more than 96% based on TOC-measurements. This was probably due to the adaptation of the microorganisms to this particular waste water contamination during continuous flow experiment. PMID:12871741

  6. Equilibrium solubilities of CO/sub 2/ and H/sub 2/S in diethanolamine (DEA) and methyldiethanolamine (MDEA) solutions

    SciTech Connect

    Ho, A.S.; Equren, P.R. )

    1988-01-01

    The ability to predict equilibrium phase behavior in systems containing CO/sub 2/ and/or H/sub 2/S in alkanolamine solutions such as diethanolamine (DEA) and methyldiethanolamine (MDEA) is of vital importance for proper design and operation of acid gases treating systems. Literature data for the solubilities of CO/sub 2/ and/or H/sub 2/S in DEA and MDEA systems have been compiled and evaluated. Experimental measurements have also been made to confirm literature data and to expand the data base. A vapor-liquid equilibrium (VLE) model similar to the one developed by Kent and Eisenberg has been developed to correlate the data. The model gives the most accurate predictions when compared to other VLE models available for predicting equilibrium acid gas partial pressures over DEA and MDEA solutions.

  7. Selective removal of hydrogen sulfide from carbon dioxide containing gases with methyldiethanolamine (MDEA) aqueous solutions

    SciTech Connect

    Yu, W.C.

    1985-01-01

    The kinetics of the chemical reactions between MDEA and H/sub 2/S can be regarded as instantaneous, since it is a proton-transfer reaction, and therefore these kinetics require no further investigation. The kinetics of the reaction between MDEA and CO/sub 2/ are more complicated and is studied here to clear the apparent contradiction in the literature (Barth et al., 1981; Blauwhoff et al., 1983). A base-catalyzed mechanism by MDEA is concluded with a kinetic equation which is first order in CO/sub 2/ and MDEA concentrations. The influence of ionic strength on these kinetics was studied, and it is concluded that a minor effect is indeed present. With the knowledge of the kinetics of these reactions, a model which describes the simultaneous absorption of H/sub 2/S and CO/sub 2/ in MDEA solutions is presented. This model can not only predict the simultaneous absorption of H/sub 2/S and CO/sub 2/ in the initial stage, but also predict an experimental observation of long time desorption of H/sub 2/S. Furthermore, this model provides analytical solutions of the mass transfer equations which take into account the interactions between the two chemical reactions. A special case, which is termed film effect, is taken into account in expanding the model into a design procedure. It is concluded that the film effect will be significant only at the lean end of the absorber. A linearized correction term is used to correct for this affect. Finally, the design procedures for both isothermal and adiabatic packed-bed absorbers are proposed on the basis of the simultaneous absorption model and the correction for film effect. No pilot plant data are included to check the calculation, because such data are not available in the open literature.

  8. Simultaneous absorption of H/sub 2/S and CO/sub 2/ in aqueous MDEA. [Methyldiethanolamine

    SciTech Connect

    Khalil, N.M.

    1984-01-01

    In the simultaneous absorption of two gases in a reactive liquid, the rates of absorption of both gases are affected by their competition for the same reactive reagent. The case of absorption of two gases into a reactive liquid where one reacts under second order reaction kinetics while the other reacts instantaneously is of practical interest, since this case represents the absorption of CO/sub 2/ and H/sub 2/S into amine solutions. The rates of absorption were modeled according to the penetration theory. The model equations consisting of a system of nonlinear differential equations with a moving boundary were solved numerically. The theoretical model was applied to a description of the selective absorption of H/sub 2/S in diethanolamine solution in the presence of CO/sub 2/. The simultaneous absorption of H/sub 2/S and CO/sub 2/ gases into MDEA was studied experimentally using a stirred gas liquid absorber. This case was modeled theoretically assuming one of the gases CO/sub 2/ undergoes a second order reaction condition with the solution while the other gas, H/sub 2/S is entirely gas film controlled. The kinetics of the reaction between both gases and MDEA was studied. Unavailable physical properties such as diffusivities and solubilities of different species were measured experimentally using laminar jet apparatus.

  9. Absorption of carbonyl sulfide in aqueous methyldiethanolamine

    SciTech Connect

    Al-Ghawas, H.A.; Ruiz-Ibanez, G.; Sandall, O.C. )

    1988-01-01

    The absorption of carbonyl sulfide in aqueous methyldiethanolamine (MDEA) was studied over a range of temperatures and MDEA concentrations. MDEA is commonly used for selective absorption of hydrogen sulfide in the presence of carbon dioxide. However, sulfur in the form of COS may also be present and it is necessary that estimates of absorption rates of this compound be made. The objective of this study is to determine the physiochemical properties needed to predict COS absorption rates in aqueous MDEA. Free gas solubility and the diffusivity of COS in MDEA solutions were measured over the temperature range 15 to 40{sup 0}C for MDEA concentrations up to 30 weight per cent using the nitrous oxide analogy method. Solubilities were measured volumetrically in an equilibrium cell and diffusivities were measured using a laminar liquid jet absorber. The kinetics of the reaction between COS and MDEA were studied by measuring absorption rates in a single wetted-sphere absorber.

  10. Heat capacity of aqueous monoethanolamine, diethanolamine, N-methyldiethanolamine, and N-methyldiethanolamine-based blends with carbon dioxide

    SciTech Connect

    Weiland, R.H.; Dingman, J.C.; Cronin, D.B.

    1997-09-01

    New data are reported on the heat capacity of CO{sub 2}-loaded, aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), and aqueous MDEA-based blends with MEA and DEA. The work reported here was motivated by the need to quantify the effect of acid gas loading on the important physical properties of gas-sweetening solvents.

  11. Solubility of carbon dioxide in methyldiethanolamine + methanol + water

    SciTech Connect

    Henni, A.; Mather, A.E.

    1995-03-01

    Aqueous solutions of methyldiethanolamine (MDEA) are attractive solvents for the selective removal of H{sub 2}S from process stream containing CO{sub 2} and hydrocarbons. The solubility of CO{sub 2} in a mixed nonaqueous solvent of methyldiethanolamine MDEA and methanol has been measured at 40 C. The results are compared with the solubility of CO{sub 2} in pure methanol. The solubility of CO{sub 2} has also been obtained at 40 and 100 C in an aqueous mixed solvent consisting of methanol (40 mass %), MDEA (40 mass %), and water (20 mass %) at partial pressures of the acid gas up to 7.04 MPa. The solubility results are compared with the nonaqueous mixed solvent results and previously reported data for aqueous methyldiethanolamine.

  12. Diffusivity of nitrous oxide in N-methyldiethanolamine + diethanolamine + water

    SciTech Connect

    Rinker, E.B.; Russell, J.W.; Tamimi, A.; Sandall, O.C.

    1995-05-01

    The tertiary amine N-methyldiethanolamine and the secondary amine diethanolamine are commonly used in the gas-treating industry as chemical solvents for the removal of acid gases such as CO{sub 2} and H{sub 2}S. The diffusion coefficients for nitrous oxide in aqueous solutions consisting of N-methyldiethanolamine (MDEA) and diethanolamine (DEA) were measured over the temperature range 293--353 K for a total amine concentration of 50 mass % and for the mass ratio of DEA to MDEA varying from 0.0441 to 0.588. The experimental diffusion coefficients were found to be relatively insensitive to the mass ratio of amines.

  13. Solubility of CO{sub 2} in aqueous methyldiethanolamine solutions

    SciTech Connect

    Rho, S.W.; Yoo, K.P.; Lee, J.S.; Nam, S.C.; Son, J.E.; Min, B.M.

    1997-11-01

    For 5.0, 20.5, 50.0, and 75.0 mass % methyldiethanolamine (MDEA) aqueous solutions, solubilities of CO{sub 2} were measured at 323.15, 348.15, and 373.15 K, respectively. Isothermal absorption capacities of CO{sub 2} as a function of MDEA concentration are presented. Lastly, the absorption enthalpy of CO{sub 2} in 50.0 mass % MDEA solution was calculated to be 54 kJ/mol CO{sub 2}.

  14. Modeling CO2 mass transfer in amine mixtures: PZ-AMP and PZ-MDEA.

    PubMed

    Puxty, Graeme; Rowland, Robert

    2011-03-15

    The most common method of carbon dioxide (CO(2)) capture is the absorption of CO(2) into a falling thin film of an aqueous amine solution. Modeling of mass transfer during CO(2) absorption is an important way to gain insight and understanding about the underlying processes that are occurring. In this work a new software tool has been used to model CO(2) absorption into aqueous piperazine (PZ) and binary mixtures of PZ with 2-amino-2-methyl-1-propanol (AMP) or methyldiethanolamine (MDEA). The tool solves partial differential and simultaneous equations describing diffusion and chemical reaction automatically derived from reactions written using chemical notation. It has been demonstrated that by using reactions that are chemically plausible the mass transfer in binary mixtures can be fully described by combining the chemical reactions and their associated parameters determined for single amines. The observed enhanced mass transfer in binary mixtures can be explained through chemical interactions occurring in the mixture without need to resort to using additional reactions or unusual transport phenomena such as the "shuttle mechanism". PMID:21329341

  15. Viscosity of aqueous solutions of n-methyldiethanolamine and of diethanolamine

    SciTech Connect

    Teng, T.T.; Maham, Y.; Hepler, L.G.; Mather, A.E. )

    1994-04-01

    Aqueous solutions of alkanolamines such as monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), di-2-propanolamine (DIPA), and bis[2-(hydroxyamino)ethyl] ether (DGA) are good solvents for the removal of acid gases such as CO[sub 2] and H[sub 2]S from the gas streams of many processes in the natural gas, petroleum, ammonia synthesis, and some chemical industries. The viscosity of aqueous solutions of methyldiethanolamine (MDEA) and of diethanolamine (DEA) have been measured at five temperatures in the range 25--80 C throughout the whole concentration range. The viscosity has been correlated as a function of composition for use in industrial calculations.

  16. Effect of heat stable salts on MDEA solution corrosivity: Part 2

    SciTech Connect

    Rooney, P.C.; DuPart, M.S.; Bacon, T.R.

    1997-04-01

    A comprehensive coupon corrosion testing program was undertaken to address the effect of various heat stable salts on methyldiethanolamine (MDEA) corrosivity to carbon steel and various stainless steels. Corrosion rates of carbon steel, 304SS, 316SS and 410SS liquid and vapor coupons towards MDEA, and MDEA containing various anions, at 180 F and 250 F, were measured in a reactor. Corrosion results of two refinery plant solutions before and after caustic neutralization were also performed. Based on these results, guidelines were determined for heat stable amine salt (HSAS) levels of oxalates, sulfates, formates, acetates and thiosulfates. In addition, caustic neutralization guidelines for MDEA heat stable salts were determined. Ongoing results include MDEA corrosivity with succinates, and malonates, glycolates, SO{sub 2} and ammonia.

  17. Operating costs cut 60% with amine switch. [Methyldiethanolamine and diethanolamine

    SciTech Connect

    Not Available

    1984-01-09

    At the Waveland, Miss., facility of United Gas Pipe Line Co., a methyldiethanolamine (MDEA) unit was supplemented by a smaller diethanolamine (DEA) unit. With the units running in parallel, product gas specifications could be met. Each unit was treating about one-half the 30 MMscfd flow of sour gas. Natural gas, purchased from nearby producers, comes into the plant containing 40-60 ppm H/sub 2/S and 4.8% CO/sub 2/. Although the absorber of the MDEA unit was adequate to handle the gas flow and remove the H/sub 2/S to specification, the reboiler capacity was not sufficient to meet a 2% CO/sub 2/ specification. MDEA concentration was limited to less than 40% by potential corrosion problems. The DEA unit was more expensive to operate, requiring sweet processed gas as boiler fuel, and consumed twice as much electricity as the MDEA unit. The combined outlet gas from the two units met volume requirements and specifications. But the system presented operational problems. Repeated foaming occurred with the MDEA unit. Daily losses of solvent were as much as 250 gal. By closely monitoring the system, United Gas was able to reduce foaming significantly by minimizing contamination with liquid hydrocarbons which had been entering with the feed gas during line surges. Extra labor was required. Several approaches were investigated involving equipment modifications and new materials. As a result of the study, United Gas concluded that the system could be optimized and all incoming gas treated in one unit by switching solvent. Conventional MDEA was replaced by a specially formulated MDEA based solvent with low foaming tendency (Union Carbide Corp.'s Ucarsol HS Solvent 101). It could be used at a 50% concentration in aqueous solution without apparent corrosion.

  18. Experimental investigation of the phase equilibria in the carbon dioxide-propane-3 M MDEA system

    SciTech Connect

    Jou, F.Y.; Mather, A.E.; Otto, F.D.; Carroll, J.J.

    1995-07-01

    The treating of liquefied petroleum gas (LPG) to remove carbon dioxide and hydrogen sulfide using aqueous alkanolamine solutions is an important aspect of gas processing. One of the amines used in the natural gas industry is methyldiethanolamine (MDEA). Measurements of the phase equilibria in the carbon dioxide-propane-3 M MDEA system have been made at 25 and 40 C at pressures up to 15.5 MPa. Vapor-liquid, liquid-liquid, and vapor-liquid-liquid equilibria were determined. The vapor-liquid equilibrium data were compared with the model of Deshmukh and Mather.

  19. Diffusivity of nitrous oxide in aqueous solutions of N-methyldiethanolamine and diethanolamine from 293 to 368 K

    SciTech Connect

    Tamimi, A.; Rinker, E.B.; Sandall, O.C. . Dept. of Chemical and Nuclear Engineering)

    1994-04-01

    The diffusion coefficients for nitrous oxide in aqueous solutions of diethanolamine (DEA) and N-methyldiethanolamine (MDEA) were determined using a wetted-sphere absorber over the temperature range 293--368 K. The ranges of amine concentrations covered in the experiments were 10--30 mass % for DEA and 10--50 mass % for MDEA. The diffusion coefficients indicated a linear dependence on amine concentration, but the temperature dependence was nonlinear. It was found that the diffusivity of N[sub 2]O in aqueous DEA is always less than that in aqueous MDEA under equivalent conditions of amine concentration and temperature.

  20. Densities and viscosities for binary mixtures of N-methyldiethanolamine + triethylene glycol monomethyl ether from 25 C to 70 C and N-methyldiethanolamine + ethanol mixtures at 40 C

    SciTech Connect

    Henni, A.; Maham, Y.; Tontiwachwuthikul, P.; Chakma, A.; Mather, A.E.

    2000-04-01

    Recent studies done on the absorption and desorption of acid gases (CO{sub 2}, H{sub 2}S) from natural gas, petroleum, and ammonia synthesis streams have shown that aqueous solutions of N-methyldiethanolamine (MDEA) can be used effectively for the selective removal of H{sub 2}S. This paper reports the measured values of the density and viscosity of binary mixtures of N-methyldiethanolamine (MDEA) and triethylene glycol monomethyl ether (TEGMME) at five temperatures in the range 25 C to 70 C over the whole concentration range. The authors also report the density and viscosity of the binary mixture MDEA + ethanol at 40 C. The results are compared with data for aqueous mixtures and other alkanolamines when these are available. The derived excess molar volumes and viscosity deviations were correlated as a function of composition. The Grunberg-Nissan interaction energy constants are also reported.

  1. Vapor-liquid equilibria in the system ethanethiol + methyldiethanolamine + water in the presence of acid gases

    SciTech Connect

    Jou, F.Y.; Mather, A.E.; Schmidt, K.A.G.; Ng, H.J.

    1999-07-01

    This investigation was carried out to determine the solubility of ethanethiol in a methyldiethanolamine (MDEA) solution. Measurements were made in the absence of acid gases, H{sub 2}H and CO{sub 2}, with individual acid gases present, and with mixtures of acid gases present. Experiments with an aqueous solution of 50 mass % MDEA were carried out at 40 and 70 C. The total pressure for most of the experiments was 6,890 kPa, which was maintained by methane. Partial pressures of ethanethiol ranged from 0.2 to 15 kPa.

  2. Gas plant converts amine unit to MDEA-based solvent

    SciTech Connect

    Mak, H.Y. )

    1992-10-01

    This paper reports that methyldiethanolamine (MDEA) has successfully replaced monoethanolamine (MEA) solvent at one of Canada's largest gas processing plants. This acid gas treating solvent lowered costs associated with pumping horsepower, reboiler duty, solvent losses, corrosion and other gas processing problems. Not all operating conditions at a gas processing plant favor MDEA or MEA. In the Rimbey plant, originally designed to process sour gas, more sweet gas feed (per volume) called for considering advantages of the lesser-used MDEA. Gulf Canada Resources operates several major sour gas plants in Alberta. The Rimbey Plant was designed in 1960 to process 400 MMscfd of sour gas with 2% H[sub 2]S and 1.32% CO[sub 2]. The amine unit was designed to circulate 2,400 gpm of 20 wt% MEA solution. The single train amine plant has four gas conductors and two amine regenerators. The present raw inlet gas flowrate to the Rimbey Plant is about 312 MMscfd which is made up of three sources: 66 MMscfd of sour gas with 1.5% H[sub 2]S and 1.8% CO[sub 2]; 65 MMscfd of high CO[sub 2] gas with 400 ppmv H[sub 2]S and 3.9% CO[sub 2]; and 181 MMscfd of sweet gas with 2.2% CO[sub 2].

  3. Series of isostructural planar lanthanide complexes [Ln(III)4(mu3-OH)2(mdeaH)2(piv)8] with single molecule magnet behavior for the Dy4 analogue.

    PubMed

    Abbas, Ghulam; Lan, Yanhua; Kostakis, George E; Wernsdorfer, Wolfgang; Anson, Christopher E; Powell, Annie K

    2010-09-01

    A series of five isostructural tetranuclear lanthanide complexes of formula [Ln(4)(mu(3)-OH)(2)(mdeaH)(2)(piv)(8)], (mdeaH(2) = N-methyldiethanolamine; piv = pivalate; Ln = Tb (1), Dy (2), Ho (3), Er (4), and Tm (5)) have been synthesized and characterized. These clusters have a planar "butterfly" Ln(4) core. Magnetically, the Ln(III) ions are weakly coupled in all cases; the Dy(4) compound 2 shows Single Molecule Magnet (SMM) behavior. PMID:20704320

  4. Design and operation of a selective sweetening plant using MDEA

    SciTech Connect

    MacKenzie, D.H.; Chiraka-Parambil, F.; Daniels, C.A.; Bullin, J.A.

    1986-01-01

    The Signalta Resources Forestburg Gas Plant was constructed during the winter of 1983 and placed on stream in April of 1984. A design outlet gas specification of 1/4 grain H/sub 2/S/100 scf was requested to ensure meeting the contract commitment of 1 grain/100 scf. The design gas flowrate was 30 MMSCFD containing 0.5% H/sub 2/S and 3% CO/sub 2/ at 415 psia and 70/sup 0/F. The overall plant is configured as shown in Figure 1. Inlet separation facilities are followed by a feed gas heater. The gas stream then flows through a filter separator followed by the amine contactor. Another filter separator is used as a sweet gas scrubber. After sweetening, the gas is routed to a dew point control refrigeration unit. Finally, a single stage of compression is required to boost the gas to 1200 psig maximum pipeline pressure. The sweetening chemical selected for the Forestburg Plant was methyldiethanolamine (MDEA). This was chosen due to its capability to remove H/sub 2/S and leave a portion of the CO/sub 2/ in the residue gas. At the time of plant commissioning it was one of the first operating MDEA facilities in Western Canada.

  5. Simultaneous absorption of H2S and Co2 into aqueous methyldiethanolamine

    SciTech Connect

    Haimour, N.; Bidarian, A.; Sandall, O.C.

    1987-01-01

    The tertiary amine methyldiethanolamine (MDEA) is finding increasing application as a chemical solvent for selective absorption of hydrogen sulfide from gases containing hydrogen sulfide and carbon dioxide. Gas streams of this type include some natural gases, synthetic gases from coal and heavy oil gasification and tail gases from sulfur plants. Selectivity for H2S is needed either to enrich Claus sulfur plant feed in H2S or to remove only H2S when CO2 removal is not necessary of economic. For the absorption of hydrogen sulfide into MDEA, the reaction which occurs can be considered to be instantaneous while carbon dioxide undergoes a second-order reaction with MDEA. In this work, the simultaneous absorption of two gases into a liquid containing a reactant with which both gases react is modelled using the film theory. Physical properties and kinetic rate parameters used in the model have been measured in the laboratory. The model is used to study the effect of process variables on the selectivity of MDEA for H2S over CO2. The simultaneous absorption of H2S and CO2 gases into aqueous MDEA is studied experimentally using a continuous stirred tank absorber. Experimental absorption rates are compared to predictions based on a multicomponent mass transfer model. The average deviations of the theoretical calculations from the experimental results are 10.2% and 12.9% for CO2 and H2S, respectively.

  6. Viscosity, density, and surface tension of binary mixtures of water and N-methyldiethanolamine and water and diethanolamine and tertiary mixtures of these amines with water over the temperature range 20--100[degree]C

    SciTech Connect

    Rinker, E.B.; Oelschlager, D.W.; Colussi, A.T.; Henry, K.R.; Sandall, O.C. . Dept. of Chemical and Nuclear Engineering)

    1994-04-01

    Aqueous solutions of N-methyldiethanolamine (MDEA) and diethanolamine (DEA) are widely used in the industrial treatment of acid gas streams containing H[sub 2]S and CO[sub 2]. The density and viscosity of aqueous solutions of N-methyldiethanolamine were measured over the temperature range 60--100 C. The density and viscosity of aqueous solutions of diethanolamine and diethanolamine + N-methyldiethanolamine were measured over the temperature range 20--100 C. The surface tension of aqueous solutions of the above mixtures was measured over the temperature range 20--80 C. The concentration ranges were 10--50 mass % N-methyldiethanolamine, 10--30 mass % diethanolamine, and 50 mass % total amine concentration with mass ratios of 0.0441--0.5883 (diethanolamine to N-methyldiethanolamine). The measured quantities were found to be in agreement with the literature where data were available.

  7. Densities and viscosities of solutions of monoethanolamine + N-Methyldiethanolamine + water and monoethanolamine + 2-amino-2-methyl-1-propanol + water

    SciTech Connect

    Li, M.H.; Lie, Y.C. . Dept. of Chemical Engineering)

    1994-07-01

    The densities and viscosities of aqueous mixtures of monoethanolamine (MEA) with N-methyldiethanolamine (MDEA) and MEA with 2-amino-2-methyl-1-propanol (AMP) have been studied at temperatures from 30 to 80 C. For density measurements, four MEA + MDEA (a total of 20 mass %) + H[sub 2]O mixtures and eight MEA + AMP (20 and 30 mass %) + H[sub 2]O mixtures were studied. For viscosity measurements, ten MEA + MDEA + H[sub 2]O mixtures and eight MEA + AMP + H[sub 2]O mixtures were measured. A Redlich-Kister equation of the excess volume was applied to represent the density of the liquid mixtures. The equation of Grunberg and Nissan of liquid viscosity was used to correlate the viscosity data. Both density and viscosity calculations show satisfactory results.

  8. Absorption of H{sub 2}S by an aqueous methyldiethanolamine solution at 296 and 343 K

    SciTech Connect

    Pani, F.; Gaunand, A.; Richon, D.; Cadours, R.; Bouallou, C.

    1997-09-01

    An apparatus developed to measure absorption kinetics of acid gases by amine solutions is described as well as the experimental procedures dealing with either the initial kinetics or kinetics for loaded solutions. Data obtained for H{sub 2}S absorption into a 50 mass % methyldiethanolamine (MDEA) aqueous solution with various initial H{sub 2}S loadings are reported for the following conditions: H{sub 2}S loadings from 0 to 0.44 mol H{sub 2}S per mol MDEA and two temperatures, 296 and 343 K. The H{sub 2}S experimental absorption rates have been used together with a model, based on mass transfer and involving an instantaneous reversible reaction, to determine the MDEA diffusion coefficient.

  9. A thermodynamic model of methyldiethanolamine-CO{sub 2}-H{sub 2}S-water

    SciTech Connect

    Posey, M.L.; Rochelle, G.T.

    1997-09-01

    Methyldiethanolamine (MDEA) is one of the favored alkanolamines in acid gas treating. It is receiving increased use due to its lower heat of reaction and lower corrosivity compared to the other amines. The electrolyte-nonrandom two-liquid model has been used to represent the thermodynamic behavior of the system: methyldiethanolamine-CO{sub 2}-H{sub 2}S-water. The Data Regression System (DRS) of Aspen Plus was used to regress parameters of the model to experimental data. pH and conductivity data were utilized to supplement vapor-liquid equilibria (VLE) data and improve confidence in model predictions at low acid gas loadings. Predictions for the mixed acid gas systems can be accurately made from the single acid gas parameter sets without the need to regress additional parameters. VLE data were fit well and the calculated heat absorption matches calorimetric data.

  10. Solubility of H/sub 2/S and CO/sub 2/ in aqueous methyldiethanolamine solutions

    SciTech Connect

    Jou, F.Y.; Mather, A.E.; Otto, F.D.

    1982-10-01

    The University of Alberta measured the solubilities of H/sub 2/S and CO/sub 2/ in 1.0, 2.0, and 4.28 kmol/m/sup 3/ aqueous solutions of methyldiethanolamine (MDEA) for temperature and acid-gas partial pressures ranging from 100/sup 0/ to 250/sup 0/F and 0.001 to 8600 kPa, respectively, used the procedure presented by Kent and Eisenberg to correlate the solubility data, and, calculated enthalpies of solution from the experimental results. Aqueous solutions of MDEA are attractive solvents for the selective removal of H/sub 2/S from process streams containing CO/sub 2/ and hydrocarbons.

  11. Vapor-liquid equilibrium of carbon dioxide in aqueous mixtures of monoethanolamine and methyldiethanolamine

    SciTech Connect

    Jou, F.Y.; Otto, F.D.; Mather, A.E. . Dept. of Chemical Engineering)

    1994-08-01

    Aqueous solutions of alkanolamines are used to separate carbon dioxide and hydrogen sulfide from gas streams. Data for the distribution of carbon dioxide between the vapor and aqueous solutions of four mixtures of monoethanolamine (MEA) and methyldiethanolamine (MDEA) have been obtained at 25, 40, 80 and 120 C over a range of pressures from 100 kPa to 20 MPa. Partial pressures of CO[sub 2] ranged from 0.001 to 19,930 kPa. Enthalpies of reaction of CO[sub 2] in the solutions have been calculated from the solubility data.

  12. Diffusion coefficients significant in modeling the absorption rate of carbon dioxide into aqueous blends of N-methyldiethanolamine and diethanolamine and of hydrogen sulfide into aqueous N-methyldiethanolamine

    SciTech Connect

    Adams, M.E.; Marshall, T.L.; Rowley, R.L.

    1998-07-01

    Absorption rates of gaseous CO{sub 2} into aqueous blends of N-methyldiethanolamine (MDEA) and diethanolamine (DEA) and of gaseous H{sub 2}S into aqueous MDEA were measured in a quiescent, inverted-tube diffusiometer by monitoring the rate of pressure drop. A numerical model for absorption, diffusion, and reaction of CO{sub 2} and H{sub 2}S in blends of MDEA, DEA, and water was developed. The model was used to regress diffusion coefficients of bicarbonate, carbamate, and MDEAH{sub 2}CO{sub 3} for the case of CO{sub 2} absorption and of bisulfide ion for the case of H{sub 2}S absorption from measured absorption rates. CO{sub 2} absorption rates and diffusion coefficients of bicarbonate, carbamate, and MDEAH{sub 2}CO{sub 3} were obtained at 298.2 K and 318.2 K in aqueous solutions containing 50 mass % total amine at DEA:MDEA mole ratios of 1:20, 1:4, 1L3, and 2:3. H{sub 2}S absorption rates and diffusion coefficients of bisulfide ion were obtained at 298.2 K and 318.2 K in aqueous solutions containing 20, 35, and 50 mass % MDEA.

  13. N-methyldiethanolamine: a multifunctional structure-directing agent for the synthesis of SAPO and AlPO molecular sieves.

    PubMed

    Wang, Dehua; Tian, Peng; Fan, Dong; Yang, Miao; Gao, Beibei; Qiao, Yuyan; Wang, Chan; Liu, Zhongmin

    2015-05-01

    In the present study, N-methyldiethanolamine (MDEA) is demonstrated to be a multifunctional structure-directing agent for the synthesis of aluminophosphate-based molecular sieves. Four types of molecular sieves, including SAPO-34, -35, AlPO-9 and -22, are for the first time acquired with MDEA as a novel template. The phase selectivity of the present synthesis is found to be condition-dependent. SAPO-34 (CHA) crystallizes from a conventional hydrothermal system with a higher MDEA concentration. When using MDEA as both the template and solvent, pure SAPO-35 (LEV) is obtained from the synthetic gel with a high P2O5/Al2O3 ratio of (2-3), in which the concentration of MDEA could be varied in a wide range. AlPO-9 and AlPO-22 (AWW) are synthesized under the similar conditions to SAPO-35, except without the addition of Si source. The physicochemical properties of the obtained samples are investigated by XRD, XRF, SEM, N2 physisorption, TG-DSC, and various NMR spectra ((13)C, (29)Si, (27)Al and (31)P). Both SAPO-34 and SAPO-35 show good thermal stability, large surface area, and high pore volume. The catalytic performance of SAPO-34 is evaluated by the methanol-to-olefins (MTO) reaction and a good (C2H4+C3H6) selectivity of 82.7% has been achieved. PMID:25616250

  14. Measurement of diffusion coefficients important in modeling the absorption rate of carbon dioxide into aqueous N-methyldiethanolamine

    SciTech Connect

    Rowley, R.L.; Adams, M.E.; Marshall, T.L.; Oscarson, J.L.; Wilding, W.V.; Anderson, D.J.

    1997-03-01

    Natural gas processors use amine treating processes to remove the acid gases H{sub 2}S and CO{sub 2} from gas streams. Absorption rates of gaseous CO{sub 2} into aqueous N-methyldiethanolamine (MDEA) solutions were measured in a quiescent, inverted-tube diffusiometer by monitoring the rate of pressure drop. The absorption rate was found to be insensitive to the diffusion coefficient of CO{sub 2} in solution but very sensitive to the diffusion rate of bicarbonate and protonated MDEA ions. Evidence also suggested that chemical reaction equilibrium is rapid relative to diffusion. A numerical model was developed on the basis of these observations. The model was used to regress diffusion coefficients of bicarbonate and protonated amine, which must be equivalent by electroneutrality arguments, from measured absorption rates. Complete modeling of the absorption process also required data for the diffusion coefficient of MDEA in water. These were measured using a Taylor dispersion apparatus. CO{sub 2} absorption rates and diffusion coefficients of bicarbonate and protonated MDEA were obtained at 298.2 K and 318.2 K in solutions containing 20, 35, and 50 mass % MDEA in water.

  15. Kinetics of the Absorption of CO{sub 2} in Aqueous Solutions of N-Methyldiethanolamine plus Triethylene Tetramine

    SciTech Connect

    Amann, J.M.G.; Bouallou, C.

    2009-04-15

    This work focuses on the development of a new solvent for CO{sub 2} capture. This new solvent is an aqueous solution with a blend of N-methyldiethanolamine (MDEA) and triethylene tetramine (TETA), an amine with four amino groups. CO{sub 2} absorption was investigated between 298 and 333 K using a Lewis cell with a constant interfacial area. Several concentrations of MDEA (17.5 and 40 wt %) and TETA (3 and 6 wt %) were assessed. The influence of the CO{sub 2} partial pressure on the absorption rate was pointed out. The addition of small amount of TETA leads to a high increase in the CO{sub 2} absorption rates. A numerical model based on the film theory was used to determine the rate coefficients between CO{sub 2} and TETA for the different solvents. The physicochemical parameters have a huge influence on the determination of the rate coefficients.

  16. Solubility of single gases carbon dioxide and hydrogen sulfide in aqueous solutions of N-methyldiethanolamine in the temperature range 313--413 K at pressures up to 5 MPa

    SciTech Connect

    Kuranov, G.; Smirnova, N.A.; Rumpf, B.; Maurer, G.

    1996-06-01

    Experimental results for the solubility of the single gases carbon dioxide and hydrogen sulfide in aqueous solutions of 2,2{prime}-methyliminodiethanol (N-methyldiethanolamine (MDEA)) at temperatures between 313 and 413 K and total pressures up to 5 MPa are reported. A model taking into account chemical reactions as well as physical interactions is used to correlate the new data. The correlation is also used to compare the new experimental data with literature data.

  17. Solubility and diffusivity of nitrous oxide in ternary mixtures of water, monoethanolamine, and N-methyldiethanolamine and solution densities and viscosities

    SciTech Connect

    Hagewiesche, D.P.; Ashour, S.S.; Sandall, O.C.

    1995-05-01

    Recently, several researchers have suggested using aqueous mixtures of small amounts of monoethanolamine and much larger amounts of N-methyldiethanolamine for the absorption of CO{sub 2} and for the selective removal of H{sub 2}S from gas streams of mixtures of CO{sub 2} and H{sub 2}S. The densities and viscosities of aqueous N-methyldiethanolamine/monoethanolamine (MDEA/MEA) blends containing 30 and 40 mass % total amine with MEA concentrations of 5, 10, and 15 mass % of the total amine concentration were measured at temperatures of 303, 313, and 323 K. The diffusion coefficients and Henry`s law constants of N{sub 2}O in these solutions were also measured and were used to estimate the diffusion coefficients and Henry`s law constants of CO{sub 2} in these solutions according to the N{sub 2}O/CO{sub 2} analogy technique.

  18. Correlation and prediction of the solubility of CO{sub 2} and H{sub 2}S in aqueous solution of methyldiethanolamine

    SciTech Connect

    Li, Y.; Mather, A.E.

    1997-07-01

    Aqueous alkanolamine solutions are frequently used for the removal of acidic gases, such as CO{sub 2} and H{sub 2}S, from industrial and natural gases. The simplified Clegg-Pitzer equations are used to correlate the solubility data for CO{sub 2} and H{sub 2}S over a wide range of solvent concentrations (12--50 wt % methyldiethanolamine (MDEA) aqueous solutions), temperature (25--120 C), partial pressure of acid gases (0.001--5,290 kPa), and acid gas loading (001--1.0 mol/mol) from different authors. The interaction parameters thus obtained can be used to predict the solubility data for the mixed acid gases in CO{sub 2}-H{sub 2}S-MDEA-H{sub 2}O systems without any additional adjustable parameters.

  19. Estimation of the CO{sub 2} absorption capacities in aqueous 2-(2-aminoethylamino)ethanol and its blends with MDEA and TEA in the presence of SO{sub 2}

    SciTech Connect

    Bonenfant, D.; Minleault, M.; Hausler, R.

    2007-12-15

    A study of carbon dioxide (CO{sub 2}) and sulfur dioxide (SO{sub 2})/CO{sub 2} mixtures absorption has been carried out in aqueous 2-(2-aminoethylamino)ethanol (AEE) solution and its blends with N-methyldiethanolamine (MDEA) and triethanolamine (TEA) to estimate the influence of SO{sub 2}, MDEA, and TEA on the CO{sub 2} absorption capacity of the AEE. The CO{sub 2} absorption loading has been estimated in 15 wt % AEE alone and in the presence of either 5 and 10 wt % MDEA or 5 and 10 wt % TEA solutions with 100 vol % CO{sub 2} and 5.03 and 15.02 vol % SO{sub 2}/CO{sub 2} mixtures at a starting temperature of 296 K and flow rates of 3.067, 3.229, and 3.605 L/min, respectively. The results revealed that the presence of SO{sub 2} in the gas decreases the CO{sub 2} absorption rate and loading in the AEE solution as a function of the concentration of SO{sub 2}. The additions of 5 and 10 wt % of MDEA and TEA do not seem to influence the CO{sub 2} absorption rate in the AEE solution. Moreover, the addition of MDEA increases slightly the CO{sub 2} absorption capacity of AEE, while TEA decreases the absorption capacity of AEE in the absence and presence Of SO{sub 2}. These effects were enhanced with increases of MDEA and TEA. Altogether, the results indicated that the blend of 15 wt % AEE + 10 wt % MDEA represents an interesting solvent which could be used as absorbent for the removal of CO{sub 2} from emission into the atmosphere by industries.

  20. Simulation of gas absorption with chemical reaction: The selective removal of hydrogen sulfide by aqueous methyldiethanolamine in packed columns

    SciTech Connect

    Lindner, J.R.

    1988-01-01

    The design of separation devices, particularly for solvent-based selective removal of H{sub 2}S from CO{sub 2}, requires an accurate mathematical model. Unfortunately, this requirement for high accuracy is often in conflict with the need for efficient computation. The addition of more and more complicated analyses, such as a move from Henry's law to a method incorporating gas and liquid activities for computing vapor liquid equilibria, may give a more accurate solution, but only at the cost of decreased computational efficiency. The efforts in this work have been directed toward two goals. The first was to develop an accurate mathematical model for the aqueous methyldiethanolamine (MDEA) system. The steady-state packed column model developed in this work has been tested with data from Schubert (1988) to verify its accuracy. The second goal was to modify the model to improve its computational efficiency. Areas such as vapor-liquid equilibrium calculations, flow hydrodynamics, and thermal effects were examined to determine what simplifications could be made, and how these simplifications affected both the accuracy and the efficiency of the model. The result of this effort is a mathematical model for multicomponent chemical absorption in a continuous contactor that balances computation efficiency with rigorous physical and chemical treatment. This model is useful not only for the analysis of the MDEA-H{sub 2}S-CO{sub 2} system, but the same framework also could be applied to other chemical absorption systems.

  1. Determination of diethanolamine or N-methyldiethanolamine in high ammonium concentration matrices by capillary electrophoresis with indirect UV detection: application to the analysis of refinery process waters.

    PubMed

    Bord, N; Crétier, G; Rocca, J-L; Bailly, C; Souchez, J-P

    2004-09-01

    Alkanolamines such as diethanolamine (DEA) and N-methyldiethanolamine (MDEA) are used in desulfurization processes in crude oil refineries. These compounds may be found in process waters following an accidental contamination. The analysis of alkanolamines in refinery process waters is very difficult due to the high ammonium concentration of the samples. This paper describes a method for the determination of DEA in high ammonium concentration refinery process waters by using capillary electrophoresis (CE) with indirect UV detection. The same method can be used for the determination of MDEA. Best results were achieved with a background electrolyte (BGE) comprising 10 mM histidine adjusted to pH 5.0 with acetic acid. The development of this electrolyte and the analytical performances are discussed. The quantification was performed by using internal standardization, by which triethanolamine (TEA) was used as internal standard. A matrix effect due to the high ammonium content has been highlighted and standard addition was therefore used. The developed method was characterized in terms of repeatability of migration times and corrected peak areas, linearity, and accuracy. Limits of detection (LODs) and quantification (LOQs) obtained were 0.2 and 0.7 ppm, respectively. The CE method was applied to the determination of DEA or MDEA in refinery process waters spiked with known amounts of analytes and it gave excellent results, since uncertainties obtained were 8 and 5%, respectively. PMID:15338092

  2. Kinetics of CO{sub 2} desorption from highly concentrated and CO{sub 2}-loaded methyldiethanolamine aqueous solutions in the range 312--383 K

    SciTech Connect

    Cadours, R.; Bouallou, C.; Gaunand, A.; Richon, D.

    1997-12-01

    Absorption by aqueous alkanolamine solutions is the dominant industrial process for acid gases removal, in particular CO{sub 2} and H{sub 2}S, from natural gas. Kinetics of CO{sub 2} desorption from CO{sub 2}-loaded methyldiethanolamine (MDEA) aqueous solutions were measured in the following conditions: 312--383 K, 25--50 wt% MDEA aqueous solutions, CO{sub 2} loadings from 5 to 85%. A thermoregulated constant interfacial area reaction cell was operated by measuring the pressure over the solution. Producing a very slight depression in the cell, the time-dependent equilibrium pressure recovery is accurately recorded during batch desorption. Kinetics are in agreement with a fast reaction regime of desorption according to the film theory. For CO{sub 2} loadings below 0.50 mol of gas/mol of amine, desorption rates are well predicted by using the kinetic constant and orders determined from absorption experiments for the reaction between CO{sub 2} and MDEA. Some discrepancies were pointed out for loadings above 0.50 mol of gas/mol of amine.

  3. Solubility of carbon dioxide in aqueous solutions of 2-amino-2-methyl-1-propanol and N-methyldiethanolamine and their mixtures in the temperature range of 313 to 353 K and pressures up to 2.7 MPa

    SciTech Connect

    Silkenbaeumer, D.; Lichtenthaler, R.N.; Rumpf, B.

    1998-08-01

    The solubility of carbon dioxide in aqueous solutions containing 2-amino-2-methyl-1-propanol (AMP) was measured in the temperature range from 313 to 353 K at total pressures up to 2.7 MPa using an analytical method. A model taking into account chemical reactions in the liquid phase as well as physical interactions is used to correlate the new data. To test the predictive capability of the model, the solubility of carbon dioxide in an aqueous solution containing AMP and N-methyldiethanolamine (MDEA) was measured at 313 K. Experimental results are reported and compared to literature data and calculations.

  4. Improvement of amine-modification with piperazine for the adsorption of CO2

    NASA Astrophysics Data System (ADS)

    Xue, Quanmin; Wu, Di; Zhou, Yaping; Zhou, Li

    2012-02-01

    Both selectivity and capacity of CO2 adsorption were considerably increased when PZ (piperazine) was added in MDEA (methyldiethylamine) that used to modify the surface of silica gels. The adsorbent saturated with CO2 was regenerated at ambient temperature through nitrogen purge. A set of PSA (pressure swing adsorption) operation with 200 cycles was carried out and applicability of the modified adsorbent was thus illustrated. The CO2 content in the column-top stream decreased from 13% to below 0.05% at steady state.

  5. Modeling CO{sub 2} and H{sub 2}S solubility in MDEA and DEA: Design implications

    SciTech Connect

    Rochelle, G.T.; Posey, M.

    1996-12-31

    The solubility of H{sub 2}S and CO{sub 2} in aqueous alkanolamines affects solution capacity and the required circulation rate for acid gas absorption. These thermodynamics also determine the relationship of steam rate and the lean loading of the solution which in turn sets the leak of acid gas from the top of the absorber. Finally, the mechanisms of mass transfer and the role of kinetics, especially in stripping, depend on the vapor/liquid equilibria. Published measurements of CO{sub 2} and H{sub 2}S solubility in methyldiethanolamine (MDEA) and diethanolamine (DEA) are not in general agreement, especially at low loading of acid gas. The available sets of solubility data have been regressed with the AspenPlus electrolyte/NRTL model. All of the parameters and constants that make up this model have been carefully evaluated. Independent thermodynamic data such as freezing point and heat of mixing have been included in the regression to strengthen the estimates of model parameters. The parameters for each set of solubility data have been evaluated in an attempt to determine which set is correct. Each evaluated model has been used to calculate the acid gas capacity and minimum stripping steam rate for several industrial cases of acid gas absorption/stripping.

  6. Experimental studies of selective acid gas removal: Absorption of hydrogen sulfide and carbon dioxide into aqueous methyldiethanolamine using packed columns

    SciTech Connect

    Schubert, C.N.

    1988-01-01

    The use of aqueous methyldiethanolamine (MDEA) for selective removal of hydrogen sulfide from acid gas streams has been studied in a 2 inch column packed with 1/4 inch ceramic Intalox saddles. The column was operated in a counter-current, steady state fashion. The feed gas composition varied between 1 and 5 mole % hydrogen sulfide and between 0 and 50 mole % carbon dioxide. In order to assist the development of packed column absorption models, the rate at which pure carbon dioxide absorbs into 2 M MDEA was measured as a function of pressure, liquid flow rate and packed bed length. The importance of end effects was carefully evaluated. In addition, draining and tracer methods were used to estimate the amount of static holdup present in the column. Using classical draining methods, as much as 50 % of the total holdup was found to be static. However, according to the step decrease in tracer method, less than 5 % of the total holdup was static. Since the step decrease in tracer method measures the amount of static holdup present in the bed under irrigated conditions, it seems likely that the draining method provides an unrealistic estimate of static holdup. Thus, although the notion of static holdup may be useful as a means of correlating mass transfer coefficients, the data indicate that very little static holdup exists in the column under irrigated conditions. Hence, in the absence of a mechanistically sound model, the choice of whether to use static holdup or dispersion as a means of accounting for deviations from plug flow in the liquid phase should be made on the basis of computational convenience.

  7. Simultaneous absorption of CO2 and H2S into aqueous blends of N-methyldiethanolamine and diethanolamine.

    PubMed

    Mandald, Bishnupada; Bandyopadhyay, Shyamalendu S

    2006-10-01

    Removal of CO2 from gaseous streams by absorption with chemical reaction in the liquid phase is usually employed in industry as a method to retain atmospheric CO2 to combat the greenhouse effect. A broad spectrum of alkanolamines and, more recently, their mixtures are being employed for the removal of acid gases such as CO2, H2S, and COS from natural and industrial gas streams. In this research, simultaneous absorption of CO2 and H2S into aqueous blends of N-methyldiethanolamine and diethanolamine is studied theoretically and experimentally. The effect of contact time, temperature, and amine concentration on the rate of absorption and the selectivity were studied by absorption experiments in a wetted wall column at atmospheric pressure and constant feed gas ratio. The diffusion-reaction processes for CO2 and H2S mass transfer in blended amines are modeled according to Higbie's penetration theory with the assumption that all reactions are reversible. A rigorous parametric sensitivity test is done to quantify the effects of possible errors in the pertinent model parameters on the prediction accuracy of the absorption rates and enhancement factors. Model results based on the kinetics-equilibrium-mass transfer coupled model developed in this work are found to be in good agreement with the experimental results of rates of absorption of CO2 and H2S into (MDEA + DEA + H2O). PMID:17051803

  8. 21 CFR 556.513 - Piperazine.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Piperazine. 556.513 Section 556.513 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Residues of New Animal Drugs § 556.513 Piperazine. A tolerance of 0.1 part per million piperazine base...

  9. 21 CFR 556.513 - Piperazine.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Piperazine. 556.513 Section 556.513 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Residues of New Animal Drugs § 556.513 Piperazine. A tolerance of 0.1 part per million piperazine base...

  10. 21 CFR 556.513 - Piperazine.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Piperazine. 556.513 Section 556.513 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Residues of New Animal Drugs § 556.513 Piperazine. A tolerance of 0.1 part per million piperazine base...

  11. 21 CFR 556.513 - Piperazine.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Piperazine. 556.513 Section 556.513 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Residues of New Animal Drugs § 556.513 Piperazine. A tolerance of 0.1 part per million piperazine base...

  12. The Neuropsychopharmacology and Toxicology of 3,4-methylenedioxy-N-ethyl-amphetamine (MDEA).

    PubMed

    Freudenmann, Roland W; Spitzer, Manfred

    2004-01-01

    This paper reviews the pharmacology and toxicology of 3,4-methylenedioxy-N-ethylamphetamine (MDEA, "eve"). MDEA is a ring-substituted amphetamine (RSA) like MDMA, its well known N-methyl analog. Both have become very popular substances of abuse in the techno- and house-music scene. They can evoke psychomotor stimulation, mild alterations of perception, sensations of closeness and a positive emotional state as well as sympathomimetic physical effects. At present, the name "ecstasy" is no longer used only for MDMA, but for the whole group of RSAs (MDA, MDMA, MDEA and MBDB) as they are chemically and pharmacologically nearly identical; moreover, many ecstasy pills contain mixtures of the RSAs. Hence, for a selective review on MDEA, it is crucial to strictly differentiate between: 1) street and chemical names, and 2) studies with or without chemically defined substances. In order to present MDEA-specific information, the pharmacodynamics and kinetics are described on the basis of MDEA challenge studies in animals and humans. In the toxicology section, we present a collection of case reports on fatalities where MDEA was toxicologically confirmed. On the question of serotonergic neurotoxicity and possible long-term consequences, however, MDEA-specific information is available from animal studies only. The neurotoxic potential of MDEA in humans is difficult to estimate, as ecstasy users do not consume pure substances. For future research, challenge studies in animals using dosing regimens adapted to human consumption patterns are needed. Such challenge studies should directly compare individual RSAs. They will represent the most viable and fruitful approach to the resolution of the highly controversial issues of serotonergic neurotoxicity and its functional consequences. PMID:15179441

  13. Piperazine-induced occupational asthma

    SciTech Connect

    Hagmar, L.; Bellander, T.; Bergoeoe, B.; Simonsson, B.G.

    1982-03-01

    Asthmatic reactions were studied among some 130 factory workers who handled amines and other chemicals. Among present employees, we found 15 cases of asthma associated with occupational exposure to chemicals; among former employees there were at least 18. The inducing agent was judged to be piperazine in 29 persons and ethylenediamine (EDA) in three. The asthma was of the late or dual type; immediate reactions alone were to seen. No one had attacks of asthma before employment, and atopic subjects were not preferentially affected. Routine spirometry revealed airway obstruction in fewer than half of the recent cases. Tests of nonspecific bronchial reactivity with methacholine in six subjects with recent asthma showed hyperactivity in five, while tow subjects with earlier asthma did not have hyperactivity. Bronchial provocation tests with piperazine in one subject were positive both in the factory and in the laboratory. The level of piperazine was 1.2 mg/m3 time-weighted average (TWA) in a work place associated with induction of the asthmatic state, and 0.3 mg/m3 in a place connected with attacks in ''sensitized'' subjects.

  14. 21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Thiabendazole, piperazine phosphate powder. 520....2380f Thiabendazole, piperazine phosphate powder. (a) Specifications. Each ounce of water dispersible powder contains 6.67 grams of thiabendazole and 8.33 grams of piperazine (as piperazine phosphate)....

  15. 21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Thiabendazole, piperazine phosphate powder. 520....2380f Thiabendazole, piperazine phosphate powder. (a) Specifications. Each ounce of water dispersible powder contains 6.67 grams of thiabendazole and 8.33 grams of piperazine (as piperazine phosphate)....

  16. Determination of MDMA, MDEA and MDA in urine by high performance liquid chromatography with fluorescence detection.

    PubMed

    da Costa, José Luiz; da Matta Chasin, Alice Aparecida

    2004-11-01

    This paper describes the development and validation of analytical methodology for the determination of the use of MDMA, MDEA and MDA in urine. After a simple liquid extraction, the analyses were carried out on a high performance liquid chromatography (HPLC) in an octadecyl column, with fluorescence detection. The mobile phase using a sodium dodecyl sulfate ion-pairing reagent allows good separation and efficiency. The method showed good linearity and precision. Recovery was between 85 and 102% and detection limits were 10, 15 and 20 ng/ml for MDA, MDMA and MDEA, respectively. No interfering substances were detected with fluorescence detection. PMID:15458720

  17. Solubility of carbon dioxide and hydrogen sulfide in aqueous N-methyldiethanolamine solutions

    SciTech Connect

    Huttenhuis, P.J.G.; Agrawal, N.J.; Versteeg, G.F.

    2009-04-15

    In this work, 72 new experimental solubility data points for H{sub 2}S and CO{sub 2} mixtures in aqueous N-methyldiethanol amine (MDEA) solutions at different methane partial pressures (up to 69 bara) are presented. They are correlated using an electrolyte equation of state (E-EOS) thermodynamic model. This model has already been used to estimate the CO{sub 2} solubility in aqueous MDEA (Huttenhuis et al. Fluid Phase Equilib. 2008, 264, 99-112) and the H{sub 2}S solubility in aqueous MDEA (Huttenhuis et al. Int. J. Oil, Gas Coal Technol. 2008, 1, 399-424). Here, the model is further extended to predict the behavior of CO{sub 2} and H{sub 2}S when they are present simultaneously in aqueous MDEA. The application of an equation of state is a new development for this type of system, i.e., of acid-gas-amine systems. The molecular interactions are described by Schwarzentruber et al.'s modification of the Redlich-Kwong-Soave equation of state, with terms added to account for ionic interactions in the liquid phase. The model is used to describe acid-gas solubility data for the CO{sub 2}-H{sub 2}S-MDEA-H{sub 2}O system reported in the open literature and experimental data reported here for the CO{sub 2}-H{sub 2}S-MDEA-H{sub 2}O-CH{sub 4} system.

  18. Piperazine pivoted transition metal dithiocarbamates

    NASA Astrophysics Data System (ADS)

    Khan, Sadaf; Nami, Shahab A. A.; Siddiqi, K. S.

    2008-03-01

    A quadridentate ligand disodium bis(2,2'-dithiopiperazinato-2,2'-diamino diethylamine) Na 2L 2 and its self assembled transition metal complexes of the type, M 2(L 2) 2 {M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)} have been reported. The piperazine pivoted homodinuclear complexes have been characterized by a range of spectral, thermal, microanalytical and conductometric techniques. On the basis of IR and 1HNMR data a symmetrical bidentate coordination of the dithiocarbamato moiety has been observed in all the cases. The TGA profile of the ligand exhibits two stage thermolytic pattern although the complexes decompose in three steps, respectively. Metal sulfide is found to be the end product. The formation of homodinuclear complexes has been ascertained on the basis of FAB mass spectral data and a probable fragmentation pattern has been proposed. On the basis of UV-visible spectroscopic results and room temperature magnetic moment data a tetrahedral geometry has been proposed for all the complexes except for the Ni(II) and Cu(II) which are found to be square-planar.

  19. 21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... powder contains 6.67 grams of thiabendazole and 8.33 grams of piperazine (as piperazine phosphate). (b) Sponsor. See No. 050604 in § 510.600(c) of this chapter. (c) Conditions of use—(1) Amount. 2 grams of thiabendazole and 2.5 grams of piperazine (0.3 ounce of powder) per 100 pounds of body weight. (2)...

  20. Enantioselective Synthesis of α-Secondary and α-Tertiary Piperazin-2-ones and Piperazines by Catalytic Asymmetric Allylic Alkylation

    PubMed Central

    Korch, Katerina M.; Eidamshaus, Christian; Behenna, Douglas C.; Nam, Sangkil; Horne, David

    2014-01-01

    The asymmetric Pd-catalyzed decarboxylative allylic alkylation of differentially N-protected piperazin-2-ones allows for the synthesis of a variety of highly enantioenriched tertiary piperazine-2-ones. Deprotection and reduction affords the corresponding tertiary piperazines, which can be employed for the synthesis of medicinally important analogs. The introduction of these chiral tertiary piperazines resulted in imatinib analogs that exhibited comparable antiproliferative activity to that of their corresponding imatinib counterparts. PMID:25382664

  1. Conformational analysis of 2-substituted piperazines.

    PubMed

    Kallel, E Adam; Vangel, Colin; Elbaum, Daniel

    2016-07-01

    The unusual activity differences of carbon linked versus oxygen linked 2-substituted piperazines as α7 nicotinic acetylcholine receptor agonists led to a conformational study of several examples. The conformational preferences of which are absent from the literature. We report the first study and explanation of the conformational preference of 2-substiturted piperazines and show an example of how this preference controls binding in a pharmaceutically relevant case. In all cases the axial conformation for these 1-acyl and 1 aryl 2-substituted piperazines was found to be preferred. For the ether linked compounds, the axial conformation was found to be further stabilized by an intramolecular hydrogen bond. The axial orientation also places the basic and pyridyl nitrogens into a special orientation that closely mimics nicotine. Molecular modeling studies confirm that the R enantiomers of the compounds can bind to the α7 nicotinic acetylcholine receptor with the basic and pyridyl nitrogens colocalized with their counterparts in Epibatidine. PMID:27212066

  2. Corrosion in MDEA sour gas treating plants: Correlation between laboratory testing and field experience

    SciTech Connect

    Bich, N.N.; Vacha, F.; Schubert, R.

    1996-08-01

    Corrosion in MDEA sour gas treating systems operating in severely loaded conditions is investigated using both laboratory data and actual gas plant experience. Effects of acid gas loading, flow turbulence, solution quality, temperature, etc. on corrosion are being studied. Preliminary results indicated severe corrosion of several mm/y would occur if acid gas loading, circulation rate and level of suspended solids are all high. A mitigation strategy based on operating envelopes is formulated.

  3. 21 CFR 556.513 - Piperazine.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Piperazine. 556.513 Section 556.513 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS TOLERANCES FOR RESIDUES OF NEW ANIMAL DRUGS IN FOOD Specific Tolerances for Residues of New Animal Drugs § 556.513...

  4. Piperazine-based nucleic acid analogs

    DOEpatents

    Schmidt, Jurgen; Silks, Louis A.; Michalczyk, Ryszard

    2005-01-11

    A novel nucleoside analog is disclosed which comprises a piperazine ring in the place of the ring ribose or deoxyribose sugar. Monomers utilizing a broad variety of nucleobases are disclosed, as well as oligomers comprising the monomers disclosed herein linked by a variety of linkages, including amide, phosphonamide, and sulfonamide linkages. A method of synthesizing the nucleoside analogs is also disclosed.

  5. Solubility of hydrogen sulfide in aqueous mixtures of monoethanolamine with N-methyldiethanolamine

    SciTech Connect

    Meng Hui Li; Keh Perng Shen . Dept. of Chemical Engineering)

    1993-01-01

    Alkanolamine aqueous solutions are frequently used for the removal of acidic gases, such as CO[sub 2] and H[sub 2]S, from gas streams in the natural gas and synthetic ammonia industries and petroleum chemical plants. The solubilities of hydrogen sulfide in aqueous mixtures of monoethanolamine (MEA) with N-methyl-diethanolamine (MDEA) have been measured at 40, 60, 80, and 100C and at partial pressures of hydrogen sulfide ranging from 1.0 to 450 kPa. The mixtures of alkanolamines studied are 4.95 kmol/m[sup 3] MEA, 3.97 kmol/m[sup 3] MEA + 0.51 kmol/m[sup 3] MDEA, 2.0 kmol/m[sup 3] MEA + 1.54 kmol/m[sup 3] MDEA, and 2.57 kmol/m[sup 3] MDEA aqueous solutions. The solubilities of hydrogen sulfide in aqueous alkanolamine solutions are reported as functions of the partial pressure of hydrogen sulfide at the temperatures of 40-100C.

  6. Simultaneous absorption of carbon dioxide and hydrogen sulfide with carbonyl sulfide contamination in aqueous methyldiethanolamine

    SciTech Connect

    Al-Ghawas, H.A.

    1988-01-01

    The primary objectives of the research were to: (1) obtain experimental data for simultaneous gas absorption systems to help formulate and test theoretical models of multicomponent mass transfer, and (2) develop the theoretical models which predict mass transfer rates from chemical reaction kinetics, system hydrodynamics and boundary conditions. To fulfill these objectives two-phase contact devices were designed and constructed. These were, a solubility of equilibrium apparatus, a laminar liquid jet apparatus, and a wetted-sphere apparatus. These devices were used to measure fundamental physiochemical properties of gases in liquids. The properties measured were the solubilities and diffusivities of N{sub 2}O, CO{sub 2}, and COS in aqueous MDEA. The reaction rate constants of the reactions between CO{sub 2} and MDEA and between COS and MDEA were also measured. In addition to these devices, a stirred tank absorber was used to obtain experimental data on multicomponent simultaneous absorption. A computer program was developed to solve the two-point boundary value problems generated by film theory. This research involved modeling and analyzing gas absorption systems with the chemical reactions taken as irreversible in one case and reversible in another. A parametric study of the case of reversible reactions revealed that for certain ranges of the parameter space the model predicted forced desorption. The program was tested against experimental data from two simultaneous absorption experiments. These were the simultaneous absorption of CO{sub 2}, COS, and N{sub 2} into aqueous MDEA and the simultaneous absorption of CO{sub 2}, H{sub 2}S, COS and N{sub 2} into aqueous MDEA. The program predictions of gas absorption rates were within 13% of the experimental values for the former experiment and within 9% for the latter.

  7. An experimental investigation into the atmospheric degradation of piperazine

    NASA Astrophysics Data System (ADS)

    White, Stephen; Angove, Dennys; Azzi, Merched; Tibbett, Anne; Campbell, Ian; Patterson, Michael

    2015-05-01

    The atmospheric degradation of piperazine was investigated using an indoor smog chamber. Experiments were carried out in the presence of nitrogen oxides (NOx), ozone or nitric acid. Piperazine reacted rapidly under all evaluated conditions: irradiated in the presence of NOx and with ozone and nitric acid in the dark. Gas phase products from the oxidation of piperazine were identified by infrared spectroscopy, DNPH cartridges followed by HPLC analysis, and by sampling chamber gas through Tenax sorbent material followed by analysis using thermal desorption GC-ITMS (gas chromatography ion trap mass spectrometry). Eight compounds were positively identified, with a further nine compounds tentatively identified using GC-MS based on molecular weight and mass spectra. Ammonia formation was observed from piperazine oxidation, and its formation was from the subsequent reactions of photooxidation products of piperazine rather than directly from the reaction of piperazine. The nitrosamine and nitramine expected from piperazine, N-nitrosopiperazine, and N-nitropiperazine, were both identified and confirmed using 15NO, with a tentative maximum yield of nitrosamine of less than 5% observed. Aerosol yields, relative to total piperazine reacted not including that which absorbed to the walls, were considerably high but were not able to be quantified absolutely due to unusual behaviour of the scanning mobility particle sizer instrument to aerosol containing amines. The reaction of piperazine with gas phase nitric acid gave rise to immediate formation of aerosol.

  8. 21 CFR 520.1804 - Piperazine phosphate capsules.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Piperazine phosphate capsules. 520.1804 Section... phosphate capsules. (a) Specifications. Each capsule contains 120, 300, or 600 milligrams of piperazine phosphate monohydrate. (b) Sponsor. See No. 051311 in § 510.600(c) of this chapter. (c) Conditions of...

  9. 21 CFR 520.1804 - Piperazine phosphate capsules.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Piperazine phosphate capsules. 520.1804 Section... phosphate capsules. (a) Specifications. Each capsule contains 120, 300, or 600 milligrams of piperazine phosphate monohydrate. (b) Sponsor. See No. 051311 in § 510.600(c) of this chapter. (c) Conditions of...

  10. 21 CFR 520.1803 - Piperazine citrate capsules.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Piperazine citrate capsules. 520.1803 Section 520.1803 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1803 Piperazine...

  11. 21 CFR 520.1803 - Piperazine citrate capsules.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Piperazine citrate capsules. 520.1803 Section 520.1803 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1803 Piperazine...

  12. 21 CFR 520.1803 - Piperazine citrate capsules.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Piperazine citrate capsules. 520.1803 Section 520.1803 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1803 Piperazine...

  13. 21 CFR 520.1803 - Piperazine citrate capsules.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Piperazine citrate capsules. 520.1803 Section 520.1803 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1803 Piperazine...

  14. 21 CFR 520.1803 - Piperazine citrate capsules.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Piperazine citrate capsules. 520.1803 Section 520.1803 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1803 Piperazine...

  15. 21 CFR 520.1804 - Piperazine phosphate capsules.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Piperazine phosphate capsules. 520.1804 Section... phosphate capsules. (a) Specifications. Each capsule contains 120, 300, or 600 milligrams of piperazine phosphate monohydrate. (b) Sponsor. See No. 051311 in § 510.600(c) of this chapter. (c) Conditions of...

  16. 21 CFR 520.1804 - Piperazine phosphate capsules.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Piperazine phosphate capsules. 520.1804 Section... phosphate capsules. (a) Specifications. Each capsule contains 120, 300, or 600 milligrams of piperazine phosphate monohydrate. (b) Sponsor. See No. 051311 in § 510.600(c) of this chapter. (c) Conditions of...

  17. 21 CFR 520.1804 - Piperazine phosphate capsules.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Piperazine phosphate capsules. 520.1804 Section... phosphate capsules. (a) Specifications. Each capsule contains 120, 300, or 600 milligrams of piperazine phosphate monohydrate. (b) Sponsor. See No. 051311 in § 510.600(c) of this chapter. (c) Conditions of...

  18. CO/sub 2/ desorption from DEA and DEA-promoted MDEA

    SciTech Connect

    Critchfield, J.E.; Rochelle, G.T. )

    1988-01-01

    CO/sub 2/ desorption rates were measured in 2 M diethanolamine and 2 M diethanolamine-promoted methyldiethanolamine solutions at 25{sup 0}C. CO/sub 2/ vapor pressure equilibria were estimated through extrapolation of the measured rates. The estimated vapor pressures were used to calculate apparent rate constants, and the resulting rate constants were interpreted as a function of CO/sub 2/ loading. The rate constants derived from the low driving force desorption experiments were compared with values obtained from high driving force, irreversible absorption experiments. In the absorption work, the effect of varied driving force on the resulting apparent rate constant was studied. The experimental results confirm that the absorption experiments were not affected by diffusion constraints. The agreement between the apparent rate constants determined from the absorption and desorption techniques was found to be very good.

  19. 21 CFR 520.1805 - Piperazine phosphate with thenium closylate tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Piperazine phosphate with thenium closylate... § 520.1805 Piperazine phosphate with thenium closylate tablets. (a) Specifications. Each scored tablet contains the equivalent of 250 milligrams piperazine hexahydrate (as piperazine phosphate) and...

  20. 21 CFR 520.1805 - Piperazine phosphate with thenium closylate tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Piperazine phosphate with thenium closylate... § 520.1805 Piperazine phosphate with thenium closylate tablets. (a) Specifications. Each scored tablet contains the equivalent of 250 milligrams piperazine hexahydrate (as piperazine phosphate) and...

  1. 21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Piperazine-carbon disulfide complex suspension... § 520.1802a Piperazine-carbon disulfide complex suspension. (a) Specifications. Each fluid ounce of suspension contains 7.5 grams of piperazine-carbon disulfide complex. The piperazine-carbon disulfide...

  2. 21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Piperazine-carbon disulfide complex suspension... § 520.1802a Piperazine-carbon disulfide complex suspension. (a) Specifications. Each fluid ounce of suspension contains 7.5 grams of piperazine-carbon disulfide complex. The piperazine-carbon disulfide...

  3. 21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Piperazine-carbon disulfide complex suspension... § 520.1802a Piperazine-carbon disulfide complex suspension. (a) Specifications. Each fluid ounce of suspension contains 7.5 grams of piperazine-carbon disulfide complex. The piperazine-carbon disulfide...

  4. 21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Piperazine-carbon disulfide complex suspension... § 520.1802a Piperazine-carbon disulfide complex suspension. (a) Specifications. Each fluid ounce of suspension contains 7.5 grams of piperazine-carbon disulfide complex. The piperazine-carbon disulfide...

  5. 21 CFR 520.1802a - Piperazine-carbon disulfide complex suspension.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Piperazine-carbon disulfide complex suspension... § 520.1802a Piperazine-carbon disulfide complex suspension. (a) Specifications. Each fluid ounce of suspension contains 7.5 grams of piperazine-carbon disulfide complex. The piperazine-carbon disulfide...

  6. 21 CFR 520.1805 - Piperazine phosphate with thenium closylate tablets.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Piperazine phosphate with thenium closylate... § 520.1805 Piperazine phosphate with thenium closylate tablets. (a) Specifications. Each scored tablet contains the equivalent of 250 milligrams piperazine hexahydrate (as piperazine phosphate) and...

  7. 21 CFR 520.1805 - Piperazine phosphate with thenium closylate tablets.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Piperazine phosphate with thenium closylate... § 520.1805 Piperazine phosphate with thenium closylate tablets. (a) Specifications. Each scored tablet contains the equivalent of 250 milligrams piperazine hexahydrate (as piperazine phosphate) and...

  8. 21 CFR 520.1805 - Piperazine phosphate with thenium closylate tablets.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Piperazine phosphate with thenium closylate... § 520.1805 Piperazine phosphate with thenium closylate tablets. (a) Specifications. Each scored tablet contains the equivalent of 250 milligrams piperazine hexahydrate (as piperazine phosphate) and...

  9. Contribution of artifacts to N-methylated piperazine cyanide adduct formation in vitro from N-alkyl piperazine analogs.

    PubMed

    Zhang, Minli; Resuello, Christina M; Guo, Jian; Powell, Mark E; Elmore, Charles S; Hu, Jun; Vishwanathan, Karthick

    2013-05-01

    In the liver microsome cyanide (CN)-trapping assays, piperazine-containing compounds formed significant N-methyl piperazine CN adducts. Two pathways for the N-methyl piperazine CN adduct formation were proposed: 1) The α-carbon in the N-methyl piperazine is oxidized to form a reactive iminium ion that can react with cyanide ion; 2) N-dealkylation occurs followed by condensation with formaldehyde and dehydration to produce N-methylenepiperazine iminium ion, which then reacts with cyanide ion to form the N-methyl CN adduct. The CN adduct from the second pathway was believed to be an artifact or metabonate. In the present study, a group of 4'-N-alkyl piperazines and 4'-N-[¹³C]methyl-labeled piperazines were used to determine which pathway was predominant. Following microsomal incubations in the presence of cyanide ions, a significant percentage of 4'-N-[¹³C]methyl group in the CN adduct was replaced by an unlabeled natural methyl group, suggesting that the second pathway was predominant. For 4'-N-alkyl piperazine, the level of 4'-N-methyl piperazine CN adduct formation was limited by the extent of prior 4'-N-dealkylation. In a separate study, when 4'-NH-piperaziens were incubated with potassium cyanide and [¹³C]-labeled formaldehyde, 4'-N-[¹³C]methyl piperazine CN-adduct was formed without NADPH or liver microsome suggesting a direct Mannich reaction is involved. However, when [¹³C]-labeled methanol or potassium carbonate was used as the one-carbon donor, 4'-N-[¹³C]methyl piperazine CN adduct was not detected without liver microsome or NADPH present. The biologic and toxicological implications of bioactivation via the second pathway necessitate further investigation because these one-carbon donors for the formation of reactive iminium ions could be endogenous and readily available in vivo. PMID:23431111

  10. Solubility of mixtures of hydrogen sulfide and carbon dioxide in aqueous N-methyldiethanolamine solutions

    SciTech Connect

    Jou, Fang Yuan; Carroll, J.J.; Mather, A.E.; Otto, F.D. . Dept. of Chemical Engineering)

    1993-01-01

    Aqueous solutions of alkanolamines are commonly used to strip acid gases (H[sub 2]S and CO[sub 2]) from streams contaminated with these components. The two most widely used amines are monoethanolamine (MEA) and diethanolamine (DEA). The solubilities of mixtures of hydrogen sulfide and carbon dioxide in a 35 wt% (3.04 kmol/m[sup 3]) aqueous solution of N-methyldiethanolamine at 40 and 100C have been measured. Partial pressures of the acid gases ranged from 0.006 to 101 kPa at 40C and from 4 to 530 kPa at 100C.

  11. Surface tension of binary mixtures of water + N-methyldiethanolamine and ternary mixtures of this amine and water with monoethanolamine, diethanolamine, and 2-amino-2-methyl-1-propanol from 25 to 50 C

    SciTech Connect

    Alvarez, E.; Rendo, R.; Sanjurjo, B.; Sanchez-Vilas, M.; Navaza, J.M.

    1998-11-01

    The surface tension of aqueous solutions of N-methyldiethanolamine and diethanolamine + N-methyldiethanolamine, monoethanolamine + N-methyldiethanolamine and 2-amino-2-methyl-1-propanol + N-methyldiethanolamine was measured at temperatures from 25 C to 50 C. For binary mixtures the concentration range was 0--50 mass % N-methyldiethanolamine, and for the tertiary mixtures the concentration range for each amine was 0--50 mass %. The experimental values were correlated with temperature and mole fraction. The maximum deviation in both cases was always less than 0.5%.

  12. Kinetics of absorption of CO{sub 2} in concentrated aqueous methyldiethanolamine solutions in the range 296 K to 343 K

    SciTech Connect

    Pani, F.; Gaunand, A.; Cadours, R.; Bouallou, C.; Richon, D.

    1997-03-01

    The kinetics of CO{sub 2} absorption by aqueous solutions of methyl diethanol amine (MDEA) were measured in the temperature range (296--343) K and MDEA concentration range (830--4,380) mol/m{sup 3} (10--50 mass %). A thermoregulated constant interfacial area Lewis-type cell was operated by recording the pressure drop during batch absorption. The kinetic results are in agreement with a fast regime of absorption according to film theory. MDEA depletion at the interface has a significant effect on the kinetics at the CO{sub 2} pressures (100 to 200 kPa) studied in this work, especially at low temperatures and low MDEA concentrations. Considering only the reaction between CO{sub 2} and MDEA, the CO{sub 2} absorption appears as a first-order reaction with respect to MDEA. The activation energy found for the reaction between CO{sub 2} and MDEA is 45 kJ/mol, but this value depends significantly (by about 10% in the worst case) on the vapor-liquid equilibrium data used.

  13. Correlation and prediction of the solubility of CO{sub 2} and H{sub 2}S in an aqueous solution of methyldiethanolamine and sulfolane

    SciTech Connect

    Qian, W.M.; Li, Y.G.; Mather, A.E.

    1995-07-01

    The Clegg-Pitzer equations with some simplifications are used to correlate the vapor-liquid equilibrium data for the CO{sub 2}-methyldiethanolamine-sulfolane-H{sub 2}O and H{sub 2}S-methyldiethanolamine-sulfolane-H{sub 2}O systems. The interaction parameters determined from data for the binary, ternary, and quaternary systems can be used to predict the quinary mixed solvent systems without any additional parameters. The model is applied to the CO{sub 2}-H{sub 2}S-methyldiethanolamine-sulfolane-H{sub 2}O system containing three neutral solvents (methyldiethanolamine, sulfolane, and H{sub 2}O), two neutral solutes (CO{sub 2} and H{sub 2}S), and three ionic species (MDEAH{sup +}, HCO{sub 3}{sup {minus}}, and HS{sup {minus}}) with three main chemical equilibria simultaneously involved.

  14. Effect of hydrogen sulfide loading on the density and viscosity of aqueous solutions of methyldiethanolamine

    SciTech Connect

    Rinker, E.B.; Colussi, A.T.; McKnight, N.L.; Sandall, O.C.

    2000-04-01

    Aqueous alkanolamine solutions are commonly used to remove acid gases such as carbon dioxide and hydrogen sulfide from natural gas. The change in the density and viscosity of aqueous methyldiethanolamine on the addition of hydrogen sulfide was investigated in this study. At 25 C densities and viscosities were measured for loadings up to 0.5 mol of H{sub 2}S per 1 mol of amine for amine concentrations up to 50 mass % and for H{sub 2}S loadings up to 0.5. It was found that the solution density increases with H{sub 2}S loading whereas the viscosity decreases as the H{sub 2}S loading increases.

  15. 21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Piperazine-carbon disulfide complex boluses. 520....1802b Piperazine-carbon disulfide complex boluses. (a) Specifications. Each bolus contains 20 grams of piperazine-carbon disulfide complex. (b) Sponsor. See 000009 in § 510.600(c) of this chapter. (c)...

  16. 21 CFR 520.1802c - Piperazine-carbon disulfide complex with phenothiazine suspension.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Piperazine-carbon disulfide complex with... ANIMAL DRUGS § 520.1802c Piperazine-carbon disulfide complex with phenothiazine suspension. (a) Specifications. Each fluid ounce contains 5 grams of piperazine-carbon disulfide complex and 0.83 gram...

  17. 21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Piperazine-carbon disulfide complex boluses. 520....1802b Piperazine-carbon disulfide complex boluses. (a) Specifications. Each bolus contains 20 grams of piperazine-carbon disulfide complex. (b) Sponsor. See 000009 in § 510.600(c) of this chapter. (c)...

  18. 21 CFR 520.1802c - Piperazine-carbon disulfide complex with phenothiazine suspension.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Piperazine-carbon disulfide complex with... ANIMAL DRUGS § 520.1802c Piperazine-carbon disulfide complex with phenothiazine suspension. (a) Specifications. Each fluid ounce contains 5 grams of piperazine-carbon disulfide complex and 0.83 gram...

  19. 21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Piperazine-carbon disulfide complex boluses. 520....1802b Piperazine-carbon disulfide complex boluses. (a) Specifications. Each bolus contains 20 grams of piperazine-carbon disulfide complex. (b) Sponsor. See 000009 in § 510.600(c) of this chapter. (c)...

  20. 21 CFR 520.1802c - Piperazine-carbon disulfide complex with phenothiazine suspension.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Piperazine-carbon disulfide complex with... ANIMAL DRUGS § 520.1802c Piperazine-carbon disulfide complex with phenothiazine suspension. (a) Specifications. Each fluid ounce contains 5 grams of piperazine-carbon disulfide complex and 0.83 gram...

  1. 21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Piperazine-carbon disulfide complex boluses. 520....1802b Piperazine-carbon disulfide complex boluses. (a) Specifications. Each bolus contains 20 grams of piperazine-carbon disulfide complex. (b) Sponsor. See 000009 in § 510.600(c) of this chapter. (c)...

  2. 21 CFR 520.1802c - Piperazine-carbon disulfide complex with phenothiazine suspension.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Piperazine-carbon disulfide complex with... ANIMAL DRUGS § 520.1802c Piperazine-carbon disulfide complex with phenothiazine suspension. (a) Specifications. Each fluid ounce contains 5 grams of piperazine-carbon disulfide complex and 0.83 gram...

  3. 21 CFR 520.1802c - Piperazine-carbon disulfide complex with phenothiazine suspension.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Piperazine-carbon disulfide complex with... ANIMAL DRUGS § 520.1802c Piperazine-carbon disulfide complex with phenothiazine suspension. (a) Specifications. Each fluid ounce contains 5 grams of piperazine-carbon disulfide complex and 0.83 gram...

  4. 21 CFR 520.1802b - Piperazine-carbon disulfide complex boluses.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Piperazine-carbon disulfide complex boluses. 520....1802b Piperazine-carbon disulfide complex boluses. (a) Specifications. Each bolus contains 20 grams of piperazine-carbon disulfide complex. (b) Sponsor. See 000009 in § 510.600(c) of this chapter. (c)...

  5. Solubility of nitrous oxide in aqueous blends of N-methyldiethanolamine and 2-amino-2-methyl-1-propanol

    SciTech Connect

    Davis, R.A.; Pogainis, B.J.

    1995-11-01

    Aqueous solutions of alkanolamines have applications in acid gas treatment for the removal of acid gases such as carbon dioxide and hydrogen sulfide. The solubility of nitrous oxide in aqueous blends of N-methyldiethanolamine and 2-amino-2-methyl-1 propanol was measured over the temperature range 10--60 C. The total composition of the alkanolamines in water ranged from 30 to 50 mass %. The experimental results were interpreted in terms of Henry`s constants.

  6. Survey and Down-Selection of Acid Gas Removal Systems for the Thermochemical Conversion of Biomass to Ethanol with a Detailed Analysis of an MDEA System

    SciTech Connect

    Nexant, Inc., San Francisco, California

    2011-05-01

    The first section (Task 1) of this report by Nexant includes a survey and screening of various acid gas removal processes in order to evaluate their capability to meet the specific design requirements for thermochemical ethanol synthesis in NREL's thermochemical ethanol design report (Phillips et al. 2007, NREL/TP-510-41168). MDEA and selexol were short-listed as the most promising acid-gas removal agents based on work described in Task 1. The second report section (Task 2) describes a detailed design of an MDEA (methyl diethanol amine) based acid gas removal system for removing CO2 and H2S from biomass-derived syngas. Only MDEA was chosen for detailed study because of the available resources.

  7. Application of ORAL.screen saliva drug test for the screening of methamphetamine, MDMA, and MDEA incorporated in hair.

    PubMed

    Miki, Akihiro; Katagi, Munehiro; Shima, Noriaki; Tsuchihashi, Hitoshi

    2004-03-01

    By the use of a one-step immunoassay drug test for oral fluid, a convenient and fairly sensitive screening method has been devised for methamphetamine (MA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDEA) incorporated in hair. These drugs, in a 10-mg portion of hair, were extracted into 5M HCl/methanol (1:20, v/v), and the extract reconstituted in 100 micro L water was assayed with the saliva drug test ORAL.screen trade mark. The limits of detection were 0.5 ng/mg hair for d-MA, 0.8 ng/mg for dl-MDMA, and 1.0 ng/mg for dl-MDEA. The results are in good agreement with those of gas chromatography-mass spectrometry (GC-MS) determination. Although all positive results must be confirmed by either GC-MS or a specific alternative methodology, this method provided a simple screening, suitable for drug enforcement purposes, while requiring only a 10-mg hair specimen. PMID:15068568

  8. A status report on the investigation of the effects of antioxidants upon oxygen degradation of methyldiethanolamine

    SciTech Connect

    Pundari, A.N.; Singh, M.; Bullin, J.A.

    1987-01-01

    Natural gas production is an important source of energy for the country. The gas directly from the gas fields is not suitable for consumption due to the presence of acidic impurities. The process of gas treating separates impurities such as carbon dioxide-(CO/sub 2/), hydrogen sulfide (H/sub 2/S), and sulfur dioxide (SO/sub 2/) from the gas stream. Industrial processes such as hydrogen manufacture and ammonia production also require acid gas removal systems. The oxygen degradation reactions of MDEA (Melhyl Diethanolamine) solutions were investigated. Several primary and secondary antioxidants were tested and found to be ineffective in the first series of batch reactor experiments at 195/sup 0/F and 50 psig O/sub 2/. This may be due to an excessively high oxygen pressure whereby the inhibitor reacted with the oxygen directly in a short period of time and thus the amine was not protected against degradation. Another possibility is that the severe experimental conditions may accelerate heat stable salts formation reactions at a constant rate. The current preliminary results are indicative that oxygen degradation reactions are quite complicated. Further studies are needed to determine the best antioxidants needed for amine sweetening systems.

  9. The acute effect in rats of 3,4-methylenedioxyethamphetamine (MDEA, "eve") on body temperature and long term degeneration of 5-HT neurones in brain: a comparison with MDMA ("ecstasy").

    PubMed

    Colado, M I; Granados, R; O'Shea, E; Esteban, B; Green, A R

    1999-06-01

    Administration of a single dose of the recreationally used drug 3,4-methylenedioxyethamphetamine (MDEA or "eve") to Dark Agouti rats resulted in an acute dose-dependent hyperthermic response. The peak effect and duration of hyperthermia of a dose of MDEA of 35 mg/kg intraperitoneally was similar to a dose of 3,4-methylenedioxymethamphetamine (MDMA or "ecstasy") of 15 mg/kg intraperitoneally. Seven days later this dose of MDMA produced a marked (approximately 50%) loss of 5-HT and its metabolite 5-HIAA in cortex, hippocampus and striatum and a similar loss of [3H]-paroxetine binding in cortex: these losses reflecting the MDMA-induced neurotoxic degeneration of 5-HT nerve endings. In contrast, administration of MDEA (15, 25 or 35 mg/kg), even at the highest dose, produced only a 20% loss in cortex and hippocampus and no decrease in striatum. The neurotoxic effect of MDEA was only weakly dose-dependent. Neither MDEA (35 mg/kg) nor MDMA (15 mg/kg) altered striatal dopamine content 7 days later. MDEA appeared to have about half the potency of MDMA in inducing acute hyperthermia and 25% of the potency in inducing degeneration of cerebral 5-HT neurones. However since higher doses of MDEA (compared to MDMA) are probably necessary to induce mood changing effects, these data do not support any contention that this compound is a "safer" recreational drug than MDMA in terms of either acute toxicity or long term neurodegeneration. PMID:10401727

  10. Probing of different conformations of piperazine using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    SenGupta, Sumana; Maiti, Nandita; Chadha, Ridhima; Kapoor, Sudhir

    2014-06-01

    Piperazine exists in a number of energetically close structural conformations, and here, we investigated the dependence of their relative abundance on the surrounding conditions by using Raman and SERS spectroscopy in pure solid, aqueous solution and Ag hydrosol. The experimental results were interpreted by DFT calculations using B3LYP functional with aug-cc-pvdz/LANL2DZ basis sets. In the chair form of piperazine, which is more stable than the skewed boat by ∼8 kcal mol-1, the two N-H bonds can remain equatorial or axial, leading to three different conformations, eq-eq, eq-ax and ax-ax. The calculated Raman spectrum of the lowest energy eq-eq conformation corresponds well with the experimental spectrum in pure solid, indicating eq-eq to be predominant. But, the contribution of the eq-ax conformation was found to be maximum in aqueous solution. The SERS spectrum revealed that eq-ax conformation was preferably adopted as piperazine was adsorbed vertically through its axial N-atom over silver nanoparticle surface.

  11. High-nuclearity homometallic iron and nickel clusters: Fe22 and Ni24 complexes from the use of N-methyldiethanolamine.

    PubMed

    Foguet-Albiol, Dolos; Abboud, Khalil A; Christou, George

    2005-09-14

    The use of N-methyldiethanolamine (mdaH2) in reactions with Fe(III) and Ni(II) sources has led to Fe22 and Ni24 products; the clusters are the highest and second-highest, respectively, homometallic clusters for these metals to date, and possess S = 0 and S = 6 ground states, respectively. PMID:16113722

  12. Synthesis and characterization of the novel phosphonates- and phosphonothioate-piperazine as flame retardants for cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tetraethyl piperazine-1,4-diyldiphosphonate (PDP) and O,O,O',O'-tetramethyl piperazine-1,4-diyldiphosphonothioate (PDSP) were synthesized in one simple step and their structures were confirmed by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and elemental analysis (EA). Print cloth, twil...

  13. 21 CFR 520.1802 - Piperazine-carbon disulfide complex oral dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Piperazine-carbon disulfide complex oral dosage forms. 520.1802 Section 520.1802 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... § 520.1802 Piperazine-carbon disulfide complex oral dosage forms....

  14. 21 CFR 520.1802 - Piperazine-carbon disulfide complex oral dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Piperazine-carbon disulfide complex oral dosage forms. 520.1802 Section 520.1802 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... § 520.1802 Piperazine-carbon disulfide complex oral dosage forms....

  15. 21 CFR 520.1802 - Piperazine-carbon disulfide complex oral dosage forms.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Piperazine-carbon disulfide complex oral dosage forms. 520.1802 Section 520.1802 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... § 520.1802 Piperazine-carbon disulfide complex oral dosage forms....

  16. 21 CFR 520.1802 - Piperazine-carbon disulfide complex oral dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Piperazine-carbon disulfide complex oral dosage forms. 520.1802 Section 520.1802 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... § 520.1802 Piperazine-carbon disulfide complex oral dosage forms....

  17. 21 CFR 520.1802 - Piperazine-carbon disulfide complex oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Piperazine-carbon disulfide complex oral dosage forms. 520.1802 Section 520.1802 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... § 520.1802 Piperazine-carbon disulfide complex oral dosage forms....

  18. 21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... an aqueous solution which contains in each fluid ounce 0.36 gram of levamisole hydrochloride and piperazine dihydrochloride equivalent to 3.98 grams of piperazine base. (2) The drug is a soluble powder which when reconstituted with water contains in each fluid ounce 0.45 gram of levamisole...

  19. 21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... an aqueous solution which contains in each fluid ounce 0.36 gram of levamisole hydrochloride and piperazine dihydrochloride equivalent to 3.98 grams of piperazine base. (2) The drug is a soluble powder which when reconstituted with water contains in each fluid ounce 0.45 gram of levamisole...

  20. Hepatotoxicity of piperazine designer drugs: Comparison of different in vitro models.

    PubMed

    Dias-da-Silva, D; Arbo, M D; Valente, M J; Bastos, M L; Carmo, H

    2015-08-01

    Piperazine derived drugs emerged on the drug market in the last decade. The aim of this study was to investigate in vitro the potential hepatotoxicity of the designer drugs N-benzylpiperazine (BZP), 1-(3-trifluoromethylphenyl)piperazine (TFMPP), 1-(4-methoxyphenyl)piperazine (MeOPP) and 1-(3,4-methylenedioxybenzyl)piperazine (MDBP) in two human hepatic cell lines (HepaRG and HepG2) and in primary rat hepatocytes. Cell death was evaluated by the MTT assay, after 24 h-incubations. Among the tested drugs, TFMPP was the most cytotoxic. HepaRG cells and primary hepatocytes revealed to be the most and the least resistant cellular models, respectively. To ascertain whether the CYP450 metabolism could explain their higher susceptibility, primary hepatocytes were co-incubated with the piperazines and the CYP450 inhibitors metyrapone and quinidine, showing that CYP450-mediated metabolism contributes to the detoxification of these drugs. Additionally, the intracellular contents of reactive species, ATP, reduced (GSH) and oxidized (GSSG) glutathione, changes in mitochondrial membrane potential (Δψm) and caspase-3 activation were further evaluated in primary cells. Overall, an increase in reactive species formation, followed by intracellular GSH and ATP depletion, loss of Δψm and caspase-3 activation was observed for all piperazines, in a concentration-dependent manner. In conclusion, piperazine designer drugs produce hepatic detrimental effects that can vary in magnitude among the different analogues. PMID:25863214

  1. Opportunities and challenges for direct C–H functionalization of piperazines

    PubMed Central

    Ye, Zhishi; Gettys, Kristen E

    2016-01-01

    Summary Piperazine ranks within the top three most utilized N-heterocyclic moieties in FDA-approved small-molecule pharmaceuticals. Herein we summarize the current synthetic methods available to perform C–H functionalization on piperazines in order to lend structural diversity to this privileged drug scaffold. Multiple approaches such as those involving α-lithiation trapping, transition-metal-catalyzed α-C–H functionalizations, and photoredox catalysis are discussed. We also highlight the difficulties experienced when successful methods for α-C–H functionalization of acyclic amines and saturated mono-nitrogen heterocyclic compounds (such as piperidines and pyrrolidines) were applied to piperazine substrates. PMID:27340462

  2. 21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) Specifications. Each 54.10 grams (1.91 ounces) of water dispersible powder contains 9.10 grams of trichlorfon, 6.25 grams of phenothiazine, and the equivalent of 20.0 grams of piperazine base (as...

  3. Pharmacological profiles of aminoindanes, piperazines, and pipradrol derivatives.

    PubMed

    Simmler, Linda D; Rickli, Anna; Schramm, York; Hoener, Marius C; Liechti, Matthias E

    2014-03-15

    Aminoindanes, piperazines, and pipradrol derivatives are novel psychoactive substances found in "Ecstasy" tablets as replacements for 3,4-methylenedioxymethamphetamine (MDMA) or substances sold as "ivory wave." The pharmacology of these MDMA- and methylphenidate-like substances is poorly known. We characterized the pharmacology of the aminoindanes 5,6-methylenedioxy-2-aminoindane (MDAI), 5-iodoaminoindane (5-IAI), and 2-aminoindane (2-AI), the piperazines meta-chlorophenylpiperazine (m-CPP), trifluoromethylphenylpiperazine (TFMPP), and 1-benzylpiperazine (BZP), and the pipradrol derivatives desoxypipradrol (2-diphenylmethylpiperidine [2-DPMP]), diphenylprolinol (diphenyl-2-pyrrolidinemethanol [D2PM]), and methylphenidate. We investigated norepinephrine (NE), dopamine (DA), and serotonin (5-hydroxytryptamine [5-HT]) uptake inhibition using human embryonic kidney 293 (HEK 293) cells that express the respective human monoamine transporters (NET, DAT, and SERT). We also evaluated the drug-induced efflux of NE, DA, and 5-HT from monoamine-preloaded cells and the binding affinity to monoamine transporters and receptors, including trace amine-associated receptor 1 (TAAR1). 5-IAI and MDAI preferentially inhibited the SERT and NET and released 5-HT. 2-AI interacted with the NET. BZP blocked the NET and released DA. m-CPP and TFMPP interacted with the SERT and serotonergic receptors. The pipradrol derivatives were potent and selective catecholamine transporter blockers without substrate releasing properties. BZP, D2PM, and 2-DPMP lacked serotonergic activity and TAAR1 binding, in contrast to the aminoindanes and phenylpiperazines. In summary, all of the substances were monoamine transporter inhibitors, but marked differences were found in their DAT vs. SERT inhibition profiles, release properties, and receptor interactions. The pharmacological profiles of D2PM and 2-DPMP likely predict a high abuse liability. PMID:24486525

  4. Chrysin-piperazine conjugates as antioxidant and anticancer agents.

    PubMed

    Patel, Rahul V; Mistry, Bhupendra; Syed, Riyaz; Rathi, Anuj K; Lee, Yoo-Jung; Sung, Jung-Suk; Shinf, Han-Seung; Keum, Young-Soo

    2016-06-10

    Synthesis of 7-(4-bromobutoxy)-5-hydroxy-2-phenyl-4H-chromen-4-one intermediate treating chrysin with 1,4-dibromobutane facilitated combination of chrysin with a wide range of piperazine moieties which were equipped via reacting the corresponding amines with bis(2-chloroethyl)amine hydrochloride in diethylene glycol monomethyl ether solvent. Free radical scavenging potential of prepared products was analyzed in vitro adopting DPPH and ABTS bioassay in addition to the evaluation of in vitro anticancer efficacies against cervical cancer cell lines (HeLa and CaSki) and an ovarian cancer cell line SK-OV-3 using SRB assay. Bearable toxicity of 7a-w was examined employing Madin-Darby canine kidney (MDCK) cell line. In addition, cytotoxic nature of the presented compounds was inspected utilizing Human bone marrow derived mesenchymal stem cells (hBM-MSCs). Overall, 7a-w indicated remarkable antioxidant power in scavenging DPPH(·) and ABTS(·+), particularly analogs 7f, 7j, 7k, 7l, 7n, 7q, 7v, 7w have shown promising free radical scavenging activity. Analogs 7j and 7o are identified to be highly active candidates against HeLa and CaSki cell lines, whereas 7h and 7l along with 7j proved to be very sensitive towards ovarian cancer cell line SKOV-3. None of the newly prepared scaffolds showed cytotoxic nature toward hBM-MSCs cells. From the structure-activity point of view, nature and position of the electron withdrawing and electron donating functional groups on the piperazine core may contribute to the anticipated antioxidant and anticancer action. Different spectroscopic techniques (FT-IR, (1)H NMR, (13)C NMR, Mass) and elemental analysis (CHN) were utilized to confirm the desired structure of final compounds. PMID:26924226

  5. Synthesis and antifungal activity of novel triazole compounds containing piperazine moiety.

    PubMed

    Wang, Yanwei; Xu, Kehan; Bai, Guojing; Huang, Lei; Wu, Qiuye; Pan, Weihua; Yu, Shichong

    2014-01-01

    Design and synthesis of triazole library antifungal agents having piperazine side chains, analogues to fluconazole were documented. The synthesis highlighted utilization of the click chemistry on the basis of the active site of the cytochrome P450 14α-demethylase (CYP51). Their structures were characterized by (1)H-NMR, (13)C-NMR, MS and IR. The influences of piperazine moiety on in vitro antifungal activities of all the target compounds were evaluated against eight human pathogenic fungi. PMID:25090121

  6. Separation and detection of ammonia, amines, and alkanolamines with single-column ion chromatography. [Alkylamines, ethanolamine and methyldiethanolamine

    SciTech Connect

    Poulson, R.E.; Borg, H.M.

    1986-03-01

    A single-column ion chromatographic method was developed for separation and detection of aqueous ammonia, C/sub 1/-, C/sub 2/-, and C/sub 3/- alkylamines, ethanolamine, and methyldiethanolamine. A precolumn concentrator was used to take detection of ammonium ion by electrical conductivity to fractional ppB levels and detection of the organic cations to ppB levels. Analysis of ppM ammonia levels in 3 wt % alkanolamine scrubber-type solutions was possible, but resolution of alkylamines was lost. A post-column reaction system for fluorescence detection of primary amine o-phthalaldehyde derivatives with reversed-phase separation allowed amine separation in the presence of large amounts of ammonia. The same system might be used in place of concentration and conductivity for determination of the alkylamine levels. A large variety of oil shale retort by-product waters and one underground coal gasification condensate were screened for alkylamines, but none were detected. 7 refs., 8 figs., 1 tab.

  7. Characterization of tunable piperidine and piperazine carbamates as inhibitors of endocannabinoid hydrolases

    PubMed Central

    Long, Jonathan Z.; Jin, Xin; Adibekian, Alexander; Li, Weiwei; Cravatt, Benjamin F.

    2010-01-01

    Monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH) are two enzymes from the serine hydrolase superfamily that degrade the endocannabinoids 2-arachidonoylglycerol and anandamide, respectively. We have recently discovered that MAGL and FAAH are both inhibited by carbamates bearing an N-piperidine/piperazine group. Piperidine/piperazine carbamates show excellent in vivo activity, raising brain endocannabinoid levels and producing CB1-dependent behavioral effects in mice, suggesting that they represent a promising class of inhibitors for studying the endogenous functions of MAGL and FAAH. Herein, we disclose a full account of the syntheses, structure-activity relationships, and inhibitory activities of piperidine/piperazine carbamates against members of the serine hydrolase family. These scaffolds can be tuned for MAGL-selective or dual MAGL-FAAH inhibition by the attachment of an appropriately substituted bisarylcarbinol or aryloxybenzyl moiety, respectively, on the piperidine/piperazine ring. Modifications to the piperidine/piperazine ring ablated inhibitory activity, suggesting a strict requirement for a six-member ring to maintain potency. PMID:20099888

  8. 2-Butyl-4-chloroimidazole based substituted piperazine-thiosemicarbazone hybrids as potent inhibitors of Mycobacterium tuberculosis.

    PubMed

    Jallapally, Anvesh; Addla, Dinesh; Yogeeswari, Perumal; Sriram, Dharmarajan; Kantevari, Srinivas

    2014-12-01

    Here a series of 2-butyl-4-chloroimidazole based substituted piperazine-thiosemicarbazone hybrids were designed by combining three different pharmacophoric fragments in single molecular architecture. 2-Butyl-4-chloro-1-(3-(4-substituted)piperazin-1-yl)propyl)-1H-imidazole-5-carbaldehydes (4a-p) prepared by reacting carboxaldehyde 2 with N-alkyl piperazines 3a-p which were condensed with thiosemicarbazine to give desired compounds 5a-p in very good yields. Among all sixteen compounds screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (MTB), two compounds (E)-2-((2-butyl-4-chloro-1-(3-(4-(o-tolyl) piperazin-1-yl)propyl)-1H-imidazol-5-yl)methylene)hydrazinecarbothioamide 5e and (E)-2-((2-butyl-4-chloro-1-(3-(4-(2-methoxyphenyl)piperazin-1-yl)propyl)-1H-imidazol-5-yl)methylene) hydrazine carbothioamide 5f were found to be the most potent antitubercular agents (MIC: 3.13 μg/mL) with low toxicity profile. PMID:25451998

  9. Piperazine-induced airway symptoms: exposure-response relationships and selection in an occupational setting

    SciTech Connect

    Hagmar, L.; Bellander, T.; Ranstam, J.; Skerfving, S.

    1984-01-01

    The heterocyclic secondary amine piperazine is known to cause asthma. In a cohort of 602 workers, employed during the period 1942-1979, at a chemical industry where piperazine is handled, a study conducted by means of a mailed questionnaire showed a strong exposure-response relationship as to frequency of work-related airway symptoms indicating asthma. In the most exposed group about a third of the workers had experienced such symptoms. Age, length of employment, smoking habits, and previous work-related asthmatic symptoms, but not atopy, modified the response. Further, there was an association between piperazine exposure and chronic bronchitis. In the most exposed group every fourth subject had chronic bronchitis. The frequency was modified by smoking habits; atopy was a confounder. Although many subjects, especially high-exposed ones, left work because of airway symptoms, there was no difference in occurrence of airway symptoms between former and present employees.

  10. Stability constants and molar absorptivities for complexes of copper(II) with N-methyldiethanolamine, 1,4-bis(2-hydroxypropyl)-2-methylpiperazine, and 2-amino-2-methyl-1-propanol.

    PubMed

    Siefker, J R; Aroc, R V

    1986-09-01

    The stability constants and molar absorptivities of complexes of Cu(2+) with N-methyldiethanolamine, 1,4-bis(2-hydroxypropyl)-2-methylpiperazine, and 2-amino-2-methyl-1-propanol have been determined from spectrophotometric data for very dilute aqueous solutions. PMID:18964197

  11. 21 CFR 520.763c - Dithiazanine iodide and piperazine citrate suspension.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... suspension. 520.763c Section 520.763c Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS... piperazine citrate). (b) Sponsor. See 000010 in § 510.600(c) of this chapter. (c) NAS/NRC status....

  12. 21 CFR 520.763c - Dithiazanine iodide and piperazine citrate suspension.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... suspension. 520.763c Section 520.763c Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS... piperazine citrate). (b) Sponsor. See 000010 in § 510.600(c) of this chapter. (c) NAS/NRC status....

  13. 21 CFR 520.763c - Dithiazanine iodide and piperazine citrate suspension.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... suspension. 520.763c Section 520.763c Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS... piperazine citrate). (b) Sponsor. See 000010 in § 510.600(c) of this chapter. (c) NAS/NRC status....

  14. 21 CFR 520.763c - Dithiazanine iodide and piperazine citrate suspension.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... suspension. 520.763c Section 520.763c Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS... piperazine citrate). (b) Sponsor. See 000010 in § 510.600(c) of this chapter. (c) NAS/NRC status....

  15. The influences of piperazine-phosphonates derivatives on flame retardancy and thermal behaviors of cotton cellulose

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an effort to create the environmentally-friendly flame retardants (FRs) for cotton cellulose, two phosphoramidates derivatives, tetraethyl piperazine-1,4-diyldiphosphonate (PDP) and diethyl 4-methylpiperazin-1-ylphosphoramidate (PAP), have been developed. Both were synthesized in high yield and ...

  16. 40 CFR 721.9800 - Poly(substituted triazinyl) piperazine (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... triazinyl) piperazine (PMN P-88-436) is subject to reporting under this section for the significant new uses...) through (c), (g), and (h). (2) Limitations or revocation of certain notification requirements. The... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses...

  17. Synthesis and antitubercular activity of 1,2,4-trisubstitued piperazines.

    PubMed

    Rohde, Kyle H; Michaels, Heather A; Nefzi, Adel

    2016-05-01

    Parallel solid phase synthesis offers a unique opportunity for the synthesis and screening of large numbers of compounds and significantly enhances the prospect of finding new leads. We report the synthesis and antitubercular activity of chiral 1,2,4-trisubstituted piperazines derived from resin bound acylated dipeptides against Mycobacterium tuberculosis strain H37Rv. PMID:27020522

  18. Thermal decomposition reactions of cotton fabric treated with piperazine-phosphonates derivatives as a flame retardant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There has been a great scientific interest in exploring the great potential of the piperazine-phosphonates in flame retardant (FR) application on cotton fabric by investigating the thermal decomposition of cotton fabric treated with them. This research tries to understand the mode of action of the t...

  19. 21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... dihydrochloride powder. 520.2520g Section 520.2520g Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... ANIMAL DRUGS § 520.2520g Trichlorfon, phenothiazine, and piperazine dihydrochloride powder. (a) Specifications. Each 54.10 grams (1.91 ounces) of water dispersible powder contains 9.10 grams of trichlorfon,...

  20. 21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... dihydrochloride powder. 520.2520g Section 520.2520g Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... ANIMAL DRUGS § 520.2520g Trichlorfon, phenothiazine, and piperazine dihydrochloride powder. (a) Specifications. Each 54.10 grams (1.91 ounces) of water dispersible powder contains 9.10 grams of trichlorfon,...

  1. The mechanism of action of piperazine-phosphonates derivatives in cotton fabric

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Piperazine-phosphonates additives are known to be very effective flame retardants on different polymeric systems, especially cotton cellulose. In order to understand their mechanism of action, we carried out the investigation of their thermal behavior on cotton fabric by, first, employing the attenu...

  2. Piperazine-phosphonate derivatives: their flame retardant and thermal degradation properties on cotton fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It has been known that phosphorus-nitrogen system shows greater flame resistance in cotton textiles at a lower level than phosphorus used alone. This research aims to compare the effectiveness of Tetraethyl piperazine-1,4-diyldiphosphonate (TEPP) as a flame retardant (FR) for cotton fabric to a prev...

  3. [Study of new blended chemical absorbents to absorb CO2].

    PubMed

    Wang, Jin-Lian; Fang, Meng-Xiang; Yan, Shui-Ping; Luo, Zhong-Yang; Cen, Ke-Fa

    2007-11-01

    Three kinds of blended absorbents were investigated on bench-scale experimental bench according to absorption rate and regeneration grade to select a reasonable additive concentration. The results show that, among methyldiethanolamine (MDEA) and piperazine (PZ) mixtures, comparing MDEA : PZ = 1 : 0.4 (m : m) with MDEA : PZ = 1 : 0.2 (m : m), the absorption rate is increased by about 70% at 0.2 mol x mol(-1). When regeneration lasting for 40 min, regeneration grade of blended absorbents with PZ concentration of 0.2, 0.4, and 0.8 is decreased to 83.06%, 77.77% and 76.67% respectively while 91.04% for PZ concentration of 0. MDEA : PZ = 1 : 0.4(m : m) is a suitable ratio for MDEA/PZ mixtures as absorption and regeneration properties of the blended absorbents are all improved. The aqueous blends with 10% primary amines and 2% tertiary amines could keep high CO2 absorption rate, and lower regeneration energy consumption. Adding 2% 2-Amino-2-methyl-1-propanol (AMP) to 10% diethanolamine (DEA), the blended amine solvents have an advantage in absorption and regeneration properties over other DEA/AMP mixtures. Blended solvents, which consist of a mixture of primary amines with a small amount of tertiary amines, have the highest absorption rate among the three. And mixed absorbents of secondary amines and a small amount of sterically hindered amines have the best regeneration property. To combine absorption and regeneration properties, blends with medium activator addition to tertiary amines are competitive. PMID:18290495

  4. Influence of superheated water on the hydrogen bonding and crystallography of piperazine-based (Co)polyamides.

    PubMed

    Vinken, Esther; Terry, Ann E; Spoelstra, Anne B; Koning, Cor E; Rastogi, Sanjay

    2009-05-01

    Here we demonstrate that superheated water is a solvent for polyamide 2,14 and piperazine-based copolyamides up to a piperazine content of 62 mol %. The incorporation of piperazine allows for a variation of the hydrogen bond density without altering the crystal structure (i.e., the piperazine units cocrystallize with the PA2,14 units (Hoffmann, S.; Vanhaecht, B.; Devroede, J.; Bras, W.; Koning, C. E.; Rastogi, S. Macromolecules 2005, 38, 1797-1803). It is shown that the crystallization of PA2,14 from superheated water greatly influences the crystal structure. Water molecules incorporated in the PA2,14 crystal lattice cause a slip on the hydrogen bonded planes, resulting in a coexistence of a triclinic and a monoclinic crystal structure. On heating above the Brill transition, the water molecules exit from the lattice, restoring the triclinic crystal structure. With increasing piperazine content, and hence decreasing hydrogen bond density, the dissolution temperature decreases. It is only possible to grow single crystals from superheated water up to a piperazine content of 62 mol %. For these single crystals, the incorporation of water molecules in the vicinity of the amide group is seen by the presence of COO- stretch vibrations with FTIR spectroscopy. These vibrations disappear on heating above the Brill transition temperature, and the water molecules leave the amide groups. For copolyamides with more than 62 mol % piperazine, no Brill transition is observed, no single crystals can be grown from water, and no water molecules are observed in the vicinity of the amide groups (Vinken, E.; Terry, A. E.; Hoffmann, S.; Vanhaecht, B.; Koning, C. E.; Rastogi, S. Macromolecules 2006, 39, 2546-2552). The high piperazine content (co)polyamides have fewer hydrogen bond donors and are therefore less likely to have interactions with the water molecules. This work demonstrates the relation among the Brill transition, the dissolution of polyamide in superheated water, and its

  5. Novel 1-(2-aryl-2-adamantyl)piperazine derivatives with antiproliferative activity.

    PubMed

    Fytas, Christos; Zoidis, Grigoris; Tsotinis, Andrew; Fytas, George; Khan, Mohsin A; Akhtar, Samar; Rahman, Khondaker M; Thurston, David E

    2015-03-26

    Novel 1-(2-aryl-2-adamantyl)piperazine derivatives have been synthesized and evaluated in vitro for their antitumor properties against HeLa cervical carcinoma, MDA MB 231 breast cancer, MIA PaCa2 pancreatic cancer, and NCI H1975 non-small cell lung cancer. The parent piperazine 6 was found to exhibit a reasonable activity toward the HeLa and MDA MB 231 tumor cell lines (IC50= 9.2 and 8.4 μΜ, respectively). Concurrent benzene ring C4-fluorination and piperidine acetylation of the piperazino NH of compound 6 resulted in the most active compound 13 of the series in both of the above cell lines (IC50=8.4 and 6.8 μΜ, respectively). Noticeably, compounds 6 and 13 exhibited a significantly low cytotoxicity level over the normal human cells HUVEC (Human Umbilical Vein Endothelial Cells) and NHDF (Normal Human Dermal Fibroblasts). PMID:25703296

  6. Syntheses, biological activities and SAR studies of novel carboxamide compounds containing piperazine and arylsulfonyl moieties.

    PubMed

    Wang, Bao-Lei; Shi, Yan-Xia; Zhang, Shu-Jun; Ma, Yi; Wang, Hong-Xue; Zhang, Li-Yuan; Wei, Wei; Liu, Xing-Hai; Li, Yong-Hong; Li, Zheng-Ming; Li, Bao-Ju

    2016-07-19

    A series of novel carboxamide compounds 19a-19j, 20a-20j and 22a-22d containing piperazine and arylsulfonyl moieties have been synthesized. The bioassay results showed that some compounds exhibited favorable herbicidal activities against dicotyledonous plants and many of them possessed excellent antifungal activities. Among 24 novel compounds, some showed superiority over the commercial fungicides Chlorothalonil, Dimethomorph, Thiophanate-methyl, Iprodione, and Zhongshengmycin at 500 mg/L concentration. Some compounds also exhibited high KARI inhibitory activity at 100 μg/mL concentration and could be used as new KARI lead inhibitors for further studies. Moreover, SAR of these new compounds were comprehensively investigated using different computational methods in which 3D-QSAR model obtained provided useful information for further structural optimization for the discovery of new fungicides. The results of this research will contribute to explore comprehensive biological activities of piperazine-containing compounds in different areas of chemistry. PMID:27092414

  7. Integration of enabling methods for the automated flow preparation of piperazine-2-carboxamide

    PubMed Central

    Ingham, Richard J; Battilocchio, Claudio; Hawkins, Joel M

    2014-01-01

    Summary Here we describe the use of a new open-source software package and a Raspberry Pi® computer for the simultaneous control of multiple flow chemistry devices and its application to a machine-assisted, multi-step flow preparation of pyrazine-2-carboxamide – a component of Rifater®, used in the treatment of tuberculosis – and its reduced derivative piperazine-2-carboxamide. PMID:24778715

  8. Scalable Synthesis of Piperazines Enabled by Visible-Light Irradiation and Aluminum Organometallics

    PubMed Central

    Suárez-Pantiga, Samuel; Colas, Kilian; Johansson, Magnus J; Mendoza, Abraham

    2015-01-01

    The development of more active C–H oxidation catalysts has inspired a rapid, scalable, and stereoselective assembly of multifunctional piperazines through a [3+3] coupling of azomethine ylides. A combination of visible-light irradiation and aluminum organometallics is essential to promote this transformation, which introduces visible-light photochemistry of main-group organometallics and sets the basis for new and promising catalysts. PMID:26337253

  9. N-(4-Chloro­phen­yl)-4-methyl­piperazine-1-carboxamide

    PubMed Central

    Li, Yu-Feng; Wang, Wen-Mei

    2011-01-01

    In the title compound, C12H16ClN3O, the piperazine ring has a chair conformation. Within this ring, the N-methyl nitro­gen atom has a pyramidal geometry and the N-carboxamide nitro­gen atom is almost planar (bond-angle sum = 359.8°). In the crystal, the mol­ecules are linked by N—H⋯O hydrogen bonds into C(4) chains propagating in [010]. PMID:22059021

  10. Screening of Transient Receptor Potential Canonical Channel Activators Identifies Novel Neurotrophic Piperazine Compounds.

    PubMed

    Sawamura, Seishiro; Hatano, Masahiko; Takada, Yoshinori; Hino, Kyosuke; Kawamura, Tetsuya; Tanikawa, Jun; Nakagawa, Hiroshi; Hase, Hideharu; Nakao, Akito; Hirano, Mitsuru; Rotrattanadumrong, Rachapun; Kiyonaka, Shigeki; Mori, Masayuki X; Nishida, Motohiro; Hu, Yaopeng; Inoue, Ryuji; Nagata, Ryu; Mori, Yasuo

    2016-03-01

    Transient receptor potential canonical (TRPC) proteins form Ca(2+)-permeable cation channels activated upon stimulation of metabotropic receptors coupled to phospholipase C. Among the TRPC subfamily, TRPC3 and TRPC6 channels activated directly by diacylglycerol (DAG) play important roles in brain-derived neurotrophic factor (BDNF) signaling, promoting neuronal development and survival. In various disease models, BDNF restores neurologic deficits, but its therapeutic potential is limited by its poor pharmacokinetic profile. Elucidation of a framework for designing small molecules, which elicit BDNF-like activity via TRPC3 and TRPC6, establishes a solid basis to overcome this limitation. We discovered, through library screening, a group of piperazine-derived compounds that activate DAG-activated TRPC3/TRPC6/TRPC7 channels. The compounds [4-(5-chloro-2-methylphenyl)piperazin-1-yl](3-fluorophenyl)methanone (PPZ1) and 2-[4-(2,3-dimethylphenyl)piperazin-1-yl]-N-(2-ethoxyphenyl)acetamide (PPZ2) activated, in a dose-dependent manner, recombinant TRPC3/TRPC6/TRPC7 channels, but not other TRPCs, in human embryonic kidney cells. PPZ2 activated native TRPC6-like channels in smooth muscle cells isolated from rabbit portal vein. Also, PPZ2 evoked cation currents and Ca(2+) influx in rat cultured central neurons. Strikingly, both compounds induced BDNF-like neurite growth and neuroprotection, which were abolished by a knockdown or inhibition of TRPC3/TRPC6/TRPC7 in cultured neurons. Inhibitors of Ca(2+) signaling pathways, except calcineurin, impaired neurite outgrowth promotion induced by PPZ compounds. PPZ2 increased activation of the Ca(2+)-dependent transcription factor, cAMP response element-binding protein. These findings suggest that Ca(2+) signaling mediated by activation of DAG-activated TRPC channels underlies neurotrophic effects of PPZ compounds. Thus, piperazine-derived activators of DAG-activated TRPC channels provide important insights for future development of a

  11. Multicomponent Synthesis and Biological Evaluation of a Piperazine-Based Dopamine Receptor Ligand Library.

    PubMed

    Stucchi, Mattia; Gmeiner, Peter; Huebner, Harald; Rainoldi, Giulia; Sacchetti, Alessandro; Silvani, Alessandra; Lesma, Giordano

    2015-08-13

    A series of 1,4-disubstituted piperazine-based compounds were designed, synthesized, and evaluated as dopamine D2/D3 receptor ligands. The synthesis relies on the key multicomponent split-Ugi reaction, assessing its great potential in generating chemical diversity around the piperazine core. With the aim of evaluating the effect of such diversity on the dopamine receptor affinity, a small library of compounds was prepared, applying post-Ugi transformations. Ligand stimulated binding assays indicated that some compounds show a significant affinity, with K i values up to 53 nM for the D2 receptor. Molecular docking studies with the D2 and D3 receptor homology models were also performed on selected compounds. They highlighted key interactions at the indole head and at the piperazine moiety, which resulted in good agreement with the known pharmacophore models, thus helping to explain the observed structure-activity relationship data. Molecular insights from this study could enable a rational improvement of the split-Ugi primary scaffold, toward more selective ligands. PMID:26288260

  12. A case of levocetirizine-induced fixed drug eruption and cross-reaction with piperazine derivatives.

    PubMed

    Kim, Mi-Yeong; Jo, Eun-Jung; Chang, Yoon-Seok; Cho, Sang-Heon; Min, Kyung-Up; Kim, Sae-Hoon

    2013-10-01

    Fixed drug eruption is an uncommon adverse drug reaction caused by delayed cell-mediated hypersensitivity. Levocetirizine is an active (R)-enatiomer of cetirizine and there have been a few reports of fixed drug eruption related to these antihistamines. We experienced a case of levocetirizine-induced fixed drug eruption and cross-reaction with other piperazine derivatives confirmed by patch test. A 73-year-old female patient presented with recurrent generalized itching, cutaneous bullae formation, rash and multiple pigmentation at fixed sites after taking drugs for common cold. She took bepotastine besilate (Talion®) and levocetirizine (Xyzal®) as antihistamine. She took acetaminophen, pseudoephedrine 60 mg / triprolidine 2.5 mg (Actifed®), dihydrocodeinebitartrate 5 mg / di-methylephedrine hydrochloride 17.5 mg / chlorpheniramine maleate 1.5 mg / guaifenesin 50 mg (Codening®) and aluminium hydroxide 200 mg / magnesium carbonate 120 mg (Antad®) at the same time. Patch test was done with suspected drugs and the result was positive with levocetirizine. We additionally performed patch test for other antihistamines such as cetirizine, hydroxyzine, fexofenadine and loratadine. Piperazine derivatives (cetirizine and hydroxyzine) were positive, but piperidine derivatives (fexofenadine and loratadine) were negative to patch test. There was no adverse drug reaction when she was challenged with fexofenadine. We report a case of levocetirizine-induced fixed drug eruption confirmed by patch test. Cross-reactions were only observed in the piperazine derivatives and piperidine antihistamine was tolerant to the patient. PMID:24260733

  13. A case of levocetirizine-induced fixed drug eruption and cross-reaction with piperazine derivatives

    PubMed Central

    Kim, Mi-Yeong; Jo, Eun-Jung; Chang, Yoon-Seok; Cho, Sang-Heon; Min, Kyung-Up

    2013-01-01

    Fixed drug eruption is an uncommon adverse drug reaction caused by delayed cell-mediated hypersensitivity. Levocetirizine is an active (R)-enatiomer of cetirizine and there have been a few reports of fixed drug eruption related to these antihistamines. We experienced a case of levocetirizine-induced fixed drug eruption and cross-reaction with other piperazine derivatives confirmed by patch test. A 73-year-old female patient presented with recurrent generalized itching, cutaneous bullae formation, rash and multiple pigmentation at fixed sites after taking drugs for common cold. She took bepotastine besilate (Talion®) and levocetirizine (Xyzal®) as antihistamine. She took acetaminophen, pseudoephedrine 60 mg / triprolidine 2.5 mg (Actifed®), dihydrocodeinebitartrate 5 mg / di-methylephedrine hydrochloride 17.5 mg / chlorpheniramine maleate 1.5 mg / guaifenesin 50 mg (Codening®) and aluminium hydroxide 200 mg / magnesium carbonate 120 mg (Antad®) at the same time. Patch test was done with suspected drugs and the result was positive with levocetirizine. We additionally performed patch test for other antihistamines such as cetirizine, hydroxyzine, fexofenadine and loratadine. Piperazine derivatives (cetirizine and hydroxyzine) were positive, but piperidine derivatives (fexofenadine and loratadine) were negative to patch test. There was no adverse drug reaction when she was challenged with fexofenadine. We report a case of levocetirizine-induced fixed drug eruption confirmed by patch test. Cross-reactions were only observed in the piperazine derivatives and piperidine antihistamine was tolerant to the patient. PMID:24260733

  14. Multicomponent Synthesis and Biological Evaluation of a Piperazine-Based Dopamine Receptor Ligand Library

    PubMed Central

    2015-01-01

    A series of 1,4-disubstituted piperazine-based compounds were designed, synthesized, and evaluated as dopamine D2/D3 receptor ligands. The synthesis relies on the key multicomponent split-Ugi reaction, assessing its great potential in generating chemical diversity around the piperazine core. With the aim of evaluating the effect of such diversity on the dopamine receptor affinity, a small library of compounds was prepared, applying post-Ugi transformations. Ligand stimulated binding assays indicated that some compounds show a significant affinity, with Ki values up to 53 nM for the D2 receptor. Molecular docking studies with the D2 and D3 receptor homology models were also performed on selected compounds. They highlighted key interactions at the indole head and at the piperazine moiety, which resulted in good agreement with the known pharmacophore models, thus helping to explain the observed structure–activity relationship data. Molecular insights from this study could enable a rational improvement of the split-Ugi primary scaffold, toward more selective ligands. PMID:26288260

  15. Solubility and diffusivity of N{sub 2}O and CO{sub 2} in (diethanolamine + N-methyldiethanolamine + water) and in (diethanolamine + 2-amino-2-methyl-1-propanol + water)

    SciTech Connect

    Li, M.H.; Lee, W.C.

    1996-05-01

    Acid gases such as CO{sub 2} and H{sub 2}S are frequently removed from natural gas, synthetic natural gas, and other process gas streams by means of absorption into aqueous alkanol-amine solutions. The solubility and diffusivity of N{sub 2}O in (diethanolamine + N-methyldiethanolamine + water) and in (diethanolamine + 2-amino-2-methyl-1-propanol + water) were measured at (30, 35, and 40)C and at atmospheric pressure. Five (diethanolamine + N-methyldiethanolamine + water) and four (diethanolamine + 2-amino-2-methyl-1-propanol + water) systems were studied. The total amine mass percent in all cases was 30. A solubility apparatus was used to measure the solubility of N{sub 2}O in amine solutions. The diffusivity was measured by a wetted wall column absorber. The N{sub 2}O analogy was used to estimate the solubility and diffusivity of CO{sub 2} in (diethanolamine + N-methyldiethanolamine + water) and in (diethanolamine + 2-amino-2-methyl-1-propanol + water).

  16. Solubility and diffusivity of N{sub 2}O and CO{sub 2} in (monoethanolamine + N-methyldiethanolamine + water) and in (monoethanolamine + 2-amino-2-methyl-1-propanol + water)

    SciTech Connect

    Li, M.H.; Lai, M.D.

    1995-03-01

    Solutions of amines are frequently used in gas-treating processes to remove acid gases, such as CO{sub 2} and H{sub 2}S, from gas streams in the natural gas and synthetic ammonia industries and petroleum chemical plants. The solubility and diffusivity of N{sub 2}O in (monoethanolamine + N-methyldiethanolamine + water) and in (monoethanolamine + 2-amino-2-methyl-l-propanol + water) were measured at 30, 35, and 40 C and at atmospheric pressure. Six (monoethanolamine + N-methyldiethanolamine + water) and five (monoethanolamine + 2-amino-2-methyl-l-propanol + water) systems were studied. The total amine mass percent in all cases was 30. The solubilities were measured by a solubility apparatus similar to that of Haimour and Sandall (1984). A wetted wall column absorber was used to obtain the diffusivity of N{sub 2}O in amines. The N{sub 2}O solubilities in amine solutions have been correlated on the basis of the excess Henry constant correlation of Wang et al. (1992). The N{sub 2}O analogy was used to estimate the solubility and diffusivity of CO{sub 2} in (monoethanolamine + N-methyldiethanolamine + water) and in (monoethanolamine + 2-amino-2-methyl-l-propanol + water).

  17. Biochip array technology immunoassay performance and quantitative confirmation of designer piperazines for urine workplace drug testing.

    PubMed

    Castaneto, Marisol S; Barnes, Allan J; Concheiro, Marta; Klette, Kevin L; Martin, Thomas A; Huestis, Marilyn A

    2015-06-01

    Designer piperazines are emerging novel psychoactive substances (NPS) with few high-throughput screening methods for their identification. We evaluated a biochip array technology (BAT) immunoassay for phenylpiperazines (PNP) and benzylpiperazines (BZP) and analyzed 20,017 randomly collected urine workplace specimens. Immunoassay performance at recommended cutoffs was evaluated for PNPI (5 μg/L), PNPII (7.5 μg/L), and BZP (5 μg/L) antibodies. Eight hundred forty positive and 206 randomly selected presumptive negative specimens were confirmed by liquid chromatography high-resolution mass spectrometry (LC-HRMS). Assay limits of detection for PNPI, PNPII, and BZP were 2.9, 6.3, and 2.1 μg/L, respectively. Calibration curves were linear (R (2) > 0.99) with upper limits of 42 μg/L for PNPI/PNII and 100 μg/L for BZP. Quality control samples demonstrated imprecision <19.3 %CV and accuracies 86.0-94.5 % of target. There were no interferences from 106 non-piperazine substances. Seventy-eight of 840 presumptive positive specimens (9.3 %) were LC-HRMS positive, with 72 positive for 1-(3-chlorophenyl)piperazine (mCPP), a designer piperazine and antidepressant trazodone metabolite. Of 206 presumptive negative specimens, one confirmed positive for mCPP (3.3 μg/L) and one for BZP (3.6 μg/L). BAT specificity (21.1 to 91.4 %) and efficiency (27.0 to 91.6 %) increased, and sensitivity slightly decreased (97.5 to 93.8 %) with optimized cutoffs of 25 μg/L PNPI, 42 μg/L PNPI, and 100 μg/L BZP. A high-throughput screening method is needed to identify piperazine NPS. We evaluated performance of the Randox BAT immunoassay to identify urinary piperazines and documented improved performance when antibody cutoffs were raised. In addition, in randomized workplace urine specimens, all but two positive specimens contained mCPP and/or trazodone, most likely from legitimate medical prescriptions. Graphical Abstract Biochip array technology (BAT) immunoassay for designer piperazines

  18. Advanced Amine Solvent Formulations and Process Integration for Near-Term CO2 Capture Success

    SciTech Connect

    Fisher, Kevin S.; Searcy, Katherine; Rochelle, Gary T.; Ziaii, Sepideh; Schubert, Craig

    2007-06-28

    This Phase I SBIR project investigated the economic and technical feasibility of advanced amine scrubbing systems for post-combustion CO2 capture at coal-fired power plants. Numerous combinations of advanced solvent formulations and process configurations were screened for energy requirements, and three cases were selected for detailed analysis: a monoethanolamine (MEA) base case and two “advanced” cases: an MEA/Piperazine (PZ) case, and a methyldiethanolamine (MDEA) / PZ case. The MEA/PZ and MDEA/PZ cases employed an advanced “double matrix” stripper configuration. The basis for calculations was a model plant with a gross capacity of 500 MWe. Results indicated that CO2 capture increased the base cost of electricity from 5 cents/kWh to 10.7 c/kWh for the MEA base case, 10.1 c/kWh for the MEA / PZ double matrix, and 9.7 c/kWh for the MDEA / PZ double matrix. The corresponding cost per metric tonne CO2 avoided was 67.20 $/tonne CO2, 60.19 $/tonne CO2, and 55.05 $/tonne CO2, respectively. Derated capacities, including base plant auxiliary load of 29 MWe, were 339 MWe for the base case, 356 MWe for the MEA/PZ double matrix, and 378 MWe for the MDEA / PZ double matrix. When compared to the base case, systems employing advanced solvent formulations and process configurations were estimated to reduce reboiler steam requirements by 20 to 44%, to reduce derating due to CO2 capture by 13 to 30%, and to reduce the cost of CO2 avoided by 10 to 18%. These results demonstrate the potential for significant improvements in the overall economics of CO2 capture via advanced solvent formulations and process configurations.

  19. Rate-based modeling of reactive absorption of CO{sub 2} and H{sub 2}S into aqueous methyldiethanolamine

    SciTech Connect

    Pacheco, M.A.; Rochelle, G.T.

    1998-10-01

    A general framework was developed to model the transport processes that take place during reactive absorption when both rate- and equilibrium-controlled reactions occur in the liquid phase. This framework was applied to the selective absorption of H{sub 2}S from fuel gas containing CO{sub 2} using aqueous methyldiethanolamine. A rate-based distillation column module was used for the column integration. The Maxwell-Stefan and enhancement factor theories were utilized. In packed columns, CO{sub 2} absorption is controlled by diffusion with fast chemical reactions; in trayed columns it is controlled primarily by physical absorption. Gas-film resistance is never significant for CO{sub 2} absorption. For H{sub 2}S absorption, gas- and liquid-film resistances are important, and diffusion of bisulfide controls the liquid-film resistance. Heat effects produce temperatures bulges that can cause equilibrium pinches at the maximum temperature. This phenomenon gives an optimum packing height for the H{sub 2}S removal. Trayed columns are more selective than packed columns for H{sub 2}S removal, primarily because of the larger number of liquid-film mass transfer units.

  20. Ozonation of piperidine, piperazine and morpholine: Kinetics, stoichiometry, product formation and mechanistic considerations.

    PubMed

    Tekle-Röttering, Agnes; Jewell, Kevin S; Reisz, Erika; Lutze, Holger V; Ternes, Thomas A; Schmidt, Winfried; Schmidt, Torsten C

    2016-01-01

    Piperidine, piperazine and morpholine as archetypes for secondary heterocyclic amines, a structural unit that is often present in pharmaceuticals (e.g., ritalin, cetirizine, timolol, ciprofloxacin) were investigated in their reaction with ozone. In principle the investigated compounds can be degraded with ozone in a reasonable time, based on their high reaction rate constants with respect to ozone (1.9 × 10(4)-2.4 × 10(5) M(-1) s(-1)). However, transformation is insufficient (13-16%), most likely due to a chain reaction, which decomposes ozone. This conclusion is based on OH scavenging experiments, leading to increased compound transformation (18-27%). The investigated target compounds are similar in their kinetic and stoichiometric characteristics. However, the mechanistic considerations based on product formation indicate various reaction pathways. Piperidine reacts with ozone via a nonradical addition reaction to N-hydroxypiperidine (yield: 92% with and 94% without scavenging, with respect to compound transformation). However, piperazine degradation with ozone does not lead to N-hydroxypiperazine. In the morpholine/ozone reaction, N-hydroxymorpholine was identified. Additional oxidation pathways in all cases involved the formation of OH with high yields. One important pathway of piperazine and morpholine by ozonation could be the formation of C-centered radicals after ozone or OH radical attack. Subsequently, O2 addition forms unstable peroxyl radicals, which in one pathway loose superoxide radicals by generating a carbon-centered cation. Subsequent hydrolysis of the carbon-centered cation leads to formaldehyde, whereby ozonation of the N-hydroxy products can proceed in the same way and in addition give rise to hydroxylamine. A second pathway of the short-lived peroxyl radicals could be a dimerization to form short-lived tetraoxides, which cleave by forming hydrogen peroxide. All three products have been found. PMID:26624229

  1. Design, synthesis and anticancer activity of novel hybrid compounds between benzofuran and N-aryl piperazine.

    PubMed

    Mao, Ze-Wei; Zheng, Xi; Lin, Yu-Ping; Hu, Chun-Yan; Wang, Xiu-Li; Wan, Chun-Ping; Rao, Gao-Xiong

    2016-08-01

    A series of novel hybrid compounds between benzofuran and N-aryl piperazine have been designed and prepared. These derivatives were evaluated for their in vitro anti-tumor activity against a panel of human tumor cell lines by MTT assay. The results demonstrated that amide derivatives were more bioactive than sulfonamide compounds in general, and that chloro or trifluoromethyl substituent was vital for modulating cytotoxic activity. In particular, compound 13 was found to be the most potent compound against 4 strains human tumor cell lines, and exhibited cytotoxic activity selectively against Hela (0.03μM). PMID:27371110

  2. 1-Methyl­piperazine-1,4-dium bis­(hydrogen oxalate)

    PubMed Central

    Essid, Manel; Marouani, Houda; Rzaigui, Mohamed

    2014-01-01

    In the crystal structure of the title compound, C5H14N2 2+·2HC2O4 −, the two crystallographically independent hydrogen oxalate anions are linked by strong inter­molecular O—H⋯O hydrogen bonds, forming two independent corrugated chains parallel to the b axis. These chains are further connected by N—H⋯O and C—H⋯O hydrogen bonds originating from the organic cations, forming a three-dimensional network. The diprotonated piperazine ring adopts a chair conformation, with the methyl group occupying an equatorial position. PMID:24765024

  3. (4-(Bis(4-Fluorophenyl)Methyl)Piperazin-1-yl)(Cyclohexyl)Methanone Hydrochloride (LDK1229): A New Cannabinoid CB1 Receptor Inverse Agonist from the Class of Benzhydryl Piperazine Analogs

    PubMed Central

    Mahmoud, Mariam M.; Olszewska, Teresa; Liu, Hui; Shore, Derek M.; Hurst, Dow P.; Reggio, Patricia H.; Lu, Dai

    2015-01-01

    Some inverse agonists of cannabinoid receptor type 1 (CB1) have been demonstrated to be anorectic antiobesity drug candidates. However, the first generation of CB1 inverse agonists, represented by rimonabant (SR141716A), otenabant, and taranabant, are centrally active, with a high level of psychiatric side effects. Hence, the discovery of CB1 inverse agonists with a chemical scaffold distinct from these holds promise for developing peripherally active CB1 inverse agonists with fewer side effects. We generated a new CB1 inverse agonist, (4-(bis(4-fluorophenyl)methyl)piperazin-1-yl)(cyclohexyl)methanone hydrochloride (LDK1229), from the class of benzhydryl piperazine analogs. This compound binds to CB1 more selectively than cannabinoid receptor type 2, with a Ki value of 220 nM. Comparable CB1 binding was also observed by analogs 1-[bis(4-fluorophenyl)methyl]-4-cinnamylpiperazine dihydrochloride (LDK1203) and 1-[bis(4-fluorophenyl)methyl]-4-tosylpiperazine hydrochloride (LDK1222), which differed by the substitution on the piperazine ring where the piperazine of LDK1203 and LDK1222 are substituted by an alkyl group and a tosyl group, respectively. LDK1229 exhibits efficacy comparable with SR141716A in antagonizing the basal G protein coupling activity of CB1, as indicated by a reduction in guanosine 5′-O-(3-thio)triphosphate binding. Consistent with inverse agonist behavior, increased cell surface localization of CB1 upon treatment with LDK1229 was also observed. Although docking and mutational analysis showed that LDK1229 forms similar interactions with the receptor as SR141716A does, the benzhydryl piperazine scaffold is structurally distinct from the first-generation CB1 inverse agonists. It offers new opportunities for developing novel CB1 inverse agonists through the optimization of molecular properties, such as the polar surface area and hydrophilicity, to reduce the central activity observed with SR141716A. PMID:25411367

  4. Synthesis and characterization of a disubstituted piperazine derivative with T-type channel blocking action and analgesic properties

    PubMed Central

    Pudukulatham, Zubaidha; Zhang, Fang-Xiong; Gadotti, Vinicius M; M’Dahoma, Said; Swami, Prabhuling; Tamboli, Yasinalli

    2016-01-01

    Background T-type calcium channels are important contributors to signaling in the primary afferent pain pathway and are thus important targets for the development of analgesics. It has been previously reported that certain piperazine-based compounds such as flunarizine are able to inhibit T-type calcium channels. Thus, we hypothesized that novel piperazine compounds could potentially act as analgesics. Results Here, we have created a series of 14 compound derivatives around a diphenyl methyl-piperazine core pharmacophore. Testing their effects on transiently expressed Cav3.2 calcium channels revealed one derivative (3-((4-(bis(4-fluorophenyl)methyl)piperazin-1-yl)methyl)-4-(2-methoxyphenyl)-1,2,5-oxadiazole 2-oxide, compound 10e) as a potent blocker. 10e mediate tonic block of these channels with an IC50 of around 4 micromolar. 10e also blocked Cav3.1 and Cav3.3 channels, but only weakly affected high-voltage-activated Cav1.2 and Cav2.2 channels. Intrathecal delivery of 10e mediated relief from formalin and complete Freund’s adjuvant induced inflammatory pain that was ablated by genetic knockout of Cav3.2 channels. Conclusions Altogether, our data identify a novel T-type calcium channel blocker with tight structure activity relationship (SAR) and relevant in vivo efficacy in inflammatory pain conditions. PMID:27053601

  5. Excretion of N-mononitrosopiperazine after low level exposure to piperazine in air: effects of dietary nitrate and ascorbate

    SciTech Connect

    Bellander, T.; Osterdahl, B.G.; Hagmar, L.

    1988-04-01

    The secondary amine piperazine may be nitrosated in vivo, following oral intake or occupational exposure by inhalation. The suspected carcinogen N-mononitrosopiperazine could be formed in the human stomach, and in part excreted in the urine. In this study, 0.4 microgram N-mononitrosopiperazine, determined by gas chromatography-Thermal Energy Analysis, was observed in the urine in one of four volunteers, at an experimental exposure by inhalation of 0.3 mg piperazine/m3. The intake of spinach and beetroot caused an increased nitrosation of piperazine, and up to 1.7 microgram N-mononitrosopiperazine was excreted in the urine in the four individuals. This excretion indicates that about 5% of the absorbed piperazine dose was converted to N-mononitrosopiperazine. With the same nitrate-rich diet, but with the addition of citrus fruits and fresh vegetables, the highest excretion was 0.6 microgram N-mononitrosopiperazine. The excretion was significantly correlated with the ratio between the maximum level of nitrite in saliva and the ascorbate level in plasma. There was also a significant interindividual variation. N,N'-Dinitrosopiperazine was not found in any sample of urine.

  6. Nitrosamine formation in amine scrubbing at desorber temperatures.

    PubMed

    Fine, Nathan A; Goldman, Mark J; Rochelle, Gary T

    2014-01-01

    Amine scrubbing is a thermodynamically efficient and industrially proven method for carbon capture, but amine solvents can nitrosate in the desorber, forming potentially carcinogenic nitrosamines. The kinetics of reactions involving nitrite and monoethanolamine (MEA), diethanolamine (DEA), methylethanolamine (MMEA), and methyldiethanolamine (MDEA) were determined under desorber conditions. The nitrosations of MEA, DEA, and MMEA are first order in nitrite, carbamate species, and hydronium ion. Nitrosation of MDEA, a tertiary amine, is not catalyzed by the addition of CO2 since it cannot form a stable carbamate. Concentrated and CO2 loaded MEA was blended with low concentrations of N-(2-hydroxyethyl) glycine (HeGly), hydroxyethyl-ethylenediamine (HEEDA), and DEA, secondary amines common in MEA degradation. Nitrosamine yield was proportional to the concentration of secondary amine and was a function of CO2 loading and temperature. Blends of tertiary amines with piperazine (PZ) showed n-nitrosopiperazine (MNPZ) yields close to unity, validating the slow nitrosation rates hypothesized for tertiary amines. These results provide a useful tool for estimating nitrosamine accumulation over a range of amine solvents. PMID:24956458

  7. Copper(I) cyanide networks: synthesis, structure, and luminescence behavior. Part 2. Piperazine ligands and hexamethylenetetramine.

    PubMed

    Lim, Mi Jung; Murray, Courtney A; Tronic, Tristan A; deKrafft, Kathryn E; Ley, Amanda N; deButts, Jordan C; Pike, Robert D; Lu, Haiyan; Patterson, Howard H

    2008-08-01

    A variety of photoluminescent, and in some cases thermochromic, metal-organic networks of CuCN were self-assembled in aqueous reactions with amine ligands: (CuCN) 2(Pip) ( 1a), (CuCN) 20(Pip) 7 ( 1b), (CuCN) 7(MePip) 2 ( 2), (CuCN) 2(Me 2Pip) ( 3a), (CuCN) 4(Me 2Pip) ( 3b), (CuCN) 7(EtPip) 2 ( 4), (CuCN) 4(Et 2Pip) ( 5), (CuCN) 3(BzPip) 2 ( 6a), (CuCN) 5(BzPip) 2 ( 6b), (CuCN) 7(BzPip) 2 ( 6c), (CuCN) 4(BzPip) ( 6d), (CuCN) 2(Bz 2Pip) ( 7), (CuCN)(Ph 2CHPip) ( 8a), (CuCN) 2(Ph 2CHPip) ( 8b), (CuCN) 3(HMTA) 2 ( 9a), (CuCN) 5(HMTA) 2 ( 9b), and (CuCN) 5(HMTA) ( 9c) (Pip = piperazine, MePip = N-methylpiperazine, Me 2Pip = N, N'-dimethylpiperazine, EtPip = N-ethylpiperazine, Et 2Pip = N, N'-diethylpiperazine, BzPip = N-benzylpiperazine, Bz 2Pip = N, N'-dibenzylpiperazine, Ph 2CHPip = N-(diphenylmethyl)piperazine, and HMTA = hexamethylenetetramine). New X-ray structures are reported for 1b, 2, 3b, 4, 5, 6a, 6d, 7, 8b, 9b, and 9c. An important structural theme is the formation of (6,3) (CuCN) 2(piperazine) sheets with or without threading of independent CuCN chains. Strong luminescence at ambient temperature is observed for all but complexes 6 and 7. All luminescent compounds show a broad emission band in the blue region at about 450 nm attributable to metal-to-ligand charge transfer behavior based on the large Stokes shift between excitation and emission maxima. 3, 8, and 9 are thermochromic due to an additional lower energy emission band, which is absent at 77 K. PMID:18597424

  8. Enantiomeric separation and quantitation of (+/-)-amphetamine, (+/-)-methamphetamine, (+/-)-MDA, (+/-)-MDMA, and (+/-)-MDEA in urine specimens by GC-EI-MS after derivatization with (R)-(-)- or (S)-(+)-alpha-methoxy-alpha-(trifluoromethy)phenylacetyl chloride (MTPA).

    PubMed

    Paul, Buddha D; Jemionek, John; Lesser, David; Jacobs, Aaron; Searles, Douglas A

    2004-09-01

    In drug testing, the presence of methamphetamine in urine is generally confirmed by a gas chromatography-mass spectrometry (GC-MS) method. Derivatization of the compound to a perfluoroalkylamide, prior to confirmation, typically yields better chromatographic separation. Once methamphetamine is detected, a second GC-MS test is necessary to distinguish positive results from the use of over-the-counter medication, Vicks inhaler, or from use of a prescription drug, selegiline (Deprenyl). R-(-)-Methamphetamine is the urinary product from legitimate use of these medications. The second GC-MS test is to confirm illicit use of (S)-(+)-methamphetamine. In the procedure, the two methamphetamine isomers are changed to the chromatographically separable diastereomers by a chiral derivatizing agent, (S)-(-)-trifluoroacetylprolyl chloride (TPC). But the method has inherent limitations. Racemization of the reagent produces mixed diastereomers even from pure (S)-(+)-methamphetamine. Instead of using TPC, we utilized (R)-(-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride (MTPA) to prepare the amides of diastereomers of methamphetamine. No racemization was observed with this reagent. The method was extended to resolve GC peaks of (R)-(-)- and (S)-(+)-isomers of amphetamine, 3,4-methylenedioxyamphetamine (MDA), N-methyl-MDA (MDMA), and N-ethyl-MDA (MDEA). Three ions from the drug and two ions from the deuterated internal standard were monitored to characterize and quantitate the drugs. For MDEA, only one ion was used. The quantitation was linear over 25 to 5000 ng/mL for MDEA and 25 to 10,000 ng/mL for all other drugs. Correlation coefficients were > 0.996. Precision calculated as the coefficient of variation at the calibrator concentration of 500 ng/mL was within +/- 11% for all drugs. The method was applied to test 43 urine specimens. In 91% of the methamphetamine-positive specimens, only the (S)-(+)-isomer was detected. In all MDMA-positive specimens, the concentrations

  9. Design, Synthesis and Biological Evaluation of Novel Piperazine Derivatives as CCR5 Antagonists

    PubMed Central

    Liu, Tao; Weng, Zhiyong; Dong, Xiaowu; Chen, Linjie; Ma, Ling; Cen, Shan; Zhou, Naiming; Hu, Yongzhou

    2013-01-01

    By using a fragment-assembly strategy and bioisosteric-replacement principle, a series of novel piperazine derivatives were designed, synthesized, and evaluated for their cellular target-effector fusion activities and in vitro antiviral activities against HIV-1. Preliminary structure-activity relationships (SARs) of target compounds were concluded in this study, and five compounds were found to exhibited medium to potent CCR5 fusion activities with IC50 values in low micromolar level. Among evaluated compounds, 23 h was found to be a CCR5 antagonist with an IC50 value of 6.29 µM and an anti-HIV-1 inhibitor with an IC50 value of 0.44 µM. PMID:23308267

  10. Synthesis and pharmacological evaluation of piperidine (piperazine)-substituted benzoxazole derivatives as multi-target antipsychotics.

    PubMed

    Huang, Ling; Zhang, Wenjun; Zhang, Xiaohua; Yin, Lei; Chen, Bangyin; Song, Jinchun

    2015-11-15

    The present study describes the optimization of a series of novel benzoxazole-piperidine (piperazine) derivatives combining high dopamine D2 and serotonin 5-HT1A, 5-HT2A receptor affinities. Of these derivatives, the pharmacological features of compound 29 exhibited high affinities for the DA D2, 5-HT1A and 5-HT2A receptors, but low affinities for the 5-HT2C and histamine H1 receptors and human ether-a-go-go-related gene (hERG) channels. Furthermore, compound 29 reduced apomorphine-induced climbing and 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI)-induced head twitching without observable catalepsy, even at the highest dose tested. Thus, compound 29 is a promising candidate as a multi-target antipsychotic treatment. PMID:26483200

  11. Structure characterization of 1:1 adducts of metal(II) halides and piperazine

    SciTech Connect

    Yu Jiehui Hou Qin; Wang Tiegang; Zhang Xiao; Xu Jiqing

    2007-02-15

    From the simple hydro/solvothermal reactions, two 1:1 adducts of MX{sub 2} and piperazine (pip) [CdI{sub 2}(pip)] 1 and [CoCl{sub 2}(pip)] 2 were prepared. Both were characterized by elemental analyses, IR spectra, ultra-violet visible spectra, thermogravimetric analyses and X-ray single-crystal diffraction. With pip as the bridges, the 1-D linear CdI{sub 2} chains are extended into a 2-D layered compound 1, while the mononuclear CoCl{sub 2} units are linked into a 1-D zigzag-type chain compound 2. The fluorescence emission spectrum indicates that compound 1 possesses fluorescence property with the peaks at 373nm ({lambda}{sub ex}=212nm) and 410nm ({lambda}{sub ex}=293nm)

  12. Atrazine removal by covalent bonding to piperazine functionalized PolyHIPEs.

    PubMed

    Pulko, Irena; Kolar, Mitja; Krajnc, Peter

    2007-11-01

    The removal of atrazine from water by a solid phase extraction technique using insoluble polymers is described. Porous crosslinked polymers bearing piperazine moieties were prepared in a one step reaction from the precursor 4-nitrophenylacrylate incorporating polymers (PolyHIPE type prepared by the polymerization of the continuous phase of a high internal phase emulsion and polymer beads prepared by suspension polymerization). Polymers were applied to sequester atrazine from aqueous solutions with a concentration of 33 ppb and irreversible covalent bonding to the polymers was achieved. GC/MS/MS was used to monitor the dynamics of atrazine uptake and it was found that almost complete removal of atrazine was accomplished with an excess of polymer after 48 hours at room temperature. For comparison, polymer beads of identical chemistry but lower porosity were also used and showed significantly slower action (near complete removal after 72 hours). PMID:17662371

  13. [Synthesis and bioactivities of novel dihydroartemisinin-piperazine derivatives containing sulfonamide].

    PubMed

    Ma, Chao; Li, Xue-qiang; Xu, Jian; Chen, Cou-xi

    2013-09-01

    Dihydroartemisinin is an important derivative of artemisinin. We used dihydroartemisinin as the starting material, through esterification, amination and acylation, a series of novel piperazine-sulfonamide contained dihydroartemisinin derivatives were firstly synthesized and their chemical structures were confirmed by IR, 1H NMR, 13C NMR and HR-MS. X-diffraction was used to determine the final configuration of the compound 3c. And the in vitro anti-HeLa activities of compounds 3 were analyzed with CCK-8 method. The preliminary bioassay test shows that compound 3 showed the best inhibition activities against HeLa with IC50 values of 0.14 micromol x L(-1). PMID:24358777

  14. Hypophagic and hypolocomotive effects of metachloro phenyl piperazine in rats treated with theophylline and caffeine.

    PubMed

    Alam, Nausheen; Haleem, Darakshan Jabeen; Najam, Rahila; Haider, Syeda; Ahmed, Shahida Perveen

    2011-07-01

    Long term intake of coffee is known to produce anxiety and suppression of appetite. 5- hydroxytryptamine (5-HT) acting via 5-HT-2C receptors elicits anorexia and anxiety. The present study is design to monitor metachloro phenyl piperazine (m-CPP) at a dose of 3mg/ml/kg, induces hypophagia and hypolocomotion in rats taking a solution of caffeine (a component of coffee and tea) or theophylline (a component of tea) as a sole source of water. We found that hypophagic and hypolocomotive effects of m-CPP were attenuated in theophylline but not in caffeine treated animals suggesting that long term intake of theophylline may attenuate anorexiogenic and anxiogenic effects of 5-HT. A possible role of 5-HT-2C receptors in the modulation of anxiety and appetite in people drinking coffee or tea discussed. PMID:21715256

  15. LC-MS/MS screening method for designer amphetamines, tryptamines, and piperazines in serum.

    PubMed

    Wohlfarth, Ariane; Weinmann, Wolfgang; Dresen, Sebastian

    2010-04-01

    Since the late 1990s and early 2000s, derivatives of well-known designer drugs as well as new psychoactive compounds have been sold on the illicit drug market and have led to intoxications and fatalities. The LC-MS/MS screening method presented covers 31 new designer drugs as well as cathinone, methcathinone, phencyclidine, and ketamine which were included to complete the screening spectrum. All but the last two are modified molecular structures of amphetamine, tryptamine, or piperazine. Among the amphetamine derivatives are cathinone, methcathinone, 3,4-DMA, 2,5-DMA, DOB, DOET, DOM, ethylamphetamine, MDDMA, 4-MTA, PMA, PMMA, 3,4,5-TMA, TMA-6 and members of the 2C group: 2C-B, 2C-D, 2C-H, 2C-I, 2C-P, 2C-T-2, 2C-T-4, and 2C-T-7. AMT, DPT, DiPT, MiPT, DMT, and 5MeO-DMT are contained in the tryptamine group, BZP, MDBP, TFMPP, mCPP, and MeOPP in the piperazine group. Using an Applied Biosystems LC-MS/MS API 365 TurboIonSpray it is possible to identify all 35 substances. After addition of internal standards and mixed-mode solid-phase extraction the analytes are separated using a Synergi Polar RP column and gradient elution with 1 mM ammonium formate and methanol/0.1% formic acid as mobile phases A and B. Data acquisition is performed in MRM mode with positive electro spray ionization. The assay is selective for all tested substances. Limits of detection were determined by analyzing S/N-ratios and are between 1.0 and 5.0 ng/mL. Matrix effects lie between 65% and 118%, extraction efficiencies range from 72% to 90%. PMID:20069283

  16. Piperazine as counter ion for insulin-enhancing anions [VO2(dipic-OH)]-: Synthesis, characterization and X-ray crystal structure

    NASA Astrophysics Data System (ADS)

    Ghasemi, Fatemeh; Ghasemi, Khaled; Rezvani, Ali Reza; Graiff, Claudia

    2016-01-01

    The new complex [H2Pipz][VO2(dipic-OH)]2·2H2O (1), where H2dipic-OH = 4-hydroxypyridine-2,6-dicarboxylic acid and Pipz = piperazine, was synthesized and characterized by elemental analysis, FTIR, 1H NMR, 13C NMR and UV-Vis spectroscopy and single crystal X-ray diffraction. The crystal system is triclinic with space group Pī. In this compound, piperazine is diprotonated and acts as counter ion.

  17. Synthesis, alpha-adrenoceptors affinity and alpha 1-adrenoceptor antagonistic properties of some 1,4-substituted piperazine derivatives.

    PubMed

    Marona, H; Kubacka, M; Filipek, B; Siwek, A; Dybała, M; Szneler, E; Pociecha, T; Gunia, A; Waszkielewicz, A M

    2011-10-01

    A series of different 1,4-substituted piperazine derivatives (1-11) was synthesized. It comprised 1-(substituted-phenoxyalkyl)-4-(2-methoxyphenyl)piperazine derivatives (1-5); 1,4-bis(substituted-phenoxyethyl)piperazine derivatives (6-8) and 1-(substituted-phenoxy)-3-(substituted-phenoxyalkylpiperazin-1-yl)propan-2-ol derivatives (9-11). All compounds were evaluated for affinity toward alpha 1- and alpha 2-receptors by radioligand binding assays on rat cerebral cortex using [3H]prazosin and [3H]clonidine as specific radioligand, respectively. Furthermore alpha 1-antagonistic properties were checked for most promising compounds (1-5 and 10) by means of inhibition of phenylephrine induced contraction in isolated rat aorta. Antagonistic potency stayed in agreement with radioligand binding results. The most active compounds (1-5) displaced [3H]prazosin from cortical binding sites in low nanomolar range (Ki = 2.1-13.1 nM). Compound 10 showed slightly lower affinity for alpha 1-adrenoceptor (Ki = 781 nM). Compounds 2-5 displayed the strongest antagonistic activity with pA2 values ranging from 8.441 to 8.807. Compound 1 gave a pA2 value of 7.868, while compound 10 showed the weakest antagonistic potency, giving a pA2 value of 6.374. 1-[3-(2-Chloro-6-methylphenoxy)propyl]-4-(2-methoxyphenyl)piperazine hydrochloride (5) showed the best alpha 1- affinity properties with a Ki(alpha 1) value of 2.1 nM and it was 61.05 fold more selective toward alpha 1 than alpha 2-receptors. The best properties showed 1-[3-(2,6-dimethylphenoxy)propyl]-4-(2-methoxyphenyl)piperazine hydrochloride (4) with a Ki(alpha 1) value of 2.4 nM, a 142.13 fold better selectivity to alpha 1 - over alpha 2-adrenoceptors and the best antagonistic potency (pA2 = 8.807). It is worth to emphasized that all most promising compounds possessed an 1-(o-methoxyphenyl)piperazine moiety which probably plays an important role in the affinity to alpha-adrenoceptors. PMID:22026152

  18. DFT Study of Solvent Effects on Conformational Equilibria and Vibrational Spectra of 4-(1-PYRROLIDINYL)PIPERAZINE

    NASA Astrophysics Data System (ADS)

    Baglayan, O.; Kesan, G.; Parlak, C.; Senyel, M.

    2012-06-01

    The optimized structural parameters (bond lengths, bond and dihedral angles), conformational equilibria and normal mode frequencies and corresponding vibrational assignments of 4-(1-Pyrrolidinyl)piperazine (4-pypp) have been examined by means of B3LYP hybrid density functional theory (DFT) method with 6-31++G(d,p) basis set. Furthermore, reliable vibrational assignments have made on the basis of potential energy distribution (PED) calculated and the thermodynamics functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of 4-pypp (C_8H17N_3) have been predicted. Calculations are employed for different conformations of 4-pypp both in gas phase and in solution. Solvent effects are investigated using chloroform and dimethylsulfoxide. Results from the theoretical values are showed that the structural parameters, mole fractions of stable conformers, vibrational frequencies, IR intensities and Raman activities of 4-pypp are solvent dependent. {Keywords}: 4-(1-Pyrrolidinyl)piperazine, vibrational spectra, solvent effect, DFT.

  19. Synthesis and antioxidant activity of some 1-aryl/aralkyl piperazine derivatives with xanthine moiety at N4

    PubMed Central

    Andonova, Lily; Zheleva-Dimitrova, Dimitrina; Georgieva, Maya; Zlatkov, Alexander

    2014-01-01

    Piperazine nucleus is one of the most important heterocyclic systems exhibiting remarkable pharmacological activities. Thus, in the current study six new aryl/aralkyl substituted piperazine derivatives, containing methylxanthine moiety were synthesized and their structures were confirmed by IR and 1H NMR analysis. All compounds were in vitro screened for their activity as antioxidants using DPPH (2,2′-Diphenyl-1-picrylhydrazyl), ABTS (2,2′-azinobis-(3-ethylbenzo thiazine-6-sulfonic acid)) and FRAP (ferric reducing/antioxidant power) methods. The antioxidant activity of the studied compounds against lipid peroxidation was also measured. The highest antioxidant activity was demonstrated by compound 3c. It is obvious that the presence of a hydroxyl group in the structure is essential for the antioxidant properties and should be taken into consideration in further design of structures with potential antioxidant properties. PMID:26019603

  20. Solubility of carbon dioxide in aqueous mixtures of alkanolamines

    SciTech Connect

    Dawodu, O.F.; Meisen, A. . Dept. of Chemical Engineering)

    1994-07-01

    The solubility of CO[sub 2] in water + N-methyldiethanolamine + monoethanolamine (MDEA + MEA) and water + N-methyldiethanolamine + diethanolamine (MDEA + DEA) are reported at two compositions of 3.4 M MDEA + 0.8 M MEA or DEA and 2.1 M MDEA + 2.1 M MEA or DEA at temperatures from 70 to 180 C and CO[sub 2] partial pressures from 100 to 3,850 kPa. The solubility of CO[sub 2] in the blends decreased with an increase in temperature but increased with an increase in CO[sub 2] partial pressure. At low partial pressures of CO[sub 2] and the same total amine concentration, the equilibrium CO[sub 2] loadings were in the order MDEA + MEA > MDEA + DEA > MDEA. However, at high CO[sub 2] partial pressures, the equilibrium CO[sub 2] loadings in the MDEA solutions were higher than those of the MDEA + MEA and MDEA + DEA blends of equal molar strengths due to the stoichiometric loading limitations of MEA and DEA. The nonadditivity of the equilibrium loadings for single amine systems highlights the need for independent measurements on amine blends.

  1. Effects of gepirone, an aryl-piperazine anxiolytic drug, on aggressive behavior and brain monoaminergic neurotransmission.

    PubMed

    McMillen, B A; Scott, S M; Williams, H L; Sanghera, M K

    1987-04-01

    Gepirone (BMY 13805), a buspirone analog, was used to determine the antianxiety mechanism of the arylpiperazine class of drugs. Because of the weak effects of these drugs on conflict behavior, isolation-induced aggressive mice were used as the antianxiety model. Gepirone, like buspirone, potently inhibited attacks against group housed intruder mice (ED50 = 4.5 mg/kg i.p.) without causing sedation or ataxia. Inhibition of aggression was potentiated by co-administration of 0.25 mg/kg methiothepin or 2.5 mg/kg methysergide. Gepirone had variable effects on dopamine metabolism and reduced 5-hydroxytryptamine (5HT) metabolism about one third after a dose of 2.5 mg/kg. In contrast to buspirone, which markedly increased dopaminergic impulse flow, gepirone inhibited the firing of most cells recorded from the substantia nigra zona compacta in doses of 2.3-10 mg/kg i.v. and the effects were reversible by administration of haloperidol. The common metabolite of buspirone and gepirone, 1-(2-pyrimidinyl)-piperazine, caused increased firing rates only. Gepirone potently inhibited serotonergic impulse flow recorded from the dorsal raphe nucleus (88.3% after 0.04 mg/kg) and this effect was partially reversed by serotonergic antagonists. Both buspirone and gepirone displaced [3H]-5HT from the 5HT1a binding site in the hippocampus with IC50 values of 10 and 58 nM, respectively. Non-alkyl substituted aryl-piperazines displaced [3H]-5HT from both 5HT1a and 5HT1b binding sites. Thus, although gepirone may be a weak postsynaptic 5HT agonist, its primary effect is to decrease 5HT neurotransmission. In support of this conclusion was the observed potentiation of antiaggressive effects by blocking 5HT receptors wit small doses of methiothepin or methysergide, which would exacerbate the decreased release of 5HT caused by gepirone. These results are in harmony with reports that decreased serotonergic activity has anxiolytic-like effects in animal models of anxiety. PMID:2439924

  2. Efficacy and safety of Linkus, Aminophylline diphenhydramine and acefyllin piperazine for the treatment of cough in children.

    PubMed

    Rehman, Hina; Naveed, Safila; Usmanghani, Khan

    2016-05-01

    To evaluate the safety and efficacy of Linkus, Aminophylline with Diphenhydramine group and Acefyllin Piperazine with Diphenhydramine cough syrup on children having cough and sleep difficulty associated with cough. To determine the effects of Linkus polyherbal syrup (group A) and compared with other parallel allopathic groups (Group B and C) for cough on children and associated sleep quality and improvement. 360 children having cough inducted in 3 different groups randomly selected. Three parallel groups were the part of the study. The first study group was the herbal syrup Linkus, second group of children were taking a syrup of multinational pharmaceutical industry having Aminophylline plus Diphenhydramine however the third group received another famous brand having Acefyllin Piperazine with Diphenhydramine. Informed assent and informed consent have taken from the study subjects and their parents. Subjects with acute cough were included in the study however the subjects with chronic cough considered to be excluded. Every group of individual in the study was informed about the investigational drugs provided. Ethnic groups, frequency of cough and diseases illness (<0.05) were determine on every group on the investigational syrup. Cough impact on child and its sleep of three different syrups (every group) were assessed on day1 and day 14(p<0.001) via a likert scale. For the evaluation of pain assessment Wong baker face scale were used and level of significance in each group (p<0.001). Significant results were observed in the Linkus Group as compared to the other parallel groups including Aminophylline plus Diphenhydramine and Acefyllin Piperazine with Diphenhydramine on day 14 (p<0.001). Side effects on group B and group C (Aminophylline with Diphenhydramine and Acefyllin Piperazine with Diphenhydramine) were almost similar in number however Linkus syrup has minimum side effects on study duration. Polyherbal syrup Linkus shows better results in treatment of cough

  3. Acid gas treating by aqueous alkanolamines. Annual report, January-December 1993

    SciTech Connect

    Sandall, O.C.; Rinker, E.B.; Ashour, S.

    1993-12-01

    The objective of the work is to investigate the simultaneous absorption or desorption of CO2 and H2S into and from a mixed aqueous amine solvent consisting of methyldiethanolamine (MDEA) and diethanolamine (DEA). In work completed thus far, density, viscosity, gas diffusivity, gas solubility, surface tension, and amine solution vapor pressure have been measured for aqueous MDEA, DEA, and MDEA/DEA mixtures over the temperature range 20 to 100 deg. C and for concentrations up to 50 weight %. A mathematical model, based on the penetration theory, for the simultaneous absorption (desorption) of CO2 and H2S into (from) aqueous solutions of MDEA and DEA has been developed.

  4. Acid gas treating by aqueous alkanolamines. Annual report, July-December 1992

    SciTech Connect

    Sandall, O.C.; Rinker, E.B.; Tamimi, A.; Davis, R.A.; Oelschlager, D.W.

    1992-12-01

    The objective of the work is to investigate the simultaneous absorption or desorption of CO2 and H2S into and from a mixed aqueous amine solvent consisting of methyldiethanolamine (MDEA) and diethanolamine (DEA). In work completed thus far models have been developed for single gas (either H2S or CO2) absorption into a single amine solution (MDEA or DEA). Density and viscosity measurements have been made for aqueous MDEA, DEA and MDEA/DEA mixtures over the temperature range 20 to 100 C and for concentrations up to 50 weight %.

  5. Novel piperazine core compound induces death in human liver cancer cells: possible pharmacological properties.

    PubMed

    Samie, Nima; Muniandy, Sekaran; Kanthimathi, M S; Haerian, Batoul Sadat; Raja Azudin, Raja Elina

    2016-01-01

    The current study evaluates the cytotoxic mechanism of a novel piperazine derivate designated as PCC against human liver cancer cells. In this context, human liver cancer cell lines, SNU-475 and 243, human monocyte/macrophage cell line, CRL-9855, and human B lymphocyte cell line, CCL-156, were used to determine the IC50 of PCC using the standard MTT assay. PCC displayed a strong suppressive effect on SNU-475 and SNU-423 cells with an IC50 value of 6.98 ± 0.11 μg/ml and 7.76 ± 0.45 μg/ml respectively, after 24 h of treatment. Significant dipping in the mitochondrial membrane potential and elevation in the released of cytochrome c from the mitochondria indicated the induction of the intrinsic apoptosis pathway by PCC. Activation of this pathway was further evidenced by significant activation of caspase 3/7 and 9. PCC was also shown to activate the extrinsic pathways of apoptosis via activation of caspase-8 which is linked to the suppression of NF-ƙB translocation to the nucleus. Cell cycle arrest in the G1 phase was confirmed by flow cytometry and up-regulation of glutathione reductase expression was quantified by qPCR. This study suggests that PCC is a simultaneous inducer of intrinsic and extrinsic pathways of apoptosis in liver cancer cell lines. PMID:27072064

  6. Corrosion in CO{sub 2} capture process using blended monoethanolamine and piperazine

    SciTech Connect

    Nainar, M.; Veawab, A.

    2009-10-15

    This work explores the promise of aqueous solutions of blended monoethanolamine (MEA) and piperazine (PZ) as a cost-effective solvent for carbon dioxide (CO{sub 2}) capture, from industrial flue gas streams with respect to corrosion, which is regarded as one of the, most severe operational problems in typical CO{sub 2} capture plants. Electrochemical corrosion experiments were carried out using the potentiodynamic polarization technique for corrosion measurements. The results show that the blended MEA/PZ solutions are more corrosive than the MEA solutions. The corrosion rate of carbon steel increases with concentration of PZ, total amine concentration, CO{sub 2} loading of solution, solution temperature, and the presence of heat stable salts. Among the tested heat-stable salts, formate is the most corrosive salt, followed by acetate, oxalate, and thiosulfate in the absence of oxygen (O{sub 2}), while acetate is the most corrosive salt followed by formate, oxalate, and thiosulfate in the presence of O{sub 2}.

  7. Charge-transfer complexes of 1-(2-aminoethyl) piperazine with σ- and π-acceptors

    NASA Astrophysics Data System (ADS)

    Mostafa, Adel; Bazzi, Hassan S.

    2010-11-01

    The solid charge-transfer (CT) molecular complexes formed in the reaction of 1-(2-aminoethyl) piperazine (AEPIP) with the σ-acceptor iodine and π-acceptors 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 7,7,8,8-tetracyanoquinodi-methane (TCNQ), 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TBCHD) and 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL) were studied in chloroform at 25 °C. The products were investigated through electronic and infrared spectra as well as elemental analysis. The obtained results showed that the formed solid CT-complexes have the formulas [(AEPIP) I] +I5-, [(AEPIP)(DDQ) 2], [(AEPIP)(TCNQ) 2], [(AEPIP) 2(TBCHD) 3] and [(AEPIP)(CHL)] which are in full agreement with the known reaction stoichiometries in solution as well as the elemental analysis measurements. The formation constant KCT, molar extinction coefficient ɛCT, free energy change Δ G0 and CT energy ECT have been calculated for the CT-complexes [(AEPIP)(DDQ) 2], [(AEPIP)(TCNQ) 2] and [(AEPIP)(CHL)] as well.

  8. Regio- and Stereoselective Synthesis of Spiropyrrolizidines and Piperazines through Azomethine Ylide Cycloaddition Reaction.

    PubMed

    Haddad, Saoussen; Boudriga, Sarra; Porzio, François; Soldera, Armand; Askri, Moheddine; Knorr, Michael; Rousselin, Yoann; Kubicki, Marek M; Golz, Christopher; Strohmann, Carsten

    2015-09-18

    A series of original spiropyrrolizidine derivatives has been prepared by a one-pot three-component [3 + 2] cycloaddition reaction of (E)-3-arylidene-1-phenyl-pyrrolidine-2,5-diones, l-proline, and the cyclic ketones 1H-indole-2,3-dione (isatin), indenoquinoxaline-11-one and acenaphthenequinone. We disclose an unprecedented isomerization of some spiroadducts leading to a new family of spirooxindolepyrrolizidines. Furthermore, these cycloadducts underwent retro-1,3-dipolar cycloaddition yielding unexpected regioisomers. Upon treatment of the dipolarophiles with in situ generated azomethine ylides from l-proline or acenaphthenequinone, formation of spiroadducts and unusual polycyclic fused piperazines through a stepwise [3 + 3] cycloaddition pathway is observed. The stereochemistry of these N-heterocycles has been confirmed by several X-ray diffraction studies. Some of these compounds exhibit extensive hydrogen bonding in the crystalline state. To enlighten the observed regio- and stereoselectivity of the [3 + 2] cycloaddition, calculations using the DFT approach at the B3LYP/6-31G(d,p) level were carried out. It was found that this reaction is under kinetic control. PMID:26291879

  9. Decomposition of nitrosamines in CO2 capture by aqueous piperazine or monoethanolamine.

    PubMed

    Fine, Nathan A; Nielsen, Paul T; Rochelle, Gary T

    2014-05-20

    Amine scrubbing is an efficient method for carbon capture and sequestration, but secondary amines present in all amine solvents can form carcinogenic nitrosamines. Decomposition kinetics for n-nitrosopiperazine (MNPZ), nitrosodiethanolamine (NDELA), and nitroso-(2-hydroxyethyl) glycine (NHeGly) were measured over a range of temperature, base concentration, base strength, and CO2 loading pertinent to amine scrubbing. MNPZ and NDELA decomposition is first order in the nitrosamine, half order in base concentration, and base-catalyzed with a Brønsted slope of β = 0.5. The activation energy is 94, 106, and 112 kJ/mol for MNPZ, NDELA, and NHeGly, respectively. MNPZ readily decomposes at 150 °C in 5 M piperazine, making thermal decomposition an important mechanism for MNPZ control. However, NHeGly and NDELA are too stable at 120 °C in 7 M monoethanolamine (MEA) for thermal decomposition to be important. Base treatment during reclaiming could rapidly and selectively decompose NHeGly and NDELA to mitigate nitrosamine accumulation in MEA. PMID:24730662

  10. Novel piperazine core compound induces death in human liver cancer cells: possible pharmacological properties

    PubMed Central

    Samie, Nima; Muniandy, Sekaran; Kanthimathi, M. S.; Haerian, Batoul Sadat; Raja Azudin, Raja Elina

    2016-01-01

    The current study evaluates the cytotoxic mechanism of a novel piperazine derivate designated as PCC against human liver cancer cells. In this context, human liver cancer cell lines, SNU-475 and 243, human monocyte/macrophage cell line, CRL-9855, and human B lymphocyte cell line, CCL-156, were used to determine the IC50 of PCC using the standard MTT assay. PCC displayed a strong suppressive effect on SNU-475 and SNU-423 cells with an IC50 value of 6.98 ± 0.11 μg/ml and 7.76 ± 0.45 μg/ml respectively, after 24 h of treatment. Significant dipping in the mitochondrial membrane potential and elevation in the released of cytochrome c from the mitochondria indicated the induction of the intrinsic apoptosis pathway by PCC. Activation of this pathway was further evidenced by significant activation of caspase 3/7 and 9. PCC was also shown to activate the extrinsic pathways of apoptosis via activation of caspase-8 which is linked to the suppression of NF-ƙB translocation to the nucleus. Cell cycle arrest in the G1 phase was confirmed by flow cytometry and up-regulation of glutathione reductase expression was quantified by qPCR. This study suggests that PCC is a simultaneous inducer of intrinsic and extrinsic pathways of apoptosis in liver cancer cell lines. PMID:27072064

  11. Mechanism of action of novel piperazine containing a toxicant against human liver cancer cells

    PubMed Central

    Kanthimathi, MS; Haerian, Batoul Sadat

    2016-01-01

    The purpose of this study was to assess the cytotoxic potential of a novel piperazine derivative (PCC) against human liver cancer cells. SNU-475 and 423 human liver cancer cell lines were used to determine the IC50 of PCC using the standard MTT assay. PCC displayed a strong suppressive effect on liver cancer cells with an IC50 value of 6.98 ± 0.11 µM and 7.76 ± 0.45 µM against SNU-475 and SNU-423 respectively after 24 h of treatment. Significant dipping in the mitochondrial membrane potential and elevation in the released of cytochrome c from the mitochondria indicated the induction of the intrinsic apoptosis pathway by PCC. Activation of this pathway was further evidenced by significant activation of caspase 3/7 and 9. PCC was also shown to activate the extrinsic pathways of apoptosis via activation of caspase-8 which is linked to the suppression of NF-κB translocation to the nucleus. Cell cycle arrest in the G1 phase was confirmed by flow cytometry and up-regulation of glutathione reductase expression was quantified by qPCR. Results of this study suggest that PCC is a potent anti-cancer agent inducing both intrinsic and extrinsic pathways of apoptosis in liver cancer cell lines. PMID:27019772

  12. Quantum chemical studies on solvents for post-combustion carbon dioxide capture: calculation of pKa and carbamate stability of disubstituted piperazines.

    PubMed

    Gangarapu, Satesh; Wierda, Gerben J; Marcelis, Antonius T M; Zuilhof, Han

    2014-06-23

    Piperazine is a widely studied solvent for post-combustion carbon dioxide capture. To investigate the possibilities of further improving this process, the electronic and steric effects of -CH(3), -CH(2)F, -CH(2)OH, -CH(2)NH(2), -COCH3 , and -CN groups of 2,5-disubstituted piperazines on the pKa and carbamate stability towards hydrolysis are investigated by quantum chemical methods. For the calculations, B3LYP, M11L, and spin-component-scaled MP2 (SCS-MP2) methods are used and coupled with the SMD solvation model. The experimental pK(a) values of piperazine, 2-methylpiperazine, and 2,5-dimethylpiperazine agree well with the calculated values. The present study indicates that substitution of -CH(3), -CH(2) NH(2), and -CH(2) OH groups on the 2- and 5-positions of piperazine has a positive impact on the CO(2) absorption capacity by reducing the carbamate stability towards hydrolysis. Furthermore, their higher boiling points, relative to piperazine itself, will lead to a reduction of volatility-related losses. PMID:24782140

  13. Anti-nociceptive and anti-inflammatory activities of 4-[(1-phenyl-1H-pyrazol-4-yl) methyl] 1-piperazine carboxylic acid ethyl ester: A new piperazine derivative.

    PubMed

    Silva, Daiany P B; Florentino, Iziara F; Oliveira, Lanussy P; Lino, Roberta C; Galdino, Pablinny M; Menegatti, Ricardo; Costa, Elson A

    2015-10-01

    Piperazine compounds possess anti-infective, anti-carcinogenic, anxiolytic, hypotensive, anti-hypertensive and vasorelaxant properties and are attractive candidates for the development of new analgesic and anti-inflammatory drugs. This study investigates the anti-nociceptive and anti-inflammatory effects of piperazine derivative 4-[(1-phenyl-1H-pyrazol-4-yl) methyl]1-piperazine carboxylic acid ethyl ester (LQFM-008) and the involvement of the serotonergic pathway. In the formalin test, treatments with LQFM-008 (15 and 30mg/kg p.o.) reduced the licking time in both neurogenic and inflammatory phases of this test. In the tail flick and hot plate tests, LQFM008 treatment (15 and 30mg/kg p.o.) increased latency to thermal stimulus, suggesting the involvement of central mechanisms in the anti-nociceptive effect of LQFM-008. In the carrageenan-induced paw edema test, LQFM-008 (p.o.) at the doses of 15 and 30mg/kg reduced the edema at all tested time points, while the dose of 7.5mg/kg reduced the edema only for the first hour. LQFM-008 (30mg/kg p.o.) reduced both cell migration and protein exudation in the carrageenan-induced pleurisy test. Furthermore, pre-treatment with NAN-190 (0.6mg/kgi.p.) and PCPA (100mg/kgi.p.) antagonized the anti-nociceptive effect of LQFM-008 in both phases of the formalin test. Our data suggest that LQFM-008 possesses anti-inflammatory and anti-nociceptive effects mediated through the serotonergic pathway. PMID:26276732

  14. Formation of p-cresol:piperazine complex in solution monitored by spin-lattice relaxation times and pulsed field gradient NMR diffusion measurements

    NASA Astrophysics Data System (ADS)

    de Carvalho, Erika Martins; Velloso, Marcia Helena Rodrigues; Tinoco, Luzineide Wanderley; Figueroa-Villar, José Daniel

    2003-10-01

    A study of the nature of the anthelmintic p-cresol:piperazine complex in chloroform solution has been conducted using different NMR techniques: self-diffusion coefficients using DOSY; NOE, NULL, and double-selective T1 measurements to determine inter-molecular distances; and selective and non-selective T1 measurements to determine correlation times. The experimental results in solution and CP-MAS were compared to literature X-ray diffraction data using molecular modeling. It was shown that the p-cresol:piperazine complex exists in solution in a very similar manner as it does in the solid state, with one p-cresol molecule hydrogen bonded through the hydroxyl hydrogen to each nitrogen atom of piperazine. The close correspondence between the X-ray diffraction data and the inter-proton distances obtained by NULL and double selective excitation techniques indicate that those methodologies can be used to determine inter-molecular distances in solution.

  15. Effect of the piperazine unit and metal-binding site position on the solubility and anti-proliferative activity of ruthenium(II)- and osmium(II)- arene complexes of isomeric indolo[3,2-c]quinoline-piperazine hybrids.

    PubMed

    Filak, Lukas K; Kalinowski, Danuta S; Bauer, Theresa J; Richardson, Des R; Arion, Vladimir B

    2014-07-01

    In this study, the indoloquinoline backbone and piperazine were combined to prepare indoloquinoline-piperazine hybrids and their ruthenium- and osmium-arene complexes in an effort to generate novel antitumor agents with improved aqueous solubility. In addition, the position of the metal-binding unit was varied, and the effect of these structural alterations on the aqueous solubility and antiproliferative activity of their ruthenium- and osmium-arene complexes was studied. The indoloquinoline-piperazine hybrids L(1-3) were prepared in situ and isolated as six ruthenium and osmium complexes [(η(6)-p-cymene)M(L(1-3))Cl]Cl, where L(1) = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-2-N-amine, M = Ru ([1a]Cl), Os ([1b]Cl), L(2) = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-4-N-amine, M = Ru ([2a]Cl), Os ([2b]Cl), L(3) = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-8-N-amine, M = Ru ([3a]Cl), Os ([3b]Cl). The compounds were characterized by elemental analysis, one- and two-dimensional NMR spectroscopy, ESI mass spectrometry, IR and UV-vis spectroscopy, and single-crystal X-ray diffraction. The antiproliferative activity of the isomeric ruthenium and osmium complexes [1a,b]Cl-[3a,b]Cl was examined in vitro and showed the importance of the position of the metal-binding site for their cytotoxicity. Those complexes containing the metal-binding site located at the position 4 of the indoloquinoline scaffold ([2a]Cl and [2b]Cl) demonstrated the most potent antiproliferative activity. The results provide important insight into the structure-activity relationships of ruthenium- and osmium-arene complexes with indoloquinoline-piperazine hybrid ligands. These studies can be further utilized for the design and development of more potent chemotherapeutic agents. PMID:24927493

  16. Effect of the Piperazine Unit and Metal-Binding Site Position on the Solubility and Anti-Proliferative Activity of Ruthenium(II)- and Osmium(II)- Arene Complexes of Isomeric Indolo[3,2-c]quinoline—Piperazine Hybrids

    PubMed Central

    2014-01-01

    In this study, the indoloquinoline backbone and piperazine were combined to prepare indoloquinoline–piperazine hybrids and their ruthenium- and osmium-arene complexes in an effort to generate novel antitumor agents with improved aqueous solubility. In addition, the position of the metal-binding unit was varied, and the effect of these structural alterations on the aqueous solubility and antiproliferative activity of their ruthenium- and osmium-arene complexes was studied. The indoloquinoline–piperazine hybrids L1–3 were prepared in situ and isolated as six ruthenium and osmium complexes [(η6-p-cymene)M(L1–3)Cl]Cl, where L1 = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-2-N-amine, M = Ru ([1a]Cl), Os ([1b]Cl), L2 = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-4-N-amine, M = Ru ([2a]Cl), Os ([2b]Cl), L3 = 6-(4-methylpiperazin-1-yl)-N-(pyridin-2-yl-methylene)-11H-indolo[3,2-c]quinolin-8-N-amine, M = Ru ([3a]Cl), Os ([3b]Cl). The compounds were characterized by elemental analysis, one- and two-dimensional NMR spectroscopy, ESI mass spectrometry, IR and UV–vis spectroscopy, and single-crystal X-ray diffraction. The antiproliferative activity of the isomeric ruthenium and osmium complexes [1a,b]Cl–[3a,b]Cl was examined in vitro and showed the importance of the position of the metal-binding site for their cytotoxicity. Those complexes containing the metal-binding site located at the position 4 of the indoloquinoline scaffold ([2a]Cl and [2b]Cl) demonstrated the most potent antiproliferative activity. The results provide important insight into the structure–activity relationships of ruthenium- and osmium-arene complexes with indoloquinoline–piperazine hybrid ligands. These studies can be further utilized for the design and development of more potent chemotherapeutic agents. PMID:24927493

  17. Control of water molecule aggregations in copper 1,4-cyclohexanedicarboxylate coordination polymers containing pyridyl-piperazine type ligands

    NASA Astrophysics Data System (ADS)

    Qiblawi, Sultan H.; LaDuca, Robert L.

    2014-01-01

    A series of layered divalent copper coordination polymers containing 1,4-cyclohexanedicarboxylate and long-spanning pyridyl-piperazine type ligands exhibits greatly different co-crystallized water molecule aggregations depending on the specific ligands used. Both [Cu(t-14cdc)(4-bpmp)]n (1, t-14cdc = trans-1,4-cyclohexanedicarboxylate, 4-bpmp = bis(4-pyridylmethyl)piperazine) and {[Cu(t-14cdc)(4-bpfp)(H2O)2]·6H2O}n (2, 4-bpfp = bis(4-pyridylformyl)piperazine) possess 2D (4,4) coordination polymer grids. However 1 lacks any co-crystallized water and has pinched grid apertures, while 2 manifests infinite water tapes with T6(2)4(2) classification and rectangular grid apertures. {[Cu2(c-14cdc)2(4-bpmp)]·2H2O}n (3, c-14cdc = cis-1,4-cyclohexanedicarboxylate) has [Cu2(c-14cdc)]2 ribbons with paddlewheel dimeric units linked into 2D slabs by 4-bpmp tethers, along with isolated water molecule pairs. In contrast, {[Cu2(c-14cdc)2(4-bpfp)]·10H2O}n (4) shows a very similar underlying coordination polymer topology but entrains unique decameric water molecule clusters. The minor product {[Cu2(c-14cdcH)2(t-1,4-cdc)(4-bpfp)2(H2O)2]·2H2O}n (5) was isolated along with 4; this compound underwent some in situ cis to trans cyclohexane-dicarboxylate ligand isomerization and exhibits a ladder polymer motif.

  18. Design and synthesis of a series of piperazine-1-carboxamidine derivatives with antifungal activity resulting from accumulation of endogenous reactive oxygen species.

    PubMed

    François, Isabelle E; Thevissen, Karin; Pellens, Klaartje; Meert, Els M; Heeres, Jan; Freyne, Eddy; Coesemans, Erwin; Viellevoye, Marcel; Deroose, Frederik; Martinez Gonzalez, Sonia; Pastor, Joaquin; Corens, David; Meerpoel, Lieven; Borgers, Marcel; Ausma, Jannie; Dispersyn, Gerrit D; Cammue, Bruno P

    2009-10-01

    In this study, we screened a library of 500 compounds for fungicidal activity via induction of endogenous reactive oxygen species (ROS) accumulation. Structure-activity relationship studies showed that piperazine-1-carboxamidine analogues with large atoms or large side chains substituted on the phenyl group at the R(3) and R(5) positions are characterized by a high ROS accumulation capacity in Candida albicans and a high fungicidal activity. Moreover, we could link the fungicidal mode of action of the piperazine-1-carboxamidine derivatives to the accumulation of endogenous ROS. PMID:19705386

  19. Synthesis and an angiolytic role of novel piperazine-benzothiazole analogues on neovascularization, a chief tumoral parameter in neoplastic development.

    PubMed

    Al-Ghorbani, Mohammed; Pavankumar, G S; Naveen, P; Thirusangu, Prabhu; Prabhakar, B T; Khanum, Shaukath Ara

    2016-04-01

    A novel series of benzoic acid N'-[2-(4-benzothiazol-2-yl-piperazin-1-yl)-acetyl]-hydrazides 6a-j were synthesized and characterized by IR, (1)H, (13)C NMR, elemental and mass spectral analyses. The in-vitro cytotoxicity and cell viability assay of the synthesized compounds 6a-j were evaluated against Dalton's lymphoma ascites (DLA) cells. Our results showed that compound 6c with a bromo group on phenyl ring has showed promising antiproliferative efficacy. Further investigation of compound 6c on in-vivo treatment model depicts the increased tumor suppression through inhibition of angiogenesis. PMID:26918263

  20. Dimethyl phenyl piperazine iodide (DMPP) induces glioma regression by inhibiting angiogenesis

    SciTech Connect

    He, Yan-qing; Li, Yan; Wang, Xiao-yu; He, Xiao-dong; Jun, Li; Chuai, Manli; Lee, Kenneth Ka Ho; Wang, Ju; Wang, Li-jing; Yang, Xuesong

    2014-01-15

    1,1-Dimethyl-4-phenyl piperazine iodide (DMPP) is a synthetic nicotinic acetylcholine receptor (nAChR) agonist that could reduce airway inflammation. In this study, we demonstrated that DMPP could dramatically inhibit glioma size maintained on the chick embryonic chorioallantoic membrane (CAM). We first performed MTT and BrdU incorporation experiments on U87 glioma cells in vitro to understand the mechanism involved. We established that DMPP did not significantly affect U87 cell proliferation and survival. We speculated that DMPP directly caused the tumor to regress by affecting the vasculature in and around the implanted tumor on our chick CAM model. Hence, we conducted detailed analysis of DMPP's inhibitory effects on angiogenesis. Three vasculogenesis and angiogenesis in vivo models were used in the study which included (1) early chick blood islands formation, (2) chick yolk-sac membrane (YSW) and (3) CAM models. The results revealed that DMPP directly suppressed all developmental stages involved in vasculogenesis and angiogenesis – possibly by acting through Ang-1 and HIF-2α signaling. In sum, our results show that DMPP could induce glioma regression grown on CAM by inhibiting vasculogenesis and angiogenesis. - Highlights: ●We demonstrated that DMPP inhibited the growth of glioma cells on chick CAM. ●DMPP did not significantly affect the proliferation and survival of U87 cells. ●We revealed that DMPP suppressed vasculogenesis and angiogenesis in chick embryo. ●Angiogenesis in chick CAM was inhibited by DMPP via most probably Ang-1 and HIF-2α. ●DMPP could be potentially developed as an anti-tumor drug in the future.

  1. Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes

    NASA Astrophysics Data System (ADS)

    Khan, Shamim Ahmad; Nishat, Nahid; Parveen, Shadma; Rasool, Raza

    2011-10-01

    A novel tetradentate salicylic acid-formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, 1H NMR and electronic spectral studies. The thermal stability was determined by thermogravimetric analysis and thermal data revealed that all the polymer metal complexes show good thermal stability than their parent ligand. Electronic spectral data and magnetic moment values revealed that polymer metal complexes of Mn(II), Co(II) and Ni(II) show an octahedral geometry while Cu(II) and Zn(II) show distorted octahedral and tetrahedral geometry respectively. The antimicrobial screening of the ligand and coordination polymers was done by using Agar well diffusion method against various bacteria and fungi. It was evident from the data that antibacterial and antifungal activity increased on chelation and all the polymer metal complexes show excellent antimicrobial activity than their parent ligand.

  2. Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes.

    PubMed

    Khan, Shamim Ahmad; Nishat, Nahid; Parveen, Shadma; Rasool, Raza

    2011-10-15

    A novel tetradentate salicylic acid-formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, (1)H NMR and electronic spectral studies. The thermal stability was determined by thermogravimetric analysis and thermal data revealed that all the polymer metal complexes show good thermal stability than their parent ligand. Electronic spectral data and magnetic moment values revealed that polymer metal complexes of Mn(II), Co(II) and Ni(II) show an octahedral geometry while Cu(II) and Zn(II) show distorted octahedral and tetrahedral geometry respectively. The antimicrobial screening of the ligand and coordination polymers was done by using Agar well diffusion method against various bacteria and fungi. It was evident from the data that antibacterial and antifungal activity increased on chelation and all the polymer metal complexes show excellent antimicrobial activity than their parent ligand. PMID:21757398

  3. Fire self-extinguishing cotton fabric: development of piperazine derivatives containing phosphorous-sulfur-nitrogen and their flame retardant and thermal behaviors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent studies have shown interest in flame retardants containing phosphorus, nitrogen and sulfur a combination small molecule with a promising new approach in preparing an important class of flame retardant materials. Tetraethyl piperazine-1,4-diyldiphosphonate (TEPP) and O,O,O',O'-tetramethyl pip...

  4. Anti-hypertensive property of a nickel-piperazine/NO donor in spontaneously hypertensive rats.

    PubMed

    Monti, Martina; Ciccone, Valerio; Pacini, Aurora; Roggeri, Riccardo; Monzani, Enrico; Casella, Luigi; Morbidelli, Lucia

    2016-05-01

    The nickel-piperazine/NO donor compound, Ni(PipNONO)Cl, belonging to the family of compounds labelled as "metal-nonoates", due to its promising vasodilating activity, has been considered as a potential drug candidate in anti-hypertensive therapy. Drug efficacy has been evaluated in spontaneously hypertensive rats (SHR) in comparison with normotensive animals (C57BL/6 mice and WKY rats). In normotensive animals the metal-nonoate maintained blood pressure at basal level both following acute administration and after 30 days of treatment. In SHR, Ni(PipNONO)Cl reduced blood pressure in the dose range of 3-10mg/kg. When compared with a commercial NONOate, DETA/NO, used at the same doses, Ni(PipNONO)Cl was more active in reducing blood pressure in SHR than DETA/NO in the first two weeks, while the effect of the two molecules was similar in the third and fourth week. The degradation and control compound Ni(Pip)Cl2 had no effect on blood pressure and heart rate in same animal models. Remarkably, the blood pressure reduction induced by the new NO-donor Ni(PipNONO)Cl does not evoke changes in the heart rate and tolerance. Considering the mechanisms of vascular protection, 30 days of administration of Ni(PipNONO)Cl improved endothelial function in SHR by upregulating endothelial NO synthase (eNOS) through increased eNOS protein levels and downregulated Caveolin-1 (Cav-1), and by increasing superoxide dismutase 1 (SOD1) protein level in aortae. In cultured endothelial cells Ni(PipNONO)Cl restored the cell functions (cytoskeletal protein expression, migration and proliferation) altered by the inflammatory mediator interleukin-1β (IL-1β), impairing the endothelial to mesenchimal transition. In conclusion, Ni(PipNONO)Cl maintained unaltered blood pressure in normotensive mice and rats, and it exerted anti-hypertensive effect in SHR through the restoration of vascular endothelial protective functions. PMID:27063892

  5. Coordination Chemistry and Structural Dynamics of a Long and Flexible Piperazine-Derived Ligand.

    PubMed

    Hawes, Chris S; Hamilton, Sophie E; Hicks, Jamie; Knowles, Gregory P; Chaffee, Alan L; Turner, David R; Batten, Stuart R

    2016-07-01

    A long and highly flexible internally functionalized dipyridyl ligand α,α'-p-xylylenebis(1-(4-pyridylmethylene)-piper-4-azine), L, has been employed in the synthesis of a series of coordination polymer materials with Co(II), Cd(II), and Ag(I) ions. In poly-[Cd(L)(TPA)] 1 and poly-[Co(L)(IPA)], 2, (TPA = terephthalate, IPA = isophthalate) the ligand adopts a similar linear conformation to that seen in the structure of the unbound molecule and provides a long (2.6 nm) metal-metal bridging distance. Due to the mismatch of edge lengths with that provided by the carboxylate coligands, geometric distortions from the regular dia and (4,4) network geometries for 1 and 2, respectively, are observed. In poly-[Ag2(CF3SO3)2(L)], 3, the ligand coordinates through both pyridine groups and two of the four piperazine nitrogen donors, forming a high-connectivity 2-dimensional network. The compound poly-[Ag2(L)](BF4)2·2MeCN, 4, a porous 3-dimensional cds network, undergoes a fascinating and rapid single-crystal-to-single-crystal rearrangement on exchange of the acetonitrile guests for water in ambient air, forming a nonporous hydrated network poly-[Ag2(L)](BF4)2·2H2O, 5, in which the well-ordered guest water molecules mediate the rearrangement of the tetrafluoroborate anions and the framework itself through hydrogen bonding. The dynamics of the system are examined in greater detail through the preparation of a kinetic product, the dioxane-solvated species poly-[Ag2(L)](BF4)2·2C4H8O2, 6, which undergoes a slow conversion to 5 over the course of approximately 16 h, a transition which can be monitored in real time. The reverse transformation can also be observed on immersing the hydrate 5 in dioxane. The structural features and physical properties of each of the materials can be rationalized based on the flexible and multifunctional nature of the ligand molecule, as well as the coordination behavior of the chosen metal ions. PMID:27328206

  6. Comparison of impact of the different hydrophilic carriers on the properties of piperazine-containing drug.

    PubMed

    Ahmed, M O

    2001-05-01

    The objective of this study was to determine the impact of a series of nonionic surfactants on the solubility of piperazine-containing drug (meclizine, MZ) in comparison to that of natural cyclodextrins (alpha-CD and beta-CD) and dimethyl-beta-cyclodextrin (DM-beta-CD). The solubility of the drug was studied in either CDs solutions or nonionic surfactant solutions. Three classes of nonionic surfactants were used namely; polyoxyethylene (POE) sorbitan fatty acid esters (polysorbates), POE fatty acid esters (Myrjs) and polyethylene oxide (PEO) fatty alcohol ethers (Brijs and Eumulgins). The solubility of MZ was increased linearly with the increasing surfactant concentration, indicating that micellar solubilization follows the partition model. It was found that the longer the hydrocarbon chain in a homologous series, the more efficient is the solubilizing power of surfactant. For example, polysorbate 80 (Tween-80) is a more efficient solubilizer than polysorbate 20 (Tween-20), indicating that the drug was incorporated in the core of micelle more than the capsular region of the micelle. On the other hand, in case of POE fatty acid esters, the solubilizing power increased with decreasing polyoxyethylene chain as Myrj 53 was more efficient than Myrj 59. In class of PEO fatty alcohol ethers, the shorter the hydrophilic chain and longer lipophilic chain, the more efficient was the solubilizing capacity. Thus, Brij 58 was more efficient solubilizer than Brij 35 and Eumulgin C1000 was more active than Eumulgin C1500. Comparatively, Eumulgin C1000 had the highest solubilizing power for MZ among the studied PEO fatty alcohol ethers and other groups of surfactants. The solubility action of surfactants toward MZ was increased by raising the temperature of the surfactant solutions from 30 to 45 degrees C. Hydrophilic macromolecules (PEG 1000 and PEG 6000) or cosolvents (glycerol and propylene glycol) have a very slight effect on the solubility of MZ and confirm the predominance

  7. Temperature-dependence of the influence of the position-2-methyl group on the structure-directing effect of piperazine in the synthesis of open-framework aluminophosphates

    PubMed Central

    Huang, Pai; Xu, Jun; Qi, Guodong; Deng, Feng; Xu, Ruren; Yan, Wenfu

    2016-01-01

    The temperature-dependence of the influence of the position-2-methyl group on the structure-directing effect of piperazine in the synthesis of open-framework aluminophosphates was investigated. By heating the initial mixture with the composition of Al2O3:1.5 P2O5:R:125 H2O at 160 °C, where R is the structure-directing agent of 2-methylpiperazine or piperazine, layered aluminophosphates APMeP150 (R = 2-methylpiperazine) and AP2pip (R = piperazine) were obtained. When the same initial reaction mixture was heated at 190 °C, layered aluminophosphates APMeP200 (R = 2-methylpiperazine) and AP2pip (R = piperazine) were crystallized. APMeP200 and AP2pip have the same inorganic sheet topology. We investigated the crystallization processes of the four open-framework aluminophosphates and found that increasing the heating temperature slowed the crystallization of the initial mixtures. The non-bonding interactions between the inorganic layers of the four open-framework aluminophosphates and the experimental or theoretically generated structure-directing agents were calculated. The possible starting points of the crystallization of the four open-framework aluminophosphates were analysed and compared. The temperature-dependence of the influence of the position-2-methyl group on the structure-directing effect of piperazine revealed that the structure-directing effect, the most important factor in the synthesis of zeolites and related open-framework materials, is determined by multiple factors. The structural parameters of the same compound can be affected by the synthesis conditions. PMID:26912387

  8. Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt

    PubMed Central

    Sanphui, Palash; Bolla, Geetha; Nangia, Ashwini; Chernyshev, Vladimir

    2014-01-01

    Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR), p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid⋯pyridine heterosynthon and N—H⋯O catemer hydrogen bonds involving the amide group. The acid⋯amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM) hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl⋯carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine

  9. Influence of silica nanospheres on the separation performance of thin film composite poly(piperazine-amide) nanofiltration membranes

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Wang, Yihua; Song, Jie; Guan, Yipeng; Yu, Hui; Pan, Xianhui; Wu, Feiyang; Zhang, Meng

    2015-01-01

    A novel thin film nanocomposite nanofiltration (TFNN) membrane was fabricated by introducing silica nanospheres (ca. 235 ± 11 nm) in the interfacial polymerization process of trimesoyl chloride (TMC) and piperazine (PIP) over polysulfone (PS) support for investigating the effect of silica nanofiller on the separation performance (i.e., permeability and salt rejection) of conventional thin film composite poly(piperazine-amide) nanofiltration (TFCN) membrane. The physicochemical characterization results show that all of the silica nanospheres are uniformly embedded on the surface of TFNN membrane. The introduction of silica nanospheres improves the hydrophilicity of the TFCN membrane and also causes its isoelectric point shift to a lower pH value. Moreover, the active poly(piperazine-amide) barrier layer of TFNN membrane (60.8 ± 2.3 nm) is thinner than that of the pristine TFCN membrane (72.1 ± 2.5 nm) as a control sample. The separation performance tests reveal that the addition of silica nanospheres can obviously elevate the salt rejection of the pristine TFCN membrane from 87.58 ± 0.15 to 94.81 ± 0.17% under 2000 ppm of MgSO4 solution and 0.5 MPa operating pressure, simultaneously accompanied by the increases of permeate flux from 19.36 ± 0.75 to 22.65 ± 0.68 L/m2 h. Additionally, compared with pristine TFCN membrane, the fabricated TFNN membrane has relatively low salt rejection (43.20 ± 0.27%) in 0.5 MPa operating pressure for 500 ppm of NaCl aqueous solution, which demonstrates that the introduction of silica nanospheres can dramatically promote the divalent-ionic separation selectivity. Furthermore, the experimental results suggest that the nanocomposite TFNN membrane possesses stable filtration performance in the softening process of MgSO4 aqueous solution. The separation performance improvement should be attributed to the optimizations of microstructures and surface features of active barrier layer of TFNN membrane, caused by the addition of silica

  10. Synthesis and antitumor activity evaluation of quinazoline derivatives bearing piperazine-1-carbodithioate moiety at C4-position.

    PubMed

    Zhang, Ying; Yang, Chao-Rui; Tang, Xue; Cao, Sheng-Li; Ren, Ting-Ting; Gao, Man; Liao, Ji; Xu, Xingzhi

    2016-10-01

    A series of quinazoline derivatives bearing piperazine-1-carbodithioate moiety at the C4-position were synthesized using piperidine and 1-bromo-3-chloropropane as starting materials via eight steps. Final compounds 8a-q and 9a-i were evaluated for their antiproliferative activity against human lung cancer A549, breast adenocarcinoma MCF-7, and colorectal cancer HCT-116 cell lines. The results showed that fourteen of twenty-six final compounds inhibited the proliferation of three cancer cell lines with IC50 values less than 10μM. When treated with a representative compound 8n, HCT-116 cells were arrested at G0/G1 phase of the cell cycle. This provided a clue to further investigation of the mechanism of action. PMID:27575478

  11. Crystal structure of the 1:2:2 adduct of piperazine, o-phthalic acid and water.

    PubMed

    Jin, Zhi Min; Pan, Yuan Jiang; He, Ling; Li, Zu Guang; Yu, Kai Bei

    2003-02-01

    The adduct of piperazine, o-phthalic acid and water (1:2:2), C20H26N2O10, crystallizes in the monoclinic space group P21/c with a = 6.129(1), b = 12.810(2), c = 13.137(2)A, beta = 95.87(1) degrees, V = 1026.0(3)A3, Z = 2. The piperazinium adopts a chair comformer, and is tied with the hydrogen orthophthalate via a hydrogen bond of the N-H...O type. Because of bifurcated hydrogen bonding of C(sp3)H-O [3.0801(17) and 3.1408(18)A] and the shortest hydrogen bond of C(sp3)H-O [2.9758(17)A], C(sp3)H-O hydrogen bonds play important roles in stablizing the title adduct. PMID:12608772

  12. Crystal structure of piperazine-1,4-diium bis­(4-amino­benzene­sulfonate)

    PubMed Central

    Kumar, K. Sathesh; Ranjith, S.; Sudhakar, S.; Srinivasan, P.; Ponnuswamy, M. N.

    2015-01-01

    The asymmetric unit of the title salt, C4H12N2 2+·2C6H6NO3S−, consists of half a piperazindiium dication, located about an inversion centre, and a 4-amino­benzene­sulfonate anion. The piperazine ring adopts a chair conformation. In the crystal, the cations and anions are linked via N—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional framework. Within the framework there are C—H⋯π inter­actions and the N—H⋯O hydrogen bonds result in the formation of R 4 4(22) and R 3 4(13) ring motifs. PMID:26870510

  13. Novel Piperazine-based Compounds Inhibit Microtubule Dynamics and Sensitize Colon Cancer Cells to Tumor Necrosis Factor-induced Apoptosis*

    PubMed Central

    Chopra, Avijeet; Anderson, Amy; Giardina, Charles

    2014-01-01

    We recently identified a series of mitotically acting piperazine-based compounds that potently increase the sensitivity of colon cancer cells to apoptotic ligands. Here we describe a structure-activity relationship study on this compound class and identify a highly active derivative ((4-(3-chlorophenyl)piperazin-1-yl)(2-ethoxyphenyl)methanone), referred to as AK301, the activity of which is governed by the positioning of functional groups on the phenyl and benzoyl rings. AK301 induced mitotic arrest in HT29 human colon cancer cells with an ED50 of ≈115 nm. Although AK301 inhibited growth of normal lung fibroblast cells, mitotic arrest was more pronounced in the colon cancer cells (50% versus 10%). Cells arrested by AK301 showed the formation of multiple microtubule organizing centers with Aurora kinase A and γ-tubulin. Employing in vitro and in vivo assays, tubulin polymerization was found to be slowed (but not abolished) by AK301. In silico molecular docking suggests that AK301 binds to the colchicine-binding domain on β-tubulin, but in a novel orientation. Cells arrested by AK301 expressed elevated levels of TNFR1 on their surface and more readily activated caspases-8, -9, and -3 in the presence of TNF. Relative to other microtubule destabilizers, AK301 was the most active TNF-sensitizing agent and also stimulated Fas- and TRAIL-induced apoptosis. In summary, we report a new class of mitosis-targeting agents that effectively sensitizes cancer cells to apoptotic ligands. These compounds should help illuminate the role of microtubules in regulating apoptotic ligand sensitivity and may ultimately be useful for developing agents that augment the anti-cancer activities of the immune response. PMID:24338023

  14. Temperature- and pH-responsive nanoparticles of biocompatible polyurethanes for doxorubicin delivery.

    PubMed

    Wang, Anning; Gao, Hui; Sun, Yanfang; Sun, Yu-long; Yang, Ying-Wei; Wu, Guolin; Wang, Yinong; Fan, Yunge; Ma, Jianbiao

    2013-01-30

    A series of temperature- and pH-responsive polyurethanes based on hexamethylene diisocyanate (HDI) and 4,4'-diphenylmethane diisocyanate (MDI) were synthesized by a coupling reaction with bis-1,4-(hydroxyethyl) piperazine (HEP), N-methyldiethanolamine (MDEA) and N-butyldiethanolamine (BDEA), respectively. The chemical structure, molecular weight, thermal property and crystallization properties were characterized by Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) spectroscopy. The resulting polyurethanes were then used to prepare nanoparticles either by direct dispersion method or dialysis method. Their pH and temperature responsibilities were evaluated by optical transmittance and size measurement in aqueous media. Interestingly, HDI-based and MDI-based polyurethanes exhibited different pH and temperature responsive properties. Nanoparticles based on HDI-HEP and HDI-MDEA were temperature-responsive, while MDI-based biomaterials were not. All of them showed pH-sensitive behavior. The possible responsive mechanism was investigated by (1)H NMR spectroscopy. The cytotoxicity of the polyurethanes was evaluated using methylthiazoletetrazolium (MTT) assay in vitro. It was shown that the HDI-based polyurethanes were non-toxic, and could be applied to doxorubicin (DOX) encapsulation. The experimental results indicated that DOX could be efficiently encapsulated into polyurethane nanoparticles and uptaken by Huh-7 cells. The loaded DOX molecules could be released from the drug-loaded polyurethane nanoparticles upon pH and temperature changes, responsively. PMID:23262421

  15. Heat of Dissolution Measurements for CO2 in Mixed Alkanolamine Solvents

    SciTech Connect

    Vinayak N. Kabadi

    2006-09-30

    The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}-alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for the choice of mixed solvents for efficient CO{sub 2} capture with potential for commercialization.

  16. HEAT OF DISSOLUTION MEASUREMENTS FOR CO2 IN MIXED ALKANOLAMINE SOLVENTS

    SciTech Connect

    Vinayak N. Kabadi

    2005-05-23

    The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}-alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for the choice of mixed solvents for efficient CO{sub 2} capture with potential for commercialization.

  17. Heat of Dissolution Measurements for CO2 in Mixed Alkanolamine Solvents

    SciTech Connect

    Vinayak N. Kabadi

    2006-05-29

    The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}-alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for the choice of mixed solvents for efficient CO{sub 2} capture with potential for commercialization.

  18. Heat of Dissolution Measurements for CO2 in Mixed Alkanolamine Solvents

    SciTech Connect

    Vinayak N. Kabadi

    2005-12-01

    The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}- alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for the choice of mixed solvents for efficient CO{sub 2} capture with potential for commercialization.

  19. HEAT OF DISSOLUTION MEASUREMENTS FOR CO2 IN MIXED ALKANOLAMINE SOLVENTS

    SciTech Connect

    Vinayak N. Kabadi

    2004-11-15

    The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}-alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80 C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for the choice of mixed solvents for efficient CO{sub 2} capture with potential for commercialization.

  20. Heat of Dissolution Measurements for CO2 in Mixed Alkanolamine Solvents

    SciTech Connect

    Vinayak N. Kabadi

    2007-03-31

    The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}- alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for the choice of mixed solvents for efficient CO{sub 2} capture with potential for commercialization.

  1. Carbon capture and sequestration: an exploratory inhalation toxicity assessment of amine-trapping solvents and their degradation products.

    PubMed

    McDonald, Jacob D; Kracko, Dean; Doyle-Eisele, Melanie; Garner, C Edwin; Wegerski, Chris; Senft, Al; Knipping, Eladio; Shaw, Stephanie; Rohr, Annette

    2014-09-16

    Carbon dioxide (CO2) absorption with aqueous amine solvents is a method of carbon capture and sequestration (CCS) from flue gases. One concern is the possible release of amine solvents and degradation products into the atmosphere, warranting evaluation of potential pulmonary effects from inhalation. The CCS amines monoethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP) underwent oxidative and CO2-mediated degradation for 75 days. C57bl/6N mice were exposed for 7 days by inhalation of 25 ppm neat amine or equivalant concentration in the degraded mixture. The aqueous solutions were nebulized to create the inhalation atmospheres. Pulmonary response was measured by changes in inflammatory cells in bronchoalveolar lavage fluid and cytokine expression in lung tissue. Ames mutagenicity and CHO-K1 micronucleus assays were applied to assess genotoxicity. Chemical analysis of the test atmosphere and liquid revealed complex mixtures, including acids, aldehydes, and other compounds. Exposure to oxidatively degraded MEA increased (p < 0.05) total cells, neutrophils, and lymphocytes compared to control mice and caused inflammatory cytokine expression (statistical increase at p < 0.05). MEA and CO2-degraded MEA were the only atmospheres to show statistical (p < 0.05) increase in oxidative stress. CO2 degradation resulted in a different composition, less degradation, and lower observed toxicity (less magnitude and number of effects) with no genotoxicity. Overall, oxidative degradation of the amines studied resulted in enhanced toxicity (increased magnitude and number of effects) compared to the neat chemicals. PMID:25167095

  2. HEAT OF DISSOLUTION MEASUREMENTS FOR CO2 IN MIXED ALKANOLAMINE SOLVENTS

    SciTech Connect

    Vinayak N. Kabadi

    2004-04-27

    The main objective of this project is to measure heat of dissolution of CO{sub 2} in carefully selected mixed alkanolamine solvent systems, and provide such directly measured data that might be used for efficient design of CO{sub 2} capture processes, or for better understanding of thermodynamics of CO{sub 2}-alkanolamine systems. Carbon dioxide is one of the major greenhouse gases, and the need for stabilization of its composition in earth's atmosphere is vital for the future of mankind. Although technologies are available for capture and storage of CO{sub 2}, these technologies are far too expensive for economical commercialization. Reduction of cost would require research for refinement of the technology. For more economical CO{sub 2} capture and regeneration, there is a need for development of more efficient solvent systems. In this project we will extend the thermodynamic database by measuring heat of solution data of CO{sub 2} in mixed solvents made of MEA (monoethanolamine), MDEA (methyldiethanolamine), piperazine, and water. Mixed solvents of different compositions will be selected and in each case data will be measured at temperatures 40 and 80 C and various partial pressures of CO{sub 2}. At the end of the project, observations, conclusions, and recommendations will be derived for the choice of mixed solvents for efficient CO{sub 2} capture with potential for commercialization.

  3. 3,3′-(Piperazine-1,4-diium-1,4-di­yl)di­propionate dihydrate

    PubMed Central

    Jin, Shouwen; Huang, Yanfei; Fang, Hao; Wang, Tianyi; Ding, Liangliang

    2012-01-01

    During the recrystallization of 3-[4-(2-carb­oxy­eth­yl)piperazin-1-yl]propionic acid, the carb­oxy­lic acid H atoms were transferred to the piperazine N atoms, forming the title compound, C10H18N2O4·2H2O, in which the zwitterion lies about an inversion center. In the crystal, bifurcated N—H⋯(O,O) hydrogen bonds connect the zwitterions into a two-dimensional framework parallel to (-102) forming R 4 4(30) rings. O—H⋯O hydrogen bonds involving the solvent water mol­ecules connect the two-dimensional framework into a three-dimensional network. In addition, weak C—H⋯O hydrogen bonds are observed. PMID:23125633

  4. 2-[2-(4-Methyl­piperazin-1-yl)eth­yl]iso­indoline-1,3-dione

    PubMed Central

    Zhou, Mi; Shao, Ying; Xia, Yong-an; Liu, Xiao-Long; Sun, Xiao-Qiang

    2014-01-01

    In the title compound, C15H19N3O2, the piperazine ring adopts a chair conformation, with its N—C bonds in pseudo-equatorial orientations. The dihedral angle between the C atoms of the piperazine ring and the phthalamide ring system (r.m.s. deviaiton = 0.008 Å) is 89.30 (8)°. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds, generating a three-dimensional network and aromatic π–π inter­actions also occur [centroid–centroid distances = 3.556 (1)–3.716 (1) Å]. PMID:24764996

  5. Structural analysis of complexes formed by ethyl 4-phenylthiocarbamoyl piperazine-1-carboxylate with Ni(II), Zn(II) and Cd(II) through spectroscopic and DFT techniques

    NASA Astrophysics Data System (ADS)

    Prakash, Om; Gautam, Priyanka; Dani, R. K.; Nandi, Abhisikta; Singh, N. K.; Singh, Ranjan K.

    2014-04-01

    A piperazine derivative, ethyl 4-phenylthiocarbamoyl piperazine-1-carboxylate and its Ni(II), Zn(II) and Cd(II) complexes have been synthesized and characterized by elemental analyses, magnetic susceptibility measurement, UV-Visible, FTIR, Raman spectroscopic and DFT methods. The Ni(II) and Zn(II) bind through the N and S sites of the two ligand Heptpc and N site of two pyridine molecules. However, the Cd(II) binds through the only N sites of the two ligand Heptpc and N site of two pyridine molecules. On the basis of various techniques used for the characterizations of the complexes, we found that the most possible geometry of the Ni(II) and Zn(II) complexes are distorted octahedral and of the Cd(II) complex is distorted tetrahedral.

  6. (Z)-1-Di­phenyl­methyl-4-(3-phenyl­prop-2-en­yl)piperazine

    PubMed Central

    Shivaprakash, S.; Chandrasekara Reddy, G.; Jasinski, Jerry P.

    2014-01-01

    In the title compound, C26H28N2, the piperazine group adopts a chair conformation with the exocyclic N—C bonds in equatorial orientations. The dihedral angle between the geminal benzene rings is 80.46 (12)° and the C=C—C—N torsion angle is 145.9 (2)°. In the crystal, weak C—H⋯π inter­actions link the mol­ecules into [100] chains. PMID:24860379

  7. Synthesis and bioactivities of novel piperazine-containing 1,5-Diphenyl-2-penten-1-one analogues from natural product lead.

    PubMed

    Xu, Gaofei; Yang, Xinling; Jiang, Biaobiao; Lei, Peng; Liu, Xili; Wang, Qingmin; Zhang, Xuebo; Ling, Yun

    2016-04-01

    A series of novel 1,5-Diphenyl-2-penten-1-one analogues (7a-h, 8a-h) with piperazine moiety have been designed and synthesized on the basis of natural product 1,5-Diphenyl-2-penten-1-one (I). All the synthesized compounds were evaluated in vitro for anti-plant pathogenic fungi activities and insecticidal activities. The results indicated that most of these analogues exhibited moderate antifungal activities and moderate to good insecticidal activities. Amongst them, the most potent 7c, 7e and 7h keep a mortality of 100% against larva of mosquito at the concentration of 1mg/L. Initial structure-activity relationship (SAR) analysis showed that, a methyl group can influence the biological activities of these compounds significantly, the compounds with N'-unsubstituted piperazine showed much better antifungal activities and larvicidal activity against mosquito than the compounds with N'-methylated piperazine. In addition, the larvicidal activity against mosquito had sharply decline when the substituent on benzene ring was changed from 4-position to 2 or 3-position. PMID:26906636

  8. Development of a high-performance liquid chromatography with fluorescence detection method for quantification of piperazine in animal products by using precolumn derivatization.

    PubMed

    Park, Jin-A; Zhang, Dan; Kim, Dong-Soon; Kim, Seong-Kwan; Cho, Sang-Hyun; Jeong, Daun; Kim, Jin-Suk; Shim, Jae-Han; Abd El-Aty, A M; Shin, Ho-Chul

    2016-04-01

    A new high-performance liquid chromatography with ​fluorescence detection (HPLC-FLD) method was developed for determination of piperazine residues in food animal products. Samples were extracted with formic acid in water and purified using the PCX cartridge. Following purification, the samples were derivatized using dansyl chloride, and the analyte was separated using water/acetonitrile as a mobile phase. The calibration curves showed good linearity over a concentration range of 20-120 ng/g with coefficient of determination (R(2))⩾0.996. The intra-day accuracy (presented as recovery %) and precision (presented as relative standard deviation, RSD %) were 81-97.3% and 0.83-6.87%, whereas, the inter-day values were 80.5-96.8% and 1.7-6.8%, respectively. The limit of quantification (LOQ) was 20 ng/g, which was considerably lower than the maximum residue limit (MRL). The developed method was used to monitor market samples, and piperazine was not detected in any of the samples. To our knowledge, this is the first study in which the detection of piperazine in various food and animal products by using a sensitive and reliable analytical method has been described. PMID:26593624

  9. Click-based synthesis and antitubercular evaluation of novel dibenzo[b,d]thiophene-1,2,3-triazoles with piperidine, piperazine, morpholine and thiomorpholine appendages.

    PubMed

    Pulipati, Lokesh; Yogeeswari, Perumal; Sriram, Dharmarajan; Kantevari, Srinivas

    2016-06-01

    A series of novel piperidine, piperazine, morpholine and thiomorpholine appended dibenzo[b,d]thiophene-1,2,3-triazoles were designed and synthesized utilizing azide-alkyne click chemistry in the penultimate step. The required azide building block 6a-e was synthesized from commercial dibenzo[b,d]thiophene in good yields following five step reaction sequence. All the new analogues 8a-f, 9a-f, 10a-f, 11a-f &12a-f were characterized by their NMR and mass spectral analysis. Screening all thirty new compounds for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv, resulted 8a, 8f and 11e as potent analogues with MIC 0.78μg/mL, 0.78μg/mL & 1.56μg/mL, respectively, and has shown lower cytotoxicity. Interestingly, all six piperazine appended dibenzo[b,d]thiophene-1,2,3-triazoles 11a-f exhibited Mtb inhibition activity with MIC 1.56-12.5μg/mL. To some extent, the data observed here indicated Mycobacterium tuberculosis inhibition among the appendages is in the order, piperazine>thiomorpholine>morpholine. PMID:27101894

  10. Acid gas treating by aqueous alkanolamines. Annual report, January-December 1994

    SciTech Connect

    Sandall, O.C.; Rinker, E.B.; Ashour, S.

    1994-12-01

    The objective of this work is to investigate the simulateneous absorption or desorption of CO2 and H2S into and from a mixed aqueous amine solvent consisting of methyldiethanolamine (MDEA) and diethanolamine (DEA). In work completed this year the authors have measured the density, viscosity and surface tension of pure MDEA and DEA over a range in temperatures. The diffusivity of N2O was measured in aqueous blends of MDEA and DEA at 50 wt% total amine for various ratios of DEA to MDEA over the temperature range 20 to 80 deg. C. A theoretically-based model has been developed for the correlation of the physical solubility of N2O in aqueous amine solutions. A penetration theory type model which was developed to describe acid gas absorption in aqueous amine solutions was used to carry out a sensitivity analysis for the various parameters affecting the rate of absorption of CO2 in MDEA solutions.

  11. HS process: an advanced process for selective H/sub 2/S

    SciTech Connect

    Sigmund, P.W.; Butwell, K.F.; Wussler, A.J.

    1981-01-01

    Union Carbide's HS process offers improved efficiency in both H/sub 2/S removal and system costs while remaining flexible to diverse gas-conditioning requirements. The process combines three principal elements - an MDEA (methyldiethanolamine) solvent, a multistaged contactor design, and a special selective contactor tray. Prototype pilot-plant operations have demonstrated the superior performance of the HS process over existing methods.

  12. A potent new class of kappa-receptor agonist: 4-substituted 1-(arylacetyl)-2-[(dialkylamino)methyl]piperazines.

    PubMed

    Naylor, A; Judd, D B; Lloyd, J E; Scopes, D I; Hayes, A G; Birch, P J

    1993-07-23

    The synthesis of 4-substituted 1-(arylacetyl)-2-[(alkylamino)methyl]piperazines (10-22, 26, 27, and 30-33) and their activities as kappa-opioid receptor agonists are described. This includes a range of 4-acyl and 4-carboalkoxy derivatives with the latter series showing the greatest kappa-agonist activity. In particular, methyl 4-[(3,4-dichlorophenyl)acetyl]-3-[(1-pyrrolidinyl) methyl]-1-piperazinecarboxylate (18) displays exceptional potency and selectivity. It showed the following activities in functional in vitro assays: rabbit vas deferens (kappa-specific tissue) IC50 = 0.041 nM, rat vas deferens (mu-specific tissue) IC50 > 10,000 nM, and hamster vas deferens (delta-specific tissue) IC50 > 10,000 nM. Compound 18 is also a highly potent antinociceptive agent, as determined in the mouse acetylcholine-induced abdominal constriction test: ED50 = 0.000 52 mg/kg, sc. The activity of 18 resides solely in its 3(R)-enantiomer. The kappa-agonist activity in both the 4-acyl and the 4-carbamate series is sensitive to the size of the 4-substituent. In addition, it would appear that an appreciable negative electrostatic potential in this region of the molecule is an important requirement for optimal potency. PMID:8393489

  13. Formation of Diastereoisomeric Piperazine-2,5-dione from uc(dl)-Alanine in the Presence of Olivine and Water

    NASA Astrophysics Data System (ADS)

    Fuchida, Shigeshi; Naraoka, Hiroshi; Masuda, Harue

    2016-04-01

    uc(dl)-Alanine (Ala) was heated with/without powdered olivine and water at 120 °C for 8 days to investigate the formation of the diastereoisomers of piperazine-2,5-dione (diketopiperazine, DKP). When only uc(dl)-Ala was heated with a small amount of water, 3.0 % of uc(dl)-Ala changed to cis- and trans-DKP after 8 days. DKPs were not detected after heating when no water was added. The presence of a small amount of water is important factor controlling peptide production rates under thermal conditions. When DL-Ala was heated with olivine powder for 8 days, the yields of cis- and trans-DKP were 6.8 and 4.9 %, respectively. The high yield of cis-DKP compared with trans-DKP was attributed to greater thermal stability of cis-DKP. After heating for 8 days, the diastereoisomeric excess of cis-DKP without olivine was 7.3 %, whereas a much higher value of 16.3 % was obtained in the presence of olivine. Taken together, these results show that olivine is not only an efficient catalyst for the formation of DKPs but that it also play a significant role in determining the diastereoisomer selectivity of these cyclic dipeptides.

  14. Pharmacological and pharmacokinetic characterization of 2-piperazine-alpha-isopropyl benzylamine derivatives as melanocortin-4 receptor antagonists.

    PubMed

    Chen, Chen; Tucci, Fabio C; Jiang, Wanlong; Tran, Joe A; Fleck, Beth A; Hoare, Sam R; Wen, Jenny; Chen, Takung; Johns, Michael; Markison, Stacy; Foster, Alan C; Marinkovic, Dragan; Chen, Caroline W; Arellano, Melissa; Harman, John; Saunders, John; Bozigian, Haig; Marks, Daniel

    2008-05-15

    A series of 2-piperazine-alpha-isopropylbenzylamine derivatives were synthesized and characterized as melanocortin-4 receptor (MC4R) antagonists. Attaching an amino acid to benzylamines 7 significantly increased their binding affinity, and the resulting compounds 8-12 bound selectively to MC4R over other melanocortin receptor subtypes and behaved as functional antagonists. These compounds were also studied for their permeability using Caco-2 cell monolayers and metabolic stability in human liver microsomes. Most compounds exhibited low permeability and high efflux ratio possibly due to their high molecular weights. They also showed moderate metabolic stability which might be associated with their moderate to high lipophilicity. Pharmacokinetic properties of these MC4R antagonists, including brain penetration, were studied in mice after oral and intravenous administrations. Two compounds identified to possess high binding affinity and selectivity, 10d and 11d, were studied in a murine cachexia model. After intraperitoneal (ip) administration of 1mg/kg dose, mice treated with 10d had significantly more food intake and weight gain than the control animals, demonstrating efficacy by blocking the MC4 receptor. Similar in vivo effects were also observed when 11d was dosed orally at 20mg/kg. These results provide further evidence that a potent and selective MC4R antagonist has potential in the treatment of cancer cachexia. PMID:18417348

  15. Thermodynamic Investigation and Mixed Ligand Complex Formation of 1,4-Bis-(3-aminopropyl)-piperazine and Biorelevant Ligands

    PubMed Central

    El-Sherif, Ahmed A.; Shehata, Mohamed R.; Shoukry, Mohamed M.; Barakat, Mohammad H.

    2012-01-01

    Thermodynamic parameters for protonation of 1,4-bis(3-aminopropyl)-piperazine (BAPP) and its metal complexation with some divalent metal ions were determined in aqueous solution at constant ionic strength (0.1 M NaNO3) using a potentiometric technique. The order of –ΔG0 and –ΔH0 was found to obey Co2+ < Ni2+ < Cu2+ > Zn2+, in accordance with the Irving-Williams order. The formation equilibria of zinc (II) complexes and the ternary complexes Zn(BAPP)L, where L = amino acid, amides, or DNA constituents), have been investigated. Ternary complexes are formed by a simultaneous mechanism. The concentration distribution of the complexes in solution was evaluated as a function of pH. Stoichiometry and stability constants for the complexes formed are reported and discussed. The stability of ternary complexes was quantitatively compared with their corresponding binary complexes in terms of the parameter Δlog K. PMID:23226992

  16. The antidepressant- and anxiolytic-like activities of new xanthone derivative with piperazine moiety in behavioral tests in mice

    PubMed Central

    Pytka, Karolina; Żmudzka, Elżbieta; Lustyk, Klaudia; Rapacz, Anna; Olczyk, Adrian; Gałuszka, Adam; Waszkielewicz, Anna; Marona, Henryk; Sapa, Jacek; Barbara, Filipek

    2016-01-01

    Objectives: Xanthones are flavonoids with numerous activities, including antioxidant, antidepressant., or anxiolytic-like. Therefore, the aim of our study was to determine antidepressant- and anxiolytic-like properties of four xanthone derivatives (3-chloro-5-[(4-methylpiperazin-1-yl)methyl]-9H-xanthen-9-one dihydrochloride [HBK-5], 6-methoxy-2-[(4-methylpiperazin-1-yl) methyl]-9H-xanthen-9-one dihydrochloride, 2-[(4-benzylpiperazin-1-yl) methyl]-6-methoxy-9H-xanthen-9-one dihydrochloride, 2-{[4-(2-methoxyphenyl) piperazin-1-yl] methyl}-9H-xanthen-9-one hydrochloride), as well as the influence on cognitive and motor function of active compounds, using animal models. Materials and Methods: To determine the antidepressant-like activity, we used forced swim test (FST) and tail suspension test (TST) in mice. We evaluated anxiolytic-like properties in the four-plate test in mice. We studied the influence on cognitive and motor function in passive avoidance step-through and chimney tests, respectively. Results: The antidepressant-like activity (in both FST and TST) showed only HBK-5. Moreover, the compound was also active in the four-plate test, which suggests that it possessed anxiolytic-like properties. HBK-5 did not cause any cognitive and motor deficits in mice at antidepressant- and anxiolytic-like doses. Conclusions: HBK-5 may have potential in the treatment of depression or anxiety disorders, but this issue needs further studies. PMID:27298499

  17. Synthesis and Structure-Activity Relationship Analysis of 5-HT₇ Receptor Antagonists: Piperazin-1-yl Substituted Unfused Heterobiaryls.

    PubMed

    Strekowski, Lucjan; Sączewski, Jarosław; Raux, Elizabeth A; Fernando, Nilmi T; Klenc, Jeff; Paranjpe, Shirish; Raszkiewicz, Aldona; Blake, Ava L; Ehalt, Adam J; Barnes, Samuel; Baranowski, Timothy C; Sullivan, Shannon M; Satała, Grzegorz; Bojarski, Andrzej J

    2016-01-01

    A series of piperazin-1-yl substituted unfused heterobiaryls was synthesized as ligands of the 5-HT₇ receptors. The goal of this project was to elucidate the structural features that affect the 5-HT₇ binding affinity of this class of compounds represented by the model ligand 4-(3-furyl)-2-(4-methylpiperazin-1-yl)pyrimidine (2). The SAR studies included systematical structural changes of the pyrimidine core moiety in 2 to quinazoline, pyridine and benzene, changes of the 3-furyl group to other heteroaryl substituents, the presence of various analogs of the 4-methylpiperazin-1-yl group, as well as additional substitutions at positions 5 and 6 of the pyrimidine. Substitution of position 6 of the pyrimidine in the model ligand with an alkyl group results in a substantial increase of the binding affinity (note a change in position numbers due to the nomenclature rules). It was also demonstrated that 4-(3-furyl) moiety is crucial for the 5-HT₇ binding affinity of the substituted pyrimidines, although, the pyrimidine core can be replaced with a pyridine ring without a dramatic loss of the binding affinity. The selected ethylpyrimidine (12) and butylpyrimidine (13) analogs of high 5-HT₇ binding affinity showed antagonistic properties in cAMP functional test and varied selectivity profile-compound 12 can be regarded as a dual 5-HT₇/5-HT2AR ligand, and 13 as a multi-receptor (5-HT₇, 5-HT2A, 5-HT₆ and D₂) agent. PMID:27043518

  18. Dithiocarbamate/piperazine bridged pyrrolobenzodiazepines as DNA-minor groove binders: synthesis, DNA-binding affinity and cytotoxic activity.

    PubMed

    Kamal, Ahmed; Sreekanth, Kokkonda; Shankaraiah, Nagula; Sathish, Manda; Nekkanti, Shalini; Srinivasulu, Vunnam

    2015-04-01

    A new series of C8-linked dithiocarbamate/piperazine bridged pyrrolo[2,1-c][1,4]benzodiazepine conjugates (5a-c, 6a,b) have been synthesized and evaluated for their cytotoxic potential and DNA-binding ability. The representative conjugates 5a and 5b have been screened for their cytotoxicity against a panel of 60 human cancer cell lines. Compound 5a has shown promising cytotoxic activity on selected cancer cell lines that display melanoma, leukemia, CNS, ovarian, breast and renal cancer phenotypes. The consequence of further replacement of the 3-cyano-3,3-diphenylpropyl 1-piperazinecarbodithioate in 5b and 5c with 4-methylpiperazine-1-carbodithioate yielded new conjugates 6a and 6b respectively. In addition, the compounds 5c and 6a,b have been evaluated for their in vitro cytotoxicity on some of the selected human cancer cell lines and these conjugates have exhibited significant cytotoxic activity. Further, the DNA-binding ability of these new conjugates has been evaluated by using thermal denaturation (ΔTm) studies. The correlation between structure and DNA-binding ability has been investigated by molecular modeling studies which predicted that 6b exhibits superior DNA-binding ability and these are in agreement with the experimental DNA-binding studies. PMID:25665519

  19. Complexation, thermal and catalytic studies of N-substituted piperazine, morpholine and thiomorpholine with some metal ions

    NASA Astrophysics Data System (ADS)

    Kacan, Mesut; Turkyilmaz, Murat; Karabulut, Ferhat; Altun, Ozlen; Baran, Yakup

    2014-01-01

    Several Cu(II), Pt(II) and Ni(II) complexes of N-substituted, piperazine (NN donor), morpholine (NO donor) and thiomorpholine (NS donor) derivatives were synthesized and their thermal behavior and catalytic activity in epoxidation reaction of cis-diphenylethylene were studied using oxygen sources NaOCl. The coordination compounds of Cu(II), Pt(II) and Ni(II) having general formula [MLCl]Cl, [ML2l]Cl2 or [ML]Cl2 with tetra coordinated geometry around metal ions have been isolated as solid. All the ligands and complexes were identified by spectroscopic methods and elemental analysis, magnetic measurements, electrical conductance and thermal analysis. A square planer structures have been proposed for all complexes. The thermal stability of the complexes discussed in terms of ligands donor atoms, geometry and central metal ions. The complexes have a similar thermal behavior for the selected metal ions. The thermogravimetric analyses suggest high thermal stability for most complexes followed by thermal decomposition in different steps. The decomposition processes were observed as water elimination, chloride anion removal and degradation of the organic ligands. Catalytic ability of the complexes were examined and found that all the complexes can effectively catalyze the epoxidation of cis-stilbene with NaOCl.

  20. 2-Benzazolyl-4-Piperazin-1-Ylsulfonylbenzenecarbohydroxamic Acids as Novel Selective Histone Deacetylase-6 Inhibitors with Antiproliferative Activity

    PubMed Central

    Wang, Lei; Kofler, Marina; Brosch, Gerald; Melesina, Jelena; Sippl, Wolfgang; Martinez, Elisabeth D.; Easmon, Johnny

    2015-01-01

    We have screened our compound collection in an established cell based assay that measures the derepression of an epigenetically silenced transgene, the locus derepression assay. The screen led to the identification of 4-[4-(1-methylbenzimidazol-2-yl)piperazin-1-yl]sulfonylbenzenecarbohydroxamic acid (9b) as an active which was found to inhibit HDAC1. In initial structure activity relationships study, the 1-methylbenzimidazole ring was replaced by the isosteric heterocycles benzimidazole, benzoxazole, and benzothiazole and the position of the hydroxamic acid substituent on the phenyl ring was varied. Whereas compounds bearing a para substituted hydroxamic acid (9a-d) were active HDAC inhibitors, the meta substituted analogues (8a-d) were appreciably inactive. Compounds 9a-d selectively inhibited HDAC6 (IC50 = 0.1–1.0μM) over HDAC1 (IC50 = 0.9–6μM) and moreover, also selectively inhibited the growth of lung cancer cells vs. patient matched normal cells. The compounds induce a cell cycle arrest in the S-phase while induction of apoptosis is neglible as compared to controls. Molecular modeling studies uncovered that the MM-GBSA energy for interaction of 9a-d with HDAC6 was higher than for HDAC1 providing structural rationale for the HDAC6 selectivity. PMID:26698121

  1. Selective gas treating produces better claus feeds

    SciTech Connect

    Goar, B.G.

    1980-01-01

    Methyldiethanolamine (MDEA) systems with 20-25% by wt MDEA solutions in water are cheaper and more convenient than monoethanolamine (MEA) or diethanolamine (DEA) systems for selective H/sub 2/S removal from gas streams containing H/sub 2/S and CO/sub 2/, because the amine circulation rate will be much less for the MDEA system; apparently, the reaction between MDEA and H/sub 2/S is gas-film-diffusion-rate limited, and the reaction between MDEA and CO/sub 2/ is kinetically controlled. MDEA systems facilitate selective H/sub 2/S absorption by controlling residence time, which is done by limiting the number of contact trays and the amine circulation rate. At high pressures, MDEA systems can remove H/sub 2/S down to 0.25-0.50 g/100 std cu ft, with only 20-30% of the CO/sub 2/ being co-absorbed. The MDEA system at the Husky (Oil Co.) Clark Avenue Gas Plant in Santa Maria, Calif., uses selective amine regeneration technology licensed from Shell Development Co. to enrich Claus unit feed from approx. 23 mole Vertical Bar3< H/sub 2/S up to approx. 50 mole % H/sub 2/S, thus allowing 94% sulfur recovery in a once-through system. Two other MDEA systems for high-pressure gas treating are discussed.

  2. N-Aryl Piperazine Metabotropic Glutamate Receptor 5 Positive Allosteric Modulators Possess Efficacy in Preclinical Models of NMDA Hypofunction and Cognitive Enhancement

    PubMed Central

    Gregory, K.J.; Herman, E.J.; Ramsey, A.J.; Hammond, A.S.; Byun, N.E.; Stauffer, S.R.; Manka, J.T.; Jadhav, S.; Bridges, T.M.; Weaver, C.D.; Niswender, C.M.; Steckler, T.; Drinkenburg, W.H.; Ahnaou, A.; Lavreysen, H.; Macdonald, G.J.; Bartolomé, J.M.; Mackie, C.; Hrupka, B.J.; Caron, M.G.; Daigle, T.L.; Lindsley, C.W.; Conn, P.J.

    2013-01-01

    Impaired transmission through glutamatergic circuits has been postulated to play a role in the underlying pathophysiology of schizophrenia. Furthermore, inhibition of the N-methyl-d-aspartate (NMDA) subtype of ionotropic glutamate receptors (NMDAR) induces a syndrome that recapitulates many of the symptoms observed in patients with schizophrenia. Selective activation of metabotropic glutamate receptor subtype 5 (mGlu5) may provide a novel therapeutic approach for treatment of symptoms associated with schizophrenia through facilitation of transmission through central glutamatergic circuits. Here, we describe the characterization of two novel N-aryl piperazine mGlu5 positive allosteric modulators (PAMs): 2-(4-(2-(benzyloxy)acetyl)piperazin-1-yl)benzonitrile (VU0364289) and 1-(4-(2,4-difluorophenyl)piperazin-1-yl)-2-((4-fluorobenzyl)oxy)ethanone (DPFE). VU0364289 and DPFE induced robust leftward shifts in the glutamate concentration-response curves for Ca2+ mobilization and extracellular signal-regulated kinases 1 and 2 phosphorylation. Both PAMs displayed micromolar affinity for the common mGlu5 allosteric binding site and high selectivity for mGlu5. VU0364289 and DPFE possessed suitable pharmacokinetic properties for dosing in vivo and produced robust dose-related effects in reversing amphetamine-induced hyperlocomotion, a preclinical model predictive of antipsychotic-like activity. In addition, DPFE enhanced acquisition of contextual fear conditioning in rats and reversed behavioral deficits in a mouse model of NMDAR hypofunction. In contrast, DPFE had no effect on reversing apomorphine-induced disruptions of prepulse inhibition of the acoustic startle reflex. These mGlu5 PAMs also increased monoamine levels in the prefrontal cortex, enhanced performance in a hippocampal-mediated memory task, and elicited changes in electroencephalogram dynamics commensurate with procognitive effects. Collectively, these data support and extend the role for the development of novel

  3. The 5-substituted piperazine as a novel secondary pharmacophore greatly improving the physical properties of urea-based inhibitors of soluble epoxide hydrolase.

    PubMed

    Li, Hui-Yuan; Jin, Yi; Morisseau, Christophe; Hammock, Bruce D; Long, Ya-Qiu

    2006-10-01

    The inhibition of the mammalian soluble epoxide hydrolase (sEH) is a promising new therapy in the treatment of hypertention and inflammation. The problems of limited water solubility and high melting points commonly displayed by the active 1,3-disubstituted ureas prevent the further development of potent urea-based sEH inhibitors. Therefore, a new class of potent inhibitors of sEH were designed and synthesized by the introduction of a polar constrained piperazino group in the right side of adasmantyl urea to increase the water solubility. A facile and general synthesis was established to prepare a series of 1-adamantan-1-yl-3-(2-piperazin-2-yl-ethyl)-ureas (1a-d) with various 5-substitutions on the 2-piperazino ring, which will advance the SAR study by the efficient making of structurally diverse analogs. The effect of the 5-substitution on the activity and the water solubility was examined. The best potency was exhibited by the 5-benzyl-substituted-piperazine-containing urea with an IC50 value of 1.37 microM against human sEH and good water solubility (S=7.46 mg/mL) and low melting point, in which the 5-substituted piperazine serves as a favorable secondary pharmacophore and a water-solubility enhancing group. Our present work provides a promising new template for the design of orally available therapeutic agents for the disorders that can be addressed by changing the in vivo concentration of the chemical mediators that contain an epoxide. PMID:16784862

  4. Strong effect of copper(II) coordination on antiproliferative activity of thiosemicarbazone-piperazine and thiosemicarbazone-morpholine hybrids.

    PubMed

    Bacher, Felix; Dömötör, Orsolya; Chugunova, Anastasia; Nagy, Nóra V; Filipović, Lana; Radulović, Siniša; Enyedy, Éva A; Arion, Vladimir B

    2015-05-21

    In this study, 2-formylpyridine thiosemicarbazones and three different heterocyclic pharmacophores were combined to prepare thiosemicarbazone–piperazine mPip-FTSC (HL1) and mPip-dm-FTSC (HL2), thiosemicarbazone–morpholine Morph-FTSC (HL3) and Morph-dm-FTSC (HL4), thiosemicarbazone–methylpyrrole-2-carboxylate hybrids mPyrr-FTSC (HL5) and mPyrr-dm-FTSC (HL6) as well as their copper(II) complexes [CuCl(mPipH-FTSC-H)]Cl (1 + H)Cl, [CuCl(mPipH-dm-FTSC-H)]Cl (2 + H)Cl, [CuCl(Morph-FTSC-H)] (3), [CuCl(Morph-dm-FTSC-H)] (4), [CuCl(mPyrr-FTSC-H)(H2O)] (5) and [CuCl(mPyrr-dm-FTSC-H)(H2O)] (6). The substances were characterized by elemental analysis, one- and two-dimensional NMR spectroscopy (HL1–HL6), ESI mass spectrometry, IR and UV–vis spectroscopy and single crystal X-ray diffraction (1–5). All compounds were prepared in an effort to generate potential antitumor agents with an improved therapeutic index. In addition, the effect of structural alterations with organic hybrids on aqueous solubility and copper(II) coordination ability was investigated. Complexation of ligands HL2 and HL4 with copper(II) was studied in aqueous solution by pH-potentiometry, UV–vis spectrophotometry and EPR spectroscopy. Proton dissociation processes of HL2 and HL4 were also characterized in detail and microscopic constants for the Z/E isomers were determined. While the hybrids HL5, HL6 and their copper(II) complexes 5 and 6 proved to be insoluble in aqueous solution, precluding antiproliferative activity studies, the thiosemicarbazone–piperazine and thiosemicarbazone–morpholine hybrids HL1–HL4, as well as copper(II) complexes 1–4 were soluble in water enabling cytotoxicity assays. Interestingly, the metal-free hybrids showed very low or even a lack of cytotoxicity (IC50 values > 300 μM) in two human cancer cell lines HeLa (cervical carcinoma) and A549 (alveolar basal adenocarcinoma), whereas their copper(II) complexes were cytotoxic showing IC50 values from 25.5 to 65.1

  5. Ethyl 4-{[3-(adamantan-1-yl)-4-phenyl-5-sulfanyl­idene-4,5-dihydro-1H-1,2,4-triazol-1-yl]meth­yl}piperazine-1-carboxyl­ate

    PubMed Central

    Al-Abdullah, Ebtehal S.; Asiri, Hanadi H.; El-Emam, Ali A.; Ng, Seik Weng

    2012-01-01

    The title mol­ecule, C26H35N5O2S, displays a chair-shaped piperazine ring, as well as a planar triazole ring whose phenyl substituent is perpendicular to the mean plane of the five-membered ring [dihedral angle = 90.00 (13)°]. The methyl­ene substituent on the piperazine ring occupies an equatorial site. Weak inter­molecular C—H⋯O hydrogen bonding is present in the crystal structure. The crystal studied was a non-merohedral twin, with a 33.9 (3)% minor component. PMID:22347127

  6. 3-(Adamantan-1-yl)-1-[(4-benzyl­piperazin-1-yl)meth­yl]-4-phenyl-1H-1,2,4-triazole-5(4H)-thione

    PubMed Central

    Al-Abdullah, Ebtehal S.; Asiri, Hanadi H.; El-Emam, Ali; Ng, Seik Weng

    2012-01-01

    The title mol­ecule, C30H37N5S, displays a chair-shaped piperazine ring, as well as an approximately planar triazole ring [maximum deviation = 0.002 (2) Å] whose phenyl substituent is nearly perpendicular to the mean plane of the five-membered ring [dihedral angle = 80.4 (1)°]. The substit­uents on the piperazine ring occupy equatorial sites. Weak inter­molecular C—H⋯S hydrogen bonding is present in the crystal structure. PMID:22346973

  7. 3-(Adamantan-1-yl)-4-phenyl-1-[(4-phenyl­piperazin-1-yl)meth­yl]-1H-1,2,4-triazole-5(4H)-thione

    PubMed Central

    Al-Abdullah, Ebtehal S.; Asiri, Hanadi H.; El-Emam, Ali; Ng, Seik Weng

    2012-01-01

    The title mol­ecule, C29H35N5S, displays a chair-shaped piperazine ring, as well as an approximately planar triazole ring (r.m.s. deviation = 0.001 Å) whose phenyl substituent is nearly perpendicular to the mean plane of the five-membered ring [dihedral angle = 88.9 (1)°]. The substituents on the piperazine ring occupy equatorial sites. In the crystal, the adamantyl cage is disordered over two sets of sites with a major component of 67.8 (5)%. Weak inter­molecular C—H⋯S hydrogen bonding is present in the crystal. PMID:22346974

  8. 3-(Adamantan-1-yl)-4-ethyl-1-{[4-(2-meth­oxy­phen­yl)piperazin-1-yl]meth­yl}-1H-1,2,4-triazole-5(4H)-thione

    PubMed Central

    El-Emam, Ali A.; Al-Tuwaijri, Hanaa M.; Al-Abdullah, Ebtehal S.; Chidan Kumar, C. S.; Fun, Hoong-Kun

    2014-01-01

    In the title compound, C26H37N5OS, the piperazine ring adopts a chair conformation. The triazole ring forms dihedral angles of 67.85 (9) and 59.41 (9)° with the piperazine and benzene rings, respectively, resulting in an approximate V-shaped conformation for the mol­ecule. An intra­molecular C—H⋯O hydrogen bond generates an S(6) ring motif. The crystal structure features C—H⋯π inter­actions, producing a two-dimensional supramolecular architecture. PMID:24526973

  9. 3-(Adamantan-1-yl)-1-[(4-benzyl­piperazin-1-yl)meth­yl]-4-ethyl-1H-1,2,4-triazole-5(4H)-thione

    PubMed Central

    Al-Abdullah, Ebtehal S.; Al-Tuwaijri, Hanaa M.; El-Emam, Ali A.; Chidan Kumar, C. S.; Fun, Hoong-Kun

    2013-01-01

    In the title compound, C26H37N5S, the piperazine ring adopts a chair conformation with the exocyclic N—C bonds in pseudo-equatorial orientations. The piperazine ring (all atoms) subtends dihedral angles of 79.47 (9) and 73.07 (9)° with the triazole and benzene rings, respectively, resulting in an approximate U-shape for the mol­ecule. No significant inter­molecular inter­actions are observed in the crystal. PMID:24454243

  10. Design, synthesis and docking studies on phenoxy-3-piperazin-1-yl-propan-2-ol derivatives as protein tyrosine phosphatase 1B inhibitors.

    PubMed

    Gupta, Swati; Pandey, Gyanendra; Rahuja, Neha; Srivastava, Arvind K; Saxena, Anil K

    2010-10-01

    A series of substituted phenoxy-3-piperazin-1-yl-propan-2-ols has been synthesized and evaluated for PTP1B inhibitory activity in vitro and for antidiabetic activity in vivo. Two molecules viz. 4a and 5b showed PTP1B inhibition of 31.58% and 35.90% at 100 μM concentration. The compound 4a also showed 40.3% normalization of plasma glucose levels at 100mg/kg in Sugar-loaded model (SLM) and 32% activity in Streptozodocin model (STZ). The docking studies of these molecules revealed that hydrogen bond formation with Arg221 is important for activity. PMID:20797859

  11. Nippostrongylus brasiliensis infection in the rat: effect of iron and protein deficiency on the anthelmintic efficacy of mebendazole, pyrantel, piperazine, and levamisole.

    PubMed Central

    Duncombe, V M; Bolin, T D; Davis, A E; Fagan, M R; Kelly, J D

    1979-01-01

    The benzimidazole anthelmintics mebendazole and fenbendazole have been shown to be much less effective against Nippostrongylus brasiliensis infections in the rat on a combined iron and protein deficient diet. In the present experiments it was shown that the anthelmintic efficacy of mebendazole was significantly impaired in the rat on either an iron deficient or a protein deficient diet. Furthermore, iron and protein deficiency reduced the efficacy of the anthelmintics pyrantel and piperazine but not levamisole. The finding that nutritional deficiencies reduce anthelmintic efficacy may well be relevant to worm eradication programmes in iron deficient and protein calorie malnourished populations. PMID:447110

  12. Design and synthesis of piperazine derivatives as a novel class of γ-secretase modulators that selectively lower Aβ₄₂ production.

    PubMed

    Takai, Takafumi; Koike, Tatsuki; Honda, Eiji; Kajita, Yuichi; Nakamura, Minoru; Morimoto, Sachie; Hoashi, Yasutaka; Kamata, Makoto; Watanabe, Tomomichi; Igari, Tomoko; Terauchi, Jun

    2015-05-01

    Novel piperazine derivatives as γ-secretase modulators (GSMs) were prepared and tested for their ability to selectively lower Aβ₄₂ production. Lead compound 3, with selective Aβ₄₂-lowering activity, was modified by replacing its imidazolylphenyl moiety with an oxazolylphenyl moiety. Optimization of the urea group significantly improved mouse microsomal stability, while retaining both activity and selectivity. These efforts led to the successful identification of an orally available and brain-penetrant GSM, 6j, which selectively reduced brain Aβ₄₂ in mice. PMID:25842363

  13. Investigation of the mode of binding of a novel series of N-benzyl-4-heteroaryl-1-(phenylsulfonyl)piperazine-2-carboxamides to the hepatitis C virus polymerase

    SciTech Connect

    Gentles, Robert G.; Sheriff, Steven; Beno, Brett R.; Wan, Changhong; Kish, Kevin; Ding, Min; Zheng, Xiaofan; Chupak, Louis; Poss, Michael A.; Witmer, Mark R.; Morin, Paul; Wang, Ying-Kai; Rigat, Karen; Lemm, Julie; Voss, Stacey; Liu, Mengping; Pelosi, Lenore; Roberts, Susan B.; Gao, Min; Kadow, John F.

    2013-11-20

    Structure based rationales for the activities of potent N-benzyl-4-heteroaryl-1-(phenylsulfonyl)piperazine-2-carboxamide inhibitors of the hepatitis C viral polymerase are described herein. These compounds bind to the hepatitis C virus non-structural protein 5B (NS5B), and co-crystal structures of select examples from this series with NS5B are reported. Comparison of co-crystal structures of a potent analog with both NS5B genotype 1a and genotype 1b provides a possible explanation for the genotype-selectivity observed with this compound class and suggests opportunities for the further optimization of the series.

  14. Synthesis and anticancer activities of 4-(4-substituted piperazin)-5,6,7-trialkoxy quinazoline derivatives.

    PubMed

    Zhang, Ying; Huang, Yin-Jiu; Xiang, Hong-Mei; Wang, Pei-Yi; Hu, De-Yu; Xue, Wei; Song, Bao-An; Yang, Song

    2014-05-01

    A series of 4-(4-substituted piperazin)-5,6,7-trialkoxy quinazoline was prepared by conventional heating methods. Among these compounds, the crystal structure of compound 10o (CCDC: 916922) was determined by X-ray crystallography. Bioassay results showed that most target compounds had certain inhibition activities against proliferation of tumor cells, and some compounds even had good broad-spectrum inhibition activities. The ethoxyl series of compounds possessed higher inhibition activities against tumor cells than the methoxyl series of compounds. Bioactivity tests showed that the IC50 values of compound 10s against PC3, MGC803, A375, and A549 cells were 1.8, 2.8, 1.3, and 2.9 μΜ, respectively, which were much higher than those of commercial gefitinib (7.2, 7.6, 7.2, and 9.8 μM, respectively). Conversely, the IC50 values of compound 10s were very low against NH3T3, indicating only weak effect on normal cells as also proven by lactate dehydrogenase and acridine orange/ethidium bromide staining. Analyses of cell configuration and cell cycle revealed that compound 10s possibly caused cells to remain at G0/G1 phase by inhibiting cell proliferation for 24 h. Compound 10s also inhibited the phosphorylation of ERK1/2 and P38 with obvious concentration dependence. Thus, these compounds can inhibit the proliferation of A549 cells through the interruption of ERK1/2 and P38signaling pathways. PMID:24675177

  15. Mechanism-Based Inactivation of Human Cytochrome P450 3A4 by Two Piperazine-Containing Compounds

    PubMed Central

    Bolles, Amanda K.; Fujiwara, Rina; Briggs, Erran D.; Nomeir, Amin A.

    2014-01-01

    Human cytochrome P450 3A4 (CYP3A4) is responsible for the metabolism of more than half of pharmaceutic drugs, and inactivation of CYP3A4 can lead to adverse drug-drug interactions. The substituted imidazole compounds 5-fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl)methyl]-1-piperazinyl]pyrimidine (SCH 66712) and 1-[(2-ethyl-4-methyl-1H-imidazol-5-yl)methyl]-4-[4-(trifluoromethyl)-2-pyridinyl]piperazine (EMTPP) have been previously identified as mechanism-based inactivators (MBI) of CYP2D6. The present study shows that both SCH 66712 and EMTPP are also MBIs of CYP3A4. Inhibition of CYP3A4 by SCH 66712 and EMTPP was determined to be concentration, time, and NADPH dependent. In addition, inactivation of CYP3A4 by SCH 66712 was shown to be unaffected by the presence of electrophile scavengers. SCH 66712 displays type I binding to CYP3A4 with a spectral binding constant (Ks) of 42.9 ± 2.9 µM. The partition ratios for SCH 66712 and EMTPP were 11 and 94, respectively. Whole protein mass spectrum analysis revealed 1:1 binding stoichiometry of SCH 66712 and EMTPP to CYP3A4 and a mass increase consistent with adduction by the inactivators without addition of oxygen. Heme adduction was not apparent. Multiple mono-oxygenation products with each inactivator were observed; no other products were apparent. These are the first MBIs to be shown to be potent inactivators of both CYP2D6 and CYP3A4. PMID:25273356

  16. Benzo[d]thiazol-2-yl(piperazin-1-yl)methanones as new anti-mycobacterial chemotypes: Design, synthesis, biological evaluation and 3D-QSAR studies.

    PubMed

    Pancholia, Sahaj; Dhameliya, Tejas M; Shah, Parth; Jadhavar, Pradeep S; Sridevi, Jonnalagadda Padma; Yogeshwari, Perumal; Sriram, Dharmarajan; Chakraborti, Asit K

    2016-06-30

    The benzo[d]thiazol-2-yl(piperazin-1-yl)methanones scaffold has been identified as new anti-mycobacterial chemotypes. Thirty-six structurally diverse benzo[d]thiazole-2-carboxamides have been prepared and subjected to assessment of their potential anti-tubercular activity through in vitro testing against Mycobacterium tuberculosis H37Rv strain and evaluation of cytotoxicity against RAW 264.7 cell lines. Seventeen compounds showed anti-mycobacterial potential having MICs in the low (1-10) μM range. The 5-trifluoromethyl benzo[d]thiazol-2-yl(piperazin-1-yl)methanones emerged to be the most promising resulting in six positive hits (2.35-7.94 μM) and showed low-cytotoxicity (<50% inhibition at 50 μg/mL). The therapeutic index of these hits is 8-64. The quantitative structure activity relationship has been established adopting a statistically reliable CoMFA model showing high prediction (rpred(2)=0.718,rncv(2)=0.995). PMID:27061982

  17. Design and synthesis of some new 1-phenyl-3/4-[4-(aryl/heteroaryl/alkyl-piperazine1-yl)-phenyl-ureas as potent anticonvulsant and antidepressant agents.

    PubMed

    Mishra, Chandra Bhushan; Kumari, Shikha; Tiwari, Manisha

    2016-05-01

    A series of 1-phenyl-3/4-[4-(aryl/heteroaryl/alkyl-piperazine1-yl)-phenyl-urea derivatives (29-42) were designed, synthesized and evaluated for their anticonvulsant activity by using maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ) seizure tests. The acute neurotoxicity was checked by rotarod assay. Most of the test compounds were found effective in both seizure tests. Compound 30 (1-{4-[4-(4-chloro-phenyl)-piperazin-1-yl]-phenyl}-3-phenyl-urea) exhibited marked anticonvulsant activity in MES as well as scPTZ tests. The phase II anticonvulsant quantification study of compound 30 indicates the ED50 value of 28.5 mg/kg against MES induced seizures. In addition, this compound also showed considerable protection against pilocarpine induced status epilepticus in rats. Seizures induced by 3-mercaptopropionic acid model and thiosemicarbazide were significantly attenuated by compound 30, which suggested its broad spectrum of anticonvulsant activity. Interestingly, compound 30 displayed better antidepressant activity than standard drug fluoxetine. Moreover, compound 30 appeared as a non-toxic chemical entity in sub-acute toxicity studies. PMID:26891908

  18. Here today, gone tomorrow…and back again? A review of herbal marijuana alternatives (K2, Spice), synthetic cathinones (bath salts), kratom, Salvia divinorum, methoxetamine, and piperazines.

    PubMed

    Rosenbaum, Christopher D; Carreiro, Stephanie P; Babu, Kavita M

    2012-03-01

    Despite their widespread Internet availability and use, many of the new drugs of abuse remain unfamiliar to health care providers. The herbal marijuana alternatives, like K2 or Spice, are a group of herbal blends that contain a mixture of plant matter in addition to chemical grade synthetic cannabinoids. The synthetic cathinones, commonly called "bath salts," have resulted in nationwide emergency department visits for severe agitation, sympathomimetic toxicity, and death. Kratom, a plant product derived from Mitragyna speciosa Korth, has opioid-like effects, and has been used for the treatment of chronic pain and amelioration of opioid-withdrawal symptoms. Salvia divinorum is a hallucinogen with unique pharmacology that has therapeutic potential but has been banned in many states due to concerns regarding its psychiatric effects. Methoxetamine has recently become available via the Internet and is marked as "legal ketamine." Moreover, the piperazine derivatives, a class of amphetamine-like compounds that includes BZP and TMFPP, are making a resurgence as "legal Ecstasy." These psychoactives are available via the Internet, frequently legal, and often perceived as safe by the public. Unfortunately, these drugs often have adverse effects, which range from minimal to life-threatening. Health care providers must be familiar with these important new classes of drugs. This paper discusses the background, pharmacology, clinical effects, detection, and management of synthetic cannabinoid, synthetic cathinone, methoxetamine, and piperazine exposures. PMID:22271566

  19. Design, synthesis and pharmacological evaluation of N-[4-(4-(alkyl/aryl/heteroaryl)-piperazin-1-yl)-phenyl]-carbamic acid ethyl ester derivatives as novel anticonvulsant agents.

    PubMed

    Kumari, Shikha; Mishra, Chandra Bhushan; Tiwari, Manisha

    2015-03-01

    A series of alkyl/aryl/heteroaryl piperazine derivatives (37-54) were designed and synthesized as potential anticonvulsant agents. The target compounds are endowed with satisfactory physicochemical as well as pharmacokinetic properties. The synthesized compounds were screened for their in vivo anticonvulsant activity in maximal electroshock (MES) and subcutaneous pentylenetetrazole (sc-PTZ) seizure tests. Further, neurotoxicity evaluation was carried out using rotarod method. Structure activity relationship studies showed that compounds possessing aromatic group at the piperazine ring displayed potent anticonvulsant activity. Majority of the compounds showed anti-MES activity whereas compounds 39, 41, 42, 43, 44, 50, 52, and 53 exhibited anticonvulsant activity in both seizure tests. All the compounds except 42, 46, 47, and 50 did not show neurotoxicity. The most active derivative, 45 demonstrated potent anticonvulsant activity in MES test at the dose of 30mg/kg (0.5h) and 100mg/kg (4h) and also delivered excellent protection in sc-PTZ test (100mg/kg) at both time intervals. Therefore, compound 45 was further assessed in PTZ-kindling model of epilepsy which is widely used model for studying epileptogenesis. This compound was effective in delaying onset of PTZ-evoked seizures at the dose of 5mg/kg in kindled animals and significantly reduced oxidative stress better than standard drug phenobarbital (PB). In result, compound 45 emerged as a most potent and safer anticonvulsant lead molecule. PMID:25619635

  20. Design, synthesis, biological screening, and molecular docking studies of piperazine-derived constrained inhibitors of DPP-IV for the treatment of type 2 diabetes.

    PubMed

    Kushwaha, Ram N; Srivastava, Rohit; Mishra, Akansha; Rawat, Arun K; Srivastava, Arvind K; Haq, Wahajul; Katti, Seturam B

    2015-04-01

    Novel piperazine-derived conformationally constrained compounds were designed, synthesized, and evaluated for in vitro Dipeptidyl peptidase-IV (DPP-IV) inhibitory activities. From a library of compounds synthesized, 1-(2-(4-(7-Chloro-4-quinolyl)piperazin-1-yl)acetyl)pyrrolidine (2g) was identified as a potential DPP-IV inhibitor exhibiting better inhibitory activity than P32/98, reference inhibitor. The in vivo studies carried out in STZ and db/db mice models indicated that the compound 2g showed moderate antihyperglycemic activity as compared to the marketed drug Sitagliptin. A two-week repeated dose study in db/db mice revealed that compound 2g significantly declined blood glucose levels with no evidence of hypoglycemia risk. Furthermore, it showed improvement in insulin resistance reversal and antidyslipidemic properties. Molecular docking studies established good binding affinity of compound 2g at the DPP-IV active site and are in favor of the observed biological data. These data collectively suggest that compound 2g is a good lead molecule for further optimization studies. PMID:25216392

  1. Cyp2D6 catalyzes 5-hydroxylation of 1-(2-pyrimidinyl)-piperazine, an active metabolite of several psychoactive drugs, in human liver microsomes.

    PubMed

    Raghavan, Nirmala; Zhang, Donglu; Zhu, Mingshe; Zeng, Jianing; Christopher, Lisa

    2005-02-01

    1-(2-Pyrimidinyl)-piperazine (1-PP) is an active metabolite of several psychoactive drugs including buspirone. 1-PP is also the major metabolite in the human circulation and in rat brains following oral administration of buspirone. This study was conducted to identify the enzyme responsible for the metabolic conversion of 1-PP to 5-hydroxy-1-(2-pyrimidinyl)-piperazine (HO-1-PP) in human liver microsomes (HLMs). The product HO-1-PP was quantified by a validated liquid chromatography-tandem mass spectrometry method. In the presence of NADPH, 1-PP (100 microM) was incubated separately with human cDNA-expressed cytochrome P450 isozymes (including CYP2D6, 3A4, 1A2, 2A6, 2C9, 2C19, 2E1, and 2B6) at 37 degrees C. CYP2D6 catalyzed the formation of HO-1-PP from 1-PP. This catalytic activity was >95% inhibited by quinidine, a CYP2D6 inhibitor. HO-1-PP formation rates correlated well with the bufuralol 1-hydroxylase (CYP2D6) activities of individual HLMs. The formation of HO-1-PP followed a Michaelis-Menten kinetics with a K(m) of 171 microM and V(max) of 313 pmol/min x mg protein in HLMs. Collectively, these results indicate that polymorphic CYP2D6 is responsible for the conversion of 1-PP to HO-1-PP. PMID:15507542

  2. The Reaction of DABCO with 4-Chloro-5H-1,2,3-dithiazoles: Synthesis and Chemistry of 4-[N-(2-Chloroethyl)piperazin-1-yl]-5H-1,2,3-dithiazoles.

    PubMed

    Koyioni, Maria; Manoli, Maria; Koutentis, Panayiotis A

    2016-01-15

    N-(4-Chloro-5H-1,2,3-dithiazol-5-ylidene)anilines react with DABCO in hot PhCl to give N-{4-[N-(2-chloroethyl)piperazin-1-yl]-5H-1,2,3-dithiazol-5-ylidene}anilines in high yields (70-92%). The reaction also works with 4-chloro-5H-1,2,3-dithiazol-5-one and -thione, giving the corresponding products in 85% and 76% yields, respectively. While the reaction of several (4-chloro-5H-1,2,3-dithiazol-5-ylidene)methanes with DABCO failed to give {4-[N-(2-chloroethyl)piperazin-1-yl]-5H-1,2,3-dithiazol-5-ylidene}methanes, these can be prepared in moderate yields via classical cycloaddition-retrocycloaddition strategies from 4-[N-(2-chloroethyl)piperazin-1-yl]-5H-1,2,3-dithiazole-5-thione. The 2-chloroethyl moiety on selected dithiazoles was also modified without cleavage of the 1,2,3-dithiazole by reaction with various nucleophiles, giving access to 4-[N-(2-substituted)piperazin-1-yl]-5H-1,2,3-dithiazoles in moderate to high yields. PMID:26671065

  3. Bis[N-(2-hy­droxy­eth­yl)-N-iso­propyl­dithio­carbamato-κ2 S,S′](piperazine-κN)cadmium: crystal structure and Hirshfeld surface analysis

    PubMed Central

    Safbri, Siti Artikah M.; Halim, Siti Nadiah Abdul; Jotani, Mukesh M.; Tiekink, Edward R. T.

    2016-01-01

    The title compound, [Cd(C6H12NOS2)2(C4H10N2)], features a distorted square-pyramidal coordination geometry about the central CdII atom. The di­thio­carbamate ligands are chelating, forming similar Cd—S bond lengths and define the approximate basal plane. One of the N atoms of the piperazine mol­ecule, which adopts a chair conformation, occupies the apical site. In the crystal, supra­molecular layers propagating in the ac plane are formed via hy­droxy-O—H⋯O(hy­droxy), hy­droxy-O—H⋯N(terminal-piperazine) and coordinated-piperazine-N—H⋯O(hy­droxy) hydrogen bonds; the layers also feature methine-C—H⋯S inter­actions and S⋯S [3.3714 (10) Å] short contacts. The layers stack along the b-axis direction with very weak terminal-piperazine-N—H⋯O(hy­droxy) inter­actions between them. An evaluation of the Hirshfeld surfaces confirms the importance of inter­molecular inter­actions involving oxygen and sulfur atoms. PMID:26958378

  4. Determination of airborne methyl isocyanate as dibutylamine or 1-(2-methoxyphenyl)piperazine derivatives by liquid and gas chromatography.

    PubMed

    Henriks-Eckerman, M L; Välimaa, J; Rosenberg, C

    2000-11-01

    The usefulness of a glass fibre filter method to collect airborne methyl isocyanate (MIC) was studied in laboratory experiments and in a workplace during manufacture of mineral wool insulation material. Filter collection was based on derivatisation in situ with 1-(2-methoxyphenyl)piperazine (2MP). 2MP impinger sampling was also evaluated in the workplace. Impinger sampling with dibutylamine (DBA) was used as an independent method. The samples were analysed by liquid and gas chromatography using various detection techniques: mass spectrometry, ultraviolet and electrochemical detection (LC-MS, LC-UV, LC-EchD and GC-MS). The sampling efficiency of 2MP filters for MIC varied with the origin of the glass fibre filter. Two Whatman filters (diameter 25 mm) with altogether 21 mumol of 2MP collected 100% of 9.8 micrograms of MIC during 30 min at an airflow rate of 1 l min-1. The workplace measurements were performed at two concentration levels, 0.003 and 0.09 mg m-3. The theoretical amounts of derivatisation reagent were 42 mumol (2MP filter), 52 mumol (2MP impinger) and 100 mumol (DBA). MIC concentrations were 20% lower by the 2MP methods compared with the DBA method (statistically significant difference). Breakthrough was 6% for the DBA method and 9% for the 2MP impinger method. To trap both MIC and isocyanic acid, which was also present in the workplace samples, a tenfold molar amount of 2MP reagent was used. The precision of sample preparation, expressed as relative standard deviation, was 3.5% (0.17 microgram ml-1, n = 6). The precision of sampling in the workplace was 15% (0.002 mg m-3, n = 6). The limit of quantification was 0.0006 mg m-3 for 30 l of air by the 2MP impinger method and 0.03-0.05 mg m-3 by the 2MP filter method. Hence, airborne MIC can be determined using 2MP as derivatisation reagent. Impinger sampling is preferable when low concentration levels are expected. PMID:11193080

  5. Crystal structure of 1,4-bis­(3-ammonio­prop­yl)piperazine-1,4-diium bis­[dichromate(VI)

    PubMed Central

    Vetrivel, S.; Vinoth, E.; Mullai, R. U.; Aruljothi, R.; NizamMohideen, M.

    2016-01-01

    The asymmetric unit of the organic–inorganic title salt, (C10H28N4)[Cr2O7]2, comprises one half of an 1,4-bis­(3-ammonio­prop­yl)piperazinediium cation (the other half being generated by the application of inversion symmetry) and a dichromate anion. The piperazine ring of the cation adopts a chair conformation, and the two CrO4 tetra­hedra of the anion are in an almost eclipsed conformation. In the crystal, the cations and anions form a layered arrangement parallel to (001). N—H⋯O hydrogen bonds between the cations and anions and additional C—H⋯O inter­actions lead to the formation of a three-dimensional network structure. PMID:27308002

  6. Efficient approach to improving the flame retardancy of poly(vinyl alcohol)/clay aerogels: incorporating piperazine-modified ammonium polyphosphate.

    PubMed

    Wang, Yu-Tao; Liao, Shi-Fu; Shang, Ke; Chen, Ming-Jun; Huang, Jian-Qian; Wang, Yu-Zhong; Schiraldi, David A

    2015-01-28

    Ammonium polyphosphates (APP) modified with piperazine (PA-APP) was used to improve the flame retardancy of poly(vinyl alcohol) (PVA)/montmorillonite (MMT) aerogels, which were prepared via an environmentally friendly freeze-drying method. The thermal stabilities of the samples were evaluated by thermogravimetric analysis (TG); the flammability behaviors of samples were investigated by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter (CC) tests. TG test results showed that the 5% weight loss temperature (T5%) of PVA/MMT/PA-APP was 10 °C higher than that of PVA/MMT/APP. In combustion testing, all of PVA/MMT/PA-APP aerogels achieved V-0 ratings and have a higher LOI values than the unmodified PVA/MMT aerogel. Moreover, the aerogel with 1% PA-APP5, which means that the content of piperazine is 5% in PA-APP, decreased the cone calorimetry THR value to 5.71 MJ/m(2), and increased the char residue to 52%. The compressive modulus of PVA/MMT/PA-APP was increased by 93.4% compared with PVA/MMT/APP because of the increase in interfacial adhesion between matrix and PA-APP fillers. The densities of the PVA/MMT/PA-APP samples were slightly lower than those of the unmodified aerogels because of reduced shrinkage in the presence of PA-APP. All the tests results indicated that the incorporation of PA-APP not only improved the thermal stability and flame retardancy of aerogels but also maintained their mechanical properties. PMID:25588129

  7. Synthesis, characterization and biological activities of metal(II) dipicolinate complexes derived from pyridine-2,6-dicarboxylic acid and 2-(piperazin-1-yl)ethanol

    NASA Astrophysics Data System (ADS)

    Büyükkıdan, Nurgün; Yenikaya, Cengiz; İlkimen, Halil; Karahan, Ceyda; Darcan, Cihan; Korkmaz, Tülin; Süzen, Yasemin

    2015-12-01

    The new water-soluble and air stable compounds (H2ppz)[Co(dipic)2]·6H2O (1), (H2ppz)[Ni(dipic)2]·6H2O (2) and (H2ppz)[Zn(dipic)2]·6H2O (3) were prepared by the reaction of corresponding metal(II) acetates and a proton transfer salt, (H2ppz) (Hdipic)2, (4) of pyridine-2,6-dicarboxylic acid (H2dipic) and 2-(piperazin-1-yl)ethanol (ppz). The compounds 1-3 were characterized by elemental, IR, UV-vis. thermal analyses, magnetic measurement and single crystal X-ray diffraction studies. The molecular structures of the title compounds consist of one 1-(2-hydroxyethyl)piperazine-1,4-diium (H2ppz+2) cation, one bis(pyridine-2,6-dicarboxylate)metal(II) [M(dipic)2]2- anion, and six uncoordinated water molecules. In compounds 1-3 the metal ions coordinate to two oxygen and one nitrogen atoms of two pyridine-2,6-dicarboxylate molecules forming an octahedral environment. Antimicrobial activities against Gram (-) wild type (Escherichia coli and Pseudomonas aeruginosa), Gram (+) wild type (Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus and Bacillus subtilis) and clinical isolate (Morganella morganii, Proteus vulgaris and Enterobacter aeruginosa) were also studied. The results were reported, discussed and compared with the corresponding starting materials ((H2ppz) (Hdipic)2 (4), H2dipic and ppz). MIC (Minimal Inhibition Concentration) values of the newly synthesized compounds were determined as 4000 μg/ml (except B. subtilis and clinical isolate E. aeruginosa, >4000 μg/ml).

  8. Critical tests in equids with fenbendazole alone or combined with piperazine: particular reference to activity on benzimidazole-resistant small strongyles.

    PubMed

    Lyons, E T; Tolliver, S C; Drudge, J H

    1983-02-01

    Seven critical tests in equids were conducted with single doses of fenbendazole (5 mg kg-1) alone (Panacur--American Hoechst, Somerville, NJ); (2 tests with paste and 1 with suspension formulation) or in combination with piperazine (American Hoechst); (40 mg base kg-1); (4 tests with paste formulation). The main purpose of the tests was evaluation of activity against benzimidazole-resistant small strongyles (Cyathostomum catinatum, Cyathostomum coronatum, Cylicocyclus nassatus, Cylicostephanus goldi, and Cylicostephanus longibursatus). Natural infections of 2 populations of benzimidazole-resistant small strongyles were evaluated; 1 was population B in 2 horses and the other was population S in 5 ponies. Removal of the 5 species of population B was 49-91% in the animal treated with fenbendazole paste alone and 100% (4 of these species present) in the animal treated with the combination. For population S, 2 of the 5 resistant species were present in small numbers in 1 animal treated with fenbendazole paste alone and all were removed; the 1 animal receiving fenbendazole suspension alone had removals of 0-70% for the 5 benzimidazole-resistant species. Also for population S, the 5 resistant species were present in 2 animals treated with the paste combination and removal was 98-100% and of 4 of the 5 resistant species in 1 animal, removal was 76-99%. Removal of large strongyles (Strongylus vulgaris and Strongylus edentatus) was 92-100% for fenbendazole paste alone or in combination with piperazine in the 5 infected animals. For Oxyuris equi, present in 1 animal treated with the combination, there was 91% removal of immature and 100% removal of mature specimens. There probHably was no activity by fenbendazole alone or the combination against bots, tapeworms, and parenteral stages of S. vulgaris and S. edentatus. The combination may have had some activity against immature Habronema spp. and mature abronema muscae. PMID:6683041

  9. Spacer conformation in biologically active molecules. Part 2. Structure and conformation of 4-[2-(diphenylmethylamino)ethyl]-1-(2-methoxyphenyl) piperazine and its diphenylmethoxy analog—potential 5-HT 1A receptor ligands

    NASA Astrophysics Data System (ADS)

    Karolak-Wojciechowska, J.; Fruziński, A.; Czylkowski, R.; Paluchowska, M. H.; Mokrosz, M. J.

    2003-09-01

    As a part of studies on biologically active molecule structures with aliphatic linking chain, the structures of 4-[2-diphenylmethylamino)ethyl]-1-(2-methoxyphenyl)piperazine dihydrochloride ( 1) and 4-[2-diphenylmethoxy)ethyl]-1-(2-methoxyphenyl)piperazine fumarate ( 2) have been reported. In both compounds, four atomic non-all-carbons linking chains (N)C-C-X-C are present. The conformation of that linking spacer depends on the nature of the X-atom. The preferred conformation for chain with XNH has been found to be fully extended while for that with XO—the bend one. It was confirmed by conformational calculations (strain energy distribution and random search) and crystallographic data, including statistics from CCDC.

  10. 1-(4,5,6,7-Tetra­hydro­thieno[3,2-c]pyridin-5-yl)-2-{4-[3-(trifluoro­meth­yl)phen­yl]piperazin-1-yl}ethanone

    PubMed Central

    Zhi, Shuang; Zheng, Guo; Liu, Ying; Liu, Deng-Ke

    2012-01-01

    In the title mol­ecule, C20H22F3N3OS, the piperazine ring has a chair conformation, and the N—C(=O)—C—N torsion angle is −59.42 (14)°. In the crystal, weak C—H⋯O and C—H⋯π inter­actions link the mol­ecules into layers parallel to (101). PMID:22590203

  11. Toward Understanding Amines and Their Degradation Products from Postcombustion CO2 Capture Processes with Aerosol Mass Spectrometry

    PubMed Central

    2015-01-01

    Amine-based postcombustion CO2 capture (PCCC) is a promising technique for reducing CO2 emissions from fossil fuel burning plants. A concern of the technique, however, is the emission of amines and their degradation byproducts. To assess the environmental risk of this technique, standardized stack sampling and analytical methods are needed. Here we report on the development of an integrated approach that centers on the application of a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) for characterizing amines and PCCC-relevant species. Molecular characterization is achieved via ion chromatography (IC) and electrospray ionization high-resolution mass spectrometry (ESI-MS). The method has been optimized, particularly, by decreasing the AMS vaporizer temperature, to gain quantitative information on the elemental composition and major nitrogen-containing species in laboratory-degraded amine solvents commonly tested for PCCC applications, including ethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP). The AMS-derived nitrogen-to-carbon (N/C) ratios for the degraded solvent and product mixtures agree well with the results from a total organic carbon and total nitrogen (TOC/TN) analyzer. In addition, marker ions identified in the AMS spectra are used to estimate the mass contributions of individual species. Overall, our results indicate that this new approach is suitable for characterizing PCCC-related mixtures as well as organic nitrogen species in other sample types. As an online instrument, AMS can be used for both real-time characterization of emissions from operating PCCC plants and ambient particles in the vicinity of the facilities. PMID:24617831

  12. Toward understanding amines and their degradation products from postcombustion CO2 capture processes with aerosol mass spectrometry.

    PubMed

    Ge, Xinlei; Shaw, Stephanie L; Zhang, Qi

    2014-05-01

    Amine-based postcombustion CO2 capture (PCCC) is a promising technique for reducing CO2 emissions from fossil fuel burning plants. A concern of the technique, however, is the emission of amines and their degradation byproducts. To assess the environmental risk of this technique, standardized stack sampling and analytical methods are needed. Here we report on the development of an integrated approach that centers on the application of a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) for characterizing amines and PCCC-relevant species. Molecular characterization is achieved via ion chromatography (IC) and electrospray ionization high-resolution mass spectrometry (ESI-MS). The method has been optimized, particularly, by decreasing the AMS vaporizer temperature, to gain quantitative information on the elemental composition and major nitrogen-containing species in laboratory-degraded amine solvents commonly tested for PCCC applications, including ethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP). The AMS-derived nitrogen-to-carbon (N/C) ratios for the degraded solvent and product mixtures agree well with the results from a total organic carbon and total nitrogen (TOC/TN) analyzer. In addition, marker ions identified in the AMS spectra are used to estimate the mass contributions of individual species. Overall, our results indicate that this new approach is suitable for characterizing PCCC-related mixtures as well as organic nitrogen species in other sample types. As an online instrument, AMS can be used for both real-time characterization of emissions from operating PCCC plants and ambient particles in the vicinity of the facilities. PMID:24617831

  13. Measurement of nitrosamine and nitramine formation from NOx reactions with amines during amine-based carbon dioxide capture for postcombustion carbon sequestration.

    PubMed

    Dai, Ning; Shah, Amisha D; Hu, Lanhua; Plewa, Michael J; McKague, Bruce; Mitch, William A

    2012-09-01

    With years of full-scale experience for precombustion CO(2) capture, amine-based technologies are emerging as the prime contender for postcombustion CO(2) capture. However, concerns for postcombustion applications have focused on the possible contamination of air or drinking water supplies downwind by potentially carcinogenic N-nitrosamines and N-nitramines released following their formation by NO(x) reactions with amines within the capture unit. Analytical methods for N-nitrosamines in drinking waters were adapted to measure specific N-nitrosamines and N-nitramines and total N-nitrosamines in solvent and washwater samples. The high levels of amines, aldehydes, and nitrite in these samples presented a risk for the artifactual formation of N-nitrosamines during sample storage or analysis. Application of a 30-fold molar excess of sulfamic acid to nitrite at pH 2 destroyed nitrite with no significant risk of artifactual nitrosation of amines. Analysis of aqueous morpholine solutions purged with different gas-phase NO and NO(2) concentrations indicated that N-nitrosamine formation generally exceeds N-nitramine formation. The total N-nitrosamine formation rate was at least an order of magnitude higher for the secondary amine piperazine (PZ) than for the primary amines 2-amino-2-methyl-1-propanol (AMP) and monoethanolamine (MEA) and the tertiary amine methyldiethanolamine (MDEA). Analysis of pilot washwater samples indicated a 59 μM total N-nitrosamine concentration for a system operated with a 25% AMP/15% PZ solvent, but only 0.73 μM for a 35% MEA solvent. Unfortunately, a greater fraction of the total N-nitrosamine signal was uncharacterized for the MEA-associated washwater. At a 0.73 μM total N-nitrosamine concentration, a ~25000-fold reduction in concentration is needed between washwater units and downwind drinking water supplies to meet proposed permit limits. PMID:22831707

  14. Amine-degradation products play no part in corrosion at gas-sweetening plants

    SciTech Connect

    Blanc, C.; Grall, M.; Demarais, G.

    1982-11-15

    Gas-sweetening units using diethanolamine (DEA) and methyldiethanolamine (MDEA) are occasionally subject to corrosion. Discounting the basic degradation products of DEA as the cause, researchers (1) confirmed the presence of formic, oxalic, and acetic acids in used amine solutions, (2) defined oxygen's role in forming these carboxylic acids, and (3) demonstrated that the acid contents of different units are about the same order of magnitude for both DEA and MDEA. In most cases, oxygen can be easily excluded from gas-treating units, especially in storage tanks, thereby limiting the formation of acid products.

  15. Solubility of acid gases in a mixed solvent

    SciTech Connect

    MacGregor, R.J.; Mather, A.E.

    1987-01-01

    The solubility of hydrogen sulphide and carbon dioxide and their mixtures has been measured at 40/sup 0/ and 100/sup 0/C in a mixed solvent consisting of 20.9 wt% (2.0 M) MDEA (methyldiethanolamine), 30.5 wt% sulfolane, and 48.6 wt% water. The results have been compared with those for aqueous 2.0 M MDEA and an analogous mixed solvent, containing AMP (2-amino-2-methyl-1-propanol), which are available in the literature. At solution loadings less than 1 mol acid gas/mol MDEA, the solubility of the acid gas was lower in the mixed solvent that in the corresponding aqueous MDEA solvent; at solution loadings greater than 1 mol acid gas/mol MDEA, the reverse was true. At all loadings and at both temperatures studied, the mixed MDEA solvent absorbed equal or lesser quantities of acid gas than the comparable mixed AMP solvent. However, the shapes of the solubility curves show that the mixed MDEA solvent would be a better choice for certain industrial applications. These data were used to modify the solubility model of Deshmukh and Mather to account for the mixed solvent effects on the system thermodynamics. Results show that the model is useful as a first approximation in predicting acid gas solubilities; agreement with experiment was generally found to be within +-15%.

  16. Liquid chromatography tandem mass spectrometry determination of selected synthetic cathinones and two piperazines in oral fluid. Cross reactivity study with an on-site immunoassay device.

    PubMed

    de Castro, Ana; Lendoiro, Elena; Fernández-Vega, Hadriana; Steinmeyer, Stefan; López-Rivadulla, Manuel; Cruz, Angelines

    2014-12-29

    Since the past few years, several synthetic cathinones and piperazines have been introduced into the drug market to substitute illegal stimulant drugs such as amphetamine and derivatives or cocaine due to their unregulated situation. These emerging drugs are not usually included in routine toxicological analysis. We developed and validated a LC-MS/MS method for the determination of methedrone, methylone, mephedrone, 3,4-methylenedioxypyrovalerone (MDPV), fluoromethcathinone, fluoromethamphetamine, 1-(3-chlorophenyl)piperazine (mCPP) and 3-trifluoromethylphenylpiperazine (TFMPP) in oral fluid. Sample extraction was performed using Strata X cartridges. Chromatographic separation was achieved in 10min using an Atlantis(®) T3 column (100mm×2.1mm, 3μm), and formic acid 0.1% and acetonitrile as mobile phase. The method was satisfactorily validated, including selectivity, linearity (0.2-0.5 to 200ng/mL), limits of detection (0.025-0.1ng/mL) and quantification (0.2-0.5ng/mL), imprecision and accuracy in neat oral fluid (%CV=0.0-12.7% and 84.8-103.6% of target concentration, respectively) and in oral fluid mixed with Quantisal™ buffer (%CV=7.2-10.3% and 80.2-106.5% of target concentration, respectively), matrix effect in neat oral fluid (-11.6 to 399.7%) and in oral fluid with Quantisal™ buffer (-69.9 to 131.2%), extraction recovery (87.9-134.3%) and recovery from the Quantisal™ (79.6-107.7%), dilution integrity (75-99% of target concentration) and stability at different conditions (-14.8 to 30.8% loss). In addition, cross reactivity produced by the studied synthetic cathinones in oral fluid using the Dräger DrugTest 5000 was assessed. All the analytes produced a methamphetamine positive result at high concentrations (100 or 10μg/mL), and fluoromethamphetamine also at low concentration (0.075μg/mL). PMID:25482853

  17. N-Methyl-d-aspartate (NMDA) Receptor NR2 Subunit Selectivity of a Series of Novel Piperazine-2,3-dicarboxylate Derivatives: Preferential Blockade of Extrasynaptic NMDA Receptors in the Rat Hippocampal CA3-CA1 Synapse

    PubMed Central

    Feng, Bihua; Tsintsadze, Timur S.; Morley, Richard M.; Irvine, Mark W.; Tsintsadze, Vera; Lozovaya, Natasha A.; Jane, David E.; Monaghan, Daniel T.

    2009-01-01

    N-Methyl-d-aspartate (NMDA) receptor antagonists that are highly selective for specific NMDA receptor 2 (NR2) subunits have several potential therapeutic applications; however, to date, only NR2B-selective antagonists have been described. Whereas most glutamate binding site antagonists display a common pattern of NR2 selectivity, NR2A > NR2B > NR2C > NR2D (high to low affinity), (2S*,3R*)-1-(phenanthrene-2-carbonyl)piperazine-2,3-dicarboxylic acid (PPDA) has a low selectivity for NR2C- and NR2D-containing NMDA receptors. A series of PPDA derivatives were synthesized and then tested at recombinant NMDA receptors expressed in Xenopus laevis oocytes. In addition, the optical isomers of PPDA were resolved; the (−) isomer displayed a 50- to 80-fold greater potency than the (+) isomer. Replacement of the phenanthrene moiety of PPDA with naphthalene or anthracene did not improve selectivity. However, phenylazobenzoyl (UBP125) or phenylethynylbenzoyl (UBP128) substitution significantly improved selectivity for NR2B-, NR2C-, and NR2D-containing receptors over NR2A-containing NMDA receptors. Phenanthrene attachment at the 3 position [(2R*,3S*)-1-(phenanthrene-3-carbonyl)piperazine-2,3-dicarboxylic acid (UBP141); (2R*,3S*)-1-(9-bromophenanthrene-3-carbonyl)piperazine-2,3-dicarboxylic acid (UBP145); (2R*,3S*)-1-(9-chlorophenanthrene-3-carbonyl)piperazine-2,3-dicarboxylic acid (UBP160); and (2R*,3S*)-1-(9-iodophenanthrene-3-carbonyl)piperazine-2,3-dicarboxylic acid (UBP161)] displayed improved NR2D selectivity. UBP141 and its 9-brominated homolog (UBP145) both display a 7- to 10- fold selectivity for NR2D-containing receptors over NR2B- or NR2A-containing receptors. Schild analysis indicates that these two compounds are competitive glutamate binding site antagonists. Consistent with a physiological role for NR2D-containing receptors in the hippocampus, UBP141 (5 μM) displayed greater selectivity than PPDA for inhibiting the slow-decaying component of the NMDA receptor

  18. Synthesis, crystal structures, molecular docking, and in vitro biological activities evaluation of transition metal complexes with 4-(3,4-dichlorophenyl) piperazine-1-carboxylic acid

    NASA Astrophysics Data System (ADS)

    Chen, Zhi-Jian; Chen, Ya-Na; Xu, Chun-Na; Zhao, Shan-Shan; Cao, Qi-Yue; Qian, Shao-Song; Qin, Jie; Zhu, Hai-Liang

    2016-08-01

    Three novel mononuclear complexes, [MⅡ(L)2·2H2O], (M = Cu, Ni or Cd; HL = 4-(3,4-dichlorophenyl)piperazine-1-carboxylic acid)were synthesized and structurally determined by single-crystal X-ray diffraction. Molecular docking study preliminarily revealed that complex 1 had potential urease inhibitory activity. In accordance with the result of calculation, in vitro tests of the inhibitory activities of complexes 1-3 against jack bean urease showed complex 1 (IC50 = 8.17 ± 0.91 μM) had better inhibitory activities than the positive reference acetohydroxamic acid (AHA) (IC50 = 26.99 ± 1.43 μM), while complexes 2 and 3 showed no inhibitory activities., kinetics study was carried out to explore the mechanism of the inhibiting of the enzyme, and the result indicated that complex 1 was a competitive inhibitor of urease. Albumin binding experiment and in vitro toxicity evaluation of complex 1 were implemented to explore its Pharmacological properties.

  19. Mononuclear zinc(II) complexes of 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols: Synthesis, structural characterization, DNA binding and cheminuclease activities

    NASA Astrophysics Data System (ADS)

    Ravichandran, J.; Gurumoorthy, P.; Karthick, C.; Kalilur Rahiman, A.

    2014-03-01

    Four new zinc(II) complexes [Zn(HL1-4)Cl2] (1-4), where HL1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, have been isolated and fully characterized using various spectro-analytical techniques. The X-ray crystal structure of complex 4 shows the distorted trigonal-bipyramidal coordination geometry around zinc(II) ion. The crystal packing is stabilized by intermolecular NH⋯O hydrogen bonding interaction. The complexes display no d-d electronic band in the visible region due to d10 electronic configuration of zinc(II) ion. The electrochemical properties of the synthesized ligands and their complexes exhibit similar voltammogram at reduction potential due to electrochemically innocent Zn(II) ion, which evidenced that the electron transfer is due to the nature of the ligand. Binding interaction of complexes with calf thymus DNA was studied by UV-Vis absorption titration, viscometric titration and cyclic voltammetry. All complexes bind with CT DNA by intercalation, giving the binding affinity in the order of 2 > 1 ≫ 3 > 4. The prominent cheminuclease activity of complexes on plasmid DNA (pBR322 DNA) was observed in the absence and presence of H2O2. Oxidative pathway reveals that the underlying mechanism involves hydroxyl radical.

  20. Synthesis and potential antitumor activity of 7-(4-substituted piperazin-1-yl)-4-oxoquinolines based on ciprofloxacin and norfloxacin scaffolds: in silico studies.

    PubMed

    Abdel-Aziz, Alaa A-M; El-Azab, Adel S; Alanazi, Amer M; Asiri, Yousif A; Al-Suwaidan, Ibrahim A; Maarouf, Azza R; Ayyad, Rezk R; Shawer, Taghreed Z

    2016-10-01

    The potential antitumor activities of a series of 7-(4-substituted piperazin-1-yl)fluoroquinolone derivatives (1-14a,b) using ciprofloxacin and norfloxacin as scaffolds are described. These compounds exhibit potent and broad spectrum antitumor activities using 60 human cell lines in addition to the inherent antibacterial activity. Compounds 1a, 2a, 3b, 6b and 7a were found to be the most potent, while 2b, 5b, and 6a were found to have an average activity. The results of this study demonstrated that compounds 1a, 2a, 3b, 6b and 7a (mean GI50; 2.63-3.09 µM) are nearly 7-fold more potent compared with the positive control 5-fluorouracil (mean GI50; 22.60 µM). More interestingly, compounds 1a, 2a, 3b, 6b and 7a have an almost antitumor activity similar to gefitinib (mean GI50; 3.24 µM) and are nearly 2-fold more potent compared to erlotinib (mean GI50; 7.29 µM). In silico study and ADME-Tox prediction methodology were used to study the antitumor activity of the most active compounds and to identify the structural features required for antitumor activity. PMID:26226179

  1. Ab initio and density functional theory calculations of molecular structure and vibrational spectra of 4-(2-Hydroxyethyl) piperazine-1-ethanesulfonic acid

    NASA Astrophysics Data System (ADS)

    Kumar, J. Sharmi; Devi, T. S. Renuga; Ramkumaar, G. R.; Bright, A.

    2016-01-01

    The FTIR and FT-Raman spectra of 4-(2-Hydroxyethyl) piperazine-1-ethanesulfonic acid were recorded and the structural and spectroscopic data of the molecule in the ground state were calculated using Hartree-Fock and Density Functional Method (B3LYP). The most stable conformer was optimized and the structural and vibrational parameters were determined. With the observed FTIR and FT-Raman data, a complete vibrational band assignment and analysis of the fundamental modes of the compound were carried out. Thermodynamic properties, Mulliken and natural atomic charge distribution were calculated using both Hartree-Fock and Density Functional Method and compared. UV-Visible and HOMO-LUMO analysis were carried out. 1H and 13C NMR chemical shifts of the molecule were calculated using gauge including atomic orbital method and were compared with experimental results. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital analysis. The first order hyperpolarizability (β) and molecular electrostatic potential of the molecule was computed using DFT calculations. The electron density based local reactivity descriptor such as Fukui functions were calculated to explain the chemically reactive site in the molecule.

  2. 1,4-Disubstituted aromatic piperazines with high 5-HT2A/D2 selectivity: Quantitative structure-selectivity investigations, docking, synthesis and biological evaluation.

    PubMed

    Möller, Dorothee; Salama, Ismail; Kling, Ralf C; Hübner, Harald; Gmeiner, Peter

    2015-09-15

    Simultaneous targeting of dopamine D2 and 5-HT2A receptors for the treatment of schizophrenia is one key feature of typical and atypical antipsychotics. In most of the top-selling antipsychotic drugs like aripiprazole and risperidone, high affinity to both receptors can be attributed to the presence of 1,4-disubstituted aromatic piperazines or piperidines as primary receptor recognition elements. Taking advantage of our in-house library of phenylpiperazine-derived dopamine receptor ligands and experimental data, we established highly significant CoMFA and CoMSIA models for the prediction of 5-HT2A over D2 selectivity. Subsequently, the models were applied to identify the selective candidates 55-57 from our newly synthesized library of GPCR ligands comprising a pyrazolo[1,5-a]pyridine head group and a 1,2,3-triazole based linker unit. The test compound 57 showed subnanomolar a Ki value (0.64 nM) for 5-HT2A and more than 10- and 30-fold selectivity over the dopamine receptor isoforms D2S and D2L, respectively. PMID:26299826

  3. Synthesis, spectroscopic and thermal studies of charge-transfer molecular complexes formed in the reaction of 1,4-bis (3-aminopropyl) piperazine with σ- and π acceptors

    NASA Astrophysics Data System (ADS)

    AlQaradawi, Siham Y.; Mostafa, Adel; Bazzi, Hassan S.

    2012-03-01

    In the present study, solid charge-transfer (CT) molecular complexes formed in the reaction of the electron donor 1,4-bis (3-aminopropyl) piperazine (APPIP) with the σ-electron acceptor iodine and π-acceptors 7,7,8,8-tetracyanoquinodimethane (TCNQ), tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), and 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TBCHD) have been investigated spectrophotometrically in chloroform at 25 °C. These were characterized through electronic and infrared spectra as well as elemental and thermal analysis. The obtained results showed that the formed solid CT-complexes have the formulas [(APPIP) I]+I3-, [(APPIP)(TCNQ)], [(APPIP)2(TCNE)3], [(APPIP)(DDQ)] and [(APPIP)(TBCHD)] in full agreement with the known reaction stoichiometries in solution as well as the elemental measurements. The formation constant KCT, molar extinction coefficient ɛCT, free energy change ΔG0, CT energy ECT and the ionization potential Ip have been calculated for the CT complexes [(APPIP) I]+I3-, [(APPIP)(TCNQ)], [(APPIP)(DDQ)] and [(APPIP)(TBCHD)].

  4. 4-(2-Meth­oxy­phen­yl)piperazin-1-ium 6-chloro-5-isopropyl-2,4-dioxopyrimidin-1-ide

    PubMed Central

    Al-Omary, Fatmah A. M.; Ghabbour, Hazem A.; El-Emam, Ali A.; Chidan Kumar, C. S.; Fun, Hoong-Kun

    2014-01-01

    In the cation of the title salt, C11H17N2O+·C7H8ClN2O2 −, the piperazine ring adopts a distorted chair conformation and contains a positively charged N atom with quaternary character. Its mean plane makes a dihedral angle of 42.36 (8)° with the phenyl ring of its 2-meth­oxy­phenyl substituent. The 2,4-dioxopyrimidin-1-ide anion is generated by deprotonation of the N atom at the 1-position of the pyrimidine­dione ring. Intra­molecular C—H⋯O hydrogen bonds generate S(6) ring motifs in both the cation and the anion. In the crystal, N—H⋯O, N—H⋯N and C—H⋯O hydrogen bonds are also observed, resulting in a two-dimensional network parallel to the ab plane. The crystal stability is further consolidated by weak C—H⋯π inter­actions. PMID:24764966

  5. Synthesis, growth, structural and optical studies of organic nonlinear optical material - Piperazine-1,4-diium bis 2,4,6-trinitrophenolate

    NASA Astrophysics Data System (ADS)

    Suguna, S.; Anbuselvi, D.; Jayaraman, D.; Nagaraja, K. S.; Jeyaraj, B.

    2014-11-01

    Piperazine-1,4-diium bis 2,4,6-trinitrophenolate is one of the useful organic materials with nonlinear optical (NLO) and pharmaceutical applications. The material was grown by slow evaporation solution growth method at room temperature. The crystal system and lattice parameters were identified by single crystal XRD analysis. The grown material crystallizes in monoclinic system with P21/n space group. The main functional groups NH2, NO2, Csbnd N, Cdbnd C, and phenolic ‘O' atom were identified using FTIR analysis. The protons and carbons of grown crystal with various chemical environments were studied by 1H and 13C NMR spectroscopy to confirm the molecular structure. The optical properties of the crystal were studied by UV-vis-NIR spectroscopy and the transmission 100% range starts from 532 nm onwards. The optical band gap was measured as 2.63 eV from the plot of (αhν)2 versus hν. The thermal stability was detected at 304.1 °C using TG-DTA analysis. The dielectric studies of the sample were carried out at different temperatures in the frequency range from 50 Hz to 5 MHz to establish the dielectric nature of the crystal. Photoconductivity measurements were carried out on the grown crystal. The Second Harmonic Generation (SHG) of the crystal was tested to confirm the nonlinear optical property.

  6. Antioxidant, DNA binding and nuclease activities of heteroleptic copper(II) complexes derived from 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols and diimines

    NASA Astrophysics Data System (ADS)

    Ravichandran, J.; Gurumoorthy, P.; Imran Musthafa, M. A.; Kalilur Rahiman, A.

    2014-12-01

    A series of heteroleptic copper(II) complexes of the type [CuL1-4(diimine)](ClO4)2 (1-8) [L1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine = 2,2‧-bipyridyl (bpy) or 1,10-phenanthroline (phen)], have been synthesized and characterized by spectroscopic methods. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions and the electronic spectra revealed the square pyramidal geometry with N4O coordination environment around copper(II) nuclei. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region. The EPR spectra of complexes with g|| (2.206-2.214) and A|| (154-172 × 10-4 cm-1) values support the square-based CuN3O coordination chromophore and the presence of unpaired electron localized in dx-y ground state. Antioxidant studies against DPPH revealed effective radical scavenging properties of the synthesized complexes. Binding studies suggest that the heteroleptic copper(II) complexes interact with calf thymus DNA (CT-DNA) through minor-groove and electrostatic interaction, and all the complexes display pronounced nuclease activity against supercoiled pBR322 DNA.

  7. Evaluation of three neutral capillary coatings for the determination of analyte-cyclodextrin binding constants by affinity capillary electrophoresis. Application to N,N'-disubstituted piperazine derivatives.

    PubMed

    Danel, Cécile; Melnyk, Patricia; Azaroual, Nathalie; Larchanché, Paul-Emmanuel; Goossens, Jean-François; Vaccher, Claude

    2016-07-15

    The performances of three neutral static coatings (hydroxypropyl cellulose, polyethylene oxide and poly(N,N-dimethylacrylamide) have been evaluated in order to determine the binding constants of the complexes formed between four polycationic compounds (piperazine derivatives) and four cyclodextrins of pharmaceutical interest (β-CD, HP-β-CD, Me-β-CD and sulfobutyl ether-β-CD) by affinity capillary electrophoresis. The physically-adsorbed poly(N,N-dimethylacrylamide) coating proves to be the more efficient to mask the silanol groups of the capillary wall since the lowest electroosmotic flow was measured for this coating. Moreover, it drastically reduces the adsorption of the compounds since it allows a correct repeatability of their migration time, higher efficiencies of the peaks and no baseline shift. Then, it was verified for four complexes that this coating allows a correct determination of the binding constants avoiding the CD adsorption which is responsible of an undervaluation of binding constants. The highest binding constants are obtained using the anionic sulfobutyl ether-β-CD (SBE-β-CD). The structure of the complex formed between the tacrine derivative and the SBE-β-CD was further investigated through 2D ROESY NMR experiments and structure-binding constant relationships. Results suggest that the inclusion in the SBE-β-CD cavity occurs through the aliphatic ring portion of the tacrine moiety. PMID:27286645

  8. Agonist activity of a novel compound, 1-[3-(3,4-methylenedioxyphenoxy)propyl]-4-phenyl piperazine (BP-554), at central 5-HT1A receptors.

    PubMed

    Matsuda, T; Seong, Y H; Aono, H; Kanda, T; Baba, A; Saito, K; Tobe, A; Iwata, H

    1989-10-24

    We used an in vitro radioligand receptor binding assay with rat cerebral cortex, hippocampus and striatum membrane preparations to show that 1-[3-(3,4-methylenedioxyphenoxy)propyl]-4-phenyl piperazine (BP-554) had much higher affinity for 5-HT1A recognition sites than for 5-HT1-non-A, 5-HT2, benzodiazepine, dopamine D-2 and alpha 2-adrenergic recognition sites. The compound inhibited the activity of forskolin-stimulated adenylate cyclase in rat hippocampal membranes. Intraperitoneal injection of BP-554 to mice decreased the concentration of only 5-hydroxy-indoleacetic acid of the amines and their metabolites in the brain and decreased the accumulation of 5-hydroxytryptophan in the brain after decarboxylase inhibition by 3-hydroxybenzylhydrazine. Furthermore, the administration of BP-554 caused hypothermia and increased serum corticosterone levels in mice. The observed effects of BP-554 were similar to those of 8-hydroxy-2-(di-n-propylamino)tetralin. These results suggest that BP-554 acts as a selective 5-HT1A receptor agonist in vivo. PMID:2533078

  9. Effect of buspirone and its metabolite 1-(2-pyrimidinyl)-piperazine on hippocampal serotoninergic system, studied in freely moving rats.

    PubMed

    Grazia De Simoni, M; Imeri, L; De Luigi, A; Fodritto, F; Garattini, S

    1990-01-01

    The effects of the anxiolytic drug buspirone and its metabolite 1-(2-pyrimidinyl)-piperazine (1PP) were studied on the serotoninergic system in the hippocampus of freely moving rats. Pulse voltammetry was used in association with chronically implanted carbon fiber microelectrodes to record 5HIAA, the serotonin metabolite in the extracellular space, almost continuously. Buspirone, 2.5 mg/kg i.p. was ineffective, but the dose of 10 mg/kg lowered 5HIAA between about 45 and 150 min; the same decrease was obtained with 40 mg/kg. This effect can be explained by an agonistic action on 5HT1 A receptors. The metabolite 1PP, which displays alpha 2 adrenoceptor blocking properties, either had no effect or raised extracellular 5HIAA, depending on the dose (1.5 or 6 mg/kg). The rapid metabolization of buspirone to 1PP can thus explain the short time course of the drug effect. Pretreatment with 1PP could only partially prevent buspirone's effect on the serotoninergic system. PMID:1689445

  10. Radiosynthesis binding affinity and biodistribution of 3-[F-18]fluoro-N-({alpha},{alpha},{alpha}-trifluoro-m-tolyl)piperazine (FTFMPP), a radioligand for the Serotonin system

    SciTech Connect

    Mishani, E.; Cristel, M.E.; McCarthy, T.J.; Welch, M.J.

    1996-05-01

    The serotonin agonist N({alpha},{alpha},{alpha}-trifluoro-m-tolyl)piperazine (TFMPP) is a potent ligand for the serotonin system. Angelini and co-workers previously synthesized the c.a [F-18]TFMPP but the low specific activity (less than 0.2GBq/mmol) limited the application of this ligand. We have recently reported the formation of phenylpiperazines by a novel alumina supported bis-alkylation. We report the application of this method and biological evaluation of 3-[F-18]FTFMPP, a fluoro derivative of TFMPP. Reaction of [F-18]fluoride with 3,5-dinitrobenzotrifluoride gave the 3-[F-18]fluoro-5-nitrobenzotrifluoride in 70% yield. Reduction of the nitro group with Raney nickel and hydrazine hydrate gave the [F-18]aniline derivative in 70% yield. Finally, the phenylpiperazine was constructed by reaction of the [F-18]aniline derivative with bis-2-bromoethyl-N-(ethoxy carbonyl)amine on basic alumina (pH=9) as a solid support. After extraction of the activity with basic MeOH and HPLC purification on normal phase the final product- [F-18]FTFMPP was obtained in 50% yield (98% radiochemical purity). The specific activity of the final product was 100GBq/mmol. The binding affinity of FTFMPP to 5-HT receptor was determined (Ki = 80-100 nM) and found to be similar to the binding affinity of the TFMPP (160-180 nM). The biodistribution of [F-18]FTFMPP was performed in rats.

  11. Ligand-based pharmacophore model of N-Aryl and N-Heteroaryl piperazine alpha 1A-adrenoceptors antagonists using GALAHAD.

    PubMed

    Zhao, Xin; Yuan, Mu; Huang, Biyun; Ji, Hong; Zhu, Liu

    2010-09-01

    Computer aided drug discovery for selective antagonism effects on alpha(1A) subtypes of G-protein coupled receptors are important in the treatment of benign prostatic hyperplasia (BPH). Ligand-based pharmacophore models of N-Aryl and N-Heteroaryl piperazine alpha(1A)-antagonists were developed using two separate training sets. Pharmacophore models were generated using the flexible align method within the GALAHAD module, implemented in SYBYL8.1 software. The most significant pharmacophore hypothesis, characterized by the conflicting demands of maximizing pharmacophore consensus, maximizing steric consensus, and minimizing energy, consisted of one positive nitrogen center, one donor atom center, two acceptor atom centers, and two hydrophobic groups. The most active compound in each class training set showed a good fit with all features of the pharmacophore proposed. The resulting models also had something in common with the hypothesis using the Catalyst software reported in other publications. These alpha(1A) pharmacophore models could predict compounds well, both in the training set and the test set. The pharmacophore models were also validated by an external dataset using a portion of the ZINC database. A 3D-QSAR model using the pharmacophore model to align the compounds was established in this study. The CoMFA model with the cross-validated q(2) value of 0.735 revealed that the model was valid. Our research provides a valuable tool for designing new therapeutic compounds with desired biological activity. PMID:20538497

  12. A mutation in reverse transcriptase of bis(heteroaryl)piperazine-resistant human immunodeficiency virus type 1 that confers increased sensitivity to other nonnucleoside inhibitors.

    PubMed Central

    Dueweke, T J; Pushkarskaya, T; Poppe, S M; Swaney, S M; Zhao, J Q; Chen, I S; Stevenson, M; Tarpley, W G

    1993-01-01

    Several nonnucleoside inhibitors of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) have been described, including Nevirapine, thiobenzimidazolone (TIBO) derivatives, pyridinone derivatives such as L-697,661, and the bis(heteroaryl)piperazines (BHAPs). HIV-1 resistant to L-697,661 or Nevirapine emerges rapidly in infected patients treated with these drugs, and the resistance is caused primarily by substitutions at amino acids 181 and 103 of RT that also confer cross resistance to the other nonnucleoside inhibitors. We describe derivation and characterization of two BHAP-resistant HIV-1 variants that differ from this pattern of cross resistance. With both variants, HIV-1 resistance to BHAP RT inhibitors was caused by a RT mutation that results in a proline-to-leucine substitution at amino acid 236 (P236L). Rather than conferring cross resistance to other RT inhibitors, this substitution sensitized RT 7- to 10-fold to Nevirapine, TIBO R82913, and L-697,661 without influencing sensitivity to nucleoside analogue RT inhibitors. This sensitization caused by P236L was also observed in cell culture with BHAP-resistant HIV-1. The effects of the P236L RT substitution suggest that emergence of BHAP-resistant virus in vivo could produce a viral population sensitized to inhibition by these other nonnucleoside RT inhibitors. PMID:7685109

  13. N-Alkyl/aryl-4-(3-substituted-3-phenylpropyl)piperazine-1-carbothioamide as dual-action vaginal microbicides with reverse transcriptase inhibition.

    PubMed

    Bala, Veenu; Mandalapu, Dhanaraju; Gupta, Sonal; Jangir, Santosh; Kushwaha, Bhavana; Chhonker, Yashpal S; Chandasana, Hardik; Krishna, Shagun; Rawat, Kavita; Krishna, Atul; Singh, Mala; Sankhwar, Satya N; Shukla, Praveen K; Maikhuri, Jagdamba P; Bhatta, Rabi S; Siddiqi, Mohammad I; Tripathi, Rajkamal; Gupta, Gopal; Sharma, Vishnu L

    2015-08-28

    The growing population and health-care burden (due to STIs and HIV) imposes a particular economic crisis over resource-poor countries. Thus a novel approach as vaginal microbicides emerges as integrated tool to control both population and anti-STIs/HIV. Our continued efforts in this field led to the synthesis of fifteen N-alkyl/aryl-4-(3-substituted-3-phenylpropyl) piperazine-1-carbothioamide (12-26) derivatives as topical vaginal microbicides which were evaluated for anti-Trichomonas, spermicidal, antifungal and reverse transcriptase (RT) inhibitory activities. All compounds were also tested for preliminary safety through cytotoxicity assays against human cervical cell line (HeLa) and the vaginal flora, Lactobacillus. Docking studies were performed to gain an insight into the binding mode and interactions of the most promising compound 12 [oxo derivative], comprising of reverse transcriptase (RT) inhibitory (72.30%), spermicidal (MEC 0.01%), anti-Trichomonas (MIC 46.72 μM) and antifungal (MIC 9.34-74.8 μM) activities, along with its hydroxyl (17) and O-alkylated 4-trifluoromethylphenoxy (22) derivative, with similar activities. The stability of compound 12 in simulated vaginal fluid (SVF) and its preliminary in vivo pharmacokinetics performed in female NZ-rabbits signifies its clinical safety in comparison to marketed spermicide Nonoxynol-9. PMID:26209833

  14. Development and characterization of novel 1-(1-Naphthyl)piperazine-loaded lipid vesicles for prevention of UV-induced skin inflammation.

    PubMed

    Menezes, Ana Catarina; Campos, Patrícia Mazureki; Euletério, Carla; Simões, Sandra; Praça, Fabíola Silva Garcia; Bentley, Maria Vitória Lopes Badra; Ascenso, Andreia

    2016-07-01

    1-(1-Naphthyl)piperazine (1-NPZ) has shown promising effects by inhibiting UV radiation-induced immunosuppression. Ultradeformable vesicles are recent advantageous systems capable of improving the (trans)dermal drug delivery. The aim of this study was to investigate 1-NPZ-loaded transethosomes (NPZ-TE) and 1-NPZ-loaded vesicles containing dimethyl sulfoxide (NPZ-DM) as novel delivery nanosystems, and to uncover their chemopreventive effect against UV-induced acute inflammation. Their physicochemical properties were evaluated as follows: vesicles size and zeta potential by dynamic and electrophoretic light scattering, respectively; vesicle deformability by pressure driven transport; rheological behavior by measuring viscosity and I-NPZ entrapment yield by HPLC. In vitro topical delivery studies were performed in order to evaluate the permeation profile of both formulations, whereas in vivo studies sought to assess the photoprotective effect of the selected formulation on irradiated hairless mice by measuring myeloperoxidase activity and the secretion of proinflammatory cytokines. Either NPZ-TE or NPZ-DM exhibited positive results in terms of physicochemical properties. In vitro data revealed an improved permeation of 1-NPZ across pig ear skin, especially by NPZ-DM. In vivo studies demonstrated that NPZ-DM exposure was capable of preventing UVB-induced inflammation and blocking mediators of inflammation in mouse skin. The successful results here obtained encourage us to continue these studies for the management of inflammatory skin conditions that may lead to the development of skin cancers. PMID:27131752

  15. Antioxidant, DNA binding and nuclease activities of heteroleptic copper(II) complexes derived from 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols and diimines.

    PubMed

    Ravichandran, J; Gurumoorthy, P; Imran Musthafa, M A; Kalilur Rahiman, A

    2014-12-10

    A series of heteroleptic copper(II) complexes of the type [CuL(1-4)(diimine)](ClO4)2 (1-8) [L(1-4)=2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine=2,2'-bipyridyl (bpy) or 1,10-phenanthroline (phen)], have been synthesized and characterized by spectroscopic methods. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions and the electronic spectra revealed the square pyramidal geometry with N4O coordination environment around copper(II) nuclei. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region. The EPR spectra of complexes with g|| (2.206-2.214) and A|| (154-172×10(-)(4)cm(-)(1)) values support the square-based CuN3O coordination chromophore and the presence of unpaired electron localized in [Formula: see text] ground state. Antioxidant studies against DPPH revealed effective radical scavenging properties of the synthesized complexes. Binding studies suggest that the heteroleptic copper(II) complexes interact with calf thymus DNA (CT-DNA) through minor-groove and electrostatic interaction, and all the complexes display pronounced nuclease activity against supercoiled pBR322 DNA. PMID:24998685

  16. Crystal structure of an unknown solvate of (piperazine-κN){5,10,15,20-tetra­kis­[4-(benzo­yloxy)phen­yl]porphyrinato-κ4 N}zinc

    PubMed Central

    Nasri, Soumaya; Ezzayani, Khaireddine; Turowska-Tyrk, Ilona; Roisnel, Thierry; Nasri, Habib

    2016-01-01

    The title compound, [Zn(C72H44N4O8)(C4H10N2)] or [Zn(TPBP)(pipz] (where TPBP and pipz are 5,10,15,20-tetra­kis­[4-(benzo­yloxy)phen­yl]porphyrinato and piperazine ligands respectively), features a distorted square-pyramidal coordin­ation geometry about the central ZnII atom. This central atom is chelated by the four N atoms of the porphyrinate anion and further coordinated by a nitro­gen atom of the piperazine axial ligand, which adopts a chair confirmation. The average Zn—N(pyrrole) bond length is 2.078 (7) Å and the Zn— N(pipz) bond length is 2.1274 (19) Å. The zinc cation is displaced by 0.4365 (4) Å from the N4C20 mean plane of the porphyrinate anion toward the piperazine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling deformations. In the crystal, the supra­molecular structure is made by parallel pairs of layers along (100), with an inter­layer distance of 4.100 Å while the distance between two pairs of layers is 4.047 Å. A region of electron density was treated with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9–18] procedure in PLATON following unsuccessful attempts to model it as being part of disordered n-hexane solvent and water mol­ecules. The given chemical formula and other crystal data do not take into account these solvent mol­ecules. PMID:27555935

  17. Crystal structure of an unknown solvate of (piperazine-κN){5,10,15,20-tetra-kis-[4-(benzo-yloxy)phen-yl]porphyrinato-κ(4) N}zinc.

    PubMed

    Nasri, Soumaya; Ezzayani, Khaireddine; Turowska-Tyrk, Ilona; Roisnel, Thierry; Nasri, Habib

    2016-07-01

    The title compound, [Zn(C72H44N4O8)(C4H10N2)] or [Zn(TPBP)(pipz] (where TPBP and pipz are 5,10,15,20-tetra-kis-[4-(benzo-yloxy)phen-yl]porphyrinato and piperazine ligands respectively), features a distorted square-pyramidal coordin-ation geometry about the central Zn(II) atom. This central atom is chelated by the four N atoms of the porphyrinate anion and further coordinated by a nitro-gen atom of the piperazine axial ligand, which adopts a chair confirmation. The average Zn-N(pyrrole) bond length is 2.078 (7) Å and the Zn- N(pipz) bond length is 2.1274 (19) Å. The zinc cation is displaced by 0.4365 (4) Å from the N4C20 mean plane of the porphyrinate anion toward the piperazine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling deformations. In the crystal, the supra-molecular structure is made by parallel pairs of layers along (100), with an inter-layer distance of 4.100 Å while the distance between two pairs of layers is 4.047 Å. A region of electron density was treated with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9-18] procedure in PLATON following unsuccessful attempts to model it as being part of disordered n-hexane solvent and water mol-ecules. The given chemical formula and other crystal data do not take into account these solvent mol-ecules. PMID:27555935

  18. (3,3-Difluoro-pyrrolidin-1-yl)-[(2S,4S)-(4-(4-pyrimidin-2-yl-piperazin-1-yl)-pyrrolidin-2-yl]-methanone: A potent, selective, orally active dipeptidyl peptidase IV inhibitor

    SciTech Connect

    Ammirati, Mark J.; Andrews, Kim M.; Boyer, David D.; Brodeur, Anne M.; Danley, Dennis E.; Doran, Shawn D.; Hulin, Bernard; Liu, Shenping; McPherson, R. Kirk; Orena, Stephen J.; Parker, Janice C.; Polivkova, Jana; Qiu, Xiayang; Soglia, Carolyn B.; Treadway, Judith L.; VanVolkenburg, Maria A.; Wilder, Donald C.; Piotrowski, David W.; Pfizer

    2010-10-01

    A series of 4-substituted proline amides was synthesized and evaluated as inhibitors of dipeptidyl pepdidase IV for the treatment of type 2 diabetes. (3,3-Difluoro-pyrrolidin-1-yl)-[(2S,4S)-(4-(4-pyrimidin-2-yl-piperazin-1-yl)-pyrrolidin-2-yl]-methanone (5) emerged as a potent (IC{sub 50} = 13 nM) and selective compound, with high oral bioavailability in preclinical species and low plasma protein binding. Compound 5, PF-00734200, was selected for development as a potential new treatment for type 2 diabetes.

  19. Synthesis, crystal structures, molecular docking, and in vitro biological activities of transition metals with 4-(2,3-dichlorophenyl)piperazine-1-carboxylic acid.

    PubMed

    Yang, Dan-Dan; Chen, Ya-Nan; Wu, Yu-Shan; Wang, Rui; Chen, Zhi-Jian; Qin, Jie; Qian, Shao-Song; Zhu, Hai-Liang

    2016-07-15

    Four novel mononuclear complexes, [Cd(L)2·2H2O] (1), [Ni(L)2·2H2O] (2) [Cu(L)2·H2O] (3), and [Zn(L)2·2H2O] (4) (CCDC numbers: 1444630-1444633 for complexes 1-4) (HL=4-(2,3-dichlorophenyl)piperazine-1-carboxylic acid) were synthesized, and have been characterized by IR spectroscopy, elemental analysis, and X-ray crystallography. Molecular docking study preliminarily revealed that complex 1 had potential telomerase inhibitory activity. In accordance with the result of calculation, in vitro tests of the inhibitory activities of complex 1 against telomerase showed complex 1 (IC50=8.17±0.91μM) had better inhibitory activities, while complexes 2, 3 and 4 showed no inhibitory activities. Antiproliferative activity in human cancer cell line HepG2 was further determined by MTT assays. The IC50 value (6.5±0.2μM) for the complex 1 having good inhibitory activity against HepG2 was at the same micromolar concentrations with cis-platinum (2.2±1.2μM). While the IC50 value for the metal-free ligand, complex 2, 3 and 4 was more than 100μM. These results indicated that telomerase was potentially an anticancer drug target and showed that complex 1 was a potent inhibitor of human telomerase as well as an antiproliferative compound. PMID:27241690

  20. Simultaneous determination of 4-methyl-piperazine-1-carbodithioc acid 3-cyano-3,3-diphenylpropyl ester hydrochloride and its major metabolite in rats by HPLC.

    PubMed

    Jiang, Xiaomei; Bai, Yihao; Ling, Xiaomei; Han, Fangbin; Li, Runtao; Cui, Jingrong

    2010-02-01

    A method for the simultaneous determination of TM208 and its major metabolite (sulfine 4-methyl-piperazine-1-carbodithioc acid 3-cyano-3,3-diphenylpropyl ester, TM208-SO) was developed and validated for the first time. The analytes were extracted from plasma samples by liquid-liquid extraction and analyzed using high-performance liquid chromatography. Flunarizine hydrochloride was used as the internal standard. Chromatographic separations were performed on a Diamonsil C(18) analytical column. The mobile phases consisted of 20 mM ammonium acetate adjusted to pH 4.20 with acetic acid (solvent A) and acetonitrile (solvent B). The analytes were detected at 254 nm after linear gradient elution. The flow rate was 0.8 mL/min. Linearity was obtained over the concentration range of 0.104-5.20 microg/mL for TM208 and 0.145-5.80 microg/mL for TM208-SO in rat plasma. The limit of quantification was 0.104 microg/mL for TM208 and 0.145 microg/mL for TM208-SO, respectively. The inter- and intra-day precision was less than 12.8% for TM208 and 14.1% for TM208-SO. And the accuracy was 96.2-111.1% for TM208 and 95.5-108.6% for TM208-SO. This analytic procedure was applied to a pharmacokinetic study of TM208 and TM208-SO in rats, and the pharmacokinetic parameters were calculated. PMID:20109290

  1. Effects of two novel D3-selective compounds, NGB 2904 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-9H-fluorene-2-carboxamide] and CJB 090 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-4-(pyridin-2-yl)benzamide], on the reinforcing and discriminative stimulus effects of cocaine in rhesus monkeys.

    PubMed

    Martelle, Jennifer L; Claytor, Renee; Ross, Jason T; Reboussin, Beth A; Newman, Amy Hauck; Nader, Michael A

    2007-05-01

    The present study examined the effects of two novel dopamine D3 receptor compounds, NGB 2904 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-9H-fluorene-2-carboxamide], an antagonist, and CJB 090 [N-(4-(4-(2,3-dichlorophenyl)piperazin-1-yl)butyl)-4-(pyridin-2-yl)benzamide], a partial agonist, in two models of cocaine abuse in rhesus monkeys. To establish a dose range and time course of effects, both compounds were shown to block quinpirole-induced yawning when administered i.m. 15, 30, or 120 min before quinpirole. Next, rhesus monkeys were trained to discriminate i.m. injections of saline (0.5 ml) and cocaine (0.3 mg/kg). Neither D3 compound (0.03-3.0 mg/kg; n=3) substituted for cocaine in any monkey. When given in combination with cocaine, CJB 090 but not NGB 2904 attenuated the discriminative stimulus effects of cocaine, shifting the cocaine dose-response curve to the right. In a separate group of monkeys, responding was maintained under a second-order schedule of either food (1.0-g pellets; n=3) or cocaine (0.1 mg/kg/injection; n=4) presentation. When responding was stable, a dose of NGB 2904 (1.0-5.6 mg/kg i.v.) or CJB 090 (0.3-3.0 mg/kg i.v.) was administered for 5 consecutive days, immediately before the session. CJB 090, but not NGB 2904, decreased cocaine- and food-maintained responding. These data indicate that compounds with relatively high affinity and selectivity for the D3 receptor can attenuate the discriminative and reinforcing stimulus effects of cocaine while not producing cocaine-like effects. The present findings support the continued examination of D3 compounds as pharmacological tools for better understanding the role of this receptor subtype in cocaine addiction and as potential lead compounds for novel therapeutic agents. PMID:17272677

  2. Diffusion coefficients and heats of mixing in aqueous alkanolamines. Annual report, January-December 1992

    SciTech Connect

    Rowley, R.L.; Oscarson, J.L.

    1993-01-01

    The objective of the work is to provide accurate data on diffusion coefficients and heats of absorption of acid gases in aqueous amine solutions to assist in the design of economical new amine treating systems and to improve the efficiency of existing plants. Specifically covered in the report are measurements of the mutual diffusion coefficient of methyldiethanolamine(MDEA) and diethanolamine in water. Measurements have been made at 25, 50 and 75C and at 0, 20, 35 and 50 wt% amine. Heats of absorption of CO2 into aqueous mixtures of MDEA have also been measured calorimetrically. Results are reported at temperatures of 120 and 260F and pressures of 500 and 1000 psia at total MDEA concentrations of 20, 35 and 50%.

  3. Density and viscosity of some partially carbonated aqueous alkanolamine solutions and their blends

    SciTech Connect

    Weiland, R.H.; Dingman, J.C.; Cronin, D.B.; Browning, G.J.

    1998-05-01

    Very little information is available concerning the effect of acid gas loading on the physical properties of amine-treating solutions flowing through the absorption and regeneration columns used in gas processing. The densities and viscosities of partially carbonated monoethanolamine (MEA), diethanolamine (DEA), and N-methyldiethanolamine (MDEA) solutions were measured at 298 K. With increasing carbon dioxide loadings, significant increases in both density and viscosity were observed. These results were combined with literature data to produce correlations for alkanolamine solution density and viscosity as a function of amine concentration, carbon dioxide loading, and temperature. The resulting single-amine correlations were used to predict the densities and viscosities of DEA + MDEA and MEA + MDEA blends. Predictions are compared with data measured for these blends.

  4. Determination of the antihypertensive drug 1-[2-ethoxy-2-(3'-pyridyl)ethyl]-4-(2'-methoxyphenyl) piperazine (IP/66) in rat and human plasma by high-performance liquid chromatography and isotope dilution mass spectrometry.

    PubMed

    Agostini, O; Moneti, G; Bonacchi, G; Fedi, M; Manzini, S

    1989-02-24

    In connection with pharmacokinetic studies on the antihypertensive drug 1-[2-ethoxy-2-(3'-pyridyl)ethyl]-4-(2'-methoxyphenyl)piperazine (IP/66) (I), appropriate high-performance liquid chromatographic (HPLC) and gas chromatographic-mass spectrometric isotope dilution (GC-MS-ID) methods for its determination in rat and human plasma, respectively, were developed. In both techniques, deproteinized and basified plasma samples were extracted and purified by adsorption on an Extrelut-1 column, then the drug was eluted with dichloromethane. Quantitative HPLC analysis was performed on a C8 reversed-phase column. The mobile phase was phosphate buffer (0.02 M, pH 2.8)-acetonitrile (65:35), with UV detection at 208 nm. The internal standard was 1-[2-butoxy-2-(3'-pyridyl)ethyl]-4-(2'-methoxyphenyl)piperazine, a homologue of I. The inter-assay coefficient of variation (C.V.) was 9.9% for a drug level of 2 micrograms/ml. Quantitative GC-MS-ID analysis was performed with a DB-17 fused-silica capillary column using the selected-ion monitoring technique. The deuterated form of I, 1-[2-ethoxy-2-(3'-pyridyl)ethyl]-4-2'-trideuteromethoxyphenyl)pipe razine, utilized as internal standard, was synthesized. The inter-assay C.V. was 7.36% for a drug level of 1 ng/ml. PMID:2723000

  5. Seeking potent anti-tubercular agents: Design, synthesis, anti-tubercular activity and docking study of various ((triazoles/indole)-piperazin-1-yl/1,4-diazepan-1-yl)benzo[d]isoxazole derivatives.

    PubMed

    Naidu, Kalaga Mahalakshmi; Srinivasarao, Singireddi; Agnieszka, Napiórkowska; Ewa, Augustynowicz-Kopeć; Kumar, Muthyala Murali Krishna; Chandra Sekhar, Kondapalli Venkata Gowri

    2016-05-01

    A series of thirty eight novel 3-(4-((substituted-1H-1,2,3-triazol-4-yl)methyl)piperazin-1-yl/1,4-diazepan-1-yl)benzo[d]isoxazole and 1-(4-(benzo[d]isoxazol-3-yl)piperazin-1-yl/1,4-diazepan-1-yl)-2-(1H-indol-3-yl)substituted-1-one analogues were synthesised, characterised using various analytical techniques and evaluated for in vitro anti-tubercular activity against Mycobacterium tuberculosis H37Rv strain and two 'wild' strains Spec. 210 and Spec. 192. The titled compounds exhibited minimum inhibitory concentration (MIC) ranging from 6.16 to >200μM. Among the tested compounds, 7i, 7y and 7z exhibited moderate activity (MIC=24.03-29.19μM) and 7j exhibited very good anti-tubercular activity (MIC=6.16μM). Furthermore, 7i, 7j, 7y and 7z were found to be non-toxic against mouse macrophage cell lines when screened for toxicity. All the synthesised compounds were docked to pantothenate synthetase enzyme site to know deferent binding interactions with the receptor. PMID:27020525

  6. Crystal structure of 1-(3-chloro­phen­yl)piperazin-1-ium picrate–picric acid (2/1)

    PubMed Central

    Kavitha, Channappa N.; Jasinski, Jerry P.; Kaur, Manpreet; Anderson, Brian J.; Yathirajan, H. S.

    2014-01-01

    The title salt {systematic name: bis­[1-(3-chloro­phen­yl)piperazinium 2,4,6-tri­nitro­phenolate]–picric acid (2/1)}, 2C10H14ClN2 +·2C6H5N3O7 −·C6H6N3O7, crystallized with two independent 1-(3-chloro­phen­yl)piperazinium cations, two picrate anions and a picric acid mol­ecule in the asymmetric unit. The six-membered piperazine ring in each cation adopts a slightly distorted chair conformation and contains a protonated N atom. In the picric acid mol­ecule, the mean planes of the nitro groups in the ortho-, meta-, and para-positions are twisted from the benzene ring by 31.5 (3), 7.7 (1), and 3.8 (2)°, respectively. In the anions, the dihedral angles between the benzene ring and the ortho-, meta-, and para-nitro groups are 36.7 (1), 5.0 (6), 4.8 (2)°, and 34.4 (9), 15.3 (8), 4.5 (1)°, respectively. The nitro group in one anion is disordered and was modeled with two sites for one O atom with an occupancy ratio of 0.627 (7):0.373 (7). In the crystal, the picric acid mol­ecule inter­acts with the picrate anion through a trifurcated O—H⋯O four-centre hydrogen bond involving an intra­molecular O—H⋯O hydrogen bond and a weak C—H⋯O inter­action. Weak inter­molecular C—H⋯O inter­actions are responsible for the formation of cation–anion–cation trimers resulting in a chain along [010]. In addition, weak C—H⋯Cl and weak π–π inter­actions [centroid–centroid distances of 3.532 (3), 3.756 (4) and 3.705 (3) Å] are observed and contribute to the stability of the crystal packing. PMID:25484834

  7. Direct Phenotypic Screening in Mice: Identification of Individual, Novel Antinociceptive Compounds from a Library of 734 821 Pyrrolidine Bis-piperazines

    PubMed Central

    2015-01-01

    The hypothesis in the current study is that the simultaneous direct in vivo testing of thousands to millions of systematically arranged mixture-based libraries will facilitate the identification of enhanced individual compounds. Individual compounds identified from such libraries may have increased specificity and decreased side effects early in the discovery phase. Testing began by screening ten diverse scaffolds as single mixtures (ranging from 17 340 to 4 879 681 compounds) for analgesia directly in the mouse tail withdrawal model. The “all X” mixture representing the library TPI-1954 was found to produce significant antinociception and lacked respiratory depression and hyperlocomotor effects using the Comprehensive Laboratory Animal Monitoring System (CLAMS). The TPI-1954 library is a pyrrolidine bis-piperazine and totals 738 192 compounds. This library has 26 functionalities at the first three positions of diversity made up of 28 392 compounds each (26 × 26 × 42) and 42 functionalities at the fourth made up of 19 915 compounds each (26 × 26 × 26). The 120 resulting mixtures representing each of the variable four positions were screened directly in vivo in the mouse 55 °C warm-water tail-withdrawal assay (ip administration). The 120 samples were then ranked in terms of their antinociceptive activity. The synthesis of 54 individual compounds was then carried out. Nine of the individual compounds produced dose-dependent antinociception equivalent to morphine. In practical terms what this means is that one would not expect multiexponential increases in activity as we move from the all-X mixture, to the positional scanning libraries, to the individual compounds. Actually because of the systematic formatting one would typically anticipate steady increases in activity as the complexity of the mixtures is reduced. This is in fact what we see in the current study. One of the final individual compounds identified, TPI 2213-17, lacked significant

  8. Direct Phenotypic Screening in Mice: Identification of Individual, Novel Antinociceptive Compounds from a Library of 734,821 Pyrrolidine Bis-piperazines.

    PubMed

    Houghten, Richard A; Ganno, Michelle L; McLaughlin, Jay P; Dooley, Colette T; Eans, Shainnel O; Santos, Radleigh G; LaVoi, Travis; Nefzi, Adel; Welmaker, Greg; Giulianotti, Marc A; Toll, Lawrence

    2016-01-11

    The hypothesis in the current study is that the simultaneous direct in vivo testing of thousands to millions of systematically arranged mixture-based libraries will facilitate the identification of enhanced individual compounds. Individual compounds identified from such libraries may have increased specificity and decreased side effects early in the discovery phase. Testing began by screening ten diverse scaffolds as single mixtures (ranging from 17,340 to 4,879,681 compounds) for analgesia directly in the mouse tail withdrawal model. The "all X" mixture representing the library TPI-1954 was found to produce significant antinociception and lacked respiratory depression and hyperlocomotor effects using the Comprehensive Laboratory Animal Monitoring System (CLAMS). The TPI-1954 library is a pyrrolidine bis-piperazine and totals 738,192 compounds. This library has 26 functionalities at the first three positions of diversity made up of 28,392 compounds each (26 × 26 × 42) and 42 functionalities at the fourth made up of 19,915 compounds each (26 × 26 × 26). The 120 resulting mixtures representing each of the variable four positions were screened directly in vivo in the mouse 55 °C warm-water tail-withdrawal assay (ip administration). The 120 samples were then ranked in terms of their antinociceptive activity. The synthesis of 54 individual compounds was then carried out. Nine of the individual compounds produced dose-dependent antinociception equivalent to morphine. In practical terms what this means is that one would not expect multiexponential increases in activity as we move from the all-X mixture, to the positional scanning libraries, to the individual compounds. Actually because of the systematic formatting one would typically anticipate steady increases in activity as the complexity of the mixtures is reduced. This is in fact what we see in the current study. One of the final individual compounds identified, TPI 2213-17, lacked significant respiratory

  9. 4-(3-Chloro-5-(trifluoromethyl)pyridin-2-yl)-N-(4-methoxypyridin-2-yl)piperazine-1-carbothioamide (ML267), a Potent Inhibitor of Bacterial Phosphopantetheinyl Transferase That Attenuates Secondary Metabolism and Thwarts Bacterial Growth

    PubMed Central

    2015-01-01

    4′-Phosphopantetheinyl transferases (PPTases) catalyze a post-translational modification essential to bacterial cell viability and virulence. We present the discovery and medicinal chemistry optimization of 2-pyridinyl-N-(4-aryl)piperazine-1-carbothioamides, which exhibit submicromolar inhibition of bacterial Sfp-PPTase with no activity toward the human orthologue. Moreover, compounds within this class possess antibacterial activity in the absence of a rapid cytotoxic response in human cells. An advanced analogue of this series, ML267 (55), was found to attenuate production of an Sfp-PPTase-dependent metabolite when applied to Bacillus subtilis at sublethal doses. Additional testing revealed antibacterial activity against methicillin-resistant Staphylococcus aureus, and chemical genetic studies implicated efflux as a mechanism for resistance in Escherichia coli. Additionally, we highlight the in vitro absorption, distribution, metabolism, and excretion and in vivo pharmacokinetic profiles of compound 55 to further demonstrate the potential utility of this small-molecule inhibitor. PMID:24450337

  10. 1-[Bis(4-fluoro­phen­yl)meth­yl]-4-[(2Z)-3-phenyl­prop-2-en-1-yl]piperazine-1,4-diium dichloride hemihydrate

    PubMed Central

    Shivaprakash, S.; Chandrasekara Reddy, G.; Jasinski, Jerry P.

    2014-01-01

    The asymmetric unit of the title monohydrated salt, 2C26H28F2N2 2+·4Cl−.H2O, consists of a 1-[bis­(4-fluoro­phen­yl)meth­yl]-4-[(2Z)-3-phenyl­prop-2-en-1-yl]piperazine-1,4-diium cation with a diprotonated piperizine ring in close proximity to two chloride anions and a single water mol­ecule that lies on a twofold rotation axis. In the cation, the piperazine ring adopts a slightly distorted chair conformation. The dihedral angles between the phenyl ring and the 4-fluoro­phenyl rings are 89.3 (9) and 35.0 (5)°. The two fluoro­phenyl rings are inclined at 65.0 (5)° to one another. In the crystal, N—H⋯Cl hydrogen bonds and weak C—H⋯Cl inter­molecular inter­actions link the mol­ecules into chains along [010]. In addition, weak C—H⋯O inter­actions between the piperizine and prop-2-en-1-yl groups with the water mol­ecule, along with weak C—H⋯Cl inter­actions between the prop-2en-1-yl and methyl groups with the chloride ions, weak C—H⋯F inter­actions between the two fluoro­phenyl groups and weak O—H⋯Cl inter­actions between the water mol­ecule and chloride ions form a three-dimensional supra­molecular network. PMID:24940270

  11. Solubility of nitrous oxide in amine solutions

    SciTech Connect

    Bensetiti, Z.; Iliuta, I.; Larachi, F.; Grandjean, B.P.A.

    1999-01-01

    The solubility of nitrous oxide (N{sub 2}O) in 13 amine solvents and solutions was correlated to amine mole fractions and temperature using feedforward neural networks. This general correlation, using a massive database, predicted N{sub 2}O solubility at temperatures between 283 and 398 K in pure solvents [H{sub 2}O, monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA), and 2-amino-2-methyl-1-propanolamine (AMP)], in binary aqueous amine solutions [H{sub 2}O/MEA, H{sub 2}O/DEA, H{sub 2}O/MDEA, and H{sub 2}O/AMP], and in ternary aqueous amine blends [AMP/MDEA/H{sub 2}O, AMP/DEA/H{sub 2}O, DEA/MDEA/H{sub 2}O, MDEA/MEA/H{sub 2}O, and AMP/MEA/H{sub 2}O]. Combined with the N{sub 2}O analogy, this present improved correlation can be advantageously implemented in amine plant design software and procedures for the prediction of CO{sub 2} solubility in amine blend solutions over wide temperature and concentration ranges.

  12. Collection of VLE data for acid gas - alkanolamine systems using Fourier transform infrared spectroscopy. Final report, September 29, 1990--September 30, 1996

    SciTech Connect

    Bullin, J.A.; Rogers, W.J.

    1996-11-01

    This report describes research from September 29, 1990 through September 30, 1996, involving the development a novel Fourier transform infrared (FTIR) spectroscopic apparatus and method for measuring vapor - liquid equilibrium (VLE) systems of carbon dioxide and hydrogen sulfide with aqueous alkanolamine solutions. The original apparatus was developed and modified as it was used to collect VLE data on acid gas systems. Vapor and liquid calibrations were performed for spectral measurements of hydrogen sulfide and carbon dioxide in the vapor and in solution with aqueous diethanolamine (DEA) and methyldiethanolamine (MDEA). VLE measurements were made of systems of hydrogen sulfide and carbon dioxide in 20 wt % DEA at 50{degrees}C and 40{degrees}C. VLE measurements were made of systems of hydrogen sulfide and carbon dioxide in 50 wt% and 23 wt% MDEA at 40{degrees}C and in 23 wt% MDEA at 50{degrees}C. VLE measurements were made of systems of hydrogen sulfide and carbon dioxide in 35 wt% MDEA + 5 wt% DEA and in 35 wt% MDEA + 10 wt% DEA at 40{degrees}C and 50{degrees}C. Measurements were made of residual amounts of carbon dioxide in each VLE system. The new FTIR spectrometer is now a consistently working and performing apparatus.

  13. Crystal structure of 3-{[4-(2-meth-oxy-phen-yl)piperazin-1-yl]meth-yl}-5-(thio-phen-2-yl)-1,3,4-oxa-diazole-2(3H)-thione.

    PubMed

    Al-Alshaikh, Monirah A; Abuelizz, Hatem A; El-Emam, Ali A; Abdelbaky, Mohammed S M; Garcia-Granda, Santiago

    2016-02-01

    The title compound, C18H20N4O2S2, is a new 1,3,4-oxa-diazole and a key pharmacophore of several biologically active agents. It is composed of a meth-yl(thio-phen-2-yl)-1,3,4-oxa-diazole-2(3H)-thione moiety linked to a 2-meth-oxy-phenyl unit via a piperazine ring that has a chair conformation. The thio-phene ring mean plane lies almost in the plane of the oxa-diazole ring, with a dihedral angle of 4.35 (9)°. The 2-meth-oxy-phenyl ring is almost normal to the oxa-diazole ring, with a dihedral angle of 84.17 (10)°. In the crystal, mol-ecules are linked by weak C-H⋯S hydrogen bonds and C-H⋯π inter-actions, forming layers parallel to the bc plane. The layers are linked via weak C-H⋯O hydrogen bonds and slipped parallel π-π inter-actions [inter-centroid distance = 3.6729 (10) Å], forming a three-dimensional structure. The thio-phene ring has an approximate 180° rotational disorder about the bridging C-C bond. PMID:26958404

  14. 1-[(4-Chloro­phen­yl)(phen­yl)meth­yl]piperazine-1,4-diium bis­(trichloro­acetate)–trichloro­acetic acid (1/1)

    PubMed Central

    Song, Yanxi; Chidan Kumar, C. S.; Akkurt, Mehmet; Chandraju, S.; Li, Hongqi

    2012-01-01

    In the title salt adduct, C17H21ClN2 2+·2C2Cl3O2 −·C2HCl3O2, the Cl atom of the dication is disordered over two positions in a 0.915 (3):0.085 (3) ratio. The Cl atoms in the trichloroacetate anions and trichloroacetic acid molecule are also disordered, with refined site-occupation factors of 0.59 (3):0.41 (3), 0.503 (12):0.417 (12) and 0.653 (12):0.347 (12). The piperazine ring adopts a chair conformation, with puckering parameters Q T = 0.587 (3) Å, θ = 2.6 (2) and Φ 334 (6)°. In the crystal, neighbouring mol­ecules are linked by N—H⋯O, O—H⋯O, N—H⋯Cl, C—H⋯O and C—H⋯Cl hydrogen bonds, forming a three-dimensional network. PMID:22969587

  15. Rational design, synthesis, anti-HIV-1 RT and antimicrobial activity of novel 3-(6-methoxy-3,4-dihydroquinolin-1(2H)-yl)-1-(piperazin-1-yl)propan-1-one derivatives.

    PubMed

    Chander, Subhash; Wang, Ping; Ashok, Penta; Yang, Liu-Meng; Zheng, Yong-Tang; Murugesan, Sankaranarayanan

    2016-08-01

    In the present study, fifteen novel 3-(6-methoxy-3,4-dihydroquinolin-1(2H)-yl)-1-(piperazin-1-yl)propan-1-one (6a-o) derivatives were designed as inhibitor of HIV-1 RT using ligand based drug design approach and in-silico evaluated for drug-likeness properties. Designed compounds were synthesized, characterized and in-vitro evaluated for RT inhibitory activity against wild HIV-1 RT strain. Among the tested compounds, four compounds (6a, 6b, 6j and 6o) exhibited significant inhibition of HIV-1 RT (IC50⩽10μg/ml). All synthesized compounds were also evaluated for anti-HIV-1 activity as well as cytotoxicity on T lymphocytes, in which compounds 6b and 6l exhibited significant anti-HIV activity (EC50 values 4.72 and 5.45μg/ml respectively) with good safety index. Four compounds (6a, 6b, 6j and 6o) found significantly active against HIV-1 RT in the in-vitro assay were in-silico evaluated against two mutant RT strains as well as one wild strain. Further, titled compounds were evaluated for in-vitro antibacterial (Escherichia coli, Pseudomonas putida, Staphylococcus aureus and Bacillus cereus) and antifungal (Candida albicans and Aspergillus niger) activities. PMID:27288643

  16. CRISPR-Cas9-modified pfmdr1 protects Plasmodium falciparum asexual blood stages and gametocytes against a class of piperazine-containing compounds but potentiates artemisinin-based combination therapy partner drugs.

    PubMed

    Ng, Caroline L; Siciliano, Giulia; Lee, Marcus C S; de Almeida, Mariana J; Corey, Victoria C; Bopp, Selina E; Bertuccini, Lucia; Wittlin, Sergio; Kasdin, Rachel G; Le Bihan, Amélie; Clozel, Martine; Winzeler, Elizabeth A; Alano, Pietro; Fidock, David A

    2016-08-01

    Emerging resistance to first-line antimalarial combination therapies threatens malaria treatment and the global elimination campaign. Improved therapeutic strategies are required to protect existing drugs and enhance treatment efficacy. We report that the piperazine-containing compound ACT-451840 exhibits single-digit nanomolar inhibition of the Plasmodium falciparum asexual blood stages and transmissible gametocyte forms. Genome sequence analyses of in vitro-derived ACT-451840-resistant parasites revealed single nucleotide polymorphisms in pfmdr1, which encodes a digestive vacuole membrane-bound ATP-binding cassette transporter known to alter P. falciparum susceptibility to multiple first-line antimalarials. CRISPR-Cas9 based gene editing confirmed that PfMDR1 point mutations mediated ACT-451840 resistance. Resistant parasites demonstrated increased susceptibility to the clinical drugs lumefantrine, mefloquine, quinine and amodiaquine. Stage V gametocytes harboring Cas9-introduced pfmdr1 mutations also acquired ACT-451840 resistance. These findings reveal that PfMDR1 mutations can impart resistance to compounds active against asexual blood stages and mature gametocytes. Exploiting PfMDR1 resistance mechanisms provides new opportunities for developing disease-relieving and transmission-blocking antimalarials. PMID:27073104

  17. A scanning tunneling microscopy investigation of the phases formed by the sulfur adsorption on Au(100) from an alkaline solution of 1,4-piperazine(bis)-dithiocarbamate of potassium

    NASA Astrophysics Data System (ADS)

    Martínez, Javier A.; Valenzuela B., José; Cao Milán, R.; Herrera, José; Farías, Mario H.; Hernández, Mayra P.

    2014-11-01

    Piperazine-dithiocarbamate of potassium (K2DTC2pz) was used as a new precursor for the spontaneous deposition of sulfur on the Au(100) surface in alkaline solution. Two new sulfur phases were studied by scanning tunneling microscopy (STM). These phases were formed by six sulfur atoms (S6 phase, hexamer) and by four sulfur atoms (S4 phase, tetramer with (√{ 2} ×√{ 2}) structure), and they were observed in coexistence with the well-known quasi-square patterns formed by eight sulfur atoms (S8 phase, octomer). A model was proposed where sulfur multilayers were formed by a (√{ 2} ×√{ 2}) phase adsorbed directly on the gold surface while one of the other structures: hexamers or octomers were deposited on top. Sulfur layers were formed on gold terraces, vacancies and islands produced by lifting reconstructed surface. Sequential high-resolution STM images allowed the direct observation of the dynamic of the octomers, while the (√{ 2} ×√{ 2}) structure remained static. Images also showed the reversible association/dissociation of the octomer.

  18. Study of a regenerative process for selective sulfur dioxide removal using organic solvents

    SciTech Connect

    Van Dam, M.H.H.; Lamine, A.S.

    1996-12-31

    In searching appropriate solvents for selective sulfur dioxide removal it has been found that sulfur dioxide solubility can be well correlated by the Gutmann donor number of the solvent. Two solvents, N-methylpyrrolidone (NMP) and methyldiethanolamine (MDEA), have been selected for experiments. Mixtures of sulfur dioxide and solvent (1:1 mole ratio) have been prepared at low temperature. These mixtures give complexes, stable under the experimental conditions, with a melting point well above the melting point of the separate components. These mixtures have been analyzed by infra red, ultraviolet/visible and nuclear magnetic resonance spectroscopy. Solubility of sulfur dioxide in NMP and MDEA has been measured at 25{degrees}C in the range of 2000-5000 ppmv using a stirred tank reactor. 14 refs., 4 figs., 2 tabs.

  19. Acid gas absorption in aqueous solutions of mixed amines

    SciTech Connect

    Rinker, E.B.; Ashour, S.S.; Sandall, O.C.

    1996-12-31

    A mass transfer model has been developed to describe the rate of absorption (or desorption) of H{sub 2}S and CO{sub 2} in aqueous blends of a tertiary and a secondary or a primary amine. The model is based on penetration theory, and all significant chemical reactions are incorporated in the model. The reactions are taken to be reversible, with reactions involving only a proton transfer considered to be at equilibrium. The particular amines studied in this research were methyldiethanolamine (MDEA), a tertiary amine, and diethanolamine (DEA), a secondary amine. Key physicochemical data needed in the model, such as diffusion coefficients, kinetic rate constants, and gas solubilities, were measured. Experimental absorption rates of CO{sub 2} and H{sub 2}S were measured in a model gas-liquid contacting device and were compared with model predictions. Experiments were carried out for single amine solutions (both MDEA and DEA) and for amine blends.

  20. Amine plant troubleshooting and optimization

    SciTech Connect

    Abry, R.G.F.; DuPart, M.S.

    1995-04-01

    A systematic method for troubleshooting and optimization of amine plants, if properly used, will result in fewer plant upsets, quick and correct responses to changing conditions and long-term profitable operations of any amine unit. It is important for amine plants to maintain safe, continuous and optimized operations for short- and long-term success. Effective and fast resolution of maine unit upsets plays a large part in this success. These considerations are as important in plants using generic amines such as monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA) and specialty amines based on MDEA. The key to troubleshooting and optimization is a systematic approach. Developing and using control charts can also be used to monitor amine plant operations. By using these techniques collectively, a formal method for troubleshooting and optimization can be established. This will ultimately result in a more trouble-free, continuous operation.

  1. Quantitative determination of the hydrolysis products of nitrogen mustards in human urine by liquid chromatography-electrospray ionization tandem mass spectrometry.

    PubMed

    Lemire, Sharon W; Ashley, David L; Calafat, Antonia M

    2003-01-01

    Nitrogen mustards are a public health concern because of their extreme vesicant properties and the possible exposure of workers during the destruction of chemical stockpiles. A sensitive, rapid, accurate, and precise analysis for the quantitation of ultratrace levels of N-ethyldiethanolamine (EDEA) and N-methyldiethanolamine (MDEA) in human urine as a means of assessing recent exposure to the nitrogen mustards bis(2-chloroethyl)ethylamine and bis(2-chloroethyl)methylamine, respectively, was developed. The method was based on solid-phase extraction, followed by analysis of the urine extract using isotope-dilution high-performance liquid chromatography-mass spectrometry with TurbolonSpray ionization and multiple-reaction monitoring. The method limits of detection were 0.41 ng/mL for EDEA and 0.96 ng/mL for MDEA in 1 mL of urine with coefficients of variation < 10% for both compounds. PMID:12587675

  2. Shell coal gasification plant (SCGP-1) environmental performance results

    SciTech Connect

    Bush, W.V.; Baker, D.C.; Tijm, P.J.A. )

    1991-07-01

    Environmental studies in slip-stream process development units at SCGP-1, Shell's advanced coal gasification demonstration plant, located near Houston, Texas, have demonstrated that the gas and water effluents from the Shell Coal Gasification Process (SCGP) are environmentally benign on a broad slate of coals. This report presents the results of those environmental studies. It contains two major subjects, which describe, respectively, the experiments on gas treating and the experiments on water treating. Gas treatment focused on the performance of aqueous methyldiethanolamine (MDEA) and sulfinol-M. 8 refs., 24 figs., 13 tabs.

  3. Surface tension of aqueous solutions of diethanolamine and triethanolamine from 25 C to 50 C

    SciTech Connect

    Vazquez, G.; Alvarez, E.; Rendo, R.; Romero, E.; Navaza, J.M.

    1996-07-01

    Aqueous solutions of alkanolamines such as monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), N-methyldiethanolamine (MDEA), and 2-amino-2-methyl-1-propanol (AMP) are good solvents for the removal of acid gases such CO{sub 2} and H{sub 2}S from the gas streams of many processes in the natural gas, ammonia synthesis, and some chemical industries. The surface tension of aqueous solutions of diethanolamine and triethanolamine was measured over the entire concentration range at temperatures of 25 C to 50 C. The experimental values were correlated with temperature and with mole fraction. The maximum deviation was in both cases always less than 0.5%.

  4. Advanced process selectively removes H/sub 2/S

    SciTech Connect

    Not Available

    1981-06-08

    A selective H/sub 2/S-removal scheme called the HS process is being tested at a New Mexico pilot plant having an 18-in-diam contactor, a 24-in-diam stripping still, and a 30-gpm solution flow capacity. The test program goals are to (1) demonstrate the technical and economic superiority of the process over other options, and (2) redefine mass-transfer and ray hydraulic data for scale-up to commercial size. The technology combines a selective chemical solvent based on methyldiethanolamine (MDEA), a unique contactor design, and an innovative selective contactor tray.

  5. Physical solubility of carbon dioxide in aqueous alkanolamines via nitrous oxide analogy

    SciTech Connect

    Browning, G.J.; Weiland, R.H. . Dept. of Chemical Engineering)

    1994-10-01

    In the petrochemical and natural gas industry, the removal of carbon dioxide and hydrogen sulfide from process gas streams is commonly achieved by reacting these impurities with aqueous alkanolamines. Van Krevelen coefficients for protonated monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA), the carbamates of MEA and DEA, and the bicarbonate ion have been determined experimentally from measurements of the solubility of N[sub 2]O at 25 C and atmospheric pressure in aqueous solutions of these ions. Measured values different significantly from values recommended by others in the absence of experimental data. By analogy with N[sub 2]O, the solubility of carbon dioxide in the same solutions can be estimated.

  6. Thermodynamic properties and ideal-gas enthalpies of formation for dicyclohexyl sulfide, diethylenetriamine, di-n-octyl sulfide, dimethyl carbonate, piperazine, hexachloroprop-1-ene, tetrakis(dimethylamino)ethylene, N,N{prime}-bis-(2-hydroxyethyl)ethylenediamine, and 1,2,4-triazolo[1,5-a]pyrimidine

    SciTech Connect

    Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Smith, N.K.

    1997-11-01

    The results of the study are aimed at improvement of group-contribution methodology for estimation of thermodynamic properties of organic substances. Specific weaknesses where particular group-contribution terms were unknown, or estimated because of lack of experimental data, are addressed by experimental studies of enthalpies of combustion in the condensed phase, vapor-pressure measurements, and differential scanning calorimetric (DSC) heat-capacity measurements. Ideal-gas enthalpies of formation of hexachloroprop-1-ene, N,N{prime}-bis(2-hydroxyethyl)ethylenediamine, dimethyl carbonate, di-n-octyl sulfide, dicyclohexyl sulfide, diethylenetriamine, tetrakis(dimethylamino)ethylene, piperazine, and 1,2,4-triazolo[1,5-a]pyrimidine are reported. Enthalpies of fusion were determined for N,N{prime}-bis(2-hydroxyethyl)ethylenediamine, piperazine and 1,2,4-triazolo[1,5-a]pyrimidine. Two-phase (solid + vapor) or (liquid + vapor) heat capacities were determined from 300 K to the critical region or earlier decomposition temperature for each compound studied. Liquid-phase densities along the saturation line were measured for N,N{prime}-bis(2-hydroxyethyl)ethylenediamine, dimethyl carbonate, and dicyclohexyl sulfide. For dimethyl carbonate and piperazine, critical temperatures and critical densities were determined from the DSC results and corresponding critical pressures derived from the fitting procedures. Fitting procedures were used to derive critical temperatures, critical pressures, and critical densities for hexachloroprop-1-ene, di-n-octyl sulfide, dicyclohexyl sulfide, and diethylenetriamine. Group-additivity parameters and 1,4-interaction terms useful in the application of group-contribution correlations were derived.

  7. Exploring the Solid State Properties of Enzymatic Poly(amine-co-ester) Terpolymers to Expand their Applications in Gene Transfection.

    PubMed

    Voevodina, Irina; Scandola, Mariastella; Zhang, Junwei; Jiang, Zhaozhong

    2014-01-01

    Polymers bearing amino functional groups are an important class of materials capable of serving as non-viral carriers for DNA delivery to living cells. In this work biodegradable poly(amine-co-ester) terpolymers were synthesized via ring-opening and polycondensation copolymerization of lactone (ε-caprolactone (CL), ω-dodecalactone, ω-pentadecalactone (PDL), and ω-hexadecalactone) with diethyl sebacate (DES) and N-methyldiethanolamine (MDEA) in diphenyl ether, catalyzed by Candida antarctica lipase B (CALB). All lactone-DES-MDEA terpolymers had random distributions of lactone, sebacate, MDEA repeat units in the polymer chains. PDL-DES-MDEA terpolymers were studied in the composition range from 21 mol% to 90 mol% PDL whereas the terpolymers with other lactones were investigated at a single composition (80 mol% lactone). DSC and WAXS analyses showed that all investigated terpolymers crystallize in their respective homopolylactone crystal lattice. Terpolymers with large lactones and a high lactone content melt well above room temperature and are hard solids, whereas terpolymers with small lactones (e.g. CL) or with a low lactone content melt below/around ambient temperature and are waxy/gluey materials. Given the importance of hydrophobicity in influencing gene delivery, water contact angle measurements were carried out on lactone-DES-MDEA terpolymers showing that it is possible to tune the hydrophilic-to-hydrophobic balance by varying polymer composition and size of lactone units. To demonstrate the feasibility of using solid terpolymers as nanocarriers for DNA delivery, PDL-DES-MDEA copolymers with 65-90% PDL were successfully transformed into free-standing nanoparticles with average particle size ranging from 163 to 175 nm. Our preliminary results showed that LucDNA-loaded nanoparticles of the terpolymer with 65% PDL were effective for luciferase gene transfection of HEK293 cells. PMID:24683469

  8. Exploring the Solid State Properties of Enzymatic Poly(amine-co-ester) Terpolymers to Expand their Applications in Gene Transfection

    PubMed Central

    Voevodina, Irina; Scandola, Mariastella; Zhang, Junwei; Jiang, Zhaozhong

    2014-01-01

    Polymers bearing amino functional groups are an important class of materials capable of serving as non-viral carriers for DNA delivery to living cells. In this work biodegradable poly(amine-co-ester) terpolymers were synthesized via ring-opening and polycondensation copolymerization of lactone (ε-caprolactone (CL), ω-dodecalactone, ω-pentadecalactone (PDL), and ω-hexadecalactone) with diethyl sebacate (DES) and N-methyldiethanolamine (MDEA) in diphenyl ether, catalyzed by Candida antarctica lipase B (CALB). All lactone-DES-MDEA terpolymers had random distributions of lactone, sebacate, MDEA repeat units in the polymer chains. PDL-DES-MDEA terpolymers were studied in the composition range from 21 mol% to 90 mol% PDL whereas the terpolymers with other lactones were investigated at a single composition (80 mol% lactone). DSC and WAXS analyses showed that all investigated terpolymers crystallize in their respective homopolylactone crystal lattice. Terpolymers with large lactones and a high lactone content melt well above room temperature and are hard solids, whereas terpolymers with small lactones (e.g. CL) or with a low lactone content melt below/around ambient temperature and are waxy/gluey materials. Given the importance of hydrophobicity in influencing gene delivery, water contact angle measurements were carried out on lactone-DES-MDEA terpolymers showing that it is possible to tune the hydrophilic-to-hydrophobic balance by varying polymer composition and size of lactone units. To demonstrate the feasibility of using solid terpolymers as nanocarriers for DNA delivery, PDL-DES-MDEA copolymers with 65–90% PDL were successfully transformed into free-standing nanoparticles with average particle size ranging from 163 to 175 nm. Our preliminary results showed that LucDNA-loaded nanoparticles of the terpolymer with 65% PDL were effective for luciferase gene transfection of HEK293 cells. PMID:24683469

  9. Acute toxicity and primary irritancy of alkylalkanolamines.

    PubMed

    Ballantyne, B; Leung, H W

    1996-12-01

    The acute handling hazards of several alkylalkanolamines were determined by investigating their potential acute toxicity and primary irritancy. Materials studied were N-methylethanolamine (MEA), N, N, -dimethylethanolamine (DMEA), N, N, -dimethylisopropanolamine (DMIPA), N-methyldiethanolamine (MDEA), and tertbutyldiethanolamine (BDEA). All these alkylalkanolamines were of comparable acute peroral toxicity in the rat (LD50 range 1.48-2.83 ml/kg). By 24 h occluded epicutaneous contact in the rabbit, MEA, DMEA and DMIPA were of moderate acute percutaneous toxicity (LD50 range 1.13-2.0 ml/kg), MDEA was of slight acute percutaneous toxicity (LD50 male 9.85 ml/kg, female 10.90 ml/kg), and BDEA of intermediate toxicity (LD50 6.4 ml/kg). Due to differences in vapor pressure the acute vapor exposure toxicity of the alkylalkanolamines to rats varied; MEA, MDEA and BDEA were of a low order of acute toxicity, and DMIPA was moderately toxic with an LT50 of 3.2 h for a saturated vapor atmosphere exposure. A 4 h-LC50 (rat combined sex) of 1461 ppm was determined for DMEA. All alkylalkanolamines studied, except MDEA, were moderately to markedly irritating and caused variable degrees of skin corrosivity; MDEA caused only transient minor skin irritation. In accord with the skin irritancy results, the eye irritancy from 0.005 ml MEA, DMEA, DMIPA and BDEA was severe, and that from MDEA was slight. Exposure to these compounds has implications for occupational health procedures. PMID:8948072

  10. The small molecule '1-(4-biphenylylcarbonyl)-4-(5-bromo-2-methoxybenzyl) piperazine oxalate' and its derivatives regulate global protein synthesis by inactivating eukaryotic translation initiation factor 2-alpha.

    PubMed

    Hong, Mi-Na; Nam, Ky-Youb; Kim, Kyung Kon; Kim, So-Young; Kim, InKi

    2016-05-01

    By environmental stresses, cells can initiate a signaling pathway in which eukaryotic translation initiation factor 2-alpha (eIF2-α) is involved to regulate the response. Phosphorylation of eIF2-α results in the reduction of overall protein neogenesis, which allows cells to conserve resources and to reprogram energy usage for effective stress control. To investigate the role of eIF2-α in cell stress responses, we conducted a viability-based compound screen under endoplasmic reticulum (ER) stress condition, and identified 1-(4-biphenylylcarbonyl)-4-(5-bromo-2-methoxybenzyl) piperazine oxalate (AMC-01) and its derivatives as eIF2-α-inactivating chemical. Molecular characterization of this signaling pathway revealed that AMC-01 induced inactivation of eIF2-α by phosphorylating serine residue 51 in a dose- and time-dependent manner, while the negative control compounds did not affect eIF2-α phosphorylation. In contrast with ER stress induction by thapsigargin, phosphorylation of eIF2-α persisted for the duration of incubation with AMC-01. By pathway analysis, AMC-01 clearly induced the activation of protein kinase RNA-activated (PKR) kinase and nuclear factor-κB (NF-κB), whereas it did not modulate the activity of PERK or heme-regulated inhibitor (HRI). Finally, we could detect a lower protein translation rate in cells incubated with AMC-01, establishing AMC-01 as a potent chemical probe that can regulate eIF2-α activity. We suggest from these data that AMC-01 and its derivative compounds can be used as chemical probes in future studies of the role of eIF2-α in protein synthesis-related cell physiology. PMID:26873011

  11. N-(3,4-Dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[(11)C]methylphenyl)thiazol-2-yl]-1-carboxamide: A promising positron emission tomography ligand for fatty acid amide hydrolase.

    PubMed

    Shimoda, Yoko; Fujinaga, Masayuki; Hatori, Akiko; Yui, Joji; Zhang, Yiding; Nengaki, Nobuki; Kurihara, Yusuke; Yamasaki, Tomoteru; Xie, Lin; Kumata, Katsushi; Ishii, Hideki; Zhang, Ming-Rong

    2016-02-15

    To visualize fatty acid amide hydrolase (FAAH) in brain in vivo, we developed a novel positron emission tomography (PET) ligand N-(3,4-dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[(11)C]methylphenyl)thiazol-2-yl]-1-carboxamide ([(11)C]DFMC, [(11)C]1). DFMC (1) was shown to have high binding affinity (IC50: 6.1nM) for FAAH. [(11)C]1 was synthesized by C-(11)C coupling reaction of arylboronic ester 2 with [(11)C]methyl iodide in the presence of Pd catalyst. At the end of synthesis, [(11)C]1 was obtained with a radiochemical yield of 20±10% (based on [(11)C]CO2, decay-corrected, n=5) and specific activity of 48-166GBq/μmol. After the injection of [(11)C]1 in mice, high uptake of radioactivity (>2% ID/g) was distributed in the lung, liver, kidney, and brain, organs with high FAAH expression. PET images of rat brains for [(11)C]1 revealed high uptakes in the cerebellar nucleus (SUV=2.4) and frontal cortex (SUV=2.0), two known brain regions with high FAAH expression. Pretreatment with the FAAH-selective inhibitor URB597 reduced the brain uptake. Higher than 90% of the total radioactivity in the rat brain was irreversible at 30min after the radioligand injection. The present results indicate that [(11)C]1 is a promising PET ligand for imaging of FAAH in living brain. PMID:26740152

  12. Pharmacological Preconditioning of Mesenchymal Stem Cells with Trimetazidine (1-[2,3,4-Trimethoxybenzyl]piperazine) Protects Hypoxic Cells against Oxidative Stress and Enhances Recovery of Myocardial Function in Infarcted Heart through Bcl-2 Expression

    PubMed Central

    Wisel, Sheik; Khan, Mahmood; Kuppusamy, M. Lakshmi; Mohan, I. Krishna; Chacko, Simi M.; Rivera, Brian K.; Sun, Benjamin C.; Hideg, Kálmán; Kuppusamy, Periannan

    2009-01-01

    Stem cell transplantation is a possible therapeutic option to repair ischemic damage to the heart. However, it is faced with a number of challenges including the survival of the transplanted cells in the ischemic region. The present study was designed to use stem cells preconditioned with trimetazidine (1-[2,3,4-trimethoxybenzyl]piperazine; TMZ), a widely used anti-ischemic drug for treating angina in cardiac patients, to increase the rate of their survival after transplantation. Bone marrow-derived rat mesenchymal stem cells (MSCs) were subjected to a simulated host tissue environment by culturing them under hypoxia (2% O2) and using hydrogen peroxide (H2O2) to induce oxidative stress. MSCs were preconditioned with 10 μM TMZ for 6 h followed by treatment with 100 μM H2O2 for 1 h and characterized for their cellular viability and metabolic activity. The preconditioned cells showed a significant protection against H2O2-induced loss of cellular viability, membrane damage, and oxygen metabolism accompanied by a significant increase in HIF-1α, survivin, phosphorylated Akt (pAkt), and Bcl-2 protein levels and Bcl-2 gene expression. The therapeutic efficacy of the TMZ-preconditioned MSCs was evaluated in an in vivo rat model of myocardial infarction induced by permanent ligation of left anterior descending coronary artery. A significant increase in the recovery of myocardial function and up-regulation of pAkt and Bcl-2 levels were observed in hearts transplanted with TMZ-preconditioned cells. This study clearly demonstrated the potential benefits of pharmacological preconditioning of MSCs with TMZ for stem cell therapy for repairing myocardial ischemic damage. PMID:19218529

  13. The antidepressant-like activity of 6-methoxy-2-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one involves serotonergic 5-HT(1A) and 5-HT(2A/C) receptors activation.

    PubMed

    Pytka, Karolina; Walczak, Maria; Kij, Agnieszka; Rapacz, Anna; Siwek, Agata; Kazek, Grzegorz; Olczyk, Adrian; Gałuszka, Adam; Waszkielewicz, Anna; Marona, Henryk; Sapa, Jacek; Filipek, Barbara

    2015-10-01

    Xanthone derivatives have been shown to posses many biological properties. Some of them act within the central nervous system and show neuroprotective or antidepressant-like properties. Taking this into account we investigated antidepressant-like activity in mice and the possible mechanism of action of 6-methoxy-2-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one (HBK-11) - a new xanthone derivative. We demonstrated that HBK-11 produced antidepressant-like effects in the forced swim test and tail suspension test, comparable to that of venlafaxine. The combined treatment with sub-effective doses of HBK-11 and fluoxetine (but not reboxetine or bupropion) significantly reduced the immobility in the forced swim test. Moreover, the antidepressant-like activity of HBK-11 in the aforementioned test was blocked by p-chlorophenylalanine, and significantly reduced by serotonergic 5HT1A receptor antagonist - WAY-1006335 and 5HT2A/C receptor antagonist - ritanserin. As none of the above treatments influenced the spontaneous locomotor activity, it can be concluded that HBK-11 mediates its activity through a serotonergic system, and its antidepressant-like effect involves 5HT1A and 5HT2A/C receptor activation. Furthermore, at antidepressant-like doses HBK-11 did not cause the mice to display locomotor deficits in rotarod or chimney tests. Considering the pharmacokinetic profile, HBK-11 demonstrated rapid absorption after i.p. administration, high clearance value, short terminal half-life, very high volume of distribution and incomplete bioavailability. The compound studied had good penetration into the brain tissue of mice. Since studied xanthone derivative seems to present interesting, untypical mechanism of antidepressant-like action i.e. 5HT2A/C receptor activation, it may have a potential in the treatment of depressive disorders, and surely requires further studies. PMID:26210317

  14. Neuroprotective targets through which 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), a sigma receptor ligand, mitigates the effects of methamphetamine in vitro

    PubMed Central

    Kaushal, Nidhi; Robson, Matthew J.; Rosen, Abagail; McCurdy, Christopher R.; Matsumoto, Rae R.

    2014-01-01

    Exposure to high or repeated doses of methamphetamine can cause hyperthermia and neurotoxicity, which are thought to increase the risk of developing a variety of neurological conditions. Sigma receptor antagonism can prevent methamphetamine-induced hyperthermia and neurotoxicity, but the underlying cellular targets through which the neuroprotection is conveyed remain unknown. Differentiated NG108-15 cells were thus used as a model system to begin elucidating the neuroprotective mechanisms targeted by sigma receptor antagonists to mitigate the effects of methamphetamine. In differentiated NG108-15 cells, methamphetamine caused the generation of reactive oxygen/nitrogen species, an increase in PERK-mediated endoplasmic reticulum stress and the activation of caspase-3, -8 and -9, ultimately resulting in apoptosis at micromolar concentrations, and necrotic cell death at higher concentrations. The sigma receptor antagonist, 6-acetyl-3-(4-(4-(4-fluorophenyl)piperazin-1-yl)butyl)benzo[d]oxazol-2(3H)-one (SN79), attenuated methamphetamine-induced increases in reactive oxygen/nitrogen species, activation of caspase-3,-8 and-9 and accompanying cellular toxicity. In contrast, 1,3-di(2-tolyl)-guanidine (DTG), a sigma receptor agonist, shifted the dose response curve of methamphetamine-induced cell death towards the left. To probe the effect of temperature on neurotoxicity, NG108-15 cells maintained at an elevated temperature (40 °C) exhibited a significant and synergistic increase in cell death in response to methamphetamine, compared to cells maintained at a normal cell culture temperature (37 °C). SN79 attenuated the enhanced cell death observed in the methamphetamine-treated cells at 40 °C. Together, the data demonstrate that SN79 reduces methamphetamine-induced reactive oxygen/nitrogen species generation and caspase activation, thereby conveying neuroprotective effects against methamphetamine under regular and elevated temperature conditions. PMID:24380829

  15. Novel Piperazine Arylideneimidazolones Inhibit the AcrAB-TolC Pump in Escherichia coli and Simultaneously Act as Fluorescent Membrane Probes in a Combined Real-Time Influx and Efflux Assay.

    PubMed

    Bohnert, Jürgen A; Schuster, Sabine; Kern, Winfried V; Karcz, Tadeusz; Olejarz, Agnieszka; Kaczor, Aneta; Handzlik, Jadwiga; Kieć-Kononowicz, Katarzyna

    2016-04-01

    In this study, we tested five compounds belonging to a novel series of piperazine arylideneimidazolones for the ability to inhibit the AcrAB-TolC efflux pump. The biphenylmethylene derivative (BM-19) and the fluorenylmethylene derivative (BM-38) were found to possess the strongest efflux pump inhibitor (EPI) activities in the AcrAB-TolC-overproducingEscherichia colistrain 3-AG100, whereas BM-9, BM-27, and BM-36 had no activity at concentrations of up to 50 μM in a Nile red efflux assay. MIC microdilution assays demonstrated that BM-19 at 1/4 MIC (intrinsic MIC, 200 μM) was able to reduce the MICs of levofloxacin, oxacillin, linezolid, and clarithromycin 8-fold. BM-38 at 1/4 MIC (intrinsic MIC, 100 μM) was able to reduce only the MICs of oxacillin and linezolid (2-fold). Both compounds markedly reduced the MIC of rifampin (BM-19, 32-fold; and BM-38, 4-fold), which is suggestive of permeabilization of the outer membrane as an additional mechanism of action. Nitrocefin hydrolysis assays demonstrated that in addition to their EPI activity, both compounds were in fact weak permeabilizers of the outer membrane. Moreover, it was found that BM-19, BM-27, BM-36, and BM-38 acted as near-infrared-emitting fluorescent membrane probes, which allowed for their use in a combined influx and efflux assay and thus for tracking of the transport of an EPI across the outer membrane by an efflux pump in real time. The EPIs BM-38 and BM-19 displayed the most rapid influx of all compounds, whereas BM-27, which did not act as an EPI, showed the slowest influx. PMID:26824939

  16. 9α-Hy-droxy-12-{[4-(4-hy-droxy-phen-yl)piperazin-1-yl]meth-yl}-4,8-dimethyl-3,14-dioxatri-cyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one.

    PubMed

    Loubidi, Mohamed; Benharref, Ahmed; El Ammari, Lahcen; Saadi, Mohamed; Berraho, Moha

    2014-05-01

    The title compound, C25H34N2O5, was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methylen-3, 14-dioxa-tri-cyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which in turn was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The mol-ecule comprises a ten-membered ring fused to a five-membered ring with an additional ep-oxy ring system fused to the ten-membered ring. The five-membered ring also carries a 4-hy-droxy-phenyl-piperazin-1-ylmethyl substituent. The ten-membered ring adopts an approximate chair-chair conformation, while the piperazine ring displays a chair conformation and the five-membered ring shows an envelope conformation with the C atom closest to the hy-droxy group forming the flap. Two C atoms in the phenyl ring and the O atom of the hydroxyl group are disordered over two sites, with an occupancy ratio of 0.53 (5):0.47 (5). An intra-molecular O-H⋯N hydrogen-bond stabilizes the mol-ecular conformation. In the crystal, C-H⋯O hydrogen bonds link the mol-ecules into zigzag chains running along the a-axis direction. PMID:24860343

  17. 12-{[4-(4-Bromo-phen-yl)piperazin-1-yl]meth-yl}-9α-hy-droxy-4,8-dimethyl-3,14-dioxatri-cyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one.

    PubMed

    Loubidi, Mohamed; Benharref, Ahmed; El Ammari, Lahcen; Saadi, Mohamed; Berraho, Moha

    2014-04-01

    The title compound, C25H33BrN2O4, was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methylen-3,14-dioxa-tri-cyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The mol-ecule is built up from two fused five- and ten-membered rings with an additional ep-oxy ring system and a bromo-phenyl-piperazine group as a substituent. The ten-membered ring adopts an approximate chair-chair-chair conformation, while the piperazine ring displays a chair conformation and the five-membered ring shows an envelope conformation with the C atom closest to the hy-droxy group forming the flap. An intra-molecular O-H⋯N hydrogen bond stabilizes the mol-ecular conformation. The crystal packing features C-H⋯O hydrogen bonds, which link the mol-ecules into zigzag chains running along the b-axis direction. PMID:24826186

  18. Studies of the biogenic amine transporters. XI. Identification of a 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazine (GBR12909) analog that allosterically modulates the serotonin transporter.

    PubMed

    Nightingale, Barbara; Dersch, Christina M; Boos, Terrence L; Greiner, Elisabeth; Calhoun, William J; Jacobson, Arthur E; Rice, Kenner C; Rothman, Richard B

    2005-08-01

    Previous studies identified partial inhibitors of serotonin (5-HT) transporter and dopamine transporter binding. We report here on a partial inhibitor of 5-HT transporter (SERT) binding identified among a group of 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazine analogs (4-[2-[bis(4-fluorophenyl)-methoxy]ethyl]-1-(2-trifluoromethyl-benzyl)-piperidine; TB-1-099). Membranes were prepared from rat brains or human embryonic kidney cells expressing the cloned human dopamine (hDAT), serotonin (hSERT), and norepinephrine (hNET) transporters. beta-(4'-(125)Iodophenyl)tropan-2beta-carboxylic acid methyl ester ([(125)I]RTI-55) binding and other assays followed published procedures. Using rat brain membranes, TB-1-099 weakly inhibited DAT binding (K(i) = 439 nM), was inactive at NET binding ([(3)H]nisoxetine), and partially inhibited SERT binding with an extrapolated plateau ("A" value) of 20%. Similarly, TB-1-099 partially inhibited [(125)I]RTI-55 binding to hSERT with an extrapolated plateau (A value) of 14%. Upon examining the effect of increasing concentrations of TB-1-099 on the apparent K(d) and B(max) of [(125)I]RTI-55 binding to hSERT, we found that TB-1-099 decreased the B(max) in a dose-dependent manner and affected the apparent K(d) in a manner well described by a sigmoid dose-response curve. TB-1-099 increased the K(d) but not to the magnitude expected for a competitive inhibitor. In rat brain synaptosomes, TB-1-099 noncompetitively inhibited [(3)H]5-HT, but not [(3)H]dopamine, uptake. Dissociation experiments indicated that TB-1-099 promoted the rapid dissociation of a small component of [(125)I]RTI-55 binding to hSERT. Association experiments demonstrated that TB-1-099 slowed [(125)I]RTI-55 binding to hSERT in a manner unlike that of the competitive inhibitor indatraline. Viewed collectively, these results support the hypothesis that TB-1-099 allosterically modulates hSERT binding and function. PMID:15860577

  19. Ether modifications to 1-[2-(3,4-dimethoxyphenyl)ethyl]-4-(3-phenylpropyl)piperazine (SA4503): effects on binding affinity and selectivity for sigma receptors and monoamine transporters

    PubMed Central

    Xu, Rong; Lord, Sarah A.; Peterson, Ryan M.; Fergason-Cantrell, Emily A.; Lever, John R.; Lever, Susan Z.

    2014-01-01

    Two series of novel ether analogs of the sigma (σ) receptor ligand 1-[2-(3,4-dimethoxyphenyl)ethyl]-4-(3-phenylpropyl)piperazine (SA4503) have been prepared. In one series, the alkyl portion of the 4-methoxy group was replaced with allyl, propyl, bromoethyl, benzyl, phenethyl, and phenylpropyl moieties. In the second series, the 3,4-dimethoxy was replaced with cyclic methylenedioxy, ethylenedioxy and propylenedioxy groups. These ligands, along with 4-O-des-methyl SA4503, were evaluated for σ1 and σ2 receptor affinity, and compared to SA4503 and several known ether analogs. SA4503 and a subset of ether analogs were also evaluated for dopamine transporter (DAT) and serotonin transporter (SERT) affinity. The highest σ1 receptor affinities, Ki values of 1.75 nM – 4.63 nM, were observed for 4-O-des-methyl SA4503, SA4503 and the methylenedioxy analog. As steric bulk increased, σ1 receptor affinity decreased, but only to a point. Allyl, propyl and bromoethyl substitutions gave σ1 receptor Ki values in the 20 nM – 30 nM range, while bulkier analogs having phenylalkyl, and Z- and E-iodoallyl, ether substitutions showed higher σ1 affinities, with Ki values in the 13 nM – 21 nM range. Most ligands studied exhibited comparable σ1 and σ2 affinities, resulting in little to no subtype selectivity. SA4503, the fluoroethyl analog and the methylenedioxy congener showed modest six- to fourteen-fold selectivity for σ1 sites. DAT and SERT interactions proved much more sensitive than σ receptor interactions to these structural modifications. For example, the benzyl congener (σ1 Ki = 20.8 nM; σ2 Ki = 16.4 nM) showed over 100-fold higher DAT affinity (Ki = 121 nM) and 6-fold higher SERT affinity (Ki = 128 nM) than the parent SA4503 (DAT Ki = 12650 nM; SERT Ki = 760 nM). Thus, ether modifications to the SA4503 scaffold can provide polyfunctional ligands having a broader spectrum of possible pharmacological actions. PMID:25468036

  20. Determination of nitrogen mustard hydrolysis products, ethanolamines by gas chromatography-mass spectrometry after tert-butyldimethylsilyl derivatization.

    PubMed

    Ohsawa, Isaac; Seto, Yasuo

    2006-07-28

    A method for determining N-ethyldiethanolamine (EDEA), N-methyldiethanolamine (MDEA) and triethanolamine (TEA), hydrolysis products of nitrogen mustards, in water, urine and blood samples using gas chromatography-mass spectrometry (GC-MS) after derivatization by tert-butyldimethylsilylation (TBDMS) is described. The sample solution was evaporated to dryness, and reacted with N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) at 60 degrees C for 1h. The TBDMS derivatives were separated on a DB-5 column and detected by electron-ionization MS. The quantitation of EDEA, MDEA and TEA was performed by measuring the respective peak areas on the extracted ion chromatograms of m/z 216, m/z 202 and m/z 346, respectively, using nonadecane (C19), the peak area of which was measured at m/z 268, as an internal standard. When the water sample was initially analyzed, considerable loss of EDEA, MDEA and TEA occurred by evaporation. The addition of hydrochloric acid (HCl) to the water sample (final 1 mM), however, permitted quantitative recoveries to be achieved (88%, 88% and 79% for EDEA-(TBDMS)2, MDEA-(TBDMS)2 and TEA-(TBDMS)3, respectively). The limits of detections (LODs, scan mode, S/N = 3) were 2.5, 2.5 and 10 ng/ml for EDEA, MDEA and TEA, respectively. Ethanolamines could be also determined in urine samples (volume 0.1 ml), with reasonable recoveries of 72-100% by the addition of HCl (final 1 mM). For the analysis of serum samples, the sample was precipitated by the addition of perchloric acid (final 3.2%), and the resulting supernatant was neutralized with potassium carbonate, and then acidified by the addition of HCl. The recovery of TBDMS derivatives of ethanolamines was found to rather low (7-31%). PMID:16707130

  1. Quantitation of biomarkers of exposure to nitrogen mustards in urine from rats dosed with nitrogen mustards and from an unexposed human population.

    PubMed

    Lemire, Sharon W; Barr, John R; Ashley, David L; Olson, Carl T; Hayes, Timothy L

    2004-01-01

    The nitrogen mustards bis(2-chloroethyl)ethylamine (HN1), bis(2-chloroethyl)methylamine (HN2), and tris(2-chloroethyl)amine (HN3) have the potential to be used as chemical terrorism agents because of their extreme vesicant properties. We modified a previously reported method to incorporate automated solid-phase extraction, improve chromatography, and include the urinary metabolite for HN3. The improved method was used to measure levels of the urinary metabolites N-ethyldiethanolamine (EDEA), N-methyldiethanolamine (MDEA), and triethanolamine (TEA) in rats dosed with HN1, HN2, and HN3, respectively, and to establish background levels of EDEA, MDEA, and TEA in human urine samples from a population with no known exposure to nitrogen mustards. Rat dosing experiments confirmed that EDEA, MDEA, and TEA could be detected in urine for at least 48 h after exposure to HN1, HN2, and HN3, respectively. Substantial amounts of EDEA (89 ng/mL), MDEA (170 ng/mL), and TEA (1105 ng/mL) were measured in the urine of rats exposed to 10 mg HN1, HN2, and HN3, respectively, 48 h after exposure. The background concentrations for TEA in the human population ranged from below the limit of detection (LOD 3 ng/mL) to approximately 6500 ng/mL. Neither EDEA (LOD 0.4 ng/mL) nor MDEA (LOD 0.8 ng/mL) was detected above the LOD in the human samples. PMID:15239850

  2. 21 CFR 520.1807 - Piperazine.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... control of parasitism. (2) Turkeys—(i) Amount. 100 milligrams per bird up to 12 weeks and 200 milligrams... veterinarian for assistance in the diagnosis, treatment, and control of parasitism. (3) Swine—(i) Amount. 50... control of parasitism....

  3. 21 CFR 520.1807 - Piperazine.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...—(1) Chickens—(i) Amount. 50 milligrams per bird under 6 weeks, 100 milligrams per bird over 6 weeks... control of parasitism. (2) Turkeys—(i) Amount. 100 milligrams per bird up to 12 weeks and 200 milligrams per bird over 12 weeks. (ii) Indications for use. For removal of large roundworm (Ascaridia...

  4. 21 CFR 520.1807 - Piperazine.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... control of parasitism. (2) Turkeys—(i) Amount. 100 milligrams per bird up to 12 weeks and 200 milligrams... veterinarian for assistance in the diagnosis, treatment, and control of parasitism. (3) Swine—(i) Amount. 50... control of parasitism....

  5. Collection of VLE data for acid gas-alkanolamine systems using Fourier transform infrared spectroscopy

    SciTech Connect

    Bullin, J.A.; Frazier, R.E.

    1991-09-01

    The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor -- liquid equilibrium (VLE) hinder the industry from converting operations to more energy efficient amine mixtures and conserving energy. Some energy reductions have been realized in the past decade by applying such amine systems as hindered'' amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate fundamental VLE data impedes the commercial application of these more efficient alkanolamine systems. The first project objective is to improve the accuracy of vapor -- liquid equilibrium measurements at low hydrogen sulfide concentrations. The second project objective is to measure the VLE for amine mixtures. By improving the accuracy of the VLE measurements on MDEA and mixtures with other amines, energy saving can be quickly and confidently implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy savings are estimated to be about 3 {times} 10{sup 14} BTU/yr.

  6. Collection of VLE data for acid gas-alkanolamine systems using Fourier transform infrared spectroscopy. Phase 1, September 29, 1990--September 30, 1991

    SciTech Connect

    Bullin, J.A.; Frazier, R.E.

    1991-09-01

    The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor -- liquid equilibrium (VLE) hinder the industry from converting operations to more energy efficient amine mixtures and conserving energy. Some energy reductions have been realized in the past decade by applying such amine systems as ``hindered`` amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate fundamental VLE data impedes the commercial application of these more efficient alkanolamine systems. The first project objective is to improve the accuracy of vapor -- liquid equilibrium measurements at low hydrogen sulfide concentrations. The second project objective is to measure the VLE for amine mixtures. By improving the accuracy of the VLE measurements on MDEA and mixtures with other amines, energy saving can be quickly and confidently implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy savings are estimated to be about 3 {times} 10{sup 14} BTU/yr.

  7. Evaluation of the electrode method for measuring H/sub 2/S vapor pressure over alkanolamine solutions

    SciTech Connect

    Austgen, D.M.; Rochelle, G.T.

    1987-01-01

    A new electrode method for measuring the equilibrium vapor pressure of H/sub 2/S over any sulfide solution was tested. The method relates the electropotential difference produced between pH and silver/sulfide ion specific electrodes to the H/sub 2/S equilibrium vapor pressure of solution. The experimental technique is simple and time efficient. In this work, H/sub 2/S equilibrium vapor pressures were measured from 10/sup -4/ kPa to 10 kPa at 25/sup 0/C in aqueous solutions of monoethanolamine-MEA (2.5 N), diethanolamine-DEA (2.0N), and methyldiethanolamine-MDEA (1.0 N and 4.28 N). The H/sub 2/S vapor-liquid equilibria (VLE) of 4.28 N MDEA was also examined at 40/sup 0/C. The results indicate that the addition of MEA to a MDEA solution reduces the H/sub 2/S vapor pressure only at low H/sub 2/S loadings.

  8. Polymerization Behavior and Polymer Properties of Eosin-Mediated Surface Modification Reactions.

    PubMed

    Avens, Heather J; Randle, Thomas James; Bowman, Christopher N

    2008-10-17

    Surface modification by surface-mediated polymerization necessitates control of the grafted polymer film thicknesses to achieve the desired property changes. Here, a microarray format is used to assess a range of reaction conditions and formulations rapidly in regards to the film thicknesses achieved and the polymerization behavior. Monomer formulations initiated by eosin conjugates with varying concentrations of poly(ethylene glycol) diacrylate (PEGDA), N-methyldiethanolamine (MDEA), and 1-vinyl-2-pyrrolidone (VP) were evaluated. Acrylamide with MDEA or ascorbic acid as a coinitiator was also investigated. The best formulation was found to be 40 wt% acrylamide with MDEA which yielded four to eight fold thicker films (maximum polymer thickness increased from 180 nm to 1420 nm) and generated visible films from 5-fold lower eosin surface densities (2.8 vs. 14 eosins/µm(2)) compared to a corresponding PEGDA formulation. Using a microarray format to assess multiple initiator surface densities enabled facile identification of a monomer formulation that yields the desired polymer properties and polymerization behavior across the requisite range of initiator surface densities. PMID:19838291

  9. Collection of VLE data for acid gas---alkanolamine systems using fourier transform infrared spectroscopy. [Vapor-liquid equilibrium

    SciTech Connect

    Bullin, J.A.; Frazier, R.E.

    1992-01-01

    The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor--liquid equilibrium (VLE) hinder the industry from converting operations to more energy efficient amine mixtures and conserving energy. Some energy reductions have been realized in the past decade by applying such amine systems as hindered'' amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate fundamental VLE data impedes the commercial application of these more efficient alkanolamine systems. The first project objective is to improve the accuracy of vapor--liquid equilibrium measurements at low hydrogen sulfide concentrations. The second project objective is to measure the VLE for amine mixtures. By improving the accuracy of the VLE measurements on MDEA and mixtures with other amines, energy saving can be quickly and confidently implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy savings are estimated to be about 3 [times] 10[sup 14] BTU/yr.

  10. Polymerization Behavior and Polymer Properties of Eosin-Mediated Surface Modification Reactions

    PubMed Central

    Avens, Heather J.; Randle, Thomas James; Bowman, Christopher N.

    2008-01-01

    Surface modification by surface-mediated polymerization necessitates control of the grafted polymer film thicknesses to achieve the desired property changes. Here, a microarray format is used to assess a range of reaction conditions and formulations rapidly in regards to the film thicknesses achieved and the polymerization behavior. Monomer formulations initiated by eosin conjugates with varying concentrations of poly(ethylene glycol) diacrylate (PEGDA), N-methyldiethanolamine (MDEA), and 1-vinyl-2-pyrrolidone (VP) were evaluated. Acrylamide with MDEA or ascorbic acid as a coinitiator was also investigated. The best formulation was found to be 40 wt% acrylamide with MDEA which yielded four to eight fold thicker films (maximum polymer thickness increased from 180 nm to 1420 nm) and generated visible films from 5-fold lower eosin surface densities (2.8 vs. 14 eosins/µm2) compared to a corresponding PEGDA formulation. Using a microarray format to assess multiple initiator surface densities enabled facile identification of a monomer formulation that yields the desired polymer properties and polymerization behavior across the requisite range of initiator surface densities. PMID:19838291

  11. Densities of aqueous blended amines

    SciTech Connect

    Hsu, C.H.; Li, M.H.

    1997-05-01

    Solutions of alkanolamines are an industrially important class of compounds used in the natural gas and synthetic ammonia industries and petroleum chemical plants for the removal of CO{sub 2} and H{sub 2}S from gas streams. The densities of aqueous mixtures of diethanolamine (DEA) + N-methyldiethanolamine (MDEA) + water, DEA + 2-amino-2-methyl-1-propanol (AMP) + water, and monoethanolamine (MEA) + 2-piperidineethanol (2-PE) + water were measured from 30 C to 80 C. A Redlich-Kister equation of the excess volume was applied to represent the density. Based on the available density data for five ternary systems: MEA + MDEA + H{sub 2}O, MEA + AMP + H{sub 2}O, DEA + MDEA + H{sub 2}O, DEA + AMP + H{sub 2}O, and MEA + 2-PE + H{sub 2}O, a generalized set of binary parameters were determined. The density calculations show quite satisfactory results. The overall average absolute percent deviation is about 0.04% for a total of 686 data points.

  12. Viscosities of aqueous blended amines

    SciTech Connect

    Hsu, C.H.; Li, M.H.

    1997-07-01

    Solutions of alkanolamines are an industrially important class of compounds used in the natural gas, oil refineries, petroleum chemical plants, and synthetic ammonia industries for the removal of acidic components like CO{sub 2} and H{sub 2}S from gas streams. The viscosities of aqueous mixtures of diethanolamine (DEA) + N-methyldiethanolamine (MDEA), DEA + 2-amino-2-methyl-1-propanol (AMP), and monoethanolamine (MEA) + 2-piperidineethanol (2-PE) were measured from 30 C to 80 C. A Redlich-Kister equation for the viscosity deviation was applied to represent the viscosity. On the basis of the available viscosity data for five ternary systems, MEA + MDEA + H{sub 2}O, MEA + AMP + H{sub 2}O, DEA + MDEA + H{sub 2}O, DEA + AMP + H{sub 2}O, and MEA + 2-PE + H{sub 2}O, a generalized set of binary parameters were determined. For the viscosity calculation of the systems tested, the overall average absolute percent deviation is about 1.0% for a total of 499 data points.

  13. Alternative stripper configurations for CO{sub 2} capture by aqueous amines

    SciTech Connect

    Oyenekan, B.A.; Rochelle, G.T.

    2007-12-15

    Aqueous absorption/stripping is a promising technology for the capture of CO{sub 2} from existing or new coal-fired power plants. Four new stripper configurations (matrix, internal exchange, flashing feed, and multipressure with split feed) have been evaluated with seven model solvents that approximate the thermodynamic and rate properties of 7m (30 wt %) monoethanolamine (MEA), potassium carbonate promoted bypiperazine (PZ), promoted MEA, methyldiethanolamine (MDEA) promoted by PZ, and hindered amines. The results show that solvents with high heats of absorption (MEA, MEA/PZ) favor operation at normal pressure. The relative performance of the alternative configurations is matrix > internal exchange > multipressure with split feed > flashing feed. MEA/PZ and MDEA/PZ are attractive alternatives to 7m MEA. The best solvent and process configuration, matrix with MDEA/PZ, offers 22 and 15% energy savings over the baseline and improved baseline, respectively,with stripping and compression to 10 MPa. The energy requirement for stripping and compression to 10 MPa is about 20% of the power output from a 500 MW power plant with 90% CO{sub 2} removal.

  14. Collection of VLE data for acid gas---alkanolamine systems using fourier transform infrared spectroscopy. Phase 2, October 1, 1991--September 30, 1992

    SciTech Connect

    Bullin, J.A.; Frazier, R.E.

    1992-12-01

    The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor--liquid equilibrium (VLE) hinder the industry from converting operations to more energy efficient amine mixtures and conserving energy. Some energy reductions have been realized in the past decade by applying such amine systems as ``hindered`` amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate fundamental VLE data impedes the commercial application of these more efficient alkanolamine systems. The first project objective is to improve the accuracy of vapor--liquid equilibrium measurements at low hydrogen sulfide concentrations. The second project objective is to measure the VLE for amine mixtures. By improving the accuracy of the VLE measurements on MDEA and mixtures with other amines, energy saving can be quickly and confidently implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy savings are estimated to be about 3 {times} 10{sup 14} BTU/yr.

  15. Collection of VLE data for acid gas-alkanolamine systems using Fourier transform infrared spectroscopy. Technical report, October 1, 1994--July 31, 1995

    SciTech Connect

    Bullin, J.A.; Rogers, W.J.

    1995-08-01

    The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. The natural gas industry requires vapor-liquid equilibrium (VLE) data to develop more energy efficient amine mixtures. Some energy reductions have been realized in the past decade by applying such amine systems as hindered amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate VLE data impedes the commercial application of these more efficient alkanolamine systems. The first objective of this project is to improve the accuracy of vapor-liquid equilibrium measurements at low hydrogen sulfide concentrations. The second objective is to make VLE measurements for amine mixtures. By improving the accuracy of the VLE data on MDEA and other amines, energy savings can be implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy saved is estimated to be 3 {times} 10{sup 14} BTU/yr. 14 refs., 31 figs., 12 tabs.

  16. Crystal structure of 3-{[4-(2-meth­oxy­phen­yl)piperazin-1-yl]meth­yl}-5-(thio­phen-2-yl)-1,3,4-oxa­diazole-2(3H)-thione

    PubMed Central

    Al-Alshaikh, Monirah A.; Abuelizz, Hatem A.; El-Emam, Ali A.; Abdelbaky, Mohammed S. M.; Garcia-Granda, Santiago

    2016-01-01

    The title compound, C18H20N4O2S2, is a new 1,3,4-oxa­diazole and a key pharmacophore of several biologically active agents. It is composed of a meth­yl(thio­phen-2-yl)-1,3,4-oxa­diazole-2(3H)-thione moiety linked to a 2-meth­oxy­phenyl unit via a piperazine ring that has a chair conformation. The thio­phene ring mean plane lies almost in the plane of the oxa­diazole ring, with a dihedral angle of 4.35 (9)°. The 2-meth­oxy­phenyl ring is almost normal to the oxa­diazole ring, with a dihedral angle of 84.17 (10)°. In the crystal, mol­ecules are linked by weak C—H⋯S hydrogen bonds and C—H⋯π inter­actions, forming layers parallel to the bc plane. The layers are linked via weak C—H⋯O hydrogen bonds and slipped parallel π–π inter­actions [inter­centroid distance = 3.6729 (10) Å], forming a three-dimensional structure. The thio­phene ring has an approximate 180° rotational disorder about the bridging C—C bond. PMID:26958404

  17. Discovery of 8-Cyclopentyl-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidine-6-carbonitrile (7x) as a Potent Inhibitor of Cyclin-Dependent Kinase 4 (CDK4) and AMPK-Related Kinase 5 (ARK5)

    PubMed Central

    2015-01-01

    The success of imatinib, a BCR-ABL inhibitor for the treatment of chronic myelogenous leukemia, has created a great impetus for the development of additional kinase inhibitors as therapeutic agents. However, the complexity of cancer has led to recent interest in polypharmacological approaches for developing multikinase inhibitors with low toxicity profiles. With this goal in mind, we analyzed more than 150 novel cyano pyridopyrimidine compounds and identified structure–activity relationship trends that can be exploited in the design of potent kinase inhibitors. One compound, 8-cyclopentyl-2-[4-(4-methyl-piperazin-1-yl)-phenylamino]-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidine-6-carbonitrile (7x), was found to be the most active, inducing apoptosis of tumor cells at a concentration of approximately 30–100 nM. In vitro kinase profiling revealed that 7x is a multikinase inhibitor with potent inhibitory activity against the CDK4/CYCLIN D1 and ARK5 kinases. Here, we report the synthesis, structure–activity relationship, kinase inhibitory profile, in vitro cytotoxicity, and in vivo tumor regression studies by this lead compound. PMID:24417566

  18. In situ hydrothermal syntheses, structures and photoluminescent properties of four novel metal-organic frameworks constructed by lanthanide (Ln=Ce(III), Pr(III), Eu(III)) and Cu(I) metals with flexible dicarboxylate acids and piperazine-based ligands

    NASA Astrophysics Data System (ADS)

    Ay, Burak; Karaca, Serkan; Yildiz, Emel; Lopez, Valerie; Nanao, Max H.; Zubieta, Jon

    2016-01-01

    Four novel metal-organic frameworks,[Cu2Cl2(pyrz)]n (1) and (H2pip)n[Ln2(pydc)4(H2O)2]n (Ln=Ce (2), Pr (3) and Eu (4), H2pzdc=2,3-pyrazinedicarboxylic acid, pyrz=pyrazine, H2pydc=2,6-pyridinedicarboxylic acid, H2pip=piperazine) have been synthesized under hydrothermal conditions and characterized by the elemental analysis, ICP, Far IR (FIR), FT-IR spectra, TGA, single crystal X-ray diffraction analysis and powder X-ray diffraction (PXRD). Compound 1 is two-dimensional containing Cl-Cu-Cl sites, while the lanthanide complexes contain one-dimensional infinite Ln-O-Ln chains. All the complexes show high thermal stability. The complexes 1-3 exhibit luminescence emission bands at 584, 598 and 614 nm at room temperature when excited at 300 nm. Complex 4 exhibits bright red solid-state phosphorescence upon exposure to UV radiation at room temperature.

  19. Development of (S)-N6-(2-(4-(Isoquinolin-1-yl)piperazin-1-yl)ethyl)-N6-propyl-4,5,6,7-tetrahydrobenzo[d]-thiazole-2,6-diamine and its analogue as a D3 receptor preferring agonist: Potent in vivo activity in Parkinson’s disease animal models

    PubMed Central

    Ghosh, Balaram; Antonio, Tamara; Zhen, Juan; Kharkar, Prashant; Reith, Maarten E. A.; Dutta, Aloke K.

    2010-01-01

    Here we report structure-activity relationship study of a novel hybrid series of compounds where structural alteration of aromatic hydrophobic moieties connected to the piperazine ring and bioisosteric replacement of the aromatic tetralin moieties were carried out. Binding assays were carried out with HEK-293 cells expressing either D2 or D3 receptors with tritiated spiperone to evaluate inhibition constants (Ki). Functional activity of selected compounds in stimulating GTPγS binding was assessed with CHO cells expressing human D2 receptors and AtT-20 cells expressing human D3 receptors. SAR results identified compound (−)-24c (D-301) as one of the lead molecules with preferential agonist activity for D3 receptor (EC50 (GTPγS); D3 = 0.52 nM; D2/D3 (EC50): 223). Compounds (−)-24b and (−)-24c exhibited potent radical scavenging activity. The two lead compounds (−)-24b and (−)-24c exhibited high in vivo activity in two Parkinson’s disease (PD) animal models, reserpinized rat model and 6-OH-DA induced unilaterally lesioned rat model. Future studies will explore potential use of these compounds in the neuroprotective therapy for PD. PMID:20038106

  20. Regeneration of 2-amino-2-methyl-1-propanol used for carbon dioxide absorption.

    PubMed

    Zhang, Pei; Shi, Yao; Wei, Jianwen; Zhao, Wei; Ye, Qing

    2008-01-01

    To improve the efficiency of the carbon dioxide cycling process and to reduce the regeneration energy consumption, a sterically hindered amine of 2-amino-2-methyl-1-propranol (AMP) was investigated to determine its regeneration behavior as a CO2 absorbent. The CO2 absorption and amine regeneration characteristics were experimentally examined under various operating conditions. The regeneration efficiency increased from 86.2% to 98.3% during the temperature range of 358 to 403 K. The most suitable regeneration temperature for AMP was 383 K, in this experiment condition, and the regeneration efficiency of absorption/regenerationruns descended from 98.3% to 94.0%. A number of heat-stable salts (HSS) could cause a reduction in CO2 absorption capacity and regeneration efficiency. The results indicated that aqueous AMP was easier to regenerate with less loss of absorption capacity than other amines, such as, monoethanolamine (MEA), diethanolamine (DEA), diethylenetriamine (DETA), and N-methyldiethanolamine (MDEA). PMID:18572520

  1. Michigan plant opens up nearby sour-gas field

    SciTech Connect

    Marsh, R.J.

    1987-08-31

    The article discusses several shut-in sour-gas wells in the Manistee, Mich., area which prompted the construction and subsequent start-up in May 1986 of the Manistee gas-processing plant. The plant is currently serving several wells (operated by independent oil and gas producers) which were in need of processing prior to gas sales. The new plant consists of an MDEA (methyldiethanolamine) gas-processing unit, a conventional glycol dehydrator, and a Lo-Cat (registered trademark) hydrogen sulfide oxidation process for conversion of the hydrogen sulfide to elemental sulfur. Rated at 20 MMscfd, it is capable of removing 13.3 light tons/day of sulfur. The combination of an amine plant followed by a Lo-Cat unit has been used in several smaller plants but never before on this large a scale. The Manistee plant's Lo-Cat is the largest autocirculation unit yet build, the next largest being approximately one tenth its capacity.

  2. Kinetics of the reaction between carbon dioxide and tertiary amines

    SciTech Connect

    Crooks, J.E.; Donnellan, J.P. )

    1990-02-16

    The reaction between carbon dioxide and amines is of great technical importance and has been the subject of many investigations. The authors have shown that the reaction for secondary amines in anhydrous ethanol and in aqueous solution is exclusively second-order in amine and that the zwitterion intermediate postulated by Danckwerts is probably of negligible significance in the mechanism. The reaction with tertiary amines has also been studied, but the data are less controversial. In order to complete their studies of the reactions of carbon dioxide with amines, using their conductimetric stopped-flow apparatus, they have studied this reaction for MDEA (methyldiethanolamine, IUPAC name N-methyl-2,2{prime}-iminodiethanol) and TEA (triethanolamine, IUPAC name 2,2{prime},2{double prime}-nitrilotris(ethanol)).

  3. Highly stretchable nanoalginate based polyurethane elastomers.

    PubMed

    Daemi, Hamed; Barikani, Mehdi; Barmar, Mohammad

    2013-06-20

    Highly stretchable elastomeric samples based on cationic polyurethane dispersions-sodium alginate nanoparticles (CPUD/SA) were prepared by the solution blending of sodium alginate and aqueous polyurethane dispersions. CPUDs were synthesized by step growth polymerization technique using N-methyldiethanolamine (MDEA) as a source of cationic emulsifier. The chemical structure and thermal-mechanical properties of these systems were characterized using FTIR and DMTA, respectively. The presence of nanoalginate particles including nanobead and nanorod particles were proved by SEM and EDX. It was observed that thermal properties of composites increased with increasing SA content. All prepared samples were known as thermoplastic-elastomers with high percentages of elongation. Excellent compatibility of prepared nanocomposites was proved by the DMTA data. PMID:23648022

  4. Determination of alkanolamines in cattails (Typha latifolia) utilizing electrospray ionization with selected reaction monitoring and ion-exchange chromatography.

    PubMed

    Peru, Kerry M; Headley, John V; Doucette, William J

    2004-01-01

    Selected reaction monitoring (SRM) with electrospray ionization was used as a specific detection technique for the analysis of alkanolamines in plant tissue extracts. Ion-exchange chromatography was used as the method of separation. Quantification was based on monitoring the loss of either H2O or 2(H2O) from the protonated molecule [M+H]+. The method provided increased selectivity for all analytes and better detection limits for three of the six analytes investigated compared with an earlier method using selected ion monitoring with liquid chromatography. Instrumental detection limits ranged from 6-300 pg injected for monoethanolamine (MEA), monoisopropanolamine (MIPA), diethanolamine (DEA), methyldiethanolamine (MDEA), diisopropanolamine (DIPA), and triethanolamine (TEA). Method robustness and selectivity were demonstrated by the determination of DIPA and a known transformation product MIPA in over 35 plant extract samples derived from a laboratory study of plant uptake mechanisms. PMID:15282789

  5. Kinetic study of carbon dioxide reaction with tertiary amines in aqueous solutions

    SciTech Connect

    Barth, D.; Tondre, C.; Lappai, G.; Delpuech, J.J.

    1981-11-26

    Reaction kinetics of CO/sub 2/ with triethanolamine (TEA) and methyldiethanolamine (MDEA) in aqueous solution have been studied by using a stopped-flow technique with pH detection. Rate constants are obtained from the comparison of experimental and theoretical curves giving the optical density as a function of time. At concentrations of CO/sub 2/ well below the saturation limit, the results are consistent with the hydration reactions of the CO/sub 2/ molecules either with neutral water molecules or with hydroxide ions, depending upon the pH, itself governed by the ionization equilibrium of the dissolved amine. Moreover, a specific (catalytic) reaction, first order with respect to both carbon dioxide and amine (rate constant, 2.85 M/sup -1/ s/sup -1/ at 25/sup 0/C), has been shown to contribute significantly to the reaction rate in the case of the first amine (TEA) only.

  6. A more energy efficient product for carbon dioxide separation

    SciTech Connect

    Niswander, R.H.; Edwards, D.J.; DuPart, M.S.; Tse, J.P.

    1993-01-01

    Aqueous solutions of alkanolamines such as monoethanolamine (MEA) have been used for years to separate carbon dioxide and hydrogen sulfide from other gases in continuous absorption/desorption processes to meet very low treated gas specifications. However, MEA can undergo side reactions with CO{sub 2} which produce various types of degradation compounds. These by-products reduce performance of the solvent leading to increased energy consumption and corrosion. This can be a serious problem in applications such as the removal of CO{sub 2} in synthesis gas and natural gas treating with down stream cryogenic equipment. Formulated alkanolamine products based on methyldiethanolamine (MDEA) have made significant advances in energy efficiency, but are still susceptible to degradation and decreased performance. A next generation product, GAS/SPEC CS-PLUS, has now been developed and shown to be even more energy efficient. In addition, it improves separation and overall capacity while maintaining long term performance.

  7. Offshore desulfurization unit permits gas lift operations

    SciTech Connect

    Cabes, A.; Elgue, J.; Tournier-Lasserve, J. )

    1992-01-13

    This paper reports on the installation of a desulfurization unit for the Tchibouela oil field, offshore Congo, which allowed produced low-pressure associated gas containing CO{sub 2} to be kept for gas lift operations while, for safety reasons, the large volume of H{sub 2}S at low pressure was removed prior to compression. Since October 1989, the world's first offshore amine sweetening unit has worked satisfactorily and continues to prove that it is an attractive production alternative. For desulfurization, a selective methyldiethanolamine (MDEA) process, developed by Elf Aquitaine, was chosen because it was the only process that met the required specifications at a low pressure of 3.5 bar (51 psi).

  8. Predict amine solution properties accurately

    SciTech Connect

    Cheng, S.; Meisen, A.; Chakma, A.

    1996-02-01

    Improved process design begins with using accurate physical property data. Especially in the preliminary design stage, physical property data such as density viscosity, thermal conductivity and specific heat can affect the overall performance of absorbers, heat exchangers, reboilers and pump. These properties can also influence temperature profiles in heat transfer equipment and thus control or affect the rate of amine breakdown. Aqueous-amine solution physical property data are available in graphical form. However, it is not convenient to use with computer-based calculations. Developed equations allow improved correlations of derived physical property estimates with published data. Expressions are given which can be used to estimate physical properties of methyldiethanolamine (MDEA), monoethanolamine (MEA) and diglycolamine (DGA) solutions.

  9. Reversible Switching of Amphiphilic Self-Assemblies of Ionic Liquids between Micelle and Vesicle by CO2.

    PubMed

    Shi, Yunlei; Xiong, Dazhen; Wang, Huiyong; Zhao, Yang; Wang, Jianji

    2016-07-12

    The creation of CO2-responsive materials that undergo structural transition between micelle and vesicle is of great importance from both theoretical and practical points of view. In this work, we have developed a series of CO2-responsive single-tailed amphiphilic ionic liquids (ILs) composed of N-alkyl-N-methyldiethanolamine cation [CnMDEA](+) (n = 8, 10, 12, 14, 16, 18) and 2-pyrrolidinone [2-Pyr](-) anion. The aggregation behavior and self-assembly structures of the ILs in aqueous solution have been investigated by conductivity, surface tension, dynamic light scattering, cryogenic transmission electron microscopy, small-angle X-ray scattering, and nuclear magnetic resonance spectroscopy. For the first time, CO2 driven reversible switching of self-assembly between spherical micelle and unilamellar vesicle is found for [CnMDEA][2-Pyr] (n = 16, 18) in aqueous solutions at 20 °C and atmospheric pressure. It is shown that the mechanism behind the reversible micelle to vesicle transition involves the formation of carbamate anion from the reaction between [2-Pyr](-) and CO2. PMID:27315131

  10. Iron(III) carboxylate/aminoalcohol coordination clusters with propeller-shaped Fe8 cores: approaching reasonable exchange energies.

    PubMed

    Botezat, Olga; van Leusen, Jan; Kravtsov, Victor Ch; Ellern, Arkady; Kögerler, Paul; Baca, Svetlana G

    2015-12-21

    A series of new octanuclear propeller-like aminoalcohol-supported Fe(III) oxocarboxylate coordination clusters, [Fe8O3(O2CCHMe2)9(tea)(teaH)3]·MeCN·2(H2O) (1), [Fe8O3(O2CCHMe2)6(N3)3(tea)(teaH)3] (2), [Fe8O3(O2CCMe3)6(N3)3(tea)(teaH)3]·0.5(EtOH) (3), and [Fe8O3(O2CCHMe2)6(N3)3(mdea)3(MeO)3] (4) (where teaH3 = triethanolamine; mdeaH2 = N-methyldiethanolamine) has been isolated and magnetochemically analyzed combining the programs wxJFinder and CONDON in an approach to avoid overparameterization issues that are common to larger spin polytopes. Dominant antiferromagnetic exchange interactions exist in all clusters along the edges of the propellers, while moderate ferromagnetic interactions are found along the propeller axes in their {Fe8O3} metallic cores. PMID:26567887

  11. Accelerated field facility development for hot sour gas

    SciTech Connect

    Kuntz, L.K.

    1983-10-01

    This paper presents the chronological plan by which a grass roots sweetening facility was constructed in a minimum amount of time. The facility design was based on production with 9% carbon dioxide and 40 ppm hydrogen sulfide. Flowing wellhead temperatures were predicted to be approximately 300/sup 0/F with flowing wellhead pressures to 11,500 psi. The production facility, with a current total nominal capacity of 100 MMcf/D, was installed as five separate parallel sweetening units. The units were put on-stream in phases in order to maintain a sweetening capacity schedule compatible with wells being put on production. The first units were available for service in three months. All five units were complete in nine months, and a permanent facility installation was commissioned three months later. The process design, equipment procurement, and installation phases of the project were pursued concurrently. Three different sweetening systems were operated during the facility development. A conventional DEA (diethanolamine) system was used because of its simple operation. Conversions were made to a proprietary MDEA (methyldiethanolamine) system in order to increase capacity. A proprietary activated MDEA was tested and operated in order to determine sweetening system selection for future facility capacity and for other applications. Included is a discussion of the project development procedure and key considerations that led to minimal development time. General comparisons are made concerning the performance of several sweetening systems.

  12. High-throughput sample preparation and simultaneous column regeneration liquid chromatography-tandem mass spectrometry method for determination of nitrogen mustard metabolites in human urine.

    PubMed

    Reddy, Muntha K; Mills, Grier; Nixon, Christopher; Wyatt, Shane A; Croley, Timothy R

    2011-08-15

    Nitrogen mustards (NMs) are known to have DNA alkylation and strong vesicant properties. Their availability to terrorist organizations makes them a potential choice for chemical attacks on civilian populations. After an exposure, it is difficult to measure NMs directly because of their rapid metabolism in the human body. Therefore to determine an individual's level of exposure to NMs, it is necessary to analyze for NM metabolites being excreted by the body. The metabolites of NMs are generated by a hydrolysis reaction, and are easily detectable by liquid chromatography tandem mass spectrometry (LC-MS/MS). This work is focused on the development of a high-throughput assay for the quantitation of N-ethyldiethanolamine (EDEA) and N-methyldiethanolamine (MDEA) metabolites of bis (2-chloroethyl) ethylethanamine (HN1) and bis (2-chloroethyl) methylethanamine (HN2), respectively. The method uses automated 96-well plate sample preparation of human urine samples and a 2-position 10-port switching valve to allow for simultaneous regeneration of the liquid chromatography (LC) columns. Using this method, over 18 h was saved through the reduction of sample preparation and analysis time when compared to a conventional method for 96 samples. The validated method provided excellent accuracy for both EDEA (100.9%) and MDEA (100.6%) with precision better than 5.27% for each analyte. PMID:21764395

  13. Patch testing with components of water-based metalworking fluids.

    PubMed

    Geier, Johannes; Lessmann, Holger; Frosch, Peter J; Pirker, Claudia; Koch, Patrick; Aschoff, Roland; Richter, Gerhard; Becker, Detlef; Eckert, Christian; Uter, Wolfgang; Schnuch, Axel; Fuchs, Thomas

    2003-08-01

    Water-based metalworking fluids (MWFs) may cause both irritant and allergic contact dermatitis. Several well-known MWF allergens are available for patch testing, but considering the wide variety of possible components used in MWF, our diagnostic arsenal covers only a small part of potential allergens. We therefore selected 13 frequently used MWF components that might be sensitizers and had not yet been tested routinely. In 5 centres, 233 dermatitis patients with present or past occupational exposure to MWF were patch tested with this and other panels. Only 7 patients showed positive reactions to the study panel. Allergic reactions to the emulsifier diglycolamine [syn. 2-(2-aminoethoxy) ethanol] were seen in 5 patients, and 1 patient each reacted positively to 2-amino-2-ethyl-1,3-propanediol (AEPD) and methyldiethanolamine (MDEA). Clinical relevance of the reactions to diglycolamine was unequivocally proven by its presence in the MWF from the patients' workplace in 3 cases. Diglycolamine seems to be an important MWF allergen, independently from monoethanolamine and diethanolamine. A test concentration of 1% petrolatum (pet.) appears to be appropriate. The importance of AEPD and MDEA as MWF allergens still remains to be established. The lack of positive test reactions to the other MWF components tested may be due to their low-sensitizing potential or too low a patch test concentration being used. PMID:14641356

  14. Modeling the simultaneous transport of two acid gases in tertiary amines with reversible reactions

    SciTech Connect

    Al-Ghawas, H.A.; Sandall, O.C.

    1988-10-01

    The objective of this work is to develop a model for the simultaneous mass transfer of two acid gases in tertiary amines accompanied by reversible chemical reactions. The model has been applied to the industrially important system of simultaneous absorption or desorption of CO/sub 2/ and H/sub 2/S in aqueous methyldiethanolamine (MDEA). In most applications the treated gas must be virtually free of H/sub 2/S; however, it is often not necessary or economical to remove substantial amounts of CO/sub 2/. Hence, selective removal of H/sub 2/S from gas streams such as natural or synthetic gases which contain CO/sub 2/ is desirable. In this research a film theory model describing the simultaneous diffusion and reversible reaction of two gases into reactive liquid has been used to predict the mass transfer enhancement factors of CO/sub 2/ and H/sub 2/S in aqueous MDEA solutions. The resulting unstable two point boundary value problem has been solved numerically for a range of the dimensionless parameters that characterize an important application for this system. In studying the simultaneous transport of CO/sub 2/ and H/sub 2/S, it is found that the reversibility of the reactions, under certain conditions, causes desorption to take place although absorption would be expected on the basis of overall driving forces. This showed that not only enhancement factors larger but also smaller than unity and even negative values are possible.

  15. Ditetraalkylammonium amino acid ionic liquids as CO₂ absorbents of high capacity.

    PubMed

    Ma, Jing-Wen; Zhou, Zheng; Zhang, Feng; Fang, Cheng-Gang; Wu, You-Ting; Zhang, Zhi-Bing; Li, Ai-Min

    2011-12-15

    By grafting butyl or ethyl onto tetramethylethylenediamine, quaternary ammonium salts with two positive charge centers were formed at the first step. Metathesis with Ag(2)O followed. Through neutralization with glycine, l-alanine, or valine, a series of new ditetraalkylammonium amino acid ionic liquids (DILs) for CO(2) capture were generated. The structures of DILs, as shown in Figure 1, were verified by using (1)H NMR and EA. These DILs were found to be of quite high viscosity which militated against their industrial application in CO(2) removal. Drawing on the experience of mixed amines' aqueous solutions, these DILs were blended with water or N-methyldiethanolamine (MDEA) aqueous solutions to act as special absorbents of CO(2). Using a Double-Tank Absorption System, the absorption performance of these DIL solutions was investigated in detail. The experimental results indicated that among the three aqueous solutions of DILs (20%, 40%, and 80 wt %), the solution of 40% DIL had a higher absorption rate of CO(2) than the other two, demonstrating the different effects of concentration and viscosity on the absorption. The solution of 40% DIL or the 15% DIL + 15% MDEA had much higher capacity for CO(2) than the corresponding monocation tetraalkylammonium AAILs, due to the special structure of the dication which could influence the solubility of CO(2) in the aqueous solution. PMID:22066493

  16. Micelles of enzymatically synthesized PEG-poly(amine-co-ester) block copolymers as pH-responsive nanocarriers for docetaxel delivery.

    PubMed

    Zhang, Xiaofang; Liu, Bo; Yang, Zhe; Zhang, Chao; Li, Hao; Luo, Xingen; Luo, Huiyan; Gao, Di; Jiang, Qing; Liu, Jie; Jiang, Zhaozhong

    2014-03-01

    A series of PEGylated poly(amine-co-ester) terpolymers were successfully synthesized in one step via lipase-catalyzed copolymerization of ω-pentadecalactone (PDL), diethyl sebacate (DES), and N-methyldiethanolamine (MDEA) comonomers in the presence of poly(ethylene glycol) methyl ether as a chain-terminating agent. The resultant amphiphilic poly(ethylene glycol)-poly(PDL-co-MDEA-co-sebacate) (PEG-PPMS) block copolymers consisted of hydrophilic PEG chain segments and hydrophobic random PPMS chain segments, which self-assembled in aqueous medium to form stable, nanosized micelles at physiological pH of 7.4. Upon decreasing the medium pH from 7.4 to 5.0, the copolymer micelles swell significantly due to protonation of the amino groups in the micelle PPMS cores. Correspondingly, docetaxel (DTX)-encapsulated PEG2K-PPMS copolymer micelles showed gradual sustained drug release at pH of 7.4, but remarkably accelerated DTX release at acidic pH of 5.0. The drug-loaded micelle particles were readily internalized by SK-BR-3 cancer cells and, compared to free DTX drug, DTX-loaded micelles of the copolymers with optimal compositions exhibited enhanced potency against the cells. Biodegradable PEG-PPMS copolymer micelles represent a new type of promising, pH-responsive nanocarriers for anticancer drug delivery, and the drug release rate from the micelles can be systematically controlled by both pH and the copolymer composition. PMID:24398083

  17. Solubility calculations for acid gases in amine blends

    SciTech Connect

    Chakravarty, T.

    1985-01-01

    Treating with alkanolamines is often used to sweeten gases containing only a few parts per million of CO/sub 2/ and H/sub 2/S. Primary amines such as monoethanolamine (MEA) have great affinity for acid gases and are able to produce high purity sweet gas; on the other hand, tertiary amines like methyldiethanolamine (MDEA) have large capacity and are easy to regenerate but, because they do not bind chemically with CO/sub 2/, they are unable to produce a sweetened gas low in this component. Recently, the use of amine blends has become a subject of potentially great commercial importance. Since, the range of possible amines and blend formulations is large, a method for predicting equilibrium solubility is needed. A rigorous thermodynamic model has been developed which uses the extended Debye-Huckel expression, is very similar to one developed for single-amine solutions, and involves the fitting of binary interaction parameters to experimental data. In this work the interaction parameters found to be important in the activity coefficient expression were fitted to each single-acid-gas single-amine subsystem using all published solubility data. The resulting model was then validated by comparing mixed-acid-gas single-amine solubility predictions with published VLE data. MEA-MDEA and DEA-MDEA blends have been studied in detail in this work. It is found that each amine contributes to the overall acid gas solubility in a nonlinear way and that the solubility curves can exhibit maxima and minima as a function of the relative concentrations of the amines.

  18. Heterometallic [Mn5-Ln4] single-molecule magnets with high anisotropy barriers.

    PubMed

    Mereacre, Valeriu; Ako, Ayuk M; Clérac, Rodolphe; Wernsdorfer, Wolfgang; Hewitt, Ian J; Anson, Christopher E; Powell, Annie K

    2008-01-01

    The reaction of [Mn6O2(Piv)(10)(4-Me-py)(2.5)(PivH)(1.5)] (1) (py: pyridine, Piv: pivilate) with N-methyldiethanolamine (mdeaH2) and Ln(NO3)3 x 6 H2O in MeCN leads to a series of nonanuclear compounds [Mn5Ln4(O)6(mdea)2(mdeaH)2(Piv)6(NO3)4(H2O)2]2 MeCN (Ln=Tb(III) (2), Dy(III) (3), Ho(III) (4), Y(III) (5)). Single-crystal X-ray diffraction shows that compounds 2-5 are isostructural, with the central core composed of two distorted {Mn(IV)Mn(III)Ln2O4} cubanes sharing a Mn(IV) vertex, representing a new heterometallic 3d-4f motif for this class of ligand. The four new compounds display single-molecule magnet (SMM) behaviour, which is modulated by the lanthanide ion used. Moreover, the values found for Delta(eff) and tau(o) for 3 of 38.6 K and 3.0 x 10(-9) s respectively reveal that the complex 3 exhibits the highest energy barrier recorded so far for 3d-4f SMMs. The slow relaxation of the magnetisation for 3 was confirmed by mu-SQUID measurements on an oriented single crystal and the observation of M versus H hysteresis loops below 1.9 K. PMID:18348132

  19. 21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... oral dose. Administer as a drench or by stomach tube suspended in 1 pint of warm water; by dose syringe... stomach tube or drench, it shall also bear the statement “Caution: Federal law restricts this drug to use by or on the order of a licensed veterinarian;” if not labeled for use by stomach tube or drench,...

  20. 21 CFR 520.2380f - Thiabendazole, piperazine phosphate powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... oral dose. Administer as a drench or by stomach tube suspended in 1 pint of warm water; by dose syringe... stomach tube or drench, it shall also bear the statement “Caution: Federal law restricts this drug to use by or on the order of a licensed veterinarian;” if not labeled for use by stomach tube or drench,...

  1. 21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... weight for the control of large strongyles, small strongyles, pinworms, Strongyloides and ascarids... Craterostomum spp., Oesophagodontus spp., Poteriostomum spp., Oxyuris spp., Strongyloides spp., and...

  2. 21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... weight for the control of large strongyles, small strongyles, pinworms, Strongyloides and ascarids... Craterostomum spp., Oesophagodontus spp., Poteriostomum spp., Oxyuris spp., Strongyloides spp., and...

  3. 21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... weight for the control of large strongyles, small strongyles, pinworms, Strongyloides and ascarids... Craterostomum spp., Oesophagodontus spp., Poteriostomum spp., Oxyuris spp., Strongyloides spp., and...

  4. 21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... weight for the control of large strongyles, small strongyles, pinworms, Strongyloides and ascarids... Craterostomum spp., Oesophagodontus spp., Poteriostomum spp., Oxyuris spp., Strongyloides spp., and...

  5. 21 CFR 520.2380d - Thiabendazole, piperazine citrate suspension.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... weight for the control of large strongyles, small strongyles, pinworms, Strongyloides and ascarids... Craterostomum spp., Oesophagodontus spp., Poteriostomum spp., Oxyuris spp., Strongyloides spp., and...

  6. Synthesis of Pyrimidine Incorporated Piperazine Derivatives and their Antimicrobial Activity

    PubMed Central

    Thriveni, K. S.; Padmashali, B.; Siddesh, M. B.; Sandeep, C.

    2014-01-01

    Thiophene substituted chalcones (1a-e) were cyclised with thiourea in presence of potassium hydroxide to get 4-substituted-6-(thiophen-2-yl)pyrimidine-2-thiols (2a-e) which were then stirred with methyl iodide to obtain 4-substituted-2-(methylsulfanyl)-6-(thiophen-2-yl)pyrimidines (3a-e). Compounds (3a-e) were refluxed with different N-methylpiperazine and N-phenylpiperazine to afford 4-substituted-2-(4-methylpiperazin-1-yl)-6-(thiophen-2-yl)pyrimidines (4a-e) and 4-substituted-2-(4-phenylpiperazin-1-yl)-6-(thiophen-2-yl)pyrimidines (5a-e). The structures of all the newly synthesised compounds 4b, 4d, 5a and 5b showed good antibacterial activity at 40μg/mlconcentration. Compounds 4a, 4d, 4e, 5c and 5e showed significant antifungal activity at 40 μg/ml concentration compared with standard drugs. PMID:25284931

  7. Anion exchangers with branched functional ion exchange layers of different hydrophilicity for ion chromatography.

    PubMed

    Shchukina, O I; Zatirakha, A V; Smolenkov, A D; Nesterenko, P N; Shpigun, O A

    2015-08-21

    Novel polystyrene-divinylbenzene (PS-DVB) based anion exchangers differing from each other in the structure of the branched functional ion exchange layer are prepared to investigate the role of linker and functional site on ion exchange selectivity. The proposed method of synthesis includes the obtaining of aminated PS-DVB particles by means of their acylation with following reductive amination with methylamine. Further modification of the obtained secondary aminogroups is provided by the alkylation with either 1,4-butanediol diglycidyl ether (1,4-BDDGE) or resorcinol diglycidyl ether (RDGE), which form the linkers of different hydrophobicity, and amination of terminal epoxide rings with trimethylamine (TMA), dimethylethanolamine (DMEA), methyldiethanolamine (MDEA) or triethanolamine (TEA). The variation of the structure and hydrophobicity of the linker and terminal quaternary ammonium sites in the functional layer allows the alteration of selectivity and separation efficiency of the obtained adsorbents. The ion exchange selectivity and separation efficiency of the anion exchangers are evaluated using the model mixtures of anions (F(-), HCOO(-), Cl(-), NO2(-), Br(-), NO3(-), HPO4(2-) and SO4(2-)) in potassium hydroxide eluents. The adsorbents show the decrease of selectivity with increasing the hydrophilicity of the terminal functional site. The anion exchangers having more flexible and hydrophilic 1,4-BDDGE linker provide smaller separation factors for most of the analytes as compared with RDGE-containing adsorbents with the same terminal ion exchange sites, but are characterized with higher column efficiencies and better peak symmetry for polarizable anions. In case of 1,4-BDDGE-modified anion exchangers of the particle size of 3.3μm functionalized with DMEA and MDEA the calculated values of column efficiencies for polarizable NO3(-) and Br(-) are up to 49,000 and 53,000N/m, respectively, which is almost twice higher than the values obtained for the RDGE

  8. A liquid chromatography-electrospray ionization-tandem mass spectrometry study of ethanolamines in high salinity industrial wastewaters.

    PubMed

    Campo, Pablo; Suidan, Makram T; Chai, Yunzhou; Davis, John

    2010-01-15

    The detection and quantitation of four ethanolamines, tris(2-hydroxyethyl)amine (triethanolamine, TEA), N,N-bis(2-hydroxyethyl)methylamine (methyldiethanolamine, MDEA), N-(2-aminoethyl)ethanolamine (AEA), and N,N-diethylethanolamine (DEA), were achieved in wastewaters from two aerobic activated sludge bioreactors located in an industrial wastewater treatment plant. The streams had salt concentrations of approximately 3% and 7% by weight in Reactor 1 and Reactor 2, respectively. The use of liquid chromatography-electrospray ionization-tandem mass spectrometry avoided the need for some sample preparation steps such as extraction, concentration, and derivatization. Ion suppression in the electrospray, attributable to the presence of sodium clusters, was attenuated by a 10-fold dilution of the wastewaters with acetonitrile. A matrix-matched calibration model averted other potential interferences. For the compounds analyzed in selected reaction monitoring mode (TEA, MDEA, and DEA), the calibration curves presented linearity in a range of 10-1000microg/L with corresponding detection limits ranging from 2 to 11microg/L, depending upon the specific analyte and aqueous matrix. AEA was calibrated in selected ion monitoring mode (100-1000microg/L), with corresponding detection limits in the two wastewaters of 74.6 and 85.3microg/L, respectively. Overall good precision (<10%) and accuracy (97-110%) were achieved for both matrices, which fell within-laboratory reproducibility. Finally, the amines were introduced into six mixed liquor samples from both reactors and quantified following the reported protocol. Again, recoveries were close to 100% with a relative standard deviation of less than 10% in all cases. PMID:20006060

  9. A model of vapor-liquid equilibria for acid gas-alkanolamine-water systems

    SciTech Connect

    Austgen, D.M. Jr.

    1989-01-01

    A physico-chemical model was developed for representing liquid phase chemical equilibria and vapor-liquid (phase) equilibria of H{sub 2}SCO{sub 2}-alkanolamine-water systems. The equilibrium composition of the liquid phase is determined by minimization of the Gibbs free energy. Activity coefficients are represented with the Electrolyte-NRTL equation treating both long-range electrostatic interactions and short-range binary interactions between liquid phase species. Vapor phase fugacity coefficients are calculated using the Redlich-Kwong-Soave Equation of State. Adjustable parameters of the model, binary interaction parameters and carbamate stability constants, were fitted on published binary system alkanolamine-water and ternary system (H{sub 2}S-alkanolamine-water, CO{sub 2}-alkanolamine-water) VLE data. The Data Regression System of ASPEN PLUS, based upon the Maximum Likelihood Principle, was used to estimate adjustable parameters. Ternary system measurements used in parameter estimation ranged in temperature from 25 to 120{degree}C in alkanolamine concentration from 1 to 5 M, in acid gas loading from 0 to 1.5 moles per mole alkanolamine, and in acid gas partial pressure from 0.1 to 1,000 kPa. Maximum likelihood estimates of ternary system H{sub 2} or CO{sub 2} equilibrium partial pressures and liquid phase concentrations were found to be in good agreement with measurements for aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), diglycolamine (DGA), and methyldiethanolamine (MDEA) indicating that the model successfully represents ternary system data. The model was extended to represent CO{sub 2} solubility in aqueous mixtures of MDEA with MEA or DEA. The solubility was measured at 40 and 80{degree}C over a wide range of CO{sub 2} partial pressures. These measurements were used to estimate additional binary parameters of the mixed solvent systems.

  10. Scheduling the blended solution as industrial CO2 absorber in separation process by back-propagation artificial neural networks.

    PubMed

    Abdollahi, Yadollah; Sairi, Nor Asrina; Said, Suhana Binti Mohd; Abouzari-lotf, Ebrahim; Zakaria, Azmi; Sabri, Mohd Faizul Bin Mohd; Islam, Aminul; Alias, Yatimah

    2015-11-01

    It is believe that 80% industrial of carbon dioxide can be controlled by separation and storage technologies which use the blended ionic liquids absorber. Among the blended absorbers, the mixture of water, N-methyldiethanolamine (MDEA) and guanidinium trifluoromethane sulfonate (gua) has presented the superior stripping qualities. However, the blended solution has illustrated high viscosity that affects the cost of separation process. In this work, the blended fabrication was scheduled with is the process arranging, controlling and optimizing. Therefore, the blend's components and operating temperature were modeled and optimized as input effective variables to minimize its viscosity as the final output by using back-propagation artificial neural network (ANN). The modeling was carried out by four mathematical algorithms with individual experimental design to obtain the optimum topology using root mean squared error (RMSE), R-squared (R(2)) and absolute average deviation (AAD). As a result, the final model (QP-4-8-1) with minimum RMSE and AAD as well as the highest R(2) was selected to navigate the fabrication of the blended solution. Therefore, the model was applied to obtain the optimum initial level of the input variables which were included temperature 303-323 K, x[gua], 0-0.033, x[MDAE], 0.3-0.4, and x[H2O], 0.7-1.0. Moreover, the model has obtained the relative importance ordered of the variables which included x[gua]>temperature>x[MDEA]>x[H2O]. Therefore, none of the variables was negligible in the fabrication. Furthermore, the model predicted the optimum points of the variables to minimize the viscosity which was validated by further experiments. The validated results confirmed the model schedulability. Accordingly, ANN succeeds to model the initial components of the blended solutions as absorber of CO2 capture in separation technologies that is able to industries scale up. PMID:26119355

  11. Synthesis of water-based cationic polyurethane for antibacterial and gene delivery applications.

    PubMed

    Wu, Geng-Hsi; Hsu, Shan-Hui

    2016-10-01

    Cationic polymers are often used as antimicrobial materials and transfection reagents. Water-based process could reduce environmental pollution and prevent the risk of solvent residue in the final product. In this study, waterborne biodegradable cationic polyurethane (WCPU) was synthesized by reacting polycaprolactone (PCL diol), isophorone diisocyanate (IPDI), and N-methyldiethanolamine (N-MDEA) under 75°C. An aqueous dispersion of WCPU nanoparticles (NPs) could be acquired by vigorous stirring under acidic condition. The particles in the dispersion had an average size of ∼80nm and a zeta potential of ∼60mV. When cast into films, the contact angle of the film was ∼67° and the zeta potential was ∼16mV. WCPU NPs demonstrated excellent antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) (100% inhibition with a contact time of 3h). Meanwhile, the antibacterial ratio of WCPU films to E. coli and S. aureus reached 100% after 24h of contact. Moreover, WCPU NPs could be used as a transfection reagent without significant toxicity for concentrations less than 1000μg/mL and showed the ability to condensate plasmid DNA. The transfection efficiency for HEK293T cells and hBMSCs was ∼60% and ∼30% at 48h, respectively, after the transfection. Therefore, the WCPU synthesized in this study has potential antibacterial and gene delivery applications. PMID:27451371

  12. Clean amine solvents economically and online

    SciTech Connect

    Price, J.; Burns, D.

    1995-08-01

    Using electrodialysis technology to clean amine solvents is economically competitive with traditional change-out or ``bleed and feed`` methods, even for small systems, because a unit shutdown is not necessary to perform the process. Electrodialysis also has advantages over other online cleanup processes like ion exchange and vacuum reclamation. Off gases and olefinic and saturate liquefied petroleum gas (LPG) streams generated during operation of fluid catalytic crackers (FCC), cokers and other refinery processing equipment must be treated to remove undesirable components like hydrogen sulfide and carbon dioxide before they can be sold or used in downstream processes. At an Arkansas City, Kansas, refinery, a classic amine-based chemical absorbent system is used for this purpose. It comprises two absorbing contacts for gas and two for liquids. The system is charged with an N-methyldiethanolamine (MDEA)-based product that selectively absorbs contaminants. Amine is regenerated by removing contaminants with steam stripping. Lean amine is then recirculated to the absorbers. This case history demonstrates the effectiveness of electrodialysis technology for contaminant removal.

  13. Hydrogen-based power generation from bioethanol steam reforming

    NASA Astrophysics Data System (ADS)

    Tasnadi-Asztalos, Zs.; Cormos, C. C.; Agachi, P. S.

    2015-12-01

    This paper is evaluating two power generation concepts based on hydrogen produced from bioethanol steam reforming at industrial scale without and with carbon capture. The power generation from bioethanol conversion is based on two important steps: hydrogen production from bioethanol catalytic steam reforming and electricity generation using a hydrogen-fuelled gas turbine. As carbon capture method to be assessed in hydrogen-based power generation from bioethanol steam reforming, the gas-liquid absorption using methyl-di-ethanol-amine (MDEA) was used. Bioethanol is a renewable energy carrier mainly produced from biomass fermentation. Steam reforming of bioethanol (SRE) provides a promising method for hydrogen and power production from renewable resources. SRE is performed at high temperatures (e.g. 800-900°C) to reduce the reforming by-products (e.g. ethane, ethene). The power generation from hydrogen was done with M701G2 gas turbine (334 MW net power output). Hydrogen was obtained through catalytic steam reforming of bioethanol without and with carbon capture. For the evaluated plant concepts the following key performance indicators were assessed: fuel consumption, gross and net power outputs, net electrical efficiency, ancillary consumptions, carbon capture rate, specific CO2 emission etc. As the results show, the power generation based on bioethanol conversion has high energy efficiency and low carbon footprint.

  14. Hydrogen-based power generation from bioethanol steam reforming

    SciTech Connect

    Tasnadi-Asztalos, Zs. Cormos, C. C. Agachi, P. S.

    2015-12-23

    This paper is evaluating two power generation concepts based on hydrogen produced from bioethanol steam reforming at industrial scale without and with carbon capture. The power generation from bioethanol conversion is based on two important steps: hydrogen production from bioethanol catalytic steam reforming and electricity generation using a hydrogen-fuelled gas turbine. As carbon capture method to be assessed in hydrogen-based power generation from bioethanol steam reforming, the gas-liquid absorption using methyl-di-ethanol-amine (MDEA) was used. Bioethanol is a renewable energy carrier mainly produced from biomass fermentation. Steam reforming of bioethanol (SRE) provides a promising method for hydrogen and power production from renewable resources. SRE is performed at high temperatures (e.g. 800-900°C) to reduce the reforming by-products (e.g. ethane, ethene). The power generation from hydrogen was done with M701G2 gas turbine (334 MW net power output). Hydrogen was obtained through catalytic steam reforming of bioethanol without and with carbon capture. For the evaluated plant concepts the following key performance indicators were assessed: fuel consumption, gross and net power outputs, net electrical efficiency, ancillary consumptions, carbon capture rate, specific CO{sub 2} emission etc. As the results show, the power generation based on bioethanol conversion has high energy efficiency and low carbon footprint.

  15. A cotton fabric modified with a hydrogel containing ZnO nanoparticles. Preparation and properties study

    NASA Astrophysics Data System (ADS)

    Staneva, Desislava; Atanasova, Daniela; Vasileva-Tonkova, Evgenia; Lukanova, Varbina; Grabchev, Ivo

    2015-08-01

    Two different methods were used to obtain composite materials based on a ZnO nanoparticles-hydrogel-cotton fabric. The hydrogels, synthesized by photopolymerization, were utilized to provide uniform distribution and binding of the nanoparticles to the fiber surface and to prevent their agglomeration. N-methyldiethanolamine (MDEA) was used as a co-initiator in hydrogel photopolymerization and as an alkaline agent in the synthesis of ZnO nanoparticles. Due to the difference in size, shape and morphology of the nanoparticles, examined by a TEM and SEM, it was found that the materials have distinct photoluminescence properties, e.g. in the entire visible or UV range. The composite materials with small size nanoparticles and photoluminescence in near UV range were investigated for antibiotic activity against the bacterial strains Pseudomonas aeruginosa and Acinetobacter johnsonii known as important pathogens in clinical infections. Significantly high antibacterial effect on the bacteria tested was achieved, especially on A. johnsonii. This suggests potential application of the new formulations as effective wound dressings to control the spread of infections.

  16. Ion-exchange membranes for bulk separation of acid gases

    SciTech Connect

    Giarratano, P.; Pellegrino, J.J.

    1992-12-01

    The field test has continued with PFSA composite membranes. The substrates have been a microporous polypropylene supplied by 3M Co. The membranes have been imbibed with either aqueous solutions of methyldiethanolamine (MDEA) or n-methylpyrrolidone (NMP). Data from five composite membranes have thusfar been obtained and are presented in the following Figure 6. The composite 1 membrane gave erratic performance before it mechanically failed, but most of the observed separation factors were high enough (>35) to be consistent with the initial results from the gel-NE 111 membrane. The separation factor for the other four composites have been consistently low (between 13 and 3). The main difference is that between composite l and the rest we installed an inertial separator to remove excess moisture from the feed stream. This separator may be too efficient and the membranes may be drying out. Another possibility is that the membranes may just not be made well enough and sufficient uncoated pores may exist to subvert the separation efficiency. We tested a membrane which had been removed from the field test rig in our laboratory permeation equipment. Those results are presented in Figures 7 and 8. Again good agreement between the field test and our lab experiments.

  17. Diffusion coefficients of several aqueous alkanolamine solutions

    SciTech Connect

    Snijder, E.D.; Riele, M.J.M. te; Versteeg, G.F.; Swaaij, W.P.M. van . Dept. of Chemical Engineering)

    1993-07-01

    In absorption processes of acid gases (H[sub 2]S, CO[sub 2], COS) in alkanolamine solutions, diffusion coefficients are used for the calculation of the mass transfer rate. The Taylor dispersion technique was applied for the determination of diffusion coefficients of various systems. Experiments with the system KCl in water showed that the experimental setup provides accurate data. For the alkanolamines monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA), and di-2-propanolamine (DIPA), correlations for the diffusion coefficient as a function of temperature at different concentrations are given. A single relation for every amine has been derived which correlates the diffusion coefficients as a function of temperature and concentration. The temperature was varied between 298 and 348 K, and the concentration between 0 and 4000-5000 mol/m[sup 3]. Furthermore, a modified Stokes-Einstein relation is presented for the prediction of the diffusion coefficients in the alkanolamines in relation to the viscosity of the solvent and the diffusion coefficient at infinite dilution. The diffusion coefficients at low concentrations are compared with some available relations for the estimation of diffusion coefficients at infinite dilution, and it appears that the agreement is fairly good.

  18. Tertiary ethanolamines more economical for removal of H/sub 2/S and carbon dioxide

    SciTech Connect

    Riesenfeld, F.C.; Brocoff, J.C.

    1986-09-01

    At present, it appears that tertiary ethanolamines, if properly used, are substantially more economical for a variety of selective and nonselective gas-purification operations than primary and secondary ethanolamines. Examples of such operations are: selective H/sub 2/S removal from natural and synthesis gases, absorption of high concentrations of CO/sub 2/ from gas streams available at high pressure, and selective H/sub 2/S removal from waste gases, e.g., Claus tail gas. The principal advantages of tertiary over primary and secondary ethanolamines are, besides their selectivity for H/sub 2/S, their lower heat of reaction with the acid gases (and consequent lower heat requirements for solution stripping); their lower vapor pressure, permitting use of high concentration and high capacity in the treating solution; their nonreactivity with COS and CS/sub 2/, avoiding formation of nonregenerable compounds; and their lower corrosiveness, allowing carbon-steel construction throughout the plant. If these features are combined, it becomes clear that tertiary ethanolamines are the proper choice for many gas-purification systems. Among the tertiary ethanolamines, methyldiethanolamine (MDEA) is the preferred amine, although triethanolamine (TEA) is also useful for CO/sub 2/ absorption.

  19. [Removal of CO2 from simulated flue gas of power plants by membrane-based gas absorption processes].

    PubMed

    Yang, Ming-Fen; Fang, Meng-Xiang; Zhang, Wei-Feng; Wang, Shu-Yuan; Xu, Zhi-Kang; Luo, Zhong-Yang; Cen, Ke-Fa

    2005-07-01

    Three typical absorbents such as aqueous of aminoacetic acid potassium (AAAP), monoethanolamine (MEA) and methyldiethanolamine(MDEA) are selected to investigate the performance of CO2 separation from flue gas via membrane contactors made of hydrophobic hollow fiber polypropylene porous membrane. Impacts of absorbents, concentrations and flow rates of feeding gas and absorbent solution, cyclic loading of CO2 on the removal rate and the mass transfer velocity of CO2 are discussed. The results demonstrate that the mass transfer velocity was 7.1 mol x (m2 x s)(-1) for 1 mol x L(-1) MEA with flow rate of 0.1 m x s(-1) and flue gas with that of 0.211 m x s(-1). For 1 mol L(-1) AAAP with flow rate of 0.05 m x s(-1) and flue gas of 0.211 m x s(-1), CO2 removal rate (eta) was 93.2 % and eta was 98% for 4 mol x L(-1) AAAP under the same conditions. AAAP being absorbent, eta was higher than 90% in a wider range of concentrations of CO2. It indicates that membrane-based absorption process is a widely-applied and promising way of CO2 removal from flue gas of power plants, which not only appropriates for CO2 removal of flue gas of widely-used PF and NGCC, but also for that of flue gas of IGCC can be utilized widely in future. PMID:16212162

  20. Screening of nitrogen mustards and their degradation products in water and decontamination solution by liquid chromatography-mass spectrometry.

    PubMed

    Chua, Hoe-Chee; Lee, Hoi-Sim; Sng, Mui-Tiang

    2006-01-13

    Analysing nitrogen mustards and their degradation products in decontamination emulsions posed a significant challenge due to the different phases present in such matrices. Extensive sample preparation may be required to isolate target analytes. Furthermore, numerous reaction products are formed in the decontamination emulsion. A fast and effective qualitative screening procedure was developed for these compounds, using liquid chromatography-mass spectrometry (LC-MS). This eliminated the need for additional sample handling and derivatisation that are required for gas chromatographic-mass spectrometric (GC-MS) analysis. A liquid chromatograph with mixed mode column and isocratic elution gave good chromatography. The feasibility of applying this technique for detecting these compounds in spiked water and decontamination emulsion was demonstrated. Detailed characterisation of the degradation products in these two matrices was carried out. The results demonstrated that N-methyldiethanolamine (MDEA), N-ethyldiethanolamine (EDEA) and triethanolamine (TEA) are not the major degradation products of their respective nitrogen mustards. Degradation profiles of nitrogen mustards in water were also established. In verification analysis, it is important not only to develop methods for the identification of the actual chemical agents; the methods must also encompass degradation products of the chemical agents as well so as to exclude false negatives. This study demonstrated the increasingly pivotal role that LC-MS play in verification analysis. PMID:16310795

  1. Synthesis, characterization and antibacterial properties of dihydroxy quaternary ammonium salts with long chain alkyl bromides.

    PubMed

    Liu, Wen-Shuai; Wang, Chun-Hua; Sun, Ju-Feng; Hou, Gui-Ge; Wang, Yu-Peng; Qu, Rong-Jun

    2015-01-01

    Five N-methyl-N-R-N,N-bis(2-hydroxyethyl) ammonium bromides (R = -benzyl (chloride, BNQAS), -dodecyl (C12QAS), -tetradecyl (C14QAS), -hexadecyl (C16QAS), -octadecyl (C18QAS)) were prepared based on N-methyldiethanolamine (MDEA) and halohydrocarbon. Five QAS were characterized by FTIR, NMR, and MS. BNQAS, C12QAS, C14QAS, and C16QAS were confirmed by X-ray single-crystal diffraction. Their antibacterial properties indicated good antibacterial abilities against E. coli, S. aureus, B. subtilis, especially C12QAS with the best antibacterial ability (100% to E. coli, 95.65% to S. aureus, and 91.41% to B. subtilis). In addition, C12QAS also displayed the best antifungal activities than BNQAS and C18QAS against Cytospora mandshurica, Botryosphaeria ribis, Physalospora piricola, and Glomerella cingulata with the ratio of full marks. The strategy provides a facile way to design and develop new types of antibacterial drugs for application in preventing the fruit rot, especially apple. PMID:25215430

  2. Ion-exchange membranes for bulk separation of acid gases

    SciTech Connect

    Giarratano, P.; Pellegrino, J.J.

    1992-01-01

    The field test has continued with PFSA composite membranes. The substrates have been a microporous polypropylene supplied by 3M Co. The membranes have been imbibed with either aqueous solutions of methyldiethanolamine (MDEA) or n-methylpyrrolidone (NMP). Data from five composite membranes have thusfar been obtained and are presented in the following Figure 6. The composite 1 membrane gave erratic performance before it mechanically failed, but most of the observed separation factors were high enough (>35) to be consistent with the initial results from the gel-NE 111 membrane. The separation factor for the other four composites have been consistently low (between 13 and 3). The main difference is that between composite l and the rest we installed an inertial separator to remove excess moisture from the feed stream. This separator may be too efficient and the membranes may be drying out. Another possibility is that the membranes may just not be made well enough and sufficient uncoated pores may exist to subvert the separation efficiency. We tested a membrane which had been removed from the field test rig in our laboratory permeation equipment. Those results are presented in Figures 7 and 8. Again good agreement between the field test and our lab experiments.

  3. Performance characteristics and modeling of carbon dioxide absorption by amines in a packed column

    SciTech Connect

    Lin, S.H.; Shyu, C.T. . Dept. of Chemical Engineering)

    1999-01-01

    Carbon dioxide (CO[sub 2]) is widely recognized as a major greenhouse gas contributing to global warming. To mitigate the global warming problem, removal of CO[sub 2] from the industrial flue gases is necessary. Absorption of carbon dioxide by amines in a packed column was experimentally investigated. The amines employed in the present study were the primary mono-ethanolamine (MEA) and tertiary N-methyldiethanolamine (MDEA), two very popular amines widely used in the industries for gas purification. The CO[sub 2] absorption characteristics by these two amines were experimentally examined under various operating conditions. A theoretical model was developed for describing the CO[sub 2] absorption behavior. Test data have revealed that the model predictions and the observed CO[sub 2] absorption breakthrough curves agree very well, validating the proposed model. Preliminary regeneration tests of exhausted amine solution were also conducted. The results indicated that the tertiary amine is easier to regenerate with less loss of absorption capacity than the primary one.

  4. Electropolymerized carbonic anhydrase immobilization for carbon dioxide capture.

    PubMed

    Merle, Geraldine; Fradette, Sylvie; Madore, Eric; Barralet, Jake E

    2014-06-17

    Biomimetic carbonation carried out with carbonic anhydrase (CA) in CO2-absorbing solutions, such as methyldiethanolamine (MDEA), is one approach that has been developed to accelerate the capture of CO2. However, there are several practical issues, such as high cost and limited enzyme stability, that need to be overcome. In this study, the capacity of CA immobilization on a porous solid support was studied to improve the instability in the tertiary amine solvent. We have shown that a 63% porosity macroporous carbon foam support makes separation and reuse facile and allows for an efficient supply and presentation of CO2 to an aqueous solvent and the enzyme catalytic center. These enzymatic supports conserved 40% of their initial activity after 42 days at 70 °C in an amine solvent, whereas the free enzyme shows no activity after 1 h in the same conditions. In this work, we have overcome the technical barrier associated with the recovery of the biocatalyst after operation, and most of all, these electropolymerized enzymatic supports have shown a remarkable increase of thermal stability in an amine-based CO2 sequestration solvent. PMID:24856780

  5. Rigorous modeling of the acid gas heat of absorption in alkanolamine solutions

    SciTech Connect

    Emilie Blanchon le Bouhelec; Pascal Mougin; Alain Barreau; Roland Solimando

    2007-08-15

    In this work, we are interested in the estimation of CO{sub 2} and H{sub 2}S heats of absorption in aqueous solutions of alkanolamine: monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA). Two methods can be used to calculate the heat release during the absorption phenomenon. The easier which consists of applying the integration of the Gibbs-Helmholtz expression remains inaccurate. The second one, more rigorous, evaluates the heat transfer through an internal energy balance for an open system. The balance expression contains partial molar enthalpies of species in the liquid phase which are calculated from the electrolyte nonrandom-two-liquid (NRTL) excess Gibbs energy model. The calculations carried out in this method can be considered as predictive regarding the NRTL model because its interaction parameters were previously and solely fitted on vapor-liquid equilibrium (VLE) data and not on experimental heat of absorption data. The comparison between both methods and experimental data for the three alkanolamines shows the contribution of this rigorous calculation to better estimate both properties (i.e., solubility and heat) and its usefulness to improve processes. Heats of absorption calculated with the second method can be used in addition to VLE data to fit NRTL parameters. This procedure leads to less-correlated parameters and allows extrapolating the model with more confidence. 63 refs., 10 figs., 6 tabs.

  6. 21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (Oxyuris equii). (2) Limitations. Aqueous solution: administer by stomach tube or drench 1 fluid ounce per 100 pounds of body weight. Reconstituted soluble powder: administer by stomach tube 1 fluid ounce...

  7. 21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (Oxyuris equii). (2) Limitations. Aqueous solution: administer by stomach tube or drench 1 fluid ounce per 100 pounds of body weight. Reconstituted soluble powder: administer by stomach tube 1 fluid ounce...

  8. 21 CFR 520.1242c - Levamisole hydrochloride and piperazine dihydrochloride.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (Oxyuris equii). (2) Limitations. Aqueous solution: administer by stomach tube or drench 1 fluid ounce per 100 pounds of body weight. Reconstituted soluble powder: administer by stomach tube 1 fluid ounce...

  9. 2-{4-[(1,3-Benzodioxol-5-yl)meth-yl]piperazin-1-yl}pyrimidine.

    PubMed

    Wu, Chunli; Li, Jieming; Wei, Huijie; Hang, Ye; Jiang, Yueming

    2013-01-01

    In the title compound, C16H18N4O2, known also as peribedil, the dihedral angle between the mean planes of the pyrimidine and benzene rings is 56.5 (8)°. The 1,3-dioxole fragment adopts an envelope conformation with the methyl-ene C atom forming the flap; this atom deviates by 0.232 (3) Å from the plane defined by the remaining atoms of the 1,3-benzodioxole unit. In the crystal, C-H⋯π inter-actions between c-glide-related mol-ecules arrange them into columns extending along the c-axis direction. The columns related by a unit translation along the b axis are packed into (100) layers via another C-H⋯π inter-action involving the pyrimidine ring as an acceptor. PMID:24046690

  10. Synthesis, growth and characterization of a new organic three dimensional framework: Piperazin-1-ium 4-aminobenzenesulfonate

    NASA Astrophysics Data System (ADS)

    Rekha, P.; Peramaiyan, G.; NizamMohideen, M.; Mohan Kumar, R.; Kanagadurai, R.

    2016-05-01

    Piperazinium p-aminobenzenesulfonate (PPABS), a new nonlinear optical material was synthesized and crystals were grown from the methanol solvent by slow evaporation solution growth method. Single crystal X-ray diffraction study elucidated the crystal structure of PPABS. It crystallizes in orthorhombic crystal system with space group of Pbca. UV-vis-NIR spectral study was performed to analyze optical transparency of PPABS crystal and found that the grown crystal has sufficient transparency in the entire visible region with lower cutoff wavelength of 321 nm. The thermal stability and decomposition stages of the sample were studied by TG/DTA analyses. The different environmental carbon and hydrogen atoms of the proposed structure were identified by NMR spectral studies. The electric field response of crystal was determined from the dielectric studies. From the Z-scan measurements, the third order nonlinear optical properties of grown crystal were studied.

  11. 21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW.... Administer by stomach tube. Do not fast horses before or after treatment. Treatment of mares in...

  12. 21 CFR 520.2520g - Trichlorfon, phenothiazine, and piperazine dihydrochloride powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW.... Administer by stomach tube. Do not fast horses before or after treatment. Treatment of mares in...

  13. The electrochemical and spectroelectrochemical properties of metal free and metallophthalocyanines containing triazole/piperazine units

    NASA Astrophysics Data System (ADS)

    Demirbaş, Ümit; Akyüz, Duygu; Mermer, Arif; Akçay, Hakkı Türker; Demirbaş, Neslihan; Koca, Atıf; Kantekin, Halit

    2016-01-01

    The synthesis and characterization of novel peripherally tetra [1,2,4]-triazole substituted metal-free phthalocyanine and its metal complexes (Zn(II), Ni(II), Pb(II), Cu(II) and Fe(II)) and the investigation of electrochemical and spectroelectrochemical properties of metal-free, Zn(II), Pb(II), Fe(II) phthalocyanines were performed for the first time in this study. Electrochemical characterizations of the complexes were performed with voltammetric and in situ spectroelectrochemical measurements. Voltammetric responses of the complexes supported the proposed structures, since complexes bearing redox inactive Pc ring metal centers just gave Pc based electron transfer reactions, while iron phthalocyanine went to metal based electron transfer reaction in addition to the Pc based ones. Electron withdrawing nature of [1,2,4]-triazole substituents shifted the redox processes toward the positive potentials. All complexes were electropolymerized during the oxidation reactions in dichloromethane (DCM) solvent. Types of the metal center of the complexes altered the electropolymerization reactions of the complexes. Spectra and colors of the electrogenerated redox species of the complexes were also determined with in situ spectroelectrochemical and in situ electrocolorimetric measurements.

  14. 2,3,5,6-Tetra­methoxy­piperazine-1,4-dicarbaldehyde

    PubMed Central

    Moosavi, Sayed Mojtaba; Taheri, Amir

    2009-01-01

    The asymmetric unit of the title compound, C10H18N2O6, contains two halves of two independent centrosymmetric mol­ecules with almost identical conformations. Weak inter­molecular C—H⋯O hydrogen bonds consolidate the crystal packing. PMID:21577809

  15. 40 CFR 721.9800 - Poly(substituted triazinyl) piperazine (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ....80(q). (b) Specific requirements. The provisions of subpart A of this part apply to this section... program. Requirements as specified in § 721.72 (b)(2), (c), (e) (concentration set at 1.0 percent), (f... subject to this section. The provisions of § 721.1725(b)(1) apply to this section....

  16. A Novel Substituted Piperazine, CM156, Attenuates the Stimulant and Toxic Effects of Cocaine in Mice

    PubMed Central

    Xu, Yan-Tong; Kaushal, Nidhi; Shaikh, Jamaluddin; Wilson, Lisa L.; Mésangeau, Christophe; McCurdy, Christopher R.

    2010-01-01

    Cocaine is a highly abused drug without effective pharmacotherapies to treat it. It interacts with sigma (σ) receptors, providing logical targets for the development of medications to counteract its actions. Cocaine causes toxic and stimulant effects that can be categorized as acute effects such as convulsions and locomotor hyperactivity and subchronic effects including sensitization and place conditioning. In the present study, 3-(4-(4-cyclohexylpiperazin-1-yl)butyl)benzo[d]thiazole-2(3H)-thione (CM156), a novel compound, was developed and tested for interactions with σ receptors using radioligand binding studies. It was also evaluated against cocaine-induced effects in behavioral studies. The results showed that CM156 has nanomolar affinities for each of the σ receptor subtypes in the brain and much weaker affinities for non-σ binding sites. Pretreatment of male Swiss-Webster mice with CM156, before administering either a convulsive or locomotor stimulant dose of cocaine, led to a significant attenuation of these acute effects. CM156 also significantly reduced the expression of behavioral sensitization and place conditioning evoked by subchronic exposure to cocaine. The protective effects of CM156 are consistent with σ receptor-mediated actions. Together with previously reported findings, the data from CM156 and related σ compounds indicate that σ receptors can be targeted to alleviate deleterious actions of cocaine. PMID:20100904

  17. Experimental Measurement and Thermodynamic Modeling of the Solubility of Carbon Dioxide in Aqueous Alkanolamine Solutions in the High Gas Loading Region

    NASA Astrophysics Data System (ADS)

    Suleman, Humbul; Maulud, Abdulhalim Shah; Man, Zakaria

    2016-09-01

    The solubility of carbon dioxide in aqueous alkanolamine solutions was investigated in the high gas loading region based on experimental measurements and thermodynamic modeling. An experimental phase equilibrium study was performed to evaluate the absorption of carbon dioxide in aqueous solutions of five representative alkanolamines, including monoethanolamine, diethanolamine, N-methyldiethanolamine, 2-amino-2-methyl-1-propanol and piperazine. The carbon dioxide loadings of these solutions were determined for a wide range of pressures (62.5 kPa to 4150 kPa), temperatures (303.15 K to 343.15 K) and alkanolamine concentrations (2 M to 4 M). The results were found to be largely consistent with those previously reported in the literature. Furthermore, a hybrid Kent-Eisenberg model was developed for the correlation of the experimental data points. This new model incorporated an equation of state/excess Gibbs energy model for determining the solubility of carbon dioxide in the high-pressure-high gas loading region. This approach also used a single correction parameter, which was a function of the alkanolamine concentration. The results of this model were in excellent agreement with our experimental results. Most notably, this model was consistent with other reported values from the literature.

  18. Synthesis of Spherical Carbon Nitride-Based Polymer Composites by Continuous Aerosol-Photopolymerization with Efficient Light Harvesting.

    PubMed

    Poostforooshan, Jalal; Badiei, Alireza; Kolahdouz, Mohammadreza; Weber, Alfred P

    2016-08-24

    Here we report a novel, facile, and sustainable approach for the preparation of spherical submicrometer carbon nitride-based polymer composites by a continuous aerosol-photopolymerization process. In this regard, spherical mesoporous carbon nitride (SMCN) nanoparticles were initially prepared via a nanocasting approach using spray-drying synthesized spherical mesoporous silica (SMS) nanoparticles as hard templates. In addition to experimental characterization, the effect of porosity on the light absorption enhancement and consequently the generation rate of electron-hole pairs inside the SMCN was simulated using a three-dimensional finite difference time-domain (FDTD) method. To produce the carbon nitride-based polymer composite, SMCN nanoparticles exhibit excellent performance in photopolymerization of butyl acrylate (PBuA) monomer in the presence of n-methyldiethanolamine (MDEA) as a co-initiator in a continuous aerosol-based process. In this one-pot synthesis, SMCN nanoparticles act not only as photoinitiators but at the same time as fillers and templates. The average aerosol residence time in the photoreactor is about 90 s. The presented aerosol-photopolymerization process avoids the need for solvent and surfactant, operates at room temperature, and, more importantly, is suitable to produce the spherical composite with hydrophobic polymers. Furthermore, we simulated the condition of SMCN nanoparticles during illumination in the gas phase process, which can freely rotate. The results demonstrated that the hole (h(+)) density is almost equally distributed in the whole part of the SMCN nanoparticles due to their rotation, leading to efficient light harvesting and more homogeneous photoreaction. The combination of the outstanding features of environmentally friendly SMCN, photopolymerization, and aerosol processing might open new avenues, especially in green chemistry, to produce novel polymer composites with multifunctional properties. PMID:27483090

  19. Self-assembled 3D heterometallic Cu(II)/Fe(II) coordination polymers with octahedral net skeletons: structural features, molecular magnetism, thermal and oxidation catalytic properties.

    PubMed

    Karabach, Yauhen Y; Guedes da Silva, M Fátima C; Kopylovich, Maximilian N; Gil-Hernández, Beatriz; Sanchiz, Joaquin; Kirillov, Alexander M; Pombeiro, Armando J L

    2010-12-01

    The new three-dimensional (3D) heterometallic Cu(II)/Fe(II) coordination polymers [Cu(6)(H(2)tea)(6)Fe(CN)(6)](n)(NO(3))(2n)·6nH(2)O (1) and [Cu(6)(Hmdea)(6)Fe(CN)(6)](n)(NO(3))(2n)·7nH(2)O (2) have been easily generated by aqueous-medium self-assembly reactions of copper(II) nitrate with triethanolamine or N-methyldiethanolamine (H(3)tea or H(2)mdea, respectively), in the presence of potassium ferricyanide and sodium hydroxide. They have been isolated as air-stable crystalline solids and fully characterized including by single-crystal X-ray diffraction analyses. The latter reveal the formation of 3D metal-organic frameworks that are constructed from the [Cu(2)(μ-H(2)tea)(2)](2+) or [Cu(2)(μ-Hmdea)(2)](2+) nodes and the octahedral [Fe(CN)(6)](4-) linkers, featuring regular (1) or distorted (2) octahedral net skeletons. Upon dehydration, both compounds show reversible escape and binding processes toward water or methanol molecules. Magnetic susceptibility measurements of 1 and 2 reveal strong antiferromagnetic [J = -199(1) cm(-1)] or strong ferromagnetic [J = +153(1) cm(-1)] couplings between the copper(II) ions through the μ-O-alkoxo atoms in 1 or 2, respectively. The differences in magnetic behavior are explained in terms of the dependence of the magnetic coupling constant on the Cu-O-Cu bridging angle. Compounds 1 and 2 also act as efficient catalyst precursors for the mild oxidation of cyclohexane by aqueous hydrogen peroxide to cyclohexanol and cyclohexanone (homogeneous catalytic system), leading to maximum total yields (based on cyclohexane) and turnover numbers (TONs) up to about 22% and 470, respectively. PMID:21028781

  20. Wipe selection for the analysis of surface materials containing chemical warfare agent nitrogen mustard degradation products by ultra-high pressure liquid chromatography-tandem mass spectrometry.

    PubMed

    Willison, Stuart A

    2012-12-28

    Degradation products arising from nitrogen mustard chemical warfare agent were deposited on common urban surfaces and determined via surface wiping, wipe extraction, and liquid chromatography–tandem mass spectrometry detection. Wipes investigated included cotton gauze, glass fiber filter, non-woven polyester fiber and filter paper, and surfaces included several porous (vinyl tile, painted drywall, wood) and mostly non-porous (laminate, galvanized steel, glass) surfaces. Wipe extracts were analyzed by ultra-high pressure liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) and compared with high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) results. An evaluation of both techniques suggests UPLC–MS/MS provides a quick and sensitive analysis of targeted degradation products in addition to being nearly four times faster than a single HPLC run, allowing for greater throughput during a wide-spread release concerning large-scale contamination and subsequent remediation events. Based on the overall performance of all tested wipes, filter paper wipes were selected over other wipes because they did not contain interferences or native species (TEA and DEA) associated with the target analytes, resulting in high percent recoveries and low background levels during sample analysis. Other wipes, including cotton gauze, would require a pre-cleaning step due to the presence of large quantities of native species or interferences of the targeted analytes. Percent recoveries obtained from a laminate surface were 47–99% for all nitrogen mustard degradation products. The resulting detection limits achieved from wipes were 0.2 ng/cm(2) for triethanolamine (TEA), 0.03 ng/cm(2) for N-ethyldiethanolamine (EDEA), 0.1 ng/cm(2) for N-methyldiethanolamine (MDEA), and 0.1 ng/cm(2) for diethanolamine (DEA). PMID:23218189

  1. Fast degradable citrate-based bone scaffold promotes spinal fusion

    PubMed Central

    Tang, Jiajun; Guo, Jinshan; Li, Zhen; Yang, Cheng; Xie, Denghui; Chen, Jian; Li, Shengfa; Li, Shaolin; Kim, Gloria B.; Bai, Xiaochun; Zhang, Zhongmin; Yang, Jian

    2015-01-01

    It is well known that high rates of fusion failure and pseudoarthrosis development (5~35%) are concomitant in spinal fusion surgery, which was ascribed to the shortage of suitable materials for bone regeneration. Citrate was recently recognized to play an indispensable role in enhancing osteconductivity and osteoinductivity, and promoting bone formation. To address the material challenges in spinal fusion surgery, we have synthesized mechanically robust and fast degrading citrate-based polymers by incorporating N-methyldiethanolamine (MDEA) into clickable poly(1, 8-octanediol citrates) (POC-click), referred to as POC-M-click. The obtained POC-M-click were fabricated into POC-M-click-HA matchstick scaffolds by compositing with hydroxyapatite (HA) for interbody spinal fusion in a rabbit model. Spinal fusion was analyzed by radiography, manual palpation, biomechanical testing, and histological evaluation. At 4 and 8 weeks post surgery, POC-M-click-HA scaffolds presented optimal degradation rates that facilitated faster new bone formation and higher spinal fusion rates (11.2±3.7, 80±4.5 at week 4 and 8, respectively) than the poly(L-lactic acid)-HA (PLLA-HA) control group (9.3±2.4 and 71.1±4.4) (p<0.05). The POC-M-click-HA scaffold-fused vertebrates possessed a maximum load and stiffness of 880.8±14.5 N and 843.2±22.4 N/mm, respectively, which were also much higher than those of the PLLA-HA group (maximum: 712.0±37.5 N, stiffness: 622.5±28.4 N/mm, p<0.05). Overall, the results suggest that POC-M-click-HA scaffolds could potentially serve as promising bone grafts for spinal fusion applications. PMID:26213625

  2. CO2 Capture by Absorption with Potassium Carbonate

    SciTech Connect

    Gary T. Rochelle; Andrew Sexton; Jason Davis; Marcus Hilliard; Qing Xu; David Van Wagener; Jorge M. Plaza

    2007-03-31

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. The best K{sup +}/PZ solvent, 4.5 m K{sup +}/4.5 m PZ, requires equivalent work of 31.8 kJ/mole CO{sub 2} when used with a double matrix stripper and an intercooled absorber. The oxidative degradation of piperazine or organic acids is reduced significantly by inhibitor A, but the production of ethylenediamine is unaffected. The oxidative degradation of piperazine in 7 m MEA/2 m PZ is catalyzed by Cu{sup ++}. The thermal degradation of MEA becomes significant at 120 C. The solubility of potassium sulfate in MEA/PZ solvents is increased at greater CO{sub 2} loading. The best solvent and process configuration, matrix with MDEA/PZ, offers 22% and 15% energy savings over the baseline and improved baseline, respectively, with stripping and compression to 10 MPa. The energy requirement for stripping and compression to 10 MPa is about 20% of the power output from a 500 MW power plant with 90% CO{sub 2} removal. The stripper rate model shows that a ''short and fat'' stripper requires 7 to 15% less equivalent work than a ''tall and skinny'' one. The stripper model was validated with data obtained from pilot plant experiments at the University of Texas with 5m K{sup +}/2.5m PZ and 6.4m K{sup +}/1.6m PZ under normal pressure and vacuum conditions using Flexipac AQ Style 20 structured packing. Experiments with oxidative degradation at low gas rates confirm the effects of Cu{sup +2} catalysis; in MEA/PZ solutions more formate and acetate is produced in the presence of Cu{sup +2}. At 150 C, the half life of 30% MEA with 0.4 moles CO{sub 2}/mole amine is about 2 weeks. At 100 C, less than 3% degradation occurred in two weeks. The solubility of potassium sulfate in MEA solution increases significantly with CO{sub 2} loading and decreases with MEA concentration. The base case corrosion

  3. Novel heteroleptic lanthanide organic frameworks containing pyridine-2,5-dicarboxylic acid and in situ generated piperazine-2,5-dicarboxylic acid from piperazine: Hydrothermal synthesis and luminescent properties

    NASA Astrophysics Data System (ADS)

    Ay, Burak; Yildiz, Emel; Kani, İbrahim

    2016-01-01

    Two novel 3D lanthanide metal-organic frameworks [Ln(pydc)(pip)1/2(H2O] (Ln=Ce (1) and Pr (2), H2pydc=2,5-pyridinedicarboxylic acid, H2pip=2,5-piperazinedicarboxylic acid have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffractions (PXRD), and single-crystal X-ray diffractions. Field emission scanning electron microscopy (FESEM) was used for morphological analysis. Complexes are isostructural and feature interesting 3D frameworks. Both compounds crystallize in the monoclinic system, space group P21/c. Structural analyses of 1 and 2 show that Ln3+ ions connect with each other through H2pydc and H2pip. To the best of our knowledge, they are the first heteroleptic lanthanide polymers obtained through in situ 2,5-piperazinedicarboxylic acid syntheses. Moreover, thermal and luminescent properties of the compounds have been investigated.

  4. Tetra­aqua­bis­(piperazin-1-ium)cobalt(II) bis­(sulfate) dihydrate

    PubMed Central

    Sahbani, Thameur; Smirani Sta, Wajda; Rzaigui, Mohamed

    2013-01-01

    In the centrosymmetric title compound, [Co(C4H11N2)2(H2O)4](SO4)2·2H2O, the CoII atom is coordinated in a distorted octa­hedral geometry by four water O atoms and two piperazinium N atoms. These four water O atoms define an equatorial plane with a maximum deviation of 0.0384 (1) Å while the two piperazinium N atoms complete the octa­hedron in the axial positions. Neighboring complex mol­ecules and sulfate anions are connected through an extensive network of N—H⋯O and O—H⋯O hydrogen bonds, which link the different chemical species into layers in the ab plane. Additional Owater—H⋯O hydrogen bonds involving the non-coordinating water mol­ecules and C—H⋯O inter­actions connect these layers into a three-dimensional supra­molecular structure. PMID:24454163

  5. 2-{4-[(1,3-Benzodioxol-5-yl)meth­yl]piperazin-1-yl}pyrimidine

    PubMed Central

    Wu, Chunli; Li, Jieming; Wei, Huijie; Hang, Ye; Jiang, Yueming

    2013-01-01

    In the title compound, C16H18N4O2, known also as peribedil, the dihedral angle between the mean planes of the pyrimidine and benzene rings is 56.5 (8)°. The 1,3-dioxole fragment adopts an envelope conformation with the methyl­ene C atom forming the flap; this atom deviates by 0.232 (3) Å from the plane defined by the remaining atoms of the 1,3-benzodioxole unit. In the crystal, C—H⋯π inter­actions between c-glide-related mol­ecules arrange them into columns extending along the c-axis direction. The columns related by a unit translation along the b axis are packed into (100) layers via another C—H⋯π inter­action involving the pyrimidine ring as an acceptor. PMID:24046690

  6. O2-Dependent Efficacy of Novel Piperidine- and Piperazine-Based Chalcones against the Human Parasite Giardia intestinalis

    PubMed Central

    Bahadur, Vijay; Mastronicola, Daniela; Tiwari, Hemandra Kumar; Kumar, Yogesh; Falabella, Micol; Pucillo, Leopoldo Paolo; Sarti, Paolo

    2014-01-01

    Giardia intestinalis is the most frequent protozoan agent of intestinal diseases worldwide. Though commonly regarded as an anaerobic pathogen, it preferentially colonizes the fairly oxygen-rich mucosa of the proximal small intestine. Therefore, when testing new potential antigiardial drugs, O2 should be taken into account, since it also reduces the efficacy of metronidazole, the gold standard drug against giardiasis. In this study, 46 novel chalcones were synthesized by microwave-assisted Claisen-Schmidt condensation, purified, characterized by high-resolution mass spectrometry, 1H and 13C nuclear magnetic resonance, and infrared spectroscopy, and tested for their toxicity against G. intestinalis under standard anaerobic conditions. As a novel approach, compounds showing antigiardial activity under anaerobiosis were also assayed under microaerobic conditions, and their selectivity against parasitic cells was assessed in a counterscreen on human epithelial colorectal adenocarcinoma cells. Among the tested compounds, three [30(a), 31(e), and 33] were more effective in the presence of O2 than under anaerobic conditions and killed the parasite 2 to 4 times more efficiently than metronidazole under anaerobiosis. Two of them [30(a) and 31(e)] proved to be selective against parasitic cells, thus representing potential candidates for the design of novel antigiardial drugs. This study highlights the importance of testing new potential antigiardial agents not only under anaerobic conditions but also at low, more physiological O2 concentrations. PMID:24217695

  7. N-(2-alkylaminoethyl)-4-(1,2,4-oxadiazol-5-yl)piperazine-1-carboxamides as highly potent smoothened antagonists.

    PubMed

    Muraglia, Ester; Ontoria, Jesus M; Branca, Danila; Dessole, Gabriella; Bresciani, Alberto; Fonsi, Massimiliano; Giuliano, Claudio; Llauger Bufi, Laura; Monteagudo, Edith; Palumbi, Maria Cecilia; Torrisi, Caterina; Rowley, Michael; Steinkühler, Christian; Jones, Philip

    2011-09-15

    Smoothened (Smo) antagonists are emerging as new therapies for the treatment of neoplasias with aberrantly reactivated hedgehog (Hh) signaling pathway. A novel series of 4-[3-(quinolin-2-yl)-1,2,4-oxadiazol-5-yl]piperazinyl ureas as smoothened antagonists was recently described, herein the series has been further optimized through the incorporation of a basic amine into the urea. This development resulted in identification of some exceptionally potent smoothened antagonists with low serum shifts, however, reductive ring opening on the 1,2,4-oxadiazole in rats limits the applicability of these compounds in in vivo studies. PMID:21802943

  8. Influence of fluorocarbon flat-membrane hydrophobicity on carbon dioxide recovery.

    PubMed

    Lin, Su-Hsia; Tung, Kuo-Lun; Chang, Hao-Wei; Lee, Kueir-Rarn

    2009-06-01

    The influence of hydrophobicity in flat-plate porous poly(vinylidene fluoride) (PVDF) and expended polytetrafluoroethylene (PTFE) membranes on CO(2) recovery using aqueous solutions of piperazine (PZ) and alkanolamine is examined. Experiments were conducted at various gas flow rates, liquid flow rates, and absorbent concentrations. The CO(2) absorption flux increased with increasing gas flow rates and absorbent concentrations. When using 2-amino-2-methyl-1-propanol (AMP) or AMP+PZ aqueous solution as absorbent, this process was dominantly governed by gas film layer diffusion and membrane diffusion. The diffusion resistance of the membrane phase was only important when using N-methyldiethanolamine as the sole absorbent. The water contact angle increased initially with increasing plasma working power and reached at steady state value of 155 degrees beyond 100 W. The elemental fluorine-to-carbon ratio (F/C) and water contact angle of the PVDF membrane increased with increasing treatment time and reached a plateau after 5min of CH(4) plasma (100 W). Increases in the CO(2) absorption fluxes of 7% and 17% were observed for plasma-treated PVDF membranes in comparison to non-treated PVDF and PTFE, respectively, when using 1M AMP as absorbent. The membrane mass transfer coefficient, k(m), for plasma-treated PVDF membranes increased from 2.1 x 10(-4) to 2.5 x 10(-4)ms(-1). Membrane durability was greatly improved by CF(4) plasma treatment (100 W/5 min) and comparable to that of PTFE membranes. PMID:19289246

  9. CO2 Capture by Absorption with Potassium Carbonate

    SciTech Connect

    Gary T. Rochelle; Eric Chen; Babatunde Oyenekan; Andrew Sexton; Jason Davis; Marus Hiilliard; Qing Xu; David Van Wagener; Jorge M. Plaza

    2006-12-31

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. The best solvent and process configuration, matrix with MDEA/PZ, offers 22% and 15% energy savings over the baseline and improved baseline, respectively, with stripping and compression to 10 MPa. The energy requirement for stripping and compression to 10 MPa is about 20% of the power output from a 500 MW power plant with 90% CO{sub 2} removal. The stripper rate model shows that a ''short and fat'' stripper requires 7 to 15% less equivalent work than a ''tall and skinny'' one. The stripper model was validated with data obtained from pilot plant experiments at the University of Texas with 5m K{sup +}/2.5m PZ and 6.4m K{sup +}/1.6m PZ under normal pressure and vacuum conditions using Flexipac AQ Style 20 structured packing. Experiments with oxidative degradation at low gas rates confirm the effects of Cu{sup +2} catalysis; in MEA/PZ solutions more formate and acetate is produced in the presence of Cu{sup +2}. At 150 C, the half life of 30% MEA with 0.4 moles CO{sub 2}/mole amine is about 2 weeks. At 100 C, less than 3% degradation occurred in two weeks. The solubility of potassium sulfate in MEA solution increases significantly with CO{sub 2} loading and decreases with MEA concentration. The base case corrosion rate in 5 M MEA/1,2M PZ is 22 mpy. With 1 wt% heat stable salt, the corrosion rate increases by 50% to 160% in the order: thiosulfate< oxalate

  10. A novel screening method for 64 new psychoactive substances and 5 amphetamines in blood by LC-MS/MS and application to real cases.

    PubMed

    Vaiano, Fabio; Busardò, Francesco P; Palumbo, Diego; Kyriakou, Chrystalla; Fioravanti, Alessia; Catalani, Valeria; Mari, Francesco; Bertol, Elisabetta

    2016-09-10

    Identification and quantification of new psychoactive substances (NPS), both in biological and non-biological samples, represent a hard challenge for forensic toxicologists. NPS are increasingly emerging on illegal drug market. Many cases of co-consumption of NPS and other substances have also been reported. Hence, the development of analytical methods aiming at the detection of a broad-spectrum of compounds (NPS and "traditional" drugs) could be helpful. In this paper, a fully validated screening method in blood for the simultaneous detection of 69 substances, including 64 NPS (28 synthetic cannabinoids, 19 synthetic cathinones, 5 phenethylamines, 3 indanes, 2 piperazines, 2 tryptamines, 2 phencyclidine, methoxetamine, ketamine and its metabolite) and 5 amphetamines (amphetamine, methamphetamine, MDMA, MDA, 3,4-methylenedioxy-N-ethylamphetamine - MDEA-) by a dynamic multiple reaction monitoring analysis through liquid chromatography - tandem mass spectrometry (LC-MS/MS) is described. This method is very fast, easy to perform and cheap as it only requires the deproteinization of 200μL of blood sample with acetonitrile. The chromatographic separation is achieved with a C18 column. The analysis is very sensitive, with limits of quantification ranging from 0.1 to 0.5ng/mL. The method is linear from 1 to 100ng/mL and the coefficient of determination (R(2)) was always above 0.9900. Precision and accuracy were acceptable at any quality control level and recovery efficiency range was 72-110%. Matrix effects did not negatively affect the analytical sensitivity. This method was successfully applied to three real cases, allowing identification and quantification of: mephedrone and methamphetamine (post-mortem); ketamine, MDMA and MDA (post-mortem); AB-FUBINACA (ante-mortem). PMID:27490334

  11. Single-molecule magnetism in a family of {Co(III)2Dy(III)2} butterfly complexes: effects of ligand replacement on the dynamics of magnetic relaxation.

    PubMed

    Langley, Stuart K; Ungur, Liviu; Chilton, Nicholas F; Moubaraki, Boujemaa; Chibotaru, Liviu F; Murray, Keith S

    2014-05-01

    The synthesis and structural characterization of four related heterometallic complexes of formulas [Dy(III)2Co(III)2(OMe)2(teaH)2(O2CPh)4(MeOH)4](NO3)2·MeOH·H2O (1a) and [Dy(III)2Co(III)2(OMe)2(teaH)2(O2CPh)4(MeOH)2(NO3)2]·MeOH·H2O (1b), [Dy(III)2Co(III)2(OMe)2(dea)2(O2CPh)4(MeOH)4](NO3)2 (2), [Dy(III)2Co(III)2(OMe)2(mdea)2(O2CPh)4(NO3)2] (3), and [Dy(III)2Co(III)2(OMe)2(bdea)2(O2CPh)4(MeOH)4](NO3)2·0.5MeOH·H2O (4a) and [Dy(III)2Co(III)2(OMe)2(bdea)2(O2CPh)4(MeOH)2(NO3)2]·MeOH·1.5H2O (4b) are reported (teaH3 = triethanolamine, deaH2 = diethanolamine, mdeaH2 = N-methyldiethanolamine, and bdeaH2 = N-n-butyldiethanolamine). Compounds 1 (≡ 1a and 1b) and 4 (≡ 4a and 4b) both display two unique molecules within the same crystal and all compounds display a butterfly type core, with the Dy(III) ions occupying the central body positions and the diamagnetic Co(III) ions the outer wing-tip sites. Compounds 1-4 were investigated via direct current and alternating current magnetic susceptibility measurements, and it was found that each complex displayed single-molecule magnet (SMM) behavior. All four compounds display unique coordination and geometric environments around the Dy(III) ions and it was found that each displays a different anisotropy barrier. Ab initio calculations were performed on 1-4 and these determined the low lying electronic structure of each Dy(III) ion and the magnetic interactions for each cluster. It was found that there was a strong correlation between the calculated energy gap between the ground and first excited states of the single-ion ligand-field split Dy(III) levels and the experimentally observed anisotropy barrier. Furthermore, the transverse g factors found for the Dy(III) ions, defining the tunnelling rates within the ground Kramers doublets, are largest for 1, which agrees with the experimental observation of the shortest relaxation time in the high-temperature domain for this complex. The magnetic exchange between the Dy

  12. Self-assembled copper(II) coordination polymers derived from aminopolyalcohols and benzenepolycarboxylates: structural and magnetic properties.

    PubMed

    Kirillov, Alexander M; Karabach, Yauhen Y; Haukka, Matti; Guedes da Silva, M Fatima C; Sanchiz, Joaquin; Kopylovich, Maximilian N; Pombeiro, Armando J L

    2008-01-01

    The new copper(II) or copper(II)/sodium(I) 1D coordination polymers [Cu2(Hmdea)2(mu-H2O)(mu2-tpa)]n.2nH2O (1), [Cu2(H2tipa)2(mu2-ipa)]n.4nH2O (2), [Cu2(H2tea)2Na(H2O)2(mu2-tma)]n.6nH2O (3), [Cu2(H2tea)2(mu2-ipa)]n.nH2O (4a), and [Cu2(H2tea)2{mu3-Na(H2O)3}(mu3-ipa)]n(NO3)n.0.5nH2O (4b) have been prepared in aqueous medium by self-assembly from copper(II) nitrate, aminopolyalcohols [methyldiethanolamine (H2mdea), triisopropanolamine (H3tipa), and triethanolamine (H3tea)] as main chelating ligands and benzenepolycarboxylic acids [terephthalic (H2tpa), isophthalic (H2ipa), and trimesic (H3tma) acid] as spacers. They have been characterized by IR spectroscopy, elemental and single-crystal X-ray diffraction analyses, the latter indicating the formation of unusual multinuclear metal cores interconnected by various benzenepolycarboxylate spacers, leading to distinct wavelike, zigzag, or linear 1D polymeric metal-organic chains. These are further extended to 2D or 3D hydrogen-bonded supramolecular networks via extensive interactions with the intercalated crystallization water molecules. The latter are associated, also with aqua ligands, by hydrogen bonds resulting in acyclic (H2O)3 clusters in 1, (H2O)8 clusters in 2, infinite 1D water chains in 3, and disordered water-nitrate associates in 4b, all playing a key role in the structure stabilization and its extension to further dimensions. Variable-temperature magnetic susceptibility measurements have shown that 1-4 exhibit a moderately strong ferromagnetic coupling through the alkoxo bridge. The small Cu-O-Cu bridging angle and the large out-of-plane displacement of the carbon atom of the alkoxo group accounts for this behavior. The magnetic data have been analyzed by means of a dinuclear and a 1D chain model, and the magnetic parameters have been determined. The magnetic exchange coupling in 3, to our knowledge, is the highest found in alkoxo-bridged copper(II) complexes. PMID:18069826

  13. 1-(4-Hy­droxy­phen­yl)piperazine-1,4-diium tetra­chlorido­cobalt(II) monohydrate

    PubMed Central

    Mghandef, Marwa; Boughzala, Habib

    2014-01-01

    The asymmetric unit of the title inorganic–organic hybrid compound, (C10H16N2O)[CoCl4]·H2O, consists of a tetrahedral [CoCl4]2− anion, together with a [C10H18N2O]2+ cation and a water mol­ecule. Crystal cohesion is achieved through N—H⋯Cl, O—H⋯Cl and N—H⋯O hydrogen bonds between organic cations, inorganic anions and the water mol­ecules, building up a three-dimensional network. PMID:24764833

  14. Dichlorido(4-meth-oxy-2-{[2-(piperazin-4-ium-1-yl)eth-yl]imino-meth-yl}phenol-ate)cadmium.

    PubMed

    Saleh Salga, Muhammad; Khaledi, Hamid; Mohd Ali, Hapipah

    2011-07-01

    In the title compound, [CdCl(2)(C(14)H(21)N(3)O(2))], the Schiff base ligand chelates the Cd(II) ion in an N,N,O-tridentate fashion. Two Cl atoms complete a distorted square-pyramidal coordination environment around the metal atom. In the crystal, adjacent mol-ecules are linked through C-H⋯π inter-actions into infinite chains along the a axis. The mol-ecules are further connected into a three-dimensional network via N-H⋯O, N-H⋯Cl and C-H⋯Cl inter-actions. The ethyl-ene group is disordered over two sets of sites in a 0.520 (10):0.480 (10) ratio. PMID:21836911

  15. New antiproliferative 7-(4-(N-substituted carbamoylmethyl)piperazin-1-yl) derivatives of ciprofloxacin induce cell cycle arrest at G2/M phase.

    PubMed

    Mohammed, Hamada H H; Abd El-Hafeez, Amer Ali; Abbas, Samar H; Abdelhafez, El-Shimaa M N; Abuo-Rahma, Gamal El-Din A

    2016-10-01

    New N-4-piperazinyl derivatives of ciprofloxacin 2a-g were prepared and tested for their cytotoxic activity. The primary in vitro one dose anticancer assay experienced promising cytotoxic activity against different cancer cell lines especially non-small cell lung cancer. Independently, compounds 2b, 2d, 2f and 2g showed anticancer activity against human non-small cell lung cancer A549 cells (IC50=14.8, 24.8, 23.6 and 20.7μM, respectively) compared to the parent ciprofloxacin (IC50 >100μM) and doxorubicin as a positive control (IC50=1μM). The flow cytometric analysis for 2b showed dose dependent G2/M arrest in A549 cells. Also, 2b increased the expression of p53 and p21 and decreased the expression of cyclin B1 and Cdc2 proteins in A549 cells without any effect on the same proteins expression in WI-38 cells. Specific inhibition of p53 by pifithrin-α reversed the G2/M phase arrest induced by the 2b compound, suggesting contribution of p53 to increase. Taken together, 2b induced G2/M phase arrest via p53/p21 dependent pathway. The results indicate that 2b can be used as a lead compound for further development of new derivatives against non-small cell lung cancer. PMID:27555286

  16. Novel push-pull heterocyclic azo disperse dyes containing piperazine moiety: Synthesis, spectral properties, antioxidant activity and dyeing performance on polyester fibers.

    PubMed

    Mohammadi, Asadollah; Khalili, Behzad; Tahavor, Marzieh

    2015-11-01

    Six novel push-pull azo disperse dyes were synthesized via classical azo coupling reaction using 2-amino-thiazolyl derivatives as the diazo components and 1-(4-bromobenzyl)-4-phenylpiperazine as a key coupling intermediate. The structures of the dyes and synthesized intermediate were confirmed by FT-IR, (1)H NMR, (13)C NMR and UV-vis analyses. The solvatochromic behavior of the dyes was studied in a set of 10 solvents of different polarity and considerable results were obtained. The prepared heterocyclic azo dyes were applied for dyeing polyester fibers and their dyeing properties were studied. The fastness properties of the dyed fabrics such as wash, light and rubbing fastness degrees were measured by standard methods. Investigation of antioxidant activity of compounds was carried out by ferric reducing antioxidant power (FRAP) method. The synthesized dyes exhibited significant antioxidant activities. PMID:26112103

  17. [The effect of piperazine analogs of aryloxyaminopropanol (IIIq and IIIb) on the occurrence of reperfusion dysrhythmias in an in vivo experiment on rats].

    PubMed

    Jadronová, O; Kuzelová, M; Seginko, J; Celková, H; Svec, P

    1996-11-01

    The present experimental study reports the beneficial effects of newly synthetized substances IIIq and IIIb in vivo. These aryloxyaminopropanol drugs have been shown to antagonize the contraction caused by calcium comparable to verapamil and flunarizine in the model of the isolated guinea pig terminal ileum. Effects of substances on both the incidence of arrhythmias during ischemia and the reperfusion period and mortality were investigated in the rat model ischemia-reperfusion injury. We can conclude that compound IIIq in a dose of 10(-6) mol/kg is effective in reducing the incidence of reperfusion-induced arrhythmias. Substance IIIb (10(-6) mol/kg) administered before ischemia was not able to suppress arrhythmias in the rat model of myocardial infarction and reperfusion. PMID:8998610

  18. Gas cleanup for indirect liquefaction

    SciTech Connect

    Wham, R.M.

    1984-08-01

    Visual aids are presented describing various classes of primary gas cleanup. These are: (1) amine systems (MDEA Process); (2) alkali salt systems; (3) physical absorption systems (Selexol Process, Stretford Process); (4) mixed solvent systems; and (5) Claus Sulfur Recovery System. Flowsheets are also presented for the MDEA, Selexol and Stretford processes.

  19. Discovery of a novel sub-class of ROMK channel inhibitors typified by 5-(2-(4-(2-(4-(1H-Tetrazol-1-yl)phenyl)acetyl)piperazin-1-yl)ethyl)isobenzofuran-1(3H)-one.

    PubMed

    Tang, Haifeng; de Jesus, Reynald K; Walsh, Shawn P; Zhu, Yuping; Yan, Yan; Priest, Birgit T; Swensen, Andrew M; Alonso-Galicia, Magdalena; Felix, John P; Brochu, Richard M; Bailey, Timothy; Thomas-Fowlkes, Brande; Zhou, Xiaoyan; Pai, Lee-Yuh; Hampton, Caryn; Hernandez, Melba; Owens, Karen; Roy, Sophie; Kaczorowski, Gregory J; Yang, Lihu; Garcia, Maria L; Pasternak, Alexander

    2013-11-01

    A sub-class of distinct small molecule ROMK inhibitors were developed from the original lead 1. Medicinal chemistry endeavors led to novel ROMK inhibitors with good ROMK functional potency and improved hERG selectivity. Two of the described ROMK inhibitors were characterized for the first in vivo proof-of-concept biology studies, and results from an acute rat diuresis model confirmed the hypothesis that ROMK inhibitors represent new mechanism diuretic and natriuretic agents. PMID:24075732

  20. N-{2-[4-(2-Meth­oxy­phen­yl)piperazin-1-yl]eth­yl}-4-nitro-N-(2-pyrid­yl)benzamide

    PubMed Central

    Lu, Chunxiong; Jiang, Quanfu

    2010-01-01

    In the title compound, C25H27N5O4, the piperizine ring adopts a chair conformation. The dihedral angles between the pyridine ring and the two benzene rings are 65.5 (4) and 70.7 (4)°, while the dihedral angle between the two benzene rings is 17.3 (3)°. An intra­molecular C—H⋯O hydrogen bond occurs. PMID:21587665

  1. Variable dimensionality in the uranium fluoride/2-methyl-piperazine system: Synthesis and structures of UFO-5, -6, and -7; Zero-, one-, and two-dimensional materials with unprecedented topologies

    SciTech Connect

    Francis, R.J.; Halasyamani, P.S.; Bee, J.S.; O'Hare, D.

    1999-02-24

    Recently, low temperature (T < 300 C) hydrothermal reactions of inorganic precursors in the presence of organic cations have proven highly productive for the synthesis of novel solid-state materials. Interest in these materials is driven by the astonishingly diverse range of structures produced, as well as by their many potential materials chemistry applications. This report describes the high yield, phase pure hydrothermal syntheses of three new uranium fluoride phases with unprecedented structure types. Through the systematic control of the synthesis conditions the authors have successfully controlled the architecture and dimensionality of the phase formed and selectively synthesized novel zero-, one-, and two-dimensional materials.

  2. Synthesis of new piperazine derived Cu(II)/Zn(II) metal complexes, their DNA binding studies, electrochemistry and anti-microbial activity: Validation for specific recognition of Zn(II) complex to DNA helix by interaction with thymine base

    NASA Astrophysics Data System (ADS)

    Bhat, Irshad-ul-Haq; Tabassum, Sartaj

    2009-06-01

    New 3,4:9,10-dibenzo-2,11-dihydroxy-1,12-bispiperazine-5,8-dioxododecane complexes [C 24H 36N 4O 6Cu] ( 1), [C 24H 32N 4O 4Zn] ( 2) have been synthesized and characterized by elemental analysis, IR, NMR, Mass, EPR, UV-vis spectroscopy and molar conductance measurements. The complexes are non-ionic in nature and possess octahedral geometry around Cu 2+, Zn 2+ central metal ions. The binding studies of 1 and 2 with calf thymus DNA (CT-DNA) were investigated by UV-vis, fluorescence, cyclic voltammetery and viscosity measurements. The calculated binding constant Kb for 1 and 2 obtained from UV-vis absorption studies was 7.6 × 10 3 M -1, 80.8 × 10 4 M -1, respectively. The intrinsic binding constants were also estimated to be 7.0 × 10 4 M -1 and 7.53 × 10 5 M -1 for 1 and 2, respectively by using emission titrations. These experimental results suggest that complexes are groove binders and interact to CT-DNA with different affinities. Both the complexes in presence and absence of CT-DNA show quasireversible wave corresponding to Cu II/Cu I and Zn II/Zn I redox couple. The changes in E1/2, Δ E, Ipa/ Ipc ascertain the interaction of 1 and 2 with CT-DNA. Further, decrease in viscosity of CT-DNA with increasing concentration of complexes was observed. In vitro, antimicrobial activity against fungi A. brassicicola, A. niger and bacteria E. coli, P. aeruginosa of complexes were carried out, which indicate that complex 2 is more active against both fungal and bacterial strains as shown by % inhibition data.

  3. Chemoprevention of Colonic Aberrant Crypt Foci by Novel Schiff Based Dichlorido(4-Methoxy-2-{[2-(Piperazin-4-Ium-1-Yl)Ethyl]Iminomethyl}Phenolate)Cd Complex in Azoxymethane-Induced Colorectal Cancer in Rats

    PubMed Central

    Hajrezaie, Maryam; Shams, Keivan; Moghadamtousi, Soheil Zorofchian; Karimian, Hamed; Hassandarvish, Pouya; Emtyazjoo, Mozhgan; Zahedifard, Maryam; Majid, Nazia Abdul; Ali, Hapipah Mohd; Abdulla, Mahmood Ameen

    2015-01-01

    Schiff-based complexes as a source of cancer chemotherapeutic compounds have been subjected to the variety of anticancer studies. The in-vitro analysis confirmed the CdCl2(C14H21N3O2) complex possess cytotoxicity and apoptosis induction properties in colon cancer cells, so lead to investigate the inhibitory efficiency of the compound on colonic aberrant crypt foci (ACF). Five groups of adult male rats were used in this study: Vehicle, cancer control, positive control groups and the groups treated with 25 and 50 mg/kg of complex for 10 weeks. The rats in vehicle group were injected subcutaneously with 15 mg/kg of sterile normal saline once a week for 2 weeks and orally administered with 5% Tween-20 (5 ml/kg) for 10 weeks, other groups were injected subcutaneously with 15 mg/kg azoxymethane once a week for 2 weeks. The rats in positive groups were injected intra-peritoneally with 35 mg/kg 5-Flourouracil four times in a month. Administration of the complex suppressed total colonic ACF formation up to 73.4% (P < 0.05). The results also showed that treatment with the complex significantly reduced the level of malondialdehyde while increasing superoxide dismutase and catalase activities. Furthermore, the down-regulation of PCNA and Bcl2 and the up-regulation of Bax was confirmed by immunohistochemical staining. PMID:26201720

  4. Evaluation of the genotoxic potential of alkylalkanolamines.

    PubMed

    Leung, H W; Ballantyne, B

    1997-09-18

    Three alkylalkanolamines, N,N-dimethylethanolamine, N-methyldiethanolamine, and tert-butyldiethanolamine, were evaluated for potential genotoxic activity using the Salmonella/microsome reverse gene mutation test, the CHO/HGPRT forward gene mutation test, a sister chromatid exchange test in cultured CHO cells, and an in vivo peripheral blood micronucleus test in Swiss-Webster mice. None of the three alkylalkanolamines produced any significant or dose-related increases in the frequencies of mutations, sister chromatid exchanges or micronuclei. These results indicate that N,N-dimethylethanolamine, N-methyldiethanolamine, and tert-butyldiethanolamine are not genotoxic in the tests conducted. PMID:9357557

  5. 2-[(4-Benzhydrylpipérazin-1-yl)méthyl]acrylonitrile

    PubMed Central

    Ben Amor, Fatma; Ould M’hamed, Mohamed; Mrabet, Hédi; Driss, Ahmed; Efrit, Mohamed Lotfi

    2008-01-01

    In the title compound, 2-[(4-benz­hydryl­piperazin-1-yl)­methyl]­acrylo­nitrile, C21H23N3, the substituted piperazine ring adopts a chair conformation and the dihedral angle between the mean planes of the aromatic rings is 71.61 (8)°. PMID:21201087

  6. Comparison of five derivatizing agents for the determination of amphetamine-type stimulants in human urine by extractive acylation and gas chromatography-mass spectrometry.

    PubMed

    Dobos, Adrienn; Hidvégi, Elod; Somogyi, Gábor Pál

    2012-06-01

    Five acylation reagents have been compared for use as derivatizing agents for the analysis of amphetamine-type stimulants (ATS) in urine by gas chromatography-mass spectrometry (GC-MS). The evaluated reagents were heptafluorobutyric anhydride, pentafluoropropionic anhydride, trifluoroacetic anhydride, acetic anhydride (AA) and N-methyl-bis(trifluoroacetamide). The ATS included amphetamine, methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA). A mixture of the ATS was added to urine (1 mL) followed by KOH solution and saturated NaHCO(3) solution. The sample was then extracted with dichloromethane and the derivatizing agent and 2 µL were injected into the GC-MS instrument. The derivatizing agents were compared with reference to the signal-to-noise (S/N) ratios, peak area values, relative standard deviations (RSDs), linearities, limits of detection (LODs) and selectivities. The acetic anhydride proved to be the best according to the S/N ratio and peak area results for amphetamine, MA, MDMA and MDEA. The best RSD values of peak areas and of S/N ratios at 3 µg/mL were also given by AA in cases of MDA, MDMA and MDEA. At 20 µg/mL, the lowest RSD values of peak areas for MDA and the lowest RSD values of S/N ratios for MA, MDA, MDMA and MDEA were again given by AA. Additionally, the highest correlation coefficients for MA, MDA, MDMA and MDEA and the lowest LOD results for MA, MDMA and MDEA were produced by AA. PMID:22582269

  7. Acidic gas capture by diamines

    DOEpatents

    Rochelle, Gary; Hilliard, Marcus

    2011-05-10

    Compositions and methods related to the removal of acidic gas. In particular, the present disclosure relates to a composition and method for the removal of acidic gas from a gas mixture using a solvent comprising a diamine (e.g., piperazine) and carbon dioxide. One example of a method may involve a method for removing acidic gas comprising contacting a gas mixture having an acidic gas with a solvent, wherein the solvent comprises piperazine in an amount of from about 4 to about 20 moles/kg of water, and carbon dioxide in an amount of from about 0.3 to about 0.9 moles per mole of piperazine.

  8. Comparative study on the regeneration of flue-gas desulfurizing agents by using conventional electrodialysis (ED) and bipolar membrane electrodialysis (BMED)

    SciTech Connect

    Chuanhui Huang; Tongwen Xu

    2006-09-01

    Piperazine (Pz) is an ideal desulfurizing agent but the heat-stable salts formed in desulfurization have caused secondary pollution and waste of resources. In the previous paper, a method was reported to regenerate piperazine by using bipolar membrane electrodialysis (BMED). To find the variety of that regeneration process, experiments were performed on the regeneration of piperazine by using ED. In comparison, ED has higher piperazine yield and current efficiency, and much lower voltage drop and energy consumption. However, its process cost is higher than that of BMED due to an extra expenditure for the base and its tank and pumps. The process cost is estimated to be 0.96 $/kg Pz for BMED and 1.14 $/kg Pz for ED. Notably, BMED has more environmental benefits and will be more economically attractive as the control on secondary pollution is strengthened and the bipolar membrane cost decreases. 9 refs., 4 figs., 1 tab.

  9. Comparative study on the regeneration of flue-gas desulfurizing agents by using conventional electrodialysis (ED) and bipolar membrane electrodialysis (BMED).

    PubMed

    Huang, Chuanhui; Xu, Tongwen

    2006-09-01

    Piperazine is an ideal desulfurizing agent but the heat-stable salts formed in desulfurization have caused secondary pollution and waste of resources. In the previous paper, a method was reported to regenerate piperazine by using BMED. To find the variety of that regeneration process, we performed experiments on the regeneration of piperazine by using ED. In comparison, ED has higher piperazine yield and current efficiency, and much lower voltage drop and energy consumption. However, its process cost is higher than that of BMED due to an extra expenditure for the base and its tank and pumps. The process cost is estimated to be 0.96 dollar/kg Pz for BMED and 1.14 dollar/kg Pz for ED. Notably, BMED has more environmental benefits and will be more economically attractive as the control on secondary pollution is strengthened and the bipolar membrane cost decreases. PMID:16999135

  10. Structural analysis of (S)-1-((1H-benzo[d][1,2,3]triazol-1-yl)oxy)-3-(4-(2-methoxyphenyl)piperazin-1-yl)propan-2-ol and binding mechanism with α1A-adrenoceptor: TDDFT calculations, X-ray crystallography and molecular docking

    NASA Astrophysics Data System (ADS)

    Xu, Wei; Shao, Binhao; Xu, Xingjie; Jiang, Renwang; Yuan, Mu

    2016-02-01

    The title compound, (S)-1-((1H-benzo[d][1,2,3]triazol-1-yl)oxy)-3-(4-(2-methoxyphenyl)piperazi-n-1-yl)propan-2-ol (1), belongs to a class of arylpiperazine derivatives that exhibit good bioactivity against α1A-adrenoceptor. The current study describes conformational analysis of five energy-minimized conformers obtained at the B3LYP/6-31G(d) level of theory. The characteristically positive rotatory strengths at an excitation energy of 256 nm were achieved using time-dependent density functional theory (TDDFT) calculations. Molecular orbital studies clearly elucidated the origins of electronic transitions at 256 nm. The absolute configuration of (S)-1 was unambiguously determined by single crystal X-ray diffraction analysis. Molecular docking solved the binding mode of 1-α1A-adrenoceptor complex. This work can serve as a basis for better drug design of highly selective antagonists with chirality.

  11. Spectral investigations, DFT computations and molecular docking studies of 1,7,8,9-tetrachloro-10,10-dimethoxy-4-{3-[4-(2-methylphenyl)piperazin-1-yl]propyl}-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione

    NASA Astrophysics Data System (ADS)

    Resmi, K. S.; Mary, Y. Sheena; Varghese, Hema Tresa; Panicker, C. Yohannan; Pakosińska-Parys, Magdalena; Alsenoy, C. Van

    2015-10-01

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of the title compound have been investigated experimentally and theoretically. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analysed using NBO analysis. The hyperpolarisability calculation reveals the present material has a reasonably good propensity for nonlinear optical activity. Due to the different potential biological activity of the title compound, molecular docking study is also reported and the compound might exhibit inhibitory activity against human M2 muscarinic acetylcholine receptor.

  12. Synthesis and spectroscopic characterization of dicyanamido-Cu(II) complexes. Part 2 : Crystal structure of the complexes of tris[2-(2-pyridylethyl)]amine, tris(2-pyridylmethyl)amine and 1,4-bis[2-(2-pyridylethyl)]piperazine

    NASA Astrophysics Data System (ADS)

    Mautner, Franz A.; Soileau, Jesse B.; Bankole, Paul K.; Gallo, August A.; Massoud, Salah S.

    2008-10-01

    Two classes of novel dicyanamido (dca)-Cu(II) complexes were synthesized with a variety of tetradentate tripod amines, tridentate amines and diazacycloalkanes with pyridyl arms of different alkyl lengths and with tetra-aza macrocycles with different cavity sizes; the mononuclear, Cu(L)(dca)]ClO 4 (L = tepa ( 1), TPA ( 2), pzdepy ( 4), hpzpy 2 ( 5), cyclen ( 7), cyclam ( 8), tacp ( 9)) or Cu(L)(dca)ClO 4 (L = MeDPA ( 10), Mepea ( 11)) and the dinuclear, [Cu 2(L') 2(dca)](ClO 4) 3 (L' = pmap ( 3), pzpy 2 ( 6)). The isolated complexes were structurally characterized by electronic and IR spectroscopy as well as by X-ray. Single crystal X-ray diffraction analysis of the complexes [Cu(tepa)(dca)]ClO 4 ( 1), [Cu(TPA)(dca)]ClO 4 ( 2) and [Cu(pzdepy)(dca)]ClO 4 ( 4) reveal their monomeric penta-coordinate nature with the isolated [Cu(L)(dca)] + cations and ClO4- counter ions. All the complexes with the exception of 2 adapt distorted square pyramidal geometry while the coordination polyhedron around the copper center in 2 may be described as a distorted trigonal bipyramidal stereochemistry. The visible spectra of the complexes in aqueous solutions or in methanol are in complete agreement with the assigned X-ray geometry around the Cu(II) centers.

  13. 4-((R)-2-{[6-((S)-3-Methoxypyrrolidin-1-yl)-2-phenylpyrimidine-4-carbonyl]amino}-3-phosphonopropionyl)piperazine-1-carboxylic Acid Butyl Ester (ACT-246475) and Its Prodrug (ACT-281959), a Novel P2Y12 Receptor Antagonist with a Wider Therapeutic Window in the Rat Than Clopidogrel.

    PubMed

    Caroff, Eva; Hubler, Francis; Meyer, Emmanuel; Renneberg, Dorte; Gnerre, Carmela; Treiber, Alexander; Rey, Markus; Hess, Patrick; Steiner, Beat; Hilpert, Kurt; Riederer, Markus A

    2015-12-10

    Recent post hoc analyses of several clinical trials with P2Y12 antagonists showed the need for new molecules being fully efficacious as antiplatelet agents and having a reduced propensity to cause major bleeding. We have previously reported the discovery of the 2-phenylpyrimidine-4-carboxamide analogs as P2Y12 antagonists with nanomolar potency in the disease-relevant platelet aggregation assay in human plasma. Herein we present the optimization steps that led to the discovery of clinical candidate ACT-246475 (30d). The key step was the replacement of the carboxylic acid functionality by a phosphonic acid group which delivered the most potent molecules of the program. In addition, low in vivo clearance in rat and dog was achieved for the first time. Since the bioavailability of 30d was low in rat and dog, we developed the bis((isopropoxycarbonyl)oxy)methyl ester prodrug (ACT-281959, 45). Compound 30d showed efficacy in the rat ferric chloride thrombosis model when administered intravenously as parent or orally as its prodrug 45. Moreover, 30d displays a wider therapeutic window as compared to clopidogrel in the rat surgical blood loss model. PMID:26550844

  14. Selective inhibition of human cytochrome P450 3A4 by N-[2(R)-hydroxy-1(S)-indanyl]-5-[2(S)-(1, 1-dimethylethylaminocarbonyl)-4-[(furo[2, 3-b]pyridin-5-yl)methyl]piperazin-1-yl]-4(S)-hydroxy-2(R)-phenylmethy lpentanamide and P-glycoprotein by valspodar in gene transfectant systems.

    PubMed

    Kawahara, I; Kato, Y; Suzuki, H; Achira, M; Ito, K; Crespi, C L; Sugiyama, Y

    2000-10-01

    Our previous report showed that L754.394 and valspodar (PSC833) are potent inhibitors of midazolam hydroxylation in human jejunum microsomes and vectorial transport of vinblastine in Caco-2 cells, respectively. In the present study, to directly examine the interactions of these compounds as well as other substrates with CYP3A4 and P-glycoprotein (P-gp), we performed in vitro inhibition studies using recombinant CYP3A4-expressed microsomes and an MDR1-transfected cell line, LLC-MDR1, respectively. In CYP3A4-expressed microsomes, both L754.394 and ketoconazole, at a concentration less than 0.5 microM, are the most potent inhibitors of the formation of 1'-hydroxymidazolam, a major metabolite of midazolam formed by CYP3A4. The greatest inhibitory effect on the transcellular transport of digoxin in LLC-MDR1 cells was observed in the presence of valspodar (<0.1 microM), followed by verapamil. From a comparison of the IC(50) values, it was shown that L754.394 and valspodar exhibited the highest selectivity for CYP3A4 and P-gp, respectively. To demonstrate such specificity, both midazolam hydroxylation and digoxin transport were observed in CYP3A4 transfected Caco-2 cells, which coexpress both P-gp and CYP3A4, in the presence or absence of L754.394 (0.5 microM) and valspodar (1.0 microM). L754.394 almost completely inhibited midazolam hydroxylation, but not digoxin transport, whereas almost complete inhibition of digoxin transport was observed in the presence of valspodar, but inhibition of the hydroxylation was minimal. Thus, the present study has demonstrated that L754.394 has a specific inhibitory effect on CYP3A4, whereas valspodar is specific for P-gp. PMID:10997946

  15. Discovery of 3-(2,6-dichloro-3,5-dimethoxy-phenyl)-1-{6-[4-(4-ethyl-piperazin-1-yl)-phenylamino]-pyrimidin-4-yl}-1-methyl-urea (NVP-BGJ398), a potent and selective inhibitor of the fibroblast growth factor receptor family of receptor tyrosine kinase.

    PubMed

    Guagnano, Vito; Furet, Pascal; Spanka, Carsten; Bordas, Vincent; Le Douget, Mickaël; Stamm, Christelle; Brueggen, Josef; Jensen, Michael R; Schnell, Christian; Schmid, Herbert; Wartmann, Markus; Berghausen, Joerg; Drueckes, Peter; Zimmerlin, Alfred; Bussiere, Dirksen; Murray, Jeremy; Graus Porta, Diana

    2011-10-27

    A novel series of N-aryl-N'-pyrimidin-4-yl ureas has been optimized to afford potent and selective inhibitors of the fibroblast growth factor receptor tyrosine kinases 1, 2, and 3 by rationally designing the substitution pattern of the aryl ring. On the basis of its in vitro profile, compound 1h (NVP-BGJ398) was selected for in vivo evaluation and showed significant antitumor activity in RT112 bladder cancer xenografts models overexpressing wild-type FGFR3. These results support the potential therapeutic use of 1h as a new anticancer agent. PMID:21936542

  16. Probing the "additive effect" in the proline and proline hydroxamic acid catalyzed asymmetric addition of nitroalkanes to cyclic enones.

    PubMed

    Hanessian, Stephen; Govindan, Subramaniyan; Warrier, Jayakumar S

    2005-11-01

    The effect of chirality and steric bulk of 2,5-disubstituted piperazines as additives in the conjugate addition of 2-nitropropane to cyclohexenone, catalyzed by l-proline, was investigated. Neither chirality nor steric bulk affects the enantioselectivity of addition, which gives 86-93% ee in the presence of achiral and chiral nonracemic 2,5-disubstituted piperazines. Proline hydroxamic acid is shown for the first time to be an effective organocatalyst in the same Michael reaction. PMID:16189834

  17. Effect of selected anthelmintics on three common helminths in the brown pelican (Pelecanus occidentalis).

    PubMed

    Grimes, J; Suto, B; Greve, J H; Albers, H F

    1989-01-01

    The effect of selected anthelmintics (albendazole, fenbendazole, piperazine dihydrochloride and clorsulon) against three major helminths (Contracaecum multipapillatum, Mesostephanus appendiculatoides, and Phagicola longus) were studied in 29 brown pelicans (Pelecanus occidentalis). Albendazole and fenbendazole were highly effective against all three parasites. Clorsulon had moderate effect against M. appendiculatoides and poor effect against C. multipapillatum and P. longus. Piperazine dihydrochloride had no effect against these helminths. PMID:2915399

  18. The skin sensitization potential of four alkylalkanolamines.

    PubMed

    Leung, H W; Blaszcak, D L

    1998-04-01

    The skin sensitization potential of 4 alkylalkanolamines (N-methylethanolamine, N,N-dimethylethanolamine, N-methyldiethanolamine and N,N-diethylethanolamine), was evaluated in a guinea pig maximation procedure by the method of Magnusson and Kligman. While all 4 alkylalkanolamines tested were irritating to the guinea pig skin, only N-methylethanolamine showed potential to induce allergic contact dermatitis. None of the remaining 3 alkylalkanolamines exhibited clear skin responses suggestive of sensitization. PMID:9554055

  19. An in situ study of amine and amide molecular interaction on Fe surfaces

    NASA Astrophysics Data System (ADS)

    Taheri, P.; Terryn, H.; Mol, J. M. C.

    2015-11-01

    The interfacial bondings formed between N,N‧-diethylmethylamine, N-methyldiethanolamine and N,N‧-dimethylsuccinamide molecules with iron surfaces have been investigated using Fourier transform infrared spectroscopy (FTIR) and electrochemical spectroscopies. In this case, the interfacial interactions have been evaluated by analyzing ex situ FTIR peaks and probing potential variations upon molecular interactions to Fe surfaces. Moreover, integrated ATR-FTIR and chronovoltammetry analyses in Kretschmann geometry have been employed to probe the interactions between the molecules and Fe surfaces in situ. The results revealed that a charge transfer between molecules and Fe surfaces takes place indicating chemisorption of the molecules on Fe surfaces. In this case, the interaction of N,N‧-diethylmethylamine and Fe surface is negligible. However, N-methyldiethanolamine molecules interact with Fe surfaces through the nitrogen atoms. Interaction of N,N‧-dimethylsuccinamide molecules and Fe surface is promoted by nitrogen and carbonyl functional groups. Moreover, interactions of N-methyldiethanolamine and N,N‧-dimethylsuccinamide molecules to Fe surfaces are encouraged by application of anodic potentials implying that the molecules and Fe surfaces are charged positively and negatively, respectively.

  20. PUTATIVE AGMATINASE INHIBITOR FOR HYPOXIC-ISCHEMIC NEW BORN BRAIN DAMAGE

    PubMed Central

    Piletz, John E.; Klenotich, Stephanie; Lee, Ken S.; Zhu, Qian Long; Valente, Edward; Collins, Michael A.; Jones, Vyvyca; Lee, Soeb Nam; Yangzheng, Feng

    2013-01-01

    Agmatine is an endogenous brain metabolite, decarboxylated arginine, which has neuroprotective properties when injected intraperitoneally (i.p.) into rat pups following hypoxic-ischemia. A previous screen for compounds based on rat brain lysates containing agmatinase with assistance from computational chemistry, led to piperazine-1-carboxamidine as a putative agmatinase inhibitor. Herein, the neuroprotective properties of piperazine-1-carboxamidine are described both in vitro and in vivo. Organotypic entorhinal-hippocampal slices were firstly prepared from seven-day-old rat pups and exposed in vitro to atmospheric oxygen depletion for 3 hrs. Upon reoxygenation the slices were treated with piperazine-1-carboxamidine or agmatine (50 μg/ml agents), or saline, and 15 hours later propidium iodine was used to stain. Piperazine-1-carboxamidine or agmatine produced substantial in vitro protection compared to post-reoxygenated saline-treated controls. An in vivo model involved surgical right carotid ligation followed by exposure to hypoxic ischemia (8% oxygen) for 2.5 hours. Piperazine-1-carboxamidine at 50 mg/kg i.p. was given 15 minutes post-reoxygenation and continued twice daily for 3 days. Cortical agmatine levels were elevated (+28.5%) following piperazine-1-carboxamidine treatment with no change in arginine or its other major metabolites. Histological staining with anti-Neun monoclonal antibody also revealed neuroprotection of CA1–3 layers of the hippocampus. Until endpoint at 22 days of age, no adverse events were observed in treated pups' body weights, rectal temperatures, or prompted ambulation. Piperazine-1-carboxamidine therefore appears to be a neuroprotective agent of a new category, agmatinase inhibitor. PMID:23334804

  1. A study to investigate the performance of the Benfield-HiPure process of natural gas sweetening using computer simulations

    NASA Astrophysics Data System (ADS)

    Ochieng, Richard

    capacity and plant energy efficiency. Due to the complexity and high investment cost of the Benfield HiPure process, potential alternatives are evaluated. The alternatives are basically MDEA based solvents with promoters to enable the simultaneous removal of H 2S and CO2. BASF's MDEA, MDEA/DEA or MDEA/DGA processes seem to be the best alternatives to the Benfield HiPure process. Using MDEA/DEA or MDEA/DGA process will reduce the capital costs of ADGAS by 50% , and up to 48% will be saved on the annual power consumption (0.33 million dollars per years) . BASF's MDEA has slightly higher capital costs due to the additional units required on the high pressure flash and the quenching units used to generate the semi-lean solution. However, BASF's MDEA process still stands as one of the best alternatives with a savings of about 102 million dollars (48%) on the capital costs and up to 36% (3.96 USD per ton of acid gas removed) on the cost stripping.

  2. P450-Based Drug-Drug Interactions of Amiodarone and its Metabolites: Diversity of Inhibitory Mechanisms.

    PubMed

    McDonald, Matthew G; Au, Nicholas T; Rettie, Allan E

    2015-11-01

    In this study, IC50 shift and time-dependent inhibition (TDI) experiments were carried out to measure the ability of amiodarone (AMIO), and its circulating human metabolites, to reversibly and irreversibly inhibit CYP1A2, CYP2C9, CYP2D6, and CYP3A4 activities in human liver microsomes. The [I]u/Ki,u values were calculated and used to predict in vivo AMIO drug-drug interactions (DDIs) for pharmaceuticals metabolized by these four enzymes. Based on these values, the minor metabolite N,N-didesethylamiodarone (DDEA) is predicted to be the major cause of DDIs with xenobiotics primarily metabolized by CYP1A2, CYP2C9, or CYP3A4, while AMIO and its N-monodesethylamiodarone (MDEA) derivative are the most likely cause of interactions involving inhibition of CYP2D6 metabolism. AMIO drug interactions predicted from the reversible inhibition of the four P450 activities were found to be in good agreement with the magnitude of reported clinical DDIs with lidocaine, warfarin, metoprolol, and simvastatin. The TDI experiments showed DDEA to be a potent inactivator of CYP1A2 (KI = 0.46 μM, kinact = 0.030 minute(-1)), while MDEA was a moderate inactivator of both CYP2D6 (KI = 2.7 μM, kinact = 0.018 minute(-1)) and CYP3A4 (KI = 2.6 μM, kinact = 0.016 minute(-1)). For DDEA and MDEA, mechanism-based inactivation appears to occur through formation of a metabolic intermediate complex. Additional metabolic studies strongly suggest that CYP3A4 is the primary microsomal enzyme involved in the metabolism of AMIO to both MDEA and DDEA. In summary, these studies demonstrate both the diversity of inhibitory mechanisms with AMIO and the need to consider metabolites as the culprit in inhibitory P450-based DDIs. PMID:26296708

  3. Crystal structure of aqua-1κO-{μ-2-[(2-hydroxy­ethyl)methylamino]ethanolato-2:1κ4 O 1,N,O 2:O 1}[μ-2,2′-(methylimino)diethanolato-1:2κ4 O,N,O′:O]dithiocyanato-1κN,2κN-chromium(III)copper(II)

    PubMed Central

    Rusanova, Julia A.; Semenaka, Valentina V.; Dyakonenko, Viktoriya V.; Shishkin, Oleg V.

    2015-01-01

    The title compound, [CrCu(C5H11NO2)(C5H12NO2)(NCS)2(H2O)] or [Cr(μ-mdea)Cu(μ-Hmdea)(NCS)2H2O], (where mdeaH2 is N-methylethanolamine, C5H13NO2) is formed as a neutral heterometal CuII/CrIII complex. The mol­ecular structure of the complex is based on a binuclear {CuCr(μ-O)2} core. The coordination environment of each metal atom involves the N,O,O atoms of the tridentate ligand, one bridging O atom of the ligand and the N atom of the thio­cyanato ligands. The CuII ion adopts a distorted square-pyramidal coordination while the CrIII ion has a distorted octa­hedral coordination geometry completed by the aqua ligand. In the crystal, the binuclear complexes are linked via two pairs of O—H⋯O hydrogen bonds to form inversion dimers, which are arranged in columns parallel to the a axis. In the μ-mdea ligand two –CH2 groups and the methyl group were refined as disordered over two sets of sites with equal occupancies. The structure was refined as a two-component twin with a twin scale factor of 0.242 (1). PMID:26396853

  4. In vitro kinetics of amiodarone and its major metabolite in two human liver cell models after acute and repeated treatments.

    PubMed

    Pomponio, Giuliana; Savary, Camille C; Parmentier, Céline; Bois, Frederic; Guillouzo, André; Romanelli, Luca; Richert, Lysiane; Di Consiglio, Emma; Testai, Emanuela

    2015-12-25

    The limited value of in vitro toxicity data for the in vivo extrapolation has been often attributed to the lack of kinetic data. Here the in vitro kinetics of amiodarone (AMI) and its mono-N-desethyl (MDEA) metabolite was determined and modelled in primary human hepatocytes (PHH) and HepaRG cells, after single and repeated administration of clinically relevant concentrations. AMI bioavailability was influenced by adsorption to the plastic and the presence of protein in the medium (e.g. 10% serum protein reduced the uptake by half in HepaRG cells). The cell uptake was quick (within 3h), AMI metabolism was efficient and a dynamic equilibrium was reached in about a week after multiple dosing. In HepaRG cells the metabolic clearance was higher than in PHH and increased over time, as well as CYP3A4. The interindividual variability in MDEA production in PHHs was not proportional to the differences in CYP3A4 activities, suggesting the involvement of other CYPs and/or AMI-related CYP inhibition. After repeated treatment AMI showed a slight potential for bioaccumulation, whereas much higher intracellular MDEA levels accumulated over time, especially in the HepaRG cells, associated with occurrence of phospholipidosis. The knowledge of in vitro biokinetics is important to transform an actual in vitro concentration-effect into an in vivo dose-effect relationship by using appropriate modelling, thus improving the in vitro-to-in vivo extrapolation. PMID:25546373

  5. New analytical technique for carbon dioxide absorption solvents

    SciTech Connect

    Pouryousefi, F.; Idem, R.O.

    2008-02-15

    The densities and refractive indices of two binary systems (water + MEA and water + MDEA) and three ternary systems (water + MEA + CO{sub 2}, water + MDEA + CO{sub 2}, and water + MEA + MDEA) used for carbon dioxide (CO{sub 2}) capture were measured over the range of compositions of the aqueous alkanolamine(s) used for CO{sub 2} absorption at temperatures from 295 to 338 K. Experimental densities were modeled empirically, while the experimental refractive indices were modeled using well-established models from the known values of their pure-component densities and refractive indices. The density and Gladstone-Dale refractive index models were then used to obtain the compositions of unknown samples of the binary and ternary systems by simultaneous solution of the density and refractive index equations. The results from this technique have been compared with HPLC (high-performance liquid chromatography) results, while a third independent technique (acid-base titration) was used to verify the results. The results show that the systems' compositions obtained from the simple and easy-to-use refractive index/density technique were very comparable to the expensive and laborious HPLC/titration techniques, suggesting that the refractive index/density technique can be used to replace existing methods for analysis of fresh or nondegraded, CO{sub 2}-loaded, single and mixed alkanolamine solutions.

  6. Measurement of 3,4-MDMA and related amines in diagnostic and forensic laboratories.

    PubMed

    Skrinska, Victor A; Gock, Susan B

    2005-01-01

    The phenylalkylamine derivatives, 3,4-methylenedioxymethamphetamine (MDMA, ecstasy, XTC, Adam), 3,4-methylenedioxyethamphetamine (MDEA, MDE, Eve), and 3,4-methylenedioxyamphetamine (MDA), are psychostimulants with hallucinogenic properties. MDA is also a metabolite of both MDMA and MDEA. These drugs are ring-substituted amphetamine derivatives that produce hallucinogenic, entactogenic ('love drug'), and stimulating effects. MDMA was initially developed as an appetite suppressant, however, its use as a therapeutic drug has been very limited. Because of its effects as a hallucinogenic psychostimulant with relatively low toxicity, it has emerged over the last two decades as a common recreational psychostimulant or 'club drug' at 'raves'. MDMA, MDEA, and MDA are often referred to as 'rave' or 'designer' drugs. They are produced in clandestine laboratories and have an increasing presence on the illicit drug market worldwide. Significant adverse health effects have been reported that include: serotonin neurotoxicity, severe psychiatric disorders, renal failure, malignant hyperthermia, hepatitis, rhabdomyolysis, and disseminated intravascular coagulation. A number of fatal outcomes associated with severe MDMA intoxication have been reported. PMID:15916245

  7. CO2 Capture by Absorption with Potassium Carbonate

    SciTech Connect

    Gary T. Rochelle; Eric Chen; Babatunde Oyenekan; Andrew Sexton; Jason Davis; Marcus Hilliard; Amornvadee Veawab

    2006-09-30

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. Ethylenediamine was detected in a degraded solution of MEA/PZ solution, suggesting that piperazine is subject to oxidation. Stripper modeling has demonstrated that vacuum strippers will be more energy efficient if constructed short and fat rather than tall and skinny. The matrix stripper has been identified as a configuration that will significantly reduce energy use. Extensive measurements of CO{sub 2} solubility in 7 m MEA at 40 and 60 C have confirmed the work by Jou and Mather. Corrosion of carbon steel without inhibitors increases from 19 to 181 mpy in lean solutions of 6.2 m MEA/PZ as piperazine increases from 0 to 3.1 m.

  8. Biosynthesis and identification of an N-oxide/N-glucuronide metabolite and first synthesis of an N-O-glucuronide metabolite of Lu AA21004.

    PubMed

    Uldam, Henriette Kold; Juhl, Martin; Pedersen, Henrik; Dalgaard, Lars

    2011-12-01

    This article describes the biosynthesis and identification of a new class of metabolites, a piperazine N-oxide/N-glucuronide metabolite 4-[2-(2,4-dimethyl-phenylsulfanyl)-phenyl]-1-β-D-glucuronic acid-piperazine 1-oxide (4). The metabolite was found in urine and plasma from humans and animals dosed with 1-[2-(2,4-dimethyl-phenylsulfanyl)-phenyl]-piperazine hydrobromide (Lu AA21004, 1), as a novel multimodal antidepressant under development for treatment of depression. Human liver microsomes in combination with uridine 5'-diphosphoglucuronic acid were used as an in vitro system to generate enough material of 4 to perform one- and two-dimensional (1)H and (13)C NMR experiments for structure elucidation. Based on rotating frame Overhauser enhancement spectroscopy NMR experiments, the distance correlation between a piperazine proton and the anomeric proton of the glucuronic acid moiety is of a magnitude similar to that of the H-3' and H-5' protons and can only be explained by proximity in space and the postulated structure (4). The structural analog, the N-O-glucuronic acid conjugate 6-{4-[2-(2,4-dimethyl-phenylsulfanyl)-phenyl]-piperazin-1-yloxy}-1-β-D-glucuronic acid (3) was also observed in biological samples from humans and animals and the first organic synthesis and structural identification of this metabolite is also reported. Treatment of the glucuronide metabolites 3 and 4 with β-glucuronidase gave mainly the expected hydrolysis product, the hydroxyl amine 4-[2-(2,4-dimethyl-phenylsulfanyl)-phenyl]-piperazin-1-ol (2). PMID:21896789

  9. CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE

    SciTech Connect

    Gary T. Rochelle; Eric Chen; J. Tim Cullinane; Marcus Hilliard; Babatunde Oyenekan; Terraun Jones

    2003-07-28

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. A rigorous thermodynamic model has been further developed with a standalone FORTRAN code to represent the CO{sub 2} vapor pressure and speciation of the new solvent. Gas chromatography has been used to measure the oxidative degradation of piperazine. The heat exchangers for the pilot plant have been received. The modifications are on schedule for start-up in November 2003.

  10. Synthesis of chiral 2,3-disubstituted 1,4-diazabicyclo[2.2.2]octane derivatives.

    PubMed

    Periasamy, Mariappan; Edukondalu, Athukuri; Reddy, Polimera Obula

    2015-04-01

    Racemic 2,3-diaryl-1,4-diazabicyclo[2.2.2]octane (DABCO) derivatives are synthesized from the readily accessible piperazines in 50-64% yield by cyclization using ethylene bromide, triethylamine, and KI at 80 °C. The enantiomerically enriched 2,3-diphenylpiperazine and the 2,3-bis(1-naphthyl)piperazine derivatives are prepared by a resolution method using commercially available optically active acids, yielding the corresponding DABCO derivatives in 51-64% yield with up to 99% ee. This mild cyclization can also be applied to enantiopure camphanyldiamine derivatives, and the products are obtained in 72-86% yields. PMID:25756201

  11. CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE

    SciTech Connect

    Gary T. Rochelle; A. Frank Seibert; J. Tim Cullinane; Terraun Jones

    2003-01-01

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. Progress has been made in this reporting period on three subtasks. The rigorous Electrolyte Non-Random Two-Liquid (electrolyte-NRTL) model has been regressed to represent CO{sub 2} solubility in potassium carbonate/bicarbonate solutions. An analytical method for piperazine has been developed using a gas chromatograph. Funding has been obtained and equipment has been donated to provide for modifications of the existing pilot plant system with stainless steel materials.

  12. Synthesis and functional survey of new Tacrine analogs modified with nitroxides or their precursors

    PubMed Central

    Kálai, Tamás; Altman, Robin; Maezawa, Izumi; Balog, Mária; Morisseau, Christophe; Petrlova, Jitka; Hammock, Bruce D.; Jin, Lee-Way; Trudell, James; Voss, John C.; Hideg, Kálmán

    2014-01-01

    A series of new Tacrine analogs modified with nitroxides or pre-nitroxides on 9-amino group via methylene or piperazine spacers were synthesized; the nitroxide or its precursors were incorporated into the Tacrine scaffold. The new compounds were tested for their hydroxyl radical and peroxyl radical scavenging ability, acetyl cholinesterase inhibitor activity and protection against Aβ-induced cytotoxicity. Based on these assays, we conclude that Tacrine analogs connected to five and six-membered nitroxides via piperazine spacers (9b, 9b/HCl and 12) exhibited the best activity, providing direction for further development of additional candidates with dual functionality (anti Alzheimer’s and antioxidant). PMID:24657571

  13. New cyclic tetrapeptide from the coral-derived endophytic bacteria Brevibacterium sp. L-4 collected from the South China Sea.

    PubMed

    Liu, Bing-Xin; Guo, Qiong; Peng, Guang-Tian; He, Xi-Xin; Chen, Xiao-Jie; Lei, Ling-Fang; Deng, Yun; Jun Su, Xian; Zhang, Cui-Xian

    2016-01-01

    One new cyclic tetrapeptide cyclic-(Tyr-Ala-Leu-Ser) (1) along with four natural compounds firstly obtained 3H-imidazole-4-carboxylic acid (2), 2-methyl-3H-imidazole-4-carboxylic acid (3), 3-ethylidene-6-isopropyl-piperazine-2,5-dione (4), and 3-isobutylidene-6-methyl piperazine-2,5-dione (5) have been isolated from the coral derived endophytic bacteria Brevibacterium sp. L-4 collected from the South China Sea. Their structures were elucidated through spectroscopic techniques including NMR (1D and 2D), MS, and EA, and their relative configurations were also assigned by NMR analysis. PMID:26214049

  14. Neutralization technology to reduce corrosion from heat stable amine salts

    SciTech Connect

    Liu, H.J.; Dean, J.W.; Bosen, S.F.

    1995-12-01

    Laboratory experiments have demonstrated the corrosivity of a contaminated N-methyldiethanolamine solution from a refinery can be reduced by adding caustic or a proprietary neutralizer. A model formic acid contaminated amine solution was shown to have similar behavior. Laboratory studies have shown there is a definite decrease in corrosivity as the pH of the amine solutions increase. Three possible mechanisms for the observed pH corrosivity behavior are discussed. Plant experience that demonstrates the usefulness of neutralization and a novel method for dissolved solids removal are presented.

  15. Excess molar enthalpies of (water + alkanolamine) systems and some thermodynamic calculations

    SciTech Connect

    Maham, Y.; Mather, A.E.; Hepler, L.G.

    1997-09-01

    Several (water + alkanolamine) systems are used for removal of acidic gases such as carbon dioxide and hydrogen sulfide from gas streams in the natural gas and petroleum industries and are of increasing importance in treating streams in the chemical production industries. The authors have made calorimetric measurements of enthalpies of mixing of (water + monoethanolamine), (water + diethanolamine), and (water + triethanolamine) at T = 298.15 K and of (water + methyldiethanolamine) at T = 298.15 and 313.15 K. Results of these measurements have been used in some thermodynamic calculations to illustrate general principals that are applicable to many systems of mixed liquids.

  16. Solubility of methane and ethane in aqueous solutions of methydiethanolamine

    SciTech Connect

    Jou, F.Y.; Mather, A.E.; Otto, F.D.; Carroll, J.J.

    1998-09-01

    Data are presented for the solubility of methane and of ethane in a 3 kmol/m{sup 3} (34.7 mass %) solution of methyldiethanolamine. Temperatures in this study ranged from 25 to 130 C and pressures to 13 MPa. The data were incorporated into a rigorous thermodynamic model that has been applied to other similar systems. The model is a combined Raoult`s law-Henry`s law approach. The solubilities in the alkanolamine solution are correlated in terms of the salting-in ratio, the ratio of the mole fraction solubility in the amine solution to that in pure water.

  17. Solubility of carbon dioxide in aqueous solutions of 2-amino-2-methyl-1,3-propanediol

    SciTech Connect

    Baek, J.I.; Yoon, J.H.

    1998-07-01

    The equilibrium solubility of carbon dioxide in aqueous solutions of 2-amino-2-methyl-1,3-propanediol (AMPD) has been measured at (30, 40, and 60) C and the partial pressure of carbon dioxide ranging from (0.5 to 3065) kPa. The concentrations of the aqueous solutions were (10 and 30) mass % AMPD. The tendency of the solubility of carbon dioxide in 30 mass % AMPD aqueous solution at 40 C was found to be similar to that in 30 mass % N-methyldiethanolamine aqueous solution.

  18. Studies of flammability and thermal degradation for flame retardant cotton fabric with P-N containing derivatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effectiveness of a phosphoramidate Tetraethyl piperazine-1,4- diyldiphosphoramidate (TEPP) as a flame retardant (FR) on cotton twill fabrics was compared with that of a previously studied Diethyl 4- methylpiperazin-1-ylphosphoramidate (DEPP). TEPP was formed in a reaction between two phosphonat...

  19. The comparison of differences in flammability and thermal degradation between cotton fabrics treated with phosphoramidate derivatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effectiveness of a phosphoramidate Tetraethyl piperazine-1,4-diyldiphosphoramidate (TEPP) as a flame retardant (FR) on cotton twill fabrics was compared with that of a previously studied Diethyl 4-methylpiperazin-1-ylphosphoramidate (DEPP). TEPP was formed in a reaction between two phosphonates...

  20. Process for separating an ethylenically unsaturated hydrocarbon from a hydrocarbon mixture

    SciTech Connect

    vanEijl, A.T.

    1986-06-24

    A process is described for separating an ethylenically unsaturated hydrocarbon from a hydrocarbon mixture characterized by: (a) distilling a hydrocarbon mixture containing the unsaturated hydrocarbon with an N-(aminoalkyl) piperazine; and (b) separating the amine/hydrocarbon mixture into at least two factions, one of which contains the amine and the unsaturated hydrocarbon.

  1. A bivalent cationic dye enabling selective photo-inactivation against Gram-negative bacteria.

    PubMed

    Li, Ke; Zhang, Yang-Yang; Jiang, Guo-Yu; Hou, Yuan-Jun; Zhang, Bao-Wen; Zhou, Qian-Xiong; Wang, Xue-Song

    2015-05-01

    A piperazine-modified Crystal Violet was found to be able to selectively inactivate Gram-negative bacteria upon visible light irradiation but left Gram-positive bacteria less damaged, which can serve as a blueprint for the development of novel narrow-spectrum agents to replenish the current arsenal of photodynamic antimicrobial chemotherapy (PACT). PMID:25857842

  2. M[superscript 2+]•EDTA Binding Affinities: A Modern Experiment in Thermodynamics for the Physical Chemistry Laboratory

    ERIC Educational Resources Information Center

    O'Brien, Leah C.; Root, Hannah B.; Wei, Chin-Chuan; Jensen, Drake; Shabestary, Nahid; De Meo, Cristina; Eder, Douglas J.

    2015-01-01

    Isothermal titration calorimetry was used to experimentally determine thermodynamic values for the ethylenediaminetetraacetic acid (EDTA)(aq) + M[superscript 2+](aq) reactions (M[superscript 2+] = Ca[superscript 2+] and Mg[superscript 2+]). Students showed that for reactions in a N-(2-hydroxyethyl)piperazine-N"-ethanesulfonic acid (HEPES)…

  3. Imipenem-cilastatin-induced leukocytoclastic vasculitis.

    PubMed

    Reiner, M R; Brunetti, V A

    1997-05-01

    A maculopapular rash has been associated with the administration of imipenem-cilastatin, an antibiotic that was used for treatment of a postoperative infection. This is a first-time association of imipenem with a leukocytoclastic vasculitic reaction. Leukocytoclastic vasculitis has been previously documented with ciprofloxacin, zidovudine, piperazine, and lithium. PMID:9158321

  4. 21 CFR 175.320 - Resinous and polymeric coatings for polyolefin films.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... of the total coating solids. Polyamide resins (CAS Reg. No. 68139-70-8), as the basic resin, derived... polyamide resin Ethylenediamine (CAS Reg. No. 107-15-3) Piperazine (CAS Reg. No. 110-85-0) in an amount not to exceed 6.4 percent by weight of the polyamide resin Polyamide resins, derived from...

  5. 21 CFR 175.320 - Resinous and polymeric coatings for polyolefin films.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... of the total coating solids. Polyamide resins (CAS Reg. No. 68139-70-8), as the basic resin, derived... polyamide resin Ethylenediamine (CAS Reg. No. 107-15-3) Piperazine (CAS Reg. No. 110-85-0) in an amount not to exceed 6.4 percent by weight of the polyamide resin Polyamide resins, derived from...

  6. Metabolism of aildenafil in vivo in rats and in vitro in mouse, rat, dog, and human liver microsomes.

    PubMed

    Li, Yan; Wu, Linan; Gu, Yuan; Si, Duanyun; Liu, Changxiao

    2014-06-01

    Aildenafil, 1-{[3-(6, 7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo [4, 3-d] primidin-5-yl)-4-ethoxyphenyl] sulfonyl}-cis-3, 5-dimethylpiperazine, a phosphodiesterase type V enzyme inhibitor (PDE5I), is under development for treatment of erectile dysfunction (ED). The purpose of this study was to elucidate metabolism of aildenafil in vivo in rats and in vitro in mouse, rat, dog, and human liver microsomes. Thirty-one phase I metabolites have been found by LTQ/Orbitrap hybrid mass spectrometry in rat urine, faeces, and bile after oral administration. Major biotransformation pathways of aildenafil included N-dealkylation of the piperazine ring, hydroxylation and dehydrogenation, aliphatic hydroxylation and loss of alkyl group of piperazine ring. Minor pathways involved hydroxylation on the phenyl ring, pyrazole N-demethylation, O-deethylation, loss of piperazine ring (cleavage of N-S bond) and dehydrogenation on the piperazine ring. Similar metabolic pathways of aildenafil were observed in the incubations of liver microsomes from mouse, rat, and dog as well as from human. The depletion rate of parent drug in mouse and rat liver microsomes was significantly different from that in human liver microsomes. The cytochrome P450 reaction phenotyping analysis was conducted using isozyme-specific inhibitors. The results indicated that CYP3A was the main isoenzyme involved in oxidative metabolism of aildenafil. Overall, these in vitro and in vivo findings should provide valuable information on possible metabolic behaviours of aildenafil in humans. PMID:24311535

  7. Nonracemic synthesis of GK-GKRP disruptor AMG-3969.

    PubMed

    Bourbeau, Matthew P; Ashton, Kate S; Yan, Jie; St Jean, David J

    2014-04-18

    A nonracemic synthesis of the glucokinase-glucokinase regulatory protein disruptor AMG-3969 (5) is reported. Key features of the synthetic approach are an asymmetric synthesis of the 2-alkynyl piperazine core via a base-promoted isomerization and a revised approach to the synthesis of the aminopyridinesulfonamide with an improved safety profile. PMID:24678849

  8. Development of the phosphorus and nitrogen containing flame retardant for value added cotton product

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is our desire to develop new crosslinking agents for cotton textiles that afford useful flame protection regardless of fabric construction. Herein we present the synthesis and the application of the triazine and piperazine derivatives as flame retardant on cotton. Novel phosphorus-nitrogen contai...

  9. Simultaneous detection of some drugs of abuse in saliva samples by SPME technique.

    PubMed

    Fucci, Nadia; De Giovanni, Nadia; Chiarotti, Marcello

    2003-06-24

    A simple method for the simultaneous determination of many drugs of abuse in saliva is referred [methadone, 2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolinium perchlorate (EDDP), cocaine, cocaethylene, amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethyl amphetamine (MDEA), N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB), cannabidiol (CBD), Delta(9)-tetrahydrocannabinol (THC), cannabinol (CBN)]. Head space-solid phase microextraction (HS-SPME) and direct immersion-solid phase microextraction (DI-SPME) followed by gas chromatographic/mass spectrometric analyses (GC/MS) were employed, and results obtained with both techniques are discussed. The method was validated testing reproducibility, sensitivity, linearity. PMID:12842356

  10. Improved sulfur removal processes evaluated for IGCC

    SciTech Connect

    Not Available

    1986-12-01

    An inherent advantage of Integrated Coal Gasification Combined Cycle (IGCC) electric power generation is the ability to easily remove and recover sulfur. During the last several years, a number of new, improved sulfur removal and recovery processes have been commercialized. An assessment is given of alternative sulfur removal processes for IGCC based on the Texaco coal gasifier. The Selexol acid gas removal system, Claus sulfur recovery, and SCOT tail gas treating are currently used in Texaco-based IGCC. Other processes considered are: Purisol, Sulfinol-M, Selefning, 50% MDEA, Sulften, and LO-CAT. 2 tables.

  11. Heat capacity of alkanolamine aqueous solutions

    SciTech Connect

    Chiu, L.F.; Li, M.H.

    1999-12-01

    Heat capacities of monoethanoloamine, diglycolamine, diethanolamine, di-w propanolamine, triethanolamine, N-methyldiethanolamine, 2-amino-2-methyl-l-propanol, and 2-piperidineethanol aqueous solutions were measured from 30 to 80 C with a differential scanning calorimeter (DSC). The mole fractions of alkanolamines studied are 0.2, 0.4, 0.6, and 0.8. Heat capacities of N-methyldiethanolamine aqueous solutions have been measured to verify the validity of C{sub p} measurements for alkanolamine aqueous solutions. The estimated uncertainty of the measured heat capacities is {plus{underscore}minus}3%, including the effect of up to 5% impurities in a substance. An excess molar heat capacity expression using the Redlich-Kister equation for the composition dependence is used to represent the measured C{sub p} of alkanolamine aqueous solutions. For a total of 374 data points, the calculation results for eight alkanolamine solutions give the overall average absolute deviations of 11.9% and 0.29% for the excess molar heat capacity and the heat capacity, respectively. The heat capacities presented in this study are, in general, of sufficient accuracy for most engineering-design calculations. Solutions of alkanolamines are industrially important mixtures used in the natural gas industry, oil refineries, petroleum chemical plants, and synthetic ammonia plants for the removal of acidic components such as CO{sub 2} and H{sub 2}S from gas streams.

  12. Asymptotic models for H{sub 2}S absorption into single and blended aqueous amines

    SciTech Connect

    Rinker, E.B.; Hanna, O.T.; Sandall, O.C.

    1997-01-01

    Asymptotic power series solutions for the mass-transfer enhancement factor for absorption of a gas component into a liquid where it undergoes irreversible instantaneous chemical reaction(s) with one and two liquid-phase reactants are developed in this work. The Pade technique is used to extend the region of applicability (accelerate the convergence) of the four-term asymptotic power series solutions. The resulting modified asymptotic expressions for the enhancement factor show excellent accuracy over a wide range and can be used to predict enhancement factors as low as 2 with an error of about 5% compared to the exact numerical solution. Predictions of these new asymptotic solutions are compared to the exact numerical solution. Predictions of these new asymptotic solutions are compared with experimental absorption data for H{sub 2}S absorption into aqueous methyldiethanolamine and H{sub 2}S absorption into aqueous mixtures of methyldiethanolamine and diethanolamine obtained in a laminar-jet absorber. The absolute mean deviations of the predictions from the experimental absorption data for the single and mixed amine solutions were 4.6% and 2.4%, respectively.

  13. Simultaneous enantioselective determination of amphetamine and congeners in hair specimens by negative chemical ionization gas chromatography-mass spectrometry.

    PubMed

    Martins, Liliane; Yegles, Michel; Chung, Heesun; Wennig, Robert

    2005-10-15

    Enantioselective quantification of amphetamine (AM), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA) enantiomers in hair using gas chromatography-mass spectrometry (GC-MS) is described. Hair specimens were digested with 1M sodium hydroxide at 100 degrees C for 30 min and extracted by a solid phase procedure using Cleanscreen ZSDAU020. Extracted analytes were derivatised with (S)-heptafluorobutyrylprolyl chloride and the resulting diastereoisomers were quantified by GC-MS operating in the negative chemical ionization mode. Extraction yields were between 73.0 and 97.9%. Limits of detection varied in the range of 2.1-45.9 pg/mg hair, whereas the lowest limits of quantification varied between 4.3 and 91.8 pg/mg hair. Intra- and inter-assay precision and respective accuracy were acceptable. The enantiomeric ratios (R versus S) of AM, MA, MDA, MDMA and MDEA were determined in hair from suspected amphetamine abusers. Only MA and AM enantiomers were detectable in this collective and the quantification data showed in most cases higher concentrations of (R)-MA and (R)-AM than those of the corresponding (S)-enantiomers. PMID:16154523

  14. Endogenous generation of hydrogen sulfide and its regulation in Shewanella oneidensis

    PubMed Central

    Wu, Genfu; Li, Ning; Mao, Yinting; Zhou, Guangqi; Gao, Haichun

    2015-01-01

    Hydrogen sulfide (H2S) has been recognized as a physiological mediator with a variety of functions across all domains of life. In this study, mechanisms of endogenous H2S generation in Shewanella oneidensis were investigated. As a research model with highly diverse anaerobic respiratory pathways, the microorganism is able to produce H2S by respiring on a variety of sulfur-containing compounds with SirACD and PsrABC enzymatic complexes, as well as through cysteine degradation with three enzymes, MdeA, SO_1095, and SseA. We showed that the SirACD and PsrABC complexes, which are predominantly, if not exclusively, responsible for H2S generation via respiration of sulfur species, do not interplay with each other. Strikingly, a screen for regulators controlling endogenous H2S generation by transposon mutagenesis identified global regulator Crp to be essential to all H2S-generating processes. In contrast, Fnr and Arc, two other global regulators that have a role in respiration, are dispensable in regulating H2S generation via respiration of sulfur species. Interestingly, Arc is involved in the H2S generation through cysteine degradation by repressing expression of the mdeA gene. We further showed that expression of the sirA and psrABC operons is subjected to direct regulation of Crp, but the mechanisms underlying the requirement of Crp for H2S generation through cysteine degradation remain elusive. PMID:25972854

  15. Co-effects of amines molecules and chitosan films on in vitro calcium carbonate mineralization.

    PubMed

    Cui, Jifei; Kennedy, John F; Nie, Jun; Ma, Guiping

    2015-11-20

    Amines monomers, N,N-dimethylaminoethyl methacrylate (DMAEMA), N,N-dimethylethanolamine (DMEA), 2-dimethylaminoethylamine (DMEDA) and N-methiyldiethanolamine (MDEA) were used to induce the formation of calcium carbonate (CaCO3) crystals on chitosan films, by using (NH4)2CO3 diffusion method at ambient temperature. The obtained CaCO3 particles were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The influence of reaction variables, such as the additive concentration and their types were also investigated on the products. The morphologies of CaCO3 crystals, inter-grown in cube-shape, were controlled by DMAEMA and DMEA. It was observed that the morphologies of CaCO3 changed from the cube grown arms to massive calcite with a hole on the face by increasing the concentrations of DMEDA and MDEA. While the precipitation grew on chitosan film without any organic additive, only single cube-shaped crystals were obtained. By these results the possible mechanisms can be proposed that electronic movement of the groups on the monomer effected ions configuration and molecules absorbed on the exposed surface, resulted the change of the surface energy, which caused the change in the morphology of CaCO3. PMID:26344256

  16. Simultaneous removal of water and BTEX from feed gas for a cryogenic plant

    SciTech Connect

    Jones, S.; Lee, S.; Evans, M.; Chen, R.

    1999-07-01

    The removal of water and benzene, toluene, ethyl benzene, xylene (BTEX) from the feed gas of a cryogenic plant is critical in order to avoid precipitation of these components in the cold section of the plant. The design of the Hannibal Gas Plant in Sfax, Tunisia, accomplishes the removal of water and BTEX simultaneously. The plant receives 7.1 million Nm{sub 3}/day of feed gas and produces high heating value pipeline quality sales gas by removing nitrogen in the cold box. A methyl diethanol amine (MDEA) treating system at the front end of the plant is designed to remove carbon dioxide. The glycol system takes the saturated gas from the MDEA contactor and reduces the water content to 7 lb/MMscf. The glycol system is also designed to remove more than half of the BTEX from the feed gas so that these aromatic components will not precipitate in the cold section of the plant. GPA experimental data were used to fit the interaction parameters for the computer simulator used to design the glycol system. The results of the plant performance test verify the validity of the design.

  17. Synthesis, In silico studies and In vitro evaluation for antioxidant and antibacterial properties of diarylmethylamines: A novel class of structurally simple and highly potent pharmacophore.

    PubMed

    Mahato, Sujit; Singh, Anuma; Rangan, Latha; Jana, Chandan K

    2016-06-10

    A series of novel diarylmethylamines were synthesized via simple three component condensation reaction. In vitro antibacterial activity of the synthesized compounds was assessed against Gram-positive and Gram-negative bacteria. Compound 1f containing phenyl and N-methyl piperazine moiety was found to be potent against both pathogenic bacteria with MIC value of 31μg/mL. Diarylmethylamine 1l containing sesamol and N-methyl piperazine units was found to be the most effective against Gram-positive bacteria with MIC value of 15μg/mL. The compound leads to the damage of the bacterial cell membrane which was demonstrated by flow cytometry (FC) and field emission scanning electron microscopy (FESEM). Radical scavenging activity of compounds 1l and 1m was found out to be comparable with that of standard antioxidant BHT. Further, in silico studies were carried out to calculate the physico-chemical parameter of the synthesized compounds. PMID:26993964

  18. Synthesis and Characterization of New 3-(4-Arylpiperazin-1-yl)-2-hydroxypropyl 4-Propoxybenzoates and Their Hydrochloride Salts.

    PubMed

    Marvanova, Pavlina; Padrtova, Tereza; Pekarek, Tomas; Brus, Jiri; Czernek, Jiri; Mokry, Petr; Humpa, Otakar; Oravec, Michal; Jampilek, Josef

    2016-01-01

    Five new 3-(4-arylpiperazin-1-yl)-2-hydroxypropyl 4-propoxybenzoates were designed and synthesized as potential dual antihypertensive agents. The compounds were prepared as free bases and subsequently transformed to hydrochloride salts. The position of protonation of nitrogen atoms in the piperazine ring of hydrochloride salts was determined by means of (13)C-CP/MAS and (15)N-CP/MAS NMR and IR spectroscopy. Using these solid-state analytical techniques, it was found that both nitrogen atoms were protonated when excess hydrogen chloride was used for preparation of salts. On the other hand, when the equimolar amount of hydrogen chloride was used, piperazine nitrogen substituted by aryl was protonated. PMID:27258242

  19. CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE

    SciTech Connect

    Gary T. Rochelle; Eric Chen; J.Tim Cullinane; Marcus Hilliard; Jennifer Lu; Babatunde Oyenekan; Ross Dugas

    2004-07-29

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. CO{sub 2} mass transfer rates are second order in piperazine concentration and increase with ionic strength. Modeling of stripper performance suggests that 5 m K{sup +}/2.5 m PZ will require 25 to 46% less heat than 7 m MEA. The first pilot plant campaign was completed on June 24. The CO{sub 2} penetration through the absorber with 20 feet of Flexipac{trademark} 1Y varied from 0.6 to 16% as the inlet CO{sub 2} varied from 3 to 12% CO{sub 2} and the gas rate varied from 0.5 to 3 kg/m{sup 2}-s.

  20. CO{sub 2} CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE

    SciTech Connect

    Gary T. Rochelle; J.Tim Cullinane; Marcus Hilliard; Eric Chen; Babatunde Oyenekan; Ross Dugas

    2005-01-31

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. Thermodynamic modeling predicts that the heat of desorption of CO{sub 2} from 5m K+/2.5 PZ from 85 kJ/mole at 40 C to 30 kJ/mole at 120 C. Mass transfer modeling of this solvent suggests that carbonate and general salt concentration play a major role in catalyzing the rate of reaction of CO{sub 2} with piperazine. Stripper modeling suggests that with the multipressure stripper, the energy consumption with a generic solvent decreases by 15% as the heat of desorption is decreased from 23.8 to 18.5 kcal/gmol. A second pilot plant campaign with 5m K+/2.5 PZ was successfully completed.