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1

Binary total pressure measurements for methanol with 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-1-butanol, and 3-methyl-2-butanol at 313.15 K  

SciTech Connect

Total pressure measurements at 313.15 K are reported for binary systems of methanol with each of seven pentanol isomers: 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-1-butanol, and 3-methyl-2-butanol. The results were obtained using a Van Ness apparatus and were fitted to the four-suffix Margules equation using Barker`s method. The four-suffix Margules equation represents the data to within an average of approximately 0.02 kPa.

Barton, D.P.; Bhethanabotla, V.R.; Campbell, S.W. [Univ. of South Florida, Tampa, FL (United States). Dept. of Chemical Engineering] [Univ. of South Florida, Tampa, FL (United States). Dept. of Chemical Engineering

1996-09-01

2

Vapor–liquid equilibria and critical points for the carbon dioxide +1-pentanol and carbon dioxide +2-pentanol systems at temperatures from 332 to 432 K  

Microsoft Academic Search

Vapor–liquid equilibria and critical points of the systems: carbon dioxide+1-pentanol at (333.08, 343.69, 374.93, 414.23 and 426.86K) up to 18.6MPa and carbon dioxide+2-pentanol at (332.10, 343.61, 374.15, 397.56, 422.28 and 431.78K) up to 15.7MPa are reported at compositions near the critical point. An apparatus capable of measurement up to 60MPa and 523K based on the static-analytic method has been used

G Silva-Oliver; Luis A Galicia-Luna; S. I Sandler

2002-01-01

3

Solubility of anthracene in binary alcohol + 2-pentanol and alcohol + 4-methyl-2-pentanol solvent mixtures  

SciTech Connect

Experimental solubilities are reported for anthracene dissolved in 16 binary mixtures containing either 2-pentanol or 4-methyl-2-pentanol with 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 1-octanol, 2-methyl-1-propanol and 3-methyl-1-butanol at 25 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the 16 systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being 0.3% and 0.5% for the combined NIBS/Redlich-Kister and modified Wilson equations, respectively.

Powell, J.R.; McHale, M.E.R.; Kauppila, A.S.M.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry] [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry

1996-07-01

4

Calorimetric study on the state of water and 1-pentanol in the water/1-pentanol/AOT/n-heptane system  

SciTech Connect

Molar enthalpies of solution of 1-pentanol in the AOT/n-heptane system as well as of water in 1-pentanol/n-heptane and in 1-pentanol/AOT/n-heptane systems have been measured at 25/sup 0/C. The results indicate that at infinite dilution, following a Poisson distribution, 1-pentanol molecules distribute between the AOT reversed micelles and the continuous organic phase, whereas at finite concentrations of 1-pentanol, reversed micelles and alcoholic aggregates coexist. It is also found that water added to 1-pentanol/AOT/n-heptane systems is incorporated in both AOT reversed micelles and alcoholic aggregates.

D'Aprano, A.; Lizzio, A.; Liveri, V.T.

1988-04-07

5

Solubility of pyrene in binary alcohol + cyclohexanol and alcohol + 1-pentanol solvent mixtures at 299.2 K  

SciTech Connect

Experimental solubilities are reported for pyrene dissolved in five binary alcohol + cyclohexanol and seven binary alcohol + 1-pentanol solvent mixtures at 26 C. Alcohol cosolvents include 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 3-methyl-1-butanol, and 2-pentanol. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the 12 systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being on the order of 0.5%.

McHale, M.E.R.; Horton, A.S.M.; Padilla, S.A.; Trufant, A.L.; De La Sancha, N.U.; Vela, E.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry] [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry

1996-11-01

6

Fragrance material review on 1-phenyl-3-methyl-3-pentanol.  

PubMed

A toxicologic and dermatologic review of 1-phenyl-3-methyl-3-pentanol when used as a fragrance ingredient is presented. 1-Phenyl-3-methyl-3-pentanol is a member of the fragrance structural group Aryl Alkyl Alcohols and is a tertiary alcohol. The AAAs are a structurally diverse class of fragrance ingredients that includes primary, secondary, and tertiary alkyl alcohols covalently bonded to an aryl (Ar) group, which may be either a substituted or unsubstituted benzene ring. The common structural element for the AAA fragrance ingredients is an alcohol group -C-(R1)(R2)OH and generically the AAA fragrances can be represented as an Ar-Alkyl-C-(R1)(R2)OH group. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 1-phenyl-3-methyl-3-pentanol were evaluated then summarized and includes physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, and genotoxicity data. A safety assessment of the entire Aryl Alkyl Alcohols will be published simultaneously with this document; please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all Aryl Alkyl Alcohols in fragrances. PMID:22033089

Scognamiglio, J; Jones, L; Letizia, C S; Api, A M

2012-09-01

7

High-pressure phase equilibria for the carbon dioxide + 3-pentanol and carbon dioxide + 3-pentanol + water systems  

SciTech Connect

High-pressure vapor-liquid equilibria for the binary carbon dioxide + 3-pentanol system were measured at 313.2 K. The phase equilibrium apparatus used in this work was of the circulation type in which the coexisting phases were recirculated, on-line sampled, and analyzed. The critical pressure and corresponding mole fraction of carbon dioxide at 313.2 K were found to be 8.22 MPa and 0.974, respectively, for this binary system. The phase equilibria for the ternary carbon dioxide + 3-pentanol + water system were also measured at 313.2 K and pressures of 2.00, 4.00, 6.00, 8.00, and 8.25 MPa. This ternary system showed the liquid-liquid-vapor (LLV) phase behavior over the range of pressure up to the critical pressure of 8.25 MPa. The binary equilibrium data were all reasonably well-correlated with the Redlich-Kwong, Soave-Redlich-Kwong, Peng-Robinson, and Patel-Teja equations of state incorporated with the eight different mixing rules: the van der Waals, Panagiotopoulos-Reic, and six modified Huron-Vidal mixing rules with UNIQUAC parameters. For the prediction of high-pressure phase equilibria for the systems containing carbon dioxide and alcohols, the SRK-MHV2 might reproduce many features of the measured behavior although further tests are needed with other systems.

Lee, H.S.; Mun, S.Y.; Lee, H. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Chemical Engineering] [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Chemical Engineering

1999-05-01

8

Measurements and analysis of excess molar volumes for the ternary mixture MTBE + 1-pentanol + decane  

Microsoft Academic Search

Summary Densities at 298.15 K and atmospheric pressure have been measured, using a DMA 4500 Anton Paar densimeter, for the ternary mixture methyl tert-butyl ether (MTBE)+1-pentanol+decane and for the involved binary mixtures MTBE+1-pentanol and 1-pentanol+decane. The excess molar volumes for the binary mixture MTBE+decane was reported in an earlier work [1]. In addition, excess molar volumes were determined from the

P. V. Verdes; M. M. Mato; J. Salgado; J. L. Legido; M. I. Paz Andrade

2005-01-01

9

Enantioselective acylation of R-2-pentanol in a solid/gas reactor catalysed by lipase B from Candida antarctica.  

E-print Network

Review Copy Enantioselective acylation of R-2-pentanol in a solid/gas reactor catalysed by lipase B enantioselective acylation of R-2-pentanol in a solid/gas reactor was demonstrated and compared to the same (CALB) through transesterification of methyl propionate and R-2-pentanol. In the present study we show

Paris-Sud XI, Université de

10

3-pentanol: a new attractant present in volatile emissions from the ambrosia beetle, Megaplatypus mutatus.  

PubMed

Megaplatypus mutatus (=Platypus mutatus) (Coleoptera: Platypodidae) is an ambrosia beetle that is native to South America. It attacks only standing live trees and causes severe stem breakage and death in commercial poplar (Populus) plantations. Previous work showed that male M. mutatus emits a sex pheromone composed mainly of (+)-sulcatol and sulcatone. We collected male volatile emissions during the hours of maximum emergence by using a specific polar microextraction phase; analyzed the extract by GC-MS; and tested the biological activity of selected compounds in the extract with a walking behavioral assay. Female M. mutatus emerged primarily between 7 and 11 h. In the chemical analyses of volatiles, a third compound, 3-pentanol, was identified in a small percentage of samples. Walking behavioral bioassays with video image analysis showed that at the doses tested, 3-pentanol elicited an attractive response from females. PMID:18850328

Gatti Liguori, Pablo; Zerba, Eduardo; Alzogaray, Raul A; Gonzalez Audino, Paola

2008-11-01

11

Field evaluation of the bacterial volatile derivative 3-pentanol in priming for induced resistance in pepper.  

PubMed

Plants are defended from attack by emission of volatile organic compounds (VOCs) that can act directly against pathogens and herbivores or indirectly by recruiting natural enemies of herbivores. However, microbial VOC have been less investigated as potential triggers of plant systemic defense responses against pathogens in the field. Bacillus amyloliquefaciens strain IN937a, a plant growth-promoting rhizobacterium that colonizes plant tissues, stimulates induced systemic resistance (ISR) via its emission of VOCs. We investigated the ISR capacity of VOCs and derivatives collected from strain IN937a against bacterial spot disease caused by Xanthomonas axonopodis pv. vesicatoria in pepper. Of 15 bacterial VOCs and their derivatives, 3-pentanol, which is a C8 amyl alcohol reported to be a component of sex pheromones in insects, was selected for further investigation. Pathogens were infiltrated into pepper leaves 10, 20, 30, and 40 days after treatment and transplantation to the field. Disease severity was assessed 7 days after transplantation. Treatment with 3-pentanol significantly reduced disease severity caused by X. axonopodis and naturally occurring Cucumber mosaic virus in field trials over 2 years. We used quantitative real-time polymerase chain analysis to examine Pathogenesis-Related genes associated with salicylic acid (SA), jasmonic acid (JA), and ethylene defense signaling. The expression of Capsicum annuum Pathogenesis-Related protein 1 (CaPR1), CaPR2, and Ca protease inhibitor2 (CaPIN2) increased in field-grown pepper plants treated with 3-pentanol. Taken together, our results show that 3-pentanol triggers induced resistance by priming SA and JA signaling in pepper under field conditions. PMID:25149655

Choi, Hye Kyung; Song, Geun Cheol; Yi, Hwe-Su; Ryu, Choong-Min

2014-08-01

12

Acoustic and volumetric studies of binary mixtures of 1,3-butanediol + 1-pentanol  

NASA Astrophysics Data System (ADS)

The results of acoustic and volumetric investigations of binary liquid mixtures of 1,3-butanediol with 1-pentanol at the temperatures (298.15, 308.15, and 318.15)?K are presented. Basing on the phase speed of ultrasound values (measured by the pulse-echo-overlap method at 2.18?MHz) and densities, the excess values of the molar volume and isentropic compressibility (volume-specific and molar), were calculated. Their composition dependencies were expressed by Redlich-Kister polynomials. It turned out that mixing of 1,3-butanediol with 1-pentanol, results in an enhanced rigidity of the mixtures in comparison with that of the pure components. What is more, this rigidity increases with increasing temperature. At the same time the volume effects (expansion) upon mixing increase with increasing temperature too. The results are discussed in terms of the variations of the structure and molecular interactions.

Zor?bski, E.

2006-11-01

13

Solvent effects on hydrogen bonding between 1-pentanol and butyl methacrylate  

Microsoft Academic Search

The hydrogen bonding between 1-pentanol and butyl methacrylate (BMA) was investigated in n-heptane, CCl4, and benzene as solvents by using FTIR spectroscopic method. Utilizing Nash method the formation constant and free energy change of 1?:?1 complexes has been determined. The results show a significant dependence of the association constant upon the solvents used. The solvent effect on the formation of

K. Dharmalingam; K. Ramachandran

2006-01-01

14

Dehydration of 1-pentanol to di- n-pentyl ether over ion-exchange resin catalysts  

Microsoft Academic Search

The dehydration reaction of 1-pentanol to di-n-pentyl ether (DNPE) and water in the liquid phase was studied at 110–180°C and 1MPa on sulfonic styrene–divinylbenzene (S\\/DVB) copolymers and the perfluoroalkanesulfonic resin NR50. S\\/DVB-based catalysts were macroreticular and gel-type resins both sulfonated conventionally and oversulfonated. Macroreticular resins tested include resins whose working phase in catalysis is gel phase (i.e. Amberlyst-15 and Amberlyst-35)

J. Tejero; F. Cunill; M. Iborra; J. F. Izquierdo; C. Fité

2002-01-01

15

Interlamellar adsorption of 1-pentanol from aqueous solution on hydrophobic clay mineral  

Microsoft Academic Search

The adsorption and desorption of aqueous 1-pentanol solutions on hydrophobized layer silicates (octadecylammonium vermiculite) were studied by determining adsorption isotherms on the one hand, and enthalpy isotherms obtained by the microcalorimetry method on the other. The adsorption displacement process was analyzed by X-ray diffraction and values of basal spacing (dL) were determined. By combining these three methods, calculations of the

I. Dekany; A. Farkas; Z. Kiraly; E. Klumpp; H. D. Narres

1996-01-01

16

Solubilization in aqueous mixed micellar solutions: Water-potassium oleate-1-pentanol-benzene  

Microsoft Academic Search

Spectral parameters of the UV absorption and emission spectrum of benzene dissolved in aqueous solutions of potassium oleate\\u000a and 1-pentanol were measured. By comparing these parameters with those for solutions of benzene in hydrocarbon solvents, it\\u000a was concluded that the major portion of the benzene solubilized in the mixed micelles was in a relatively nonpolar environment.\\u000a These results agree with

W. E. Gerbacia; H. L. Rosano; M. Zajac

1976-01-01

17

Catalytic conversion of alcohols--14. Alkene products from the conversion of 3-methyl-3-pentanol  

SciTech Connect

New experimental results obtained for the reaction of 3-methyl-3-pentanol on alumina (Al/sub 2/O/sub 3/), gallium oxide (Ga/sub 2/O/sub 3/), indium oxide (In/sub 2/O/sub 3/), and tungsten trioxide (WO/sub 3/) showed similar cis-2, trans-2, and 1-alkene distributions for Al/sub 2/O/sub 3/ and Ga/sub 2/O/sub 3/, a higher 1-alkene selectivity for In/sub 2/O/sub 3/, and a distribution for WO/sub 3/ which is near equilibrium and similar to the distribution previously reported for other metal oxide. Trans- and cis-alkenes were incorrectly assigned in previous publications.

Davis, B.H.

1980-01-01

18

Isothermal vapor-liquid equilibria for 2-methyl-2-butanol + 2-methyl-1-butanol + 1-pentanol  

SciTech Connect

Vapor-liquid equilibria (VLE) for 2-methyl-2-butanol + 2-methyl-1-butanol and 2-methyl-2-butanol + 2-methyl-1-butanol + 1-pentanol have been measured at 373.15 K. The binary VLE results have been correlated by different liquid-phase activity coefficient models. The binary interaction parameters obtained from Wilson, NRTL, and UNIQUAC models in this and a previously study are used to predict the VLE data for the ternary system. Vapor-liquid equilibrium (VLE) data are necessary for the design of distillation processes.

Aucejo, A.; Burguet, M.C.; Monton, J.B.; Munoz, R.; Sanchotello, M.; Vazquez, M.I. (Univ. of Valencia (Spain). Dept. de Ingenieria Quimica)

1994-07-01

19

Large heat capacity anomaly near the consolute point of the binary mixture nitromethane and 3-pentanol  

NASA Astrophysics Data System (ADS)

The large critical anomaly in the isobaric heat capacity Cp,x(T) of the binary mixture nitromethane + 3-pentanol is measured using high-resolution adiabatic scanning calorimetry. The unique features of this technique provided an alternative approach to the study of the critical behavior of Cp,x(T), providing further Cp,x(T) related quantities from which valuable information could be extracted. Our data are in full agreement with the predictions of the Modern Theory of Critical Phenomena; specifically, 3D-Ising model values for the critical exponent ? and the universal amplitude ratio values of the leading critical amplitudes, as well as for the first correction-to-scaling ones, provide the optimum fits to represent the experimental data. Evidence for the need of higher-order terms, i.e., first correction-to-scaling term, is given. The large value of the coefficient E for the linear temperature dependence of the background obtained is ascribed to a possible contribution of the regular linear background term, of a higher-order asymmetry term, and of the second correction-to-scaling term. Internal consistency of Cp,x(T) and its related quantities is successfully checked.

Losada-Pérez, Patricia; Tripathi, Chandra Shekhar Pati; Leys, Jan; Glorieux, Christ; Thoen, Jan

2011-01-01

20

The homogeneous nucleation of 1-pentanol in a laminar flow diffusion chamber: The effect of pressure and kind of carrier gas  

NASA Astrophysics Data System (ADS)

The influence of total pressure and kind of carrier gas on homogeneous nucleation rates of 1-pentanol was investigated using experimental method of laminar flow diffusion chamber in this study. Two different carrier gases (helium and argon) were used in the total pressure range from 50 to 400 kPa. Nucleation temperatures ranged from 265 to 290 K for 1-pentanol-helium and from 265 to 285 K for 1-pentanol-argon. Nucleation rates varied between 101 and 106 cm-3 s-1 for 1-pentanol-helium and between 102 and 105 cm-3 s-1 for 1-pentanol-argon. Both positive and slight negative pressure effects were observed depending on temperature and carrier gas. The trend of pressure effect was found similar for both carrier gases. Error analysis on thermodynamic properties was conducted, and the lowering of surface tension due to adsorption of argon on nucleated droplets was estimated. A quantitative overview of pressure effect is provided.

Brus, D.; Hyvärinen, A.-P.; Wedekind, J.; Viisanen, Y.; Kulmala, M.; Ždímal, V.; Smolík, J.; Lihavainen, H.

2008-04-01

21

Thermal decomposition of 1-pentanol and its isomers: a theoretical study.  

PubMed

Pentanol is one of the promising "next generation" alcohol fuels with high energy density and low hygroscopicity. In the present work, dominant reaction channels of thermal decomposition of three isomers of pentanol: 1-pentanol, 2-methyl-1-butanol, and 3-methyl-1-butanol were investigated by CBS-QB3 calculations. Subsequently, the temperature- and pressure-dependent rate constants for these channels were computed by RRKM/master equation simulations. The difference between the thermal decomposition behavior of pentanol and butanol were discussed, while butanol as another potential alternative alcohol fuel has been extensively studied both experimentally and theoretically. Rate constants of barrierless bond dissociation reactions of pentanol isomers were treated by the variational transition state theory. The comparison between various channels revealed that the entropies of variational transition states significantly impact the rate constants of pentanol decomposition reactions. This work provides sound quality kinetic data for major decomposition channels of three pentanol isomers in the temperature range of 800-2000 K with pressure varying from 7.6 to 7.6 × 10(4) Torr, which might be valuable for developing detailed kinetic models for pentanol combustion. PMID:22909118

Zhao, Long; Ye, Lili; Zhang, Feng; Zhang, Lidong

2012-09-20

22

Phase equilibria of the ternary system water + acetic acid + 1-pentanol  

SciTech Connect

The recovery of organic acids from dilute solutions resulting from fermentation processes is becoming very important and many solvents have been tried to improve such recovery. Liquid-liquid equilibria for the ternary system water + acetic acid + 1-pentanol were measured over a temperature range of (288 to 323) K. The results were used to estimate the interaction parameters between each of the three compounds for the NRTL and UNIQUAC models and between each of the main groups of H{sub 2}O, CH{sub 2} (paraffinic CH{sub 2}), OH, and COOH for the UNIFAC model as a function of temperature. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the three models. The NRTL and UNIQUAC models were almost equally good in predicting the overall equilibrium compositions of the studied system. The UNIFAC model satisfactorily predicted the equilibrium compositions. On the basis of this work, the distribution coefficients were also calculated and compared with the experimental values.

Fahim, M.A.; Al-Muhtaseb, S.A.; Al-Nashef, I.M. [U.A.E. Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering] [U.A.E. Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering

1996-05-01

23

Phase and reaction equilibria of acetic acid–1-pentanol–water– n-amyl acetate system at 760 mm Hg  

Microsoft Academic Search

The esterification reaction of acetic acid and alcohol is one of the processes applying reactive distillation technology. It is known that the thermodynamic properties are essential to chemical process design. In this study, the thermodynamic behaviors of vapor–liquid equilibrium (VLE) and reaction equilibrium of acetic acid, 1-pentanol, n-amyl acetate, and water mixture were determined experimentally. Since the present esterification reaction

Liang-sun Lee; Shen-jang Liang

1998-01-01

24

Temperature dependence of the volumetric properties of binary mixtures containing alcohols (1-propanol, 1-pentanol, 1-heptanol) + heptane  

SciTech Connect

Excess molar volumes of mixtures of heptane + 1-propanol, 1-pentanol, or 1-heptanol were determined from density measurements at 278.15, 288.15, 298.15, and 308.15 K. From these results ([delta]V[sup E]/[delta]T)[sub P] and ([delta]H[sup E]/[delta]P)[sub T] at 298.15 K were calculated. The results were compared with the values calculated using the Nitta-Chao theory of liquid mixtures.

Romani, L.; Peleteiro, J.; Iglesias, T.P.; Carballo, E.; Escudero, R.; Legido, J.L. (Univ. de Vigo, Orense (Spain). Dept. de Fisica Aplicada)

1994-01-01

25

Gas-phase conformational distributions for the 2-alkylalcohols 2-pentanol and 2-hexanol from microwave spectroscopy  

NASA Astrophysics Data System (ADS)

Chirped-pulse and cavity Fourier-transform microwave spectrometers were used to record rotational spectra arising from four conformational structures of 2-pentanol and 14 conformations of 2-hexanol. Each conformer's rotational spectrum consists of 10-89 transitions, making the microwave spectra of the alkylalcohols very congested. Assignments of the spectra to conformational structures were made by comparison of the experimental moments of inertia and dipole-selection-rule intensities to predictions from ab initio (MP2/6-311++G ??) model structures. The all-anti configurations of 2-pentanol and 2-hexanol were calculated to have the lowest energies and gave rise to the strongest signals. Spectra were observed from conformers up to 4 kJ mol -1 above these minimum energy structures.

Tubergen, Michael J.; Conrad, Andrew R.; Chavez, Roberto E.; Hwang, Injung; Suenram, Richard D.; Pajski, Jason J.; Pate, Brooks H.

2008-09-01

26

Phase Diagram, Electrical Conductivity, and Viscosity Study of Alpha-Sulfonated Methyl Esters Derived from Palm Stearin\\/1Pentanol\\/Hydrocarbon\\/Water Systems  

Microsoft Academic Search

Microemulsion region of sodium salt alpha-sulfonated methyl ester derived from palm stearin (?-SMEPS)\\/1-pentanol\\/alkane\\/water systems was constructed and investigated at 30.0 ± 0.1°C. The water-in-oil (w\\/o) microemulsion, bicontinuous structure, and oil-in-water (o\\/w) microemulsion regions were determined by both conductivity and viscosity methods. Results showed that the microemulsion region decreases and moved towards (?-SMEPS f 1-pentanol) rich corner with the increase in hydrocarbon chain

Wen Huei Lim

2008-01-01

27

Interfacial composition, thermodynamic properties, and structural parameters of water-in-oil microemulsions stabilized by 1-pentanol and mixed surfactants.  

PubMed

The present study is focused on the evaluation of the interfacial composition, thermodynamic properties, and structural parameters of water-in-oil mixed surfactant microemulsions [(cetylpyridinium chloride, CPC+polyoxyethylene (20) cetyl ether, Brij-58 or polyoxyethylene (20) stearyl ether, Brij-78)/1-pentanol/n-heptane, or n-decane] under various physicochemical environments by the Schulman method of cosurfactant titration of the oil/water interface. The estimation of the number of moles of 1-pentanol at the interface (n(a)(i)) and bulk oil (n(a)(o)) and its distribution between these two domains at the threshold level of stability have been emphasized. The thermodynamics of transfer of 1-pentanol from the continuous oil phase to the interface have been evaluated. n(a)(i),n(a)(i), standard Gibbs free energy (?G(t)(0)), standard enthalpy (?H(t)(0)), and standard entropy (?G(t)(0)) of transfer process have been found to be dependent on the molar ratio of water to surfactant (?), type of nonionic surfactant and its content (X(Brij-58 or Brij-78)), oil and temperature. A correlation between (?H(t)(0)) and (?S(t)(0)) is examined at different experimental temperatures. Bulk surfactant composition dependent temperature insensitive microemulsions have been reported. Associated structural parameters, such as droplet dimensions and aggregation number of surfactant and cosurfactant at the droplet interface have been evaluated using a mathematical model after suitable modifications for mixed surfactant systems. In light of these parameters, the prospect of using these microemulsion systems for the synthesis of nanoparticles and the modulation of enzyme activity has been discussed. Correlations of the results in terms of the evaluated physicochemical parameters have been attempted. PMID:22884225

Kundu, Kaushik; Guin, Gourhari; Paul, Bidyut K

2012-11-01

28

Exploring the discrepancies between experiment, theory, and simulation for the homogeneous gas-to-liquid nucleation of 1-pentanol  

NASA Astrophysics Data System (ADS)

Using an efficient Monte Carlo approach known as Aggregation-Volume-bias Monte Carlo with self-adaptive Umbrella Sampling and Histogram Reweighting (AVUS-HR), we obtained the nucleation free energy profile of 1-pentanol at various temperatures from 220 to 360 K. From these profiles, differences between the free energy barrier heights obtained from our simulations and those predicted by the classical nucleation theory (CNT) were calculated. Our results strongly support that the logarithm of the nucleation rate ratio between simulation (or experiment) and CNT increases almost linearly with the inverse temperature. Among the various factors that contribute to the discrepancy between simulation and CNT nucleation rates, the nonzero surface free energy of the monomer included in the CNT makes the largest contribution. On the molecular level, the simulations indicate that a gas-phase cluster of 1-pentanol molecules is relatively compact and can contain multiple hydrogen bonded aggregates of various sizes and that this aggregate size distribution depends strongly on temperature and also on the overall size of the cluster system.

Nellas, Ricky B.; Keasler, Samuel J.; Siepmann, J. Ilja; Chen, Bin

2010-04-01

29

A new and rapid method for the solvent extraction of Ru\\/III\\/ with 1,2,3-benzotriazole into 1-pentanol  

Microsoft Academic Search

A new and rapid method has been developed for the quantitative extraction of Ru\\/III\\/ with 1,2,3-benzotriazole \\/1,2,3-BT\\/ into 1-pentanol. The extraction coefficient value of Ru\\/III\\/ between 1-pentanol and an aqueous 5% solution of 1,2,3-BT in 2M sodium acetate-acetic acid buffer showed a maximum value of E=46 at pH 4.5. The effect of various other parameters on the extraction coefficient of

I. A. Mendes; Z. R. Turel

1986-01-01

30

Development of a Mechanism-Based Dosimetry Model for 2,4,4Trimethyl2-pentanol-Induced ?2u-Globulin Nephropathy in Male Fischer 344 Rats  

Microsoft Academic Search

Development of a Mechanism-Based Dosimetry Model for 2,4,4-Trimethyl-2-pentanol-Induced ?2u-Globulin Nephropathy in Male Fischer 344 Rats. Borghoff, S. J., Gargas, M. L., Andersen, M. E., and Conolly, R. B. (1995). Fundam. Appl. Toxicol. 25, 124-137.A mechanism-based dosimetry model was developed to describe 2,4,4-trimethyl-2-pentanol (TMP-2-OH) dosimetry and renal ?2u-globulin (?2u) nephropathy in the male Fischer 344 rat. Experimental data were collected to

Susan J. Borghoff; Michael L. Gargas; Melvin E. Andersen; Rory B. Conolly

1995-01-01

31

Surface Raman scattering of methanol, 1-propanol, 1-pentanol, and 1-butanethiol on in situ and emersed silver electrodes  

SciTech Connect

Surface Raman scattering is used to study the adsorption of several straight-chain alcohols (methanol, 1-propanol, 1-pentanol) and a straight-chain alkanethiol (1-butanethiol) at Ag electrodes. Surface-enhanced Raman scattering (SERS) studies are carried out on both in situ and emersed roughened electrodes. Normal surface Raman scattering is performed on mechanically polished, mirrored polycrystalline electrodes that have been emersed from solution. It is generally observed that the Raman scattering results, in terms of the orientation and bonding for the alcohols and the thiol, are similar on rough and mirrored electrodes. This observation suggests that SERS probes the average surface molecules in these cases and not only those existing at chemically distinct surface sites. The utility of emersed electrode approaches for molecular characterization of the electrochemical interface is demonstrated for these systems. The interfacial molecular structure for these in situ organic species appears to be maintained upon emersion.

Sobocinski, R.L.; Bryant, M.A.; Pemberton, J.E. (Univ. of Arizona, Tucson (USA))

1990-08-15

32

Viscosities and densities for heptane + 1-pentanol, + 1-hexanol, + 1-heptanol, + 1-octanol, + 1-decanol, and + 1-dodecanol at 298.15 K and 308.15 K  

SciTech Connect

Densities and viscosities for heptane + 1-pentanol, + 1-hexanol, + 1-heptanol, + 1-octanol, + 1-decanol, and + 1-dodecanol are reported at (298.15 K and 308.15) K. The viscosity deviations were calculated. The mixture viscosity data were fitted to the semiempirical equations of Grunberg-Nissan, Heric, McAllister, and Auslander.

Sastry, N.V.; Valand, M.K. [Sardar Patel Univ., Gujarat (India). Dept. of Chemistry] [Sardar Patel Univ., Gujarat (India). Dept. of Chemistry

1996-11-01

33

Viscosities and densities for heptane + 1-pentanol, + 1-hexanol, + 1-heptanol, + 1-octanol, + 1-decanol, and + 1-dodecanol at 298.15 K and 308.15 K  

Microsoft Academic Search

Densities and viscosities for heptane + 1-pentanol, + 1-hexanol, + 1-heptanol, + 1-octanol, + 1-decanol, and + 1-dodecanol are reported at (298.15 K and 308.15) K. The viscosity deviations were calculated. The mixture viscosity data were fitted to the semiempirical equations of Grunberg-Nissan, Heric, McAllister, and Auslander.

Nandhibatla V. Sastry; Mahendra K. Valand

1996-01-01

34

Densities and viscosities for binary mixtures of phenetole with 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-decanol at different temperatures  

Microsoft Academic Search

Density (?) and viscosity (?) values of the binary mixtures of phenetole+1-pentanol, + 1-hexanol, + 1-heptanol, + 1-octanol, + 1-nonanol, and + 1-decanol over the entire range of mole fraction at 293.15, 298.15, 308.15, and 318.15K have been measured at atmospheric pressure. The excess molar volume (VE), viscosity deviations (??), and excess Gibbs energy of activation (G*E) have been calculated

Adel S Al-Jimaz; Jasem A Al-Kandary; Abdul-Haq M Abdul-Latif

2004-01-01

35

Thermally stable ion-exchange resins as catalysts for the liquid-phase dehydration of 1-pentanol to di- n-pentyl ether (DNPE)  

Microsoft Academic Search

Conversion, selectivity, yield, and kinetics of the liquid-phase dehydration of 1-pentanol to di-n-pentyl ether (DNPE) were determined at 403–463 K on a recently developed sulfonated resin, Amberlyst 70, which is thermally stable up to 473 K. The behavior of Amberlyst 70 was compared with that of Nafion resin NR50, an H-Beta zeolite, and styrene-divinylbenzene resins stable up to 423 K

Roger Bringué; Montserrat Iborra; Javier Tejero; José Felipe Izquierdo; Fidel Cunill; Carles Fité; Victor J. Cruz

2006-01-01

36

Kinetic resolution of rac -2-pentanol catalyzed by Candida antarctica lipase B in the ionic liquid, 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide  

Microsoft Academic Search

The ionic liquid, 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide ([Bmim] [NTf2]), was used as a reaction medium for the kinetic resolution of rac-2-pentanol catalyzed by free Candida antarctica lipase B, using vinyl propionate at 2% (v\\/v) water content. The synthetic activity of lipase in [Bmim] [NTf2] was up 2.5-times greater than in hexane, and showed high enantioselectivity (ee > 99.99%). The optimal temperature and pH

Marilyne Noël; Pedro Lozano; Michel Vaultier; José L. Iborra

2004-01-01

37

Isothermal vapor-liquid equilibria of 1-pentanol with 2-methyl-1-butanol, 2-methyl-2-butanol, and 3-methyl-2-butanol  

SciTech Connect

The separation of liquid mixtures through distillation is one of the most common operations in chemical industry, and the efficient design of distillation equipment requires a quantitative knowledge of vapor-liquid equilibria (VLE). Vapor-liquid equilibria were measured for binary systems of 1-pentanol + 2-methyl-1-butanol, + 2-methyl-2-butanol, and + 3-methyl-2-butanol at 373.15 K. The results are thermodynamically consistent according to the point-to-point consistency test, and deviation from ideal behavior is small in all cases.

Aucejo, A.; Burguet, M.C.; Monton, J.B.; Munoz, R.; Sanchotello, M.; Vazquez, M.I. (Univ. of Valencia (Spain). Dept. de Ingenieria Quimica)

1994-07-01

38

Effect of temperature on the properties of mixed normal micelles in sodium octanoate-1-pentanol-water systems studied by positron annihilation technique  

SciTech Connect

Positron annihilation technique was applied to the study of structural properties of mixed normal micelles in sodium octanoate-1-pentanol-water systems. Measurements of positron annihilation parameters over a wide range of temperature and surfactant concentrations demonstrate the extreme sensitivity of the technique toward the structural changes associated with the second and third critical concentrations. While the third critical concentration appears to be temperature independent, the second critical concentration is shifted to slightly lower values at higher temperatures (from approx. 1.4 m to approx. 1.0 m on going from 21 to 51/sup 0/C). The plot of the Arrhenius activation energies of positronium formation as a function of surfactant molality indicates some continuous changes in the properties of the micelles below and above the third concentration.

Boussaha, A.; Ache, H.J.

1981-08-20

39

Phase equilibria in the system consisting of water and 1,1,5-trihydrooctafluoro-1-pentanol, modified with methanol or acetic acid  

SciTech Connect

In the interest of discovering new avenues in the extractive recovery of polar organic compounds from water, the authors have initiated research on systems based on 1,1,5-trihydrooctafluoro-1-pentanol (TOP). A subject of particular interest is the possibility of modifying such systems by polar solvents such as methanol, ethanol, or acetic acid, so as to vary the distribution coefficient and hence the extraction coefficient. In previous work, the authors compared phase diagrams of two-phase systems based on TOP and 1-butanol in the region of the critical point on the binodal curve of the corresponding three-component systems. For a deeper understanding of the behavior of TOP-containing two-phase systems, the authors have now investigated the phase composition of systems over the entire interval of concentrations of modifying additives, and the influence of these additives on the mutal solubility of water and TOP. 10 refs., 2 figs., 1 tab.

Dovyborov, N.A.; Indans, K.Ya.; Kalei, U.O.

1992-04-20

40

Excess parameters for binary mixtures of ethyl benzoate with 1-propanol, 1-butanol and 1-pentanol at T=303, 308, 313, 318, and 323 K  

NASA Astrophysics Data System (ADS)

Various thermo-acoustic parameters, such as excess isentropic compressibility (KsE), excess molar volume (VE), excess free length (LfE), excess Gibb's free energy (?G*E), and excess Enthalpy (HE), have been calculated from the experimentally determined data of density, viscosity and speed of sound for the binary mixtures of ethyl benzoate+1-propanol, or +1-butanol, or +1-pentanol over the entire range of composition at different temperatures (303, 308, 313, 318 and 323 K). The excess functions have been fitted to the Redlich-Kister type polynomial equation. The deviations for excess thermo-acoustic parameters have been explained on the basis of the intermolecular interactions present in these binary mixtures.

Sreehari Sastry, S.; Babu, Shaik; Vishwam, T.; Parvateesam, K.; Sie Tiong, Ha.

2013-07-01

41

High-temperature oxidation of LnCu{sub 2} intermetallics and their catalytic behavior in 4-methyl-2-pentanol decomposition  

SciTech Connect

The air-oxidation of the intermetallic compounds LaCu{sub 2}, CeCu{sub 2}, PrCu{sub 2}, and NdCu{sub 2} was followed by thermogravimetry. The mass uptake occurred over a wide range of temperature (423-1100 K), leading to two stoichiometrics according to the lanthanide; CeCu{sub 2}O{sub 4} and LnCu{sub 2}O{sub 3.5} (Ln = La, Pr, Nd). The characterization by powder X-ray diffraction, scanning electron microscopy/energy dispersive X-ray analysis, and surface area measurements showed that segregation took place with the formation of CuO along with CeO{sub 2} or Ln{sub 2}CuO{sub 4} (Ln = La, Pr, Nd). Therefore, the oxidized intermetallics are better described by the formulas CeO{sub 2}{center_dot}2CuO and Ln{sub 2}CuO{sub 4}{center_dot}3CuO. The oxidation process noticeably increased the surface areas and promoted CuO migration to the surface. These systems exhibited selectivities in 4-methyl-2-pentanol decomposition, which are associated with the lanthanide. 34 refs., 4 figs., 3 tabs.

Ballivet-Tkatchenko, D.; Branco, J. [CNRS, Toulouse (France); Matos, A.P. de [INETI/ICEN, Sacavem (Portugal)

1995-04-13

42

Excess molar enthalpies of acetone + water, cyclohexane, methanol, 1-propanol, 2-propanol, 1-butanol and 1-pentanol at 283.15, 298.15, 323.15, 343.15 and 363.15 K  

Microsoft Academic Search

Excess molar enthalpies hE of the binary systems acetone + water, cyclohexane, methanol, 1-propanol, 2-propanol, 1-butanol and 1-pentanol were measured at temperatures of 283.15, 298.15, 323.15, 343.15 and 363.15 K and at a pressure of 0.4 MPa. An LKB flow microcalorimeter was used. The experimental hE values were correlated with a modified Redlich-Kister equation.

B. Löwen; S. Schulz

1995-01-01

43

Absolute and relative rate constants for the reactions of OH and Cl with pentanols  

NASA Astrophysics Data System (ADS)

The rate constants for the reactions of OH with three pentanols have been determined in the range 267-373 K and P = 100 Torr. The data obtained were (in units of cm3molecule-1s-1): k(1-pentanol) = (6.7 ± 3.8) × 10-12 exp [(132 ± 176)/T], k(2-pentanol) = (5.2 ± 1.8) × 10-12 exp [(218 ± 116)/T], k(3-pentanol) = (5.8 ± 2.3) × 10-12 exp [(164 ± 118)/T]. The present work provides the first temperature dependence data on these reactions. In addition, using the relative rate method, the rate constants for OH and Cl with these pentanols have been measured. The results are compared with the literature data and discussed with respect to atmospheric chemistry.

Lendar, M.; Aissat, A.; Cazaunau, M.; Daële, V.; Mellouki, A.

2013-09-01

44

Structural aspects in the dielectric properties of pentyl alcohols  

NASA Astrophysics Data System (ADS)

At temperatures between 0 and 60 °C densities, shear viscosities and dielectric spectra have been measured for isomers 1-pentanol, 2-pentanol, 3-pentanol, isopentylalcohol, and tert-pentanol, as well as for mixtures of these alcohols. The density and shear viscosity data are discussed in terms of deviations from ideal mixing behavior. The dielectric spectra are evaluated to yield the extrapolated static permittivity and the relaxation time of the principal (low-frequency) relaxation term. The former parameter is analyzed in view of dipole orientation correlations, the latter one is discussed in terms of the activation enthalpy controlling the relaxation process. A noticeable result is the effect of isomer structure on both the dipole orientation correlation and the dielectric relaxation. Especially the dielectric parameters of tert-pentanol deviate significantly from the relevant parameters of the other pentanols. Such deviations are considered in the light of models of hydrogen network structure and fluctuations.

Kaatze, Udo; Behrends, Ralph; von Roden, Kerstin

2010-09-01

45

The critical behavior of the dielectric constant in the polar + polar binary liquid mixture nitromethane + 3-pentanol: An unusual sign of its critical amplitude in the one-phase region  

NASA Astrophysics Data System (ADS)

Dielectric constant measurements have been carried out in the one- and two-phase regions near the critical point of the polar + polar binary liquid mixture nitromethane + 3-pentanol. In the two-phase region, evidence for the |t|2? singularity in the coexistence-curve diameter has been detected, thus confirming the novel predictions of complete scaling theory for liquid-liquid criticality. In the one-phase region, an ``unusual'' negative sign for the amplitude of the |t|1 - ? singularity has been encountered for the first time in an upper critical solution temperature type of binary liquid mixture at atmospheric pressure. Mass density measurements have also been carried out to provide additional information related to such experimental finding, which entails an increase of the critical temperature Tc under an electric field.

Leys, Jan; Losada-Pérez, Patricia; Troncoso, Jacobo; Glorieux, Christ; Thoen, Jan

2011-07-01

46

Isobaric vapor-liquid equilibria of 1-butanol + N,N-dimethylformamide and 1-pentanol + N,N-dimethylformamide systems at 50.00 and 100.00 kPa  

SciTech Connect

The experimental determinations of vapor-liquid equilibria (VLE) are indispensable for the design of separation processes such as distillation columns, extractive distillation, and selection of solvents. Isobaric vapor-liquid equilibria were obtained for the 1-butanol + N,N-dimethylformamide and 1-pentanol + N,N-dimethylformamide systems at 50.00 and 100.00 kPa. The activity coefficients were found to be thermodynamically consistent. The data were correlated with five liquid phase activity coefficient models (Margules, Van Laar, Wilson, NRTL, and UNIQUAC). Experimental vapor pressures of N,N-dimethylformamide are also included.

Marzal, P.; Gabaldon, C.; Seco, A.; Monton, J.B. [Univ. de Valencia (Spain). Dept. de Ingenieria Quimica

1995-05-01

47

21 CFR 172.515 - Synthetic flavoring substances and adjuvants.  

Code of Federal Regulations, 2010 CFR

...alcohol; isobutyl benzyl carbinol; 4-methyl-1-phenyl-2-pentanol. Isobutyl phenylacetate. Isobutyl propionate. Isobutyl...phenylethyl methyl carbinyl acetate. 1-Phenyl-3-methyl-3-pentanol; phenylethyl methyl ethyl carbinol....

2010-04-01

48

21 CFR 172.515 - Synthetic flavoring substances and adjuvants.  

...alcohol; isobutyl benzyl carbinol; 4-methyl-1-phenyl-2-pentanol. Isobutyl phenylacetate. Isobutyl propionate. Isobutyl...phenylethyl methyl carbinyl acetate. 1-Phenyl-3-methyl-3-pentanol; phenylethyl methyl ethyl carbinol....

2014-04-01

49

21 CFR 172.515 - Synthetic flavoring substances and adjuvants.  

Code of Federal Regulations, 2011 CFR

...alcohol; isobutyl benzyl carbinol; 4-methyl-1-phenyl-2-pentanol. Isobutyl phenylacetate. Isobutyl propionate. Isobutyl...phenylethyl methyl carbinyl acetate. 1-Phenyl-3-methyl-3-pentanol; phenylethyl methyl ethyl carbinol....

2011-04-01

50

21 CFR 172.515 - Synthetic flavoring substances and adjuvants.  

Code of Federal Regulations, 2012 CFR

...alcohol; isobutyl benzyl carbinol; 4-methyl-1-phenyl-2-pentanol. Isobutyl phenylacetate. Isobutyl propionate. Isobutyl...phenylethyl methyl carbinyl acetate. 1-Phenyl-3-methyl-3-pentanol; phenylethyl methyl ethyl carbinol....

2012-04-01

51

21 CFR 172.515 - Synthetic flavoring substances and adjuvants.  

Code of Federal Regulations, 2013 CFR

...alcohol; isobutyl benzyl carbinol; 4-methyl-1-phenyl-2-pentanol. Isobutyl phenylacetate. Isobutyl propionate. Isobutyl...phenylethyl methyl carbinyl acetate. 1-Phenyl-3-methyl-3-pentanol; phenylethyl methyl ethyl carbinol....

2013-04-01

52

ch3probs Page 1 of 9 http://www.jbpub.com/fox/supplementalproblems/ch3pr.htm 11/18/2003  

E-print Network

-methylpentane d. 1-amino-2,2-dimethylpentane e. 2-amino-2-methylpentane f. 1-hexanol g. 2-pentanol #12;ch3probs Page 3 of 9 http://www.jbpub.com/fox/supplementalproblems/ch3pr.htm 11/18/2003 h. 2-methyl-1-pentanol i. 2,2-dimethyl-1-pentanol j. 2-methyl-2-pentanol 3.23 Penicillin V: ether, 2 amides, thioether

Walba, David

53

Comparative dielectric study of pentanol isomers with terahertz time-domain spectroscopy  

NASA Astrophysics Data System (ADS)

Using terahertz (THz) time-domain spectroscopy, we have measured the complex permittivity of seven pentanol isomers (1-pentanol, 2-pentanol, 3-pentanol, 2-methly-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, and 3-methyl-2-butanol) in the frequency range of 0.2-2.5 THz at temperatures from 253 to 323 K. For all samples, the complex permittivity contains the following three components: (i) a high-frequency side of dielectric relaxation processes, (ii) a broad vibration mode around 1.5 THz, and (iii) a low-frequency side of an intermolecular stretching mode located above 2.5 THz. At low temperatures, the relaxation process moves to a low-frequency range and a peak of the broad vibration mode, which is independent of temperature, is clearly observed around 1.5 THz. Spectra in the THz region change sensitively according to the molecular structure of the pentanol isomers. We have also observed the complex permittivity in the microwave range of 1 MHz-20 GHz. The behavior of the dielectric relaxation processes below GHz region much depend on the isomers. Our experimental data demonstrate that the molecular structures of the pentanol isomers influence all the molecular dynamics ranging from dielectric relaxation phenomena, which are due to reorientational motion of the molecules, to vibration dynamics within the hydrogen-bonded network structure.

Yomogida, Yoshiki; Sato, Yuki; Yamakawa, Kazuyoshi; Nozaki, Ryusuke; Mishina, Tomobumi; Nakahara, Jun'ichiro

2010-04-01

54

Static dielectric constant, viscosity, and structure of pure isomeric pentanols  

Microsoft Academic Search

Static dielectric constants, viscosities, densitites and refractive indices of 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol and 2-methyl-2-butanol were measured at 15, 25, 35 and 45°C. These results together with the previous data on n-pentanol have been analyzed in terms of the Kirkwood correlation factor gk and of the energy of activiation for viscous flow. With the exception of 2-methyl-2-butanol, gk was found

Alessandro D'Aprano; Dorina I. Donato; Valeria Agrigento

1981-01-01

55

Enthalpy of dilution of poly(ethylene glycol) monomethyl ether in 1-pentanol  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

Wohlfarth, Ch.

56

Impact of talc on pulp and froth properties in F150 and 1-pentanol frother systems  

Microsoft Academic Search

The role of frother controlling bubble size and froth properties is reasonably well understood in the air–water system. A concern is how well this relates to the three-phase flotation condition. As a model hydrophobic solid talc was used. A column was run at fixed froth depth and air rate with overflow and underflow recycled. Four frothers were examined, two polyglycols,

Seng How Kuan; James A. Finch

2010-01-01

57

Enzymatic synthesis of enantio- and diastereomerically enriched syn-3-nitro-2-pentanol  

Microsoft Academic Search

The enzymatic resolution of a commercial mixture of nitropentanol isomers was achieved. The syn isomer could be obtained in high de and ee in either the (2S,3S) or (2R,3R) configuration by combining an enantioselective enzymatic acylation or deacylation with a stereoselective elimination of the minor anti isomer.

Brian Morgan; Bhaskar R Sarikonda; David R Dodds; Michael J Homann; Robert Vail

1999-01-01

58

Solubility of anthracene in binary alcohol + 3-methoxy-1-butanol solvent mixtures  

SciTech Connect

Experimental solubilities are reported for anthracene dissolved in ten binary mixtures containing 3-methoxy-1-butanol with 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-methyl-1-butanol, 4-methyl-2-pentanol, 1-octanol, and 2-ethyl-1-hexanol at 25 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the ten systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being 0.4% and 0.5% for the combined NIBS/Redlich-Kister and modified Wilson equations, respectively.

McHale, M.E.R.; Horton, A.S.M.; Padilla, S.A.; Trufant, A.L.; Sancha, N.U. De La; Vela, E.; Powell, J.R.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry] [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry

1997-01-01

59

Reactivity of Individual Organolithium Aggregates a RINMR Study of n-Butyllithium and 2-Methoxy-6-(methoxymethyl)phenyllithium  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S-19 1-Phenyl-1-pentanol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S-20 1-(4-Diethylaminophenyl)-1-pentanol

Reich, Hans J.

60

Composition and Process for Retarding the Premature Aging of PMR Monomer Solutions and PMR Prepegs  

NASA Technical Reports Server (NTRS)

Polyimides are derived from solutions of at least one low-boiling organic solvent, e.g. isopropanol containing a mixture of polyimide-forming monomers. The monomeric solutions have an extended shelf life at ambient (room) temperatures as high as 80 C, and consist essentially of a mixture of monoalkyl ester-acids, alkyl diester-diacids and aromatic polyamines wherein the alkyl radicals of the esteracids are derived from lower molecular weight aliphatic secondary alcohols having 3 to 5 carbon atoms per molecule such as isopropanol, secondary butanol, 2-methyl-3-butanol, 2 pentanol or 3-pentanol. The solutions of the polyimide-forming monomers have a substantially improved shelf-life and are particularly useful in the aerospace and aeronautical industry for the preparation of polyimide reinforced fiber composites such as the polyimide cured carbon composites used in jet engines, missiles, and for other high temperature applications.

Alston, William B. (Inventor); Gahn, Gloria S. (Inventor)

2000-01-01

61

Dependence on molecular parameters of the heat capacity critical behaviour for nitroalkane + alcohol binary systems  

NASA Astrophysics Data System (ADS)

Heat capacities per unit volume for a set of nitroalkane + alcohol critical mixtures near their upper consolute point are presented. The selected nitroalkanes were nitromethane and nitroethane whereas the 1-alcohol series from 1-propanol to 1-decanol was studied. The critical anomaly of nitroalkane + non-primary alcohols was also investigated; 2-propanol, 2-pentanol, 3-pentanol and 5-nonanol were chosen to this end. The heat capacity data are obtained at atmospheric pressure as a function of temperature in the homogeneous and heterogeneous regions by means of a differential scanning calorimeter. The exponent and amplitudes that characterises the observed critical anomaly are determined from experimental data, being their values coherent with previous results. In addition, the critical amplitude of the correlation length was calculated using the universality of the two-scale factor. Finally, the changes in the critical parameters as a function of the molecular structure of both nitroalkane and alcohol are analysed.

Souto-Caride, M.; Troncoso, J.; Losada-Pérez, P.; Peleteiro, J.; Carballo, E.; Romani, L.

2009-04-01

62

Solubility of anthracene in binary alcohol + 2-methoxyethyl ether solvent mixtures  

SciTech Connect

Experimental solubilities are reported for anthracene dissolved in seven binary mixtures containing 2-methoxyethyl ether with 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, and 1-octanol at 25 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the seven systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being 1.1% and 0.8% for the combined NIBS/Redlich-Kister and modified Wilson equations, respectively.

Powell, J.R.; Coym, K.S.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry] [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry

1997-03-01

63

Relative permittivities and refractive indices on mixing for ( n -hexane + 1-pentanol, or 1-hexanol, or 1-heptanol ) at T = 298.15 K  

Microsoft Academic Search

A previous study on the physical properties of (1-alcohol +n -alkane) has established a correlation between dielectric permittivity at 1 GHz and excess molar volumesVE for all binary systems that were studied. In order to determine whether this behaviour is similar at lower frequencies, relative permittivity ??was measured at 100 kHz. The refractive indexnD was measured to explore the effects

M. I. Paz Andrade

2000-01-01

64

Determination of alcohol solvent orientation and bonding at silver electrodes using surface-enhanced Raman scattering: Methanol, ethanol, 1-propanol, and 1-pentanol  

SciTech Connect

Interfacial solvent structure at Ag electrodes in various straight-chain alcohol electrolyte systems has been studied using surface-enhanced Raman scattering (SERS). SERS provides detailed information regarding the nature of interfacial bonding and alkyl chain orientation. Methanol appears to be in a unique hydrogen-bonding environment at the interface, as indicated by a 10-cm{sup -1} decrease in v(C-O) frequency from its bulk solution value; C{sub 2} and longer chain alcohols at the interface show no shift in v(C-O) frequency from bulk solution. The alkyl chains are largely parallel to the surface (i.e., greater than 45{degrees} relative to the surface normal) and exist in a largely all-trans configuration at electrode potentials positive of the PZC (potential of zero charge). These molecules are oriented with the hydroxyl group at the surface and the alkyl chain tilted slightly away from the surface. At more negative potentials near the PZC, the alkyl chain conformations become more disordered, and the alkyl chains {open_quotes}stand up{close_quotes}, with the methyl group directed into bulk solution. For methanol, two distinct orientations exist simultaneously at the interface in the vicinity of the PZC. The growth of a new methylene band for C{sub 2}, C{sub 3}, and C{sub 5} alcohols at increasingly negative potentials suggests significant interaction of the methylene hydrogens with the surface. In contrast to the C{sub 3} and C{sub 5} alcohols, the C{sub 1} and C{sub 2} alcohols exhibit little bulk spectroscopic behavior, indicating distinct orientations at potentials negative of the PZC. All observations support the idea that the {alpha}-carbon is confined near the surface at all potentials for all four alcohols. The driving force for this behavior is proposed to be the formation of C-H Ag agostic bonds.

Sobocinski, R.L.; Pemberton, J.E. [Univ. of Arizona, Tucson, AZ (United States)

1992-08-01

65

Formation of the metabolic intermediate 2,4,4-trimethyl-2-pentanol during incubation of a shape Sphingomonas sp. strain with the xeno-estrogenic octylphenol  

Microsoft Academic Search

Degradation of branched octylphenol was studied in abacterial culture of a Sphingomonas sp. strain.Octylphenol is considered to be the most stabledegradation intermediate formed from the correspondingnonionic octylphenol polyethoxylates surfactantsduring biological wastewater treatment. Sinceoctylphenol can exert estrogenic effects in wildlife,a detailed study of its biodegradation is warranted.The aerobic microbiological transformation ofoctylphenol was examined with and without the additionof the easily assimilable

Tom Tanghe; Willem Dhooge; Willy Verstraete

2000-01-01

66

Experimental neurotoxicity and urinary metabolites of the C5-C7 aliphatic hydrocarbons used as glue solvents in shoe manufacture  

SciTech Connect

Rats were intermittently exposed (9 to 10 h/d, 5 to 6 d/week) to controlled concentrations of single analytical grad solvents in ambient air. After periods ranging from 7 to 30 weeks the animals were perfused with glutaraldehyde and samples of nerves were processed for light microscopy of sections and of teased fibers. Animals treated with n-hexane at 5000 ppm (14 weeks) or 2500 ppm (30 weeks) developed the typical giant axonal degeneration already described in rats treated continuously with 400 to 600 ppm of the same solvent for 7 weeks or more. No such alterations were found in rats subjected to the following intermittent respiratory treatments: n-hexane 500 ppm (30 weeks) or 1500 ppm (14 weeks), cyclohexane 1500 or 2500 (30 weeks), n-pentane 3000 ppm (30 weeks), n-heptane 1500 ppm (30 weeks), 2-methylpentane 1500 ppm (14 weeks), and 3-methylpentane 1500 ppm (14 weeks). The following metabolites were found in the urine of rats according to treatment (in parenthesis): 2-methyl-2-pentanol (2-methylpentane); 3-methyl-2-pentanol and 3-methyl-3-pentanol (3-methylpentane), 2-hexanol, 3-hexanol, gamma-valerolactone, 2,5-dimethylfuran, and 2,5-hexanedione (n-hexane). 2-Hexanol was found to be the main urinary metabolite of n-hexane, while 2,5-hexanedione was present only in a lesser proportion. This feature of rat metabolism suggests that in this species 2,5-hexanedione reaches an effective level at its site of action during intermittent respiratory treatment with n-hexane with difficulty and explains the high concentrations necessary to cause polyneuropathy in rats subjected to this treatment.

Frontali, N.; Amantini, M.C.; Spagnolo, A.; Guarcini, A.M.; Saltari, M.C.; Brugnone, F.; Perbellini, L.

1981-12-01

67

Effect of Surfactant Supplying with Refrigerant Vapor on Absorption Enhancement  

NASA Astrophysics Data System (ADS)

For the absorption of water vapor into the aqueous lithium bromide solution, eight-carbon alcohol additives such as 2-ethyl-1-hexanolhave been commonly used to improve the absorption process. However, as additives six-carbon and seven-carbon alcohols were not been tested experimentally very much. In present study, absorption of water vapor into the 62 wt% LiBr solution with several six-carbon and seven carbon alcohol additives such as 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-hexanol, 2 , 4-dimethyl-3-pentanol, 4-heptanol, 2-heptanol and 1-heptanol were investigated by using a simple stagnant pool absorber. Besides using the conventional method which mixing additive into LiBr solution, vapor phase adding method was experimented. Surface tensions of aqueous LiBr solution with different surfactant also were measured by Welhelmy plate method. Absorption of water vapor into the LiBr solution with 2-ethyl-1-hexanol and 1-heptanol were also experimented in falling film absorber by vapor phase adding method. The result showed that the lower the surface tension of LiBr aqueous solution with an additive, the better the effect of absorption enhancement by the corresponding additive, and vapor phase adding method is effective for the absorption of water vapor into the LiBr aqueous solution.

Gao, Hongtao; Matsuzaki, Tetsuya; Wang, Jianfeng; Hihara, Eiji

68

An investigation of bubble coalescence and post-rupture oscillation in non-ionic surfactant solutions using high-speed cinematography.  

PubMed

Most processes involving bubbling in a liquid require small bubbles to maximise mass/energy transfer. A common method to prevent bubbles from coalescing is by the addition of surfactants. In order to get an insight into the coalescence process, capillary bubbles were observed using a high speed cinematography. Experiments were performed in solutions of 1-pentanol, 4-methyl-2-pentanol, tri(propylene glycol) methyl ether, and poly(propylene glycol) for which information such as the coalescence time and the deformation of the resultant bubble upon coalescence was extracted. It is shown in this study that the coalescence time increases with surfactant concentration until the appearance of a plateau. The increase in coalescence time with surfactant concentration could not be attributed only to surface elasticity. The oscillation of the resultant bubble was characterised by the damping of the oscillation. The results suggested that a minimum elasticity is required to achieve an increased damping and considerable diffusion has a detrimental effect on the dynamic response of the bubble, thereby reducing the damping. PMID:24231084

Bournival, G; Ata, S; Karakashev, S I; Jameson, G J

2014-01-15

69

Comparative study of boson peak in normal and secondary alcohols with terahertz time-domain spectroscopy  

NASA Astrophysics Data System (ADS)

Using terahertz (THz) time-domain spectroscopy, we measured the complex permittivity of some normal (1-propanol, 1-butanol, and 1-pentanol) and secondary alcohols (2-propanol, 2-butanol, and 2-pentanol) in the frequency ranges from 0.2 to 2.5 THz at temperatures from 253 to 323 K. For all the samples, the complex permittivity in the THz region includes the following three components: (i) a high frequency side of dielectric relaxation processes, (ii) a broad mode around 1 THz, and (iii) a low frequency side of an intermolecular vibration mode located above 2.5 THz. The mode around 1 THz is recognized as a boson peak which is related to the local structure of disordered materials. The intensity of the boson peak in secondary alcohols is higher than that in normal alcohols. On the other hand, the number of carbon atoms slightly affects the appearance of the boson peak. These observations indicate that the position of an OH group in a molecule has a profound effect on the local structures in monohydric alcohols.

Yomogida, Yoshiki; Sato, Yuki; Nozaki, Ryusuke; Mishina, Tomobumi; Nakahara, Jun'ichiro

2010-05-01

70

46 CFR 30.25-1 - Cargoes carried in vessels certificated under the rules of this subchapter.  

Code of Federal Regulations, 2013 CFR

...3-pentanediol diisobutyrateIII2,2,4-Trimethyl-3-pentanol-1-isobutyrate #Tripropylene, seePropylene trimer...3-pentanediol-1-isobutyrate *Y2,2,4-Trimethyl-3-pentanol-1-isobutyrate #Tripropylene, seePropylene...

2013-10-01

71

46 CFR Table II to Part 150 - Grouping of Cargoes  

Code of Federal Regulations, 2013 CFR

...3-pentanediol-1-isobutyrate 2,2,4-Trimethyl-3-pentanol-1-isobutyrateTrimethyl phosphite 2Trisodium nitrilotriacetate...3-pentanediol-1-isobutyrate 2,2,4-Trimethyl-3-pentanol-1-isobutyrateTrimethyl phosphite 2Trisodium...

2013-10-01

72

Direct Observation of Two-Dimensional Electron Solvation at Alcohol/Ag(111) Interfaces S. H. Liu, A. D. Miller, K. J. Gaffney, P. Szymanski, S. Garrett-Roe, I. Bezel, and  

E-print Network

-dimensional electron solvation by methanol, 1-propanol, 1-butanol, and 1-pentanol overlayers on a Ag(111) surface-propanol, 1-butanol, and 1-pentanol adsorbed on a Ag(111) surface, though similar results have been seen

Harris, Charles B.

73

Characteristics of chemical binding to alpha 2u-globulin in vitro--evaluating structure-activity relationships  

SciTech Connect

alpha 2u-Globulin (alpha 2u) has been shown to accumulate in the kidneys of male rats treated with 2,2,4-trimethylpentane (TMP). 2,4,4-Trimethyl-2-pentanol (TMP-2-OH), a metabolite of TMP, is found reversibly bound to alpha 2u isolated from the kidneys of these treated rats. The objectives of the following study were to characterize the ability of (3H)TMP-2-OH to bind to alpha 2u in vitro and to determine whether other compounds that cause this protein to accumulate have the same binding characteristics. Although compounds that have been shown to cause the accumulation of alpha 2u in male rat kidneys compete in vitro with (3H)TMP-2-OH for binding to alpha 2u, they do so to varying degrees. The binding affinity (Kd) of the (3H)TMP-2-OH-alpha 2u complex was calculated to be on the order of 10(-7) M. The inhibition constant values (Ki) determined for d-limonene, 1,4-dichlorobenzene, and 2,5-dichlorophenol were all in the range 10(-4) M, whereas the Ki values for isophorone, 2,4,4- or 2,2,4-trimethyl-1-pentanol, and d-limonene oxide were determined to be in the range 10(-6) and 10(-7) M, respectively. TMP and 2,4,4- and 2,2,4-trimethylpentanoic acid did not compete for binding. This suggests that other factors, besides binding, are involved in the accumulation of alpha 2u. In this study the ability of a chemical to bind to alpha 2u was used as a measure of biological activity to assess structure-activity relationships among the chemicals tested and known to cause the accumulation of alpha 2u. The results so far suggest that binding is dependent on both hydrophobic interactions and hydrogen bonding.

Borghoff, S.J.; Miller, A.B.; Bowen, J.P.; Swenberg, J.A. (Chemical Industry Institute of Toxicology, Research Triangle Park, NC (USA))

1991-02-01

74

Liquid chromatographic analysis of coal surface properties. Final report, September 1991--February 1995  

SciTech Connect

Experiments on equilibrium adsorption loadings of various probe compounds on 60-200 mesh Illinois {number_sign}6 coal (PSOC-1539), Adaville {number_sign}1 coal (PSOC-1544), Wyodak coal (PSOC-1545) and Pittsburgh {number_sign}8 coal (PSOC-1549) were performed. the probe compounds include m-cresol, p-cresol, o-cresol, phenol, n-octanol, n-heptanol, n-propanol, isopropanol n-butanol, s-butanol, 2-butanol, t-butanol, 2-naphthol, cyclohexanol, 2-methyl-1-pentanol (2M1P), 4-methyl-2-pentanol (4M2P), benzene and toluene. Equilibrium adsorption of various probe compounds on the coals were measured with the inverse liquid chromatography method. Experiments on flotation of various 60-200 mesh treated coals such as Illinois {number_sign}6 coal (PSOC-1539), Adaville {number_sign}1 coal (PSOC-1544), Wyodak coal (PSOC-1545) and Pittsburgh {number_sign}8 coal (PSOC-1549) were performed. The chosen coals were treated with steam, nitrogen and air at 1 atm and 125-225{degrees}C for 24 hours. The coals were treated with water as well as 20-1000 ppm aqueous alcohol solutions for 3-24 hours at 150-225{degrees}C. The coals also were treated with 20-ppm alcohol aqueous solutions for 1-24 hours at the 0.002-g/min mass flow rate of alcohol aqueous solutions and at 225{degrees}C. Flotation experiments were conducted with a 500-cm{sup 3} batch-type micro flotation apparatus, introducing nitrogen at the bottom of the apparatus. This final report was prepared with the experimental data obtained during the period of September 1991-March 1994.

Kwon, K.C.

1996-03-01

75

Relationship between selected indoor volatile organic compounds, so-called microbial VOC, and the prevalence of mucous membrane symptoms in single family homes.  

PubMed

Microorganisms are known to produce a range of volatile organic compounds, so-called microbial VOC (MVOC). Chamber studies where humans were exposed to MVOC addressed the acute effects of objective and/or subjective signs of mucosal irritation. However, the effect of MVOC on inhabitants due to household exposure is still unclear. The purpose of this epidemiological study was to measure indoor MVOC levels in single family homes and to evaluate the relationship between exposure to them and sick building syndrome (SBS). All inhabitants of the dwellings were given a self-administered questionnaire with standardized questions to assess their symptoms. Air samples were collected and the concentrations of eight selected compounds in indoor air were analyzed by gas chromatography/mass spectrometry - selective ion monitoring mode (GC/MS-SIM). The most frequently detected MVOC was 1-pentanol at a detection rate of 78.6% and geometric mean of 0.60 microg/m(3). Among 620 participants, 120 (19.4%) reported one or more mucous symptoms; irritation of the eyes, nose, airway, or coughing every week (weekly symptoms), and 30 (4.8%) reported that the symptoms were home-related (home-related symptoms). Weekly symptoms were not associated with any of MVOC, whereas significant associations between home-related mucous symptoms and 1-octen-3-ol (per log(10)-unit: odds ratio (OR) 5.6, 95% confidence interval (CI): 2.1 to 14.8) and 2-pentanol (per log(10)-unit: OR 2.3, 95% CI: 1.0 to 4.9) were obtained after adjustment for gender, age, and smoking. Associations between home-related symptoms and 1-octen-3-ol remained after mutual adjustment. However, concentrations of the selected compounds in indoors were lower than the estimated safety level in animal studies. Thus, the statistically significant association between 1-octen-3-ol may be due to a direct effect of the compounds or the associations may be being associated with other offending compounds. Additional studies are needed to evaluate these possibilities. PMID:20188399

Araki, Atsuko; Kawai, Toshio; Eitaki, Yoko; Kanazawa, Ayako; Morimoto, Kanehisa; Nakayama, Kunio; Shibata, Eiji; Tanaka, Masatoshi; Takigawa, Tomoko; Yoshimura, Takesumi; Chikara, Hisao; Saijo, Yasuaki; Kishi, Reiko

2010-04-15

76

New aspects of the behaviour of alkyltrimethylammonium bromide micelles : light scattering and viscosimetric studies  

E-print Network

présence de 1-pentanol ont aussi été réanalysés. Abstract. 2014 Micellar solutions of dodecyl-, tetradecyl in the presence of 1-pentanol have been reexamined. J. Physique 45 (1984) 1263-1270 JUILLET 1984, Classification

Paris-Sud XI, Université de

77

46 CFR 30.25-1 - Cargoes carried in vessels certificated under the rules of this subchapter.  

Code of Federal Regulations, 2012 CFR

...Trimethylol propane polyethoxylate D2,2,4-Trimethyl-1,3-pentanediol diisobutyrate III2,2,4-Trimethyl-3-pentanol-1-isobutyrate #Tripropylene, see Propylene trimerTripropylene glycol IIITripropylene glycol methyl...

2012-10-01

78

46 CFR Table II to Part 150 - Grouping of Cargoes  

Code of Federal Regulations, 2011 CFR

...3-pentanediol diisobutyrate 2,2,4-Trimethyl-1,3-pentanediol-1-isobutyrate 2,2,4-Trimethyl-3-pentanol-1-isobutyrate Trimethyl phosphite 2 Trisodium nitrilotriacetate Trixylyl phosphate Trixylenyl phosphate...

2011-10-01

79

46 CFR 30.25-1 - Cargoes carried in vessels certificated under the rules of this subchapter.  

Code of Federal Regulations, 2011 CFR

...Trimethylol propane polyethoxylate D2,2,4-Trimethyl-1,3-pentanediol diisobutyrate III2,2,4-Trimethyl-3-pentanol-1-isobutyrate #Tripropylene, see Propylene trimerTripropylene glycol IIITripropylene glycol methyl...

2011-10-01

80

46 CFR Table II to Part 150 - Grouping of Cargoes  

Code of Federal Regulations, 2012 CFR

...3-pentanediol diisobutyrate 2,2,4-Trimethyl-1,3-pentanediol-1-isobutyrate 2,2,4-Trimethyl-3-pentanol-1-isobutyrate Trimethyl phosphite 2 Trisodium nitrilotriacetate Trixylyl phosphate Trixylenyl phosphate...

2012-10-01

81

46 CFR Table II to Part 150 - Grouping of Cargoes  

Code of Federal Regulations, 2010 CFR

...3-pentanediol diisobutyrate 2,2,4-Trimethyl-1,3-pentanediol-1-isobutyrate 2,2,4-Trimethyl-3-pentanol-1-isobutyrate Trimethyl phosphite 2 Trisodium nitrilotriacetate Trixylyl phosphate Trixylenyl phosphate...

2010-10-01

82

78 FR 68026 - Foreign-Trade Zone (FTZ) 99-Wilmington, Delaware, Notification of Proposed Production Activity...  

Federal Register 2010, 2011, 2012, 2013

...The chemical inputs sourced from abroad are: 2S,3R-1- (dimethylamino)-3-(3-methoxyphenyl)-2-methyl-3-pentanol; and, (2R,3R)- 3-(3-methoxyphenyl)-N,N,2-trimethylpentanamine monohydrobromide (duty rate,...

2013-11-13

83

Microemulsion polymerization of butyl acrylate and methyl methacrylate  

Microsoft Academic Search

Microemulsions of n-butyl acrylate (BA) were prepared with the following surfactant\\/cosurfactant systems: ethoxylated nonylphenol (EONP30)\\/1-pentanol,\\u000a EONP30\\/acrylic acid, sodium dodecyl sulphate\\/ 1-pentanol and cetyltrimethylam-monium bromide (CTAB)\\/ 1-pentanol. Microemulsions\\u000a of BA and methyl methacrylate (MMA) were also prepared using CTAB without cosurfactant. Polymerizations were carried out by\\u000a both batch and semi continuous methods with the lipophilic initiators 2,2?-azobis(isobuty-ronitrile) and benzoyl peroxide\\u000a and

A. Hammond; P. Budd; C. Price

84

Effect of pentanol on the mean interfacial solvent and electrostatic characteristics of cationic micelles  

SciTech Connect

The effect of 1-pentanol on the mean interfacial solvent properties and the mean electrostatic surface potential of a number of cationic dodecyltrimethylammonium halide micelles has been ascertained by utilizing the solvatochromic acid-base indicator E/sub T/(30). The effective interfacial dielectric constant of a dodecyltrimethylammonium halide micelle has been found to increase slightly upon the addition of 1-pentanol. The micellar surface potential has been found to decrease with increasing 1-pentanol concentration. The experimental surface potentials have been compared with those obtained by numerically solving the unmodified nonlinearized Poisson-Boltzmann equation. The comparison indicated that the degree of specific counterion binding to the micellar headgroups decreases with increasing 1-pentanol concentration.

Kibblewhite, J.; Drummond, C.J.; Grieser, F.; Healy, T.W.

1987-08-27

85

The effect of substrate structure on the chemoselectivity of Candida1 antarctica lipase B-catalyzed acylation of amino-alcohols2  

E-print Network

of three amino-17 alcohols (alaninol, 4-amino-1-pentanol and 6-amino-1-hexanol) was studied using myristic acylation was improved when the carbon chain included four carbons or more (4-amino-1-28 pentanol and 6

Boyer, Edmond

86

VOLUME 78, NUMBER 25 P H Y S I C A L R E V I E W L E T T E R S 23 JUNE 1997 Direct Observation of a Defect-Mediated Viscoelastic Transition in a Hydrogel  

E-print Network

are constructed of 4:1 pentanol:lipid, where the lipid is dimyristoylphosphatidyl- choline (DMPC) and PEG-lipid. Pentanol reduces the bending rigidity of the lipid membranes k kBT and increases thermal membrane

Zasadzinski, Joseph A.

87

Effect of pentanol on the mean interfacial solvent and electrostatic characteristics of cationic micelles  

Microsoft Academic Search

The effect of 1-pentanol on the mean interfacial solvent properties and the mean electrostatic surface potential of a number of cationic dodecyltrimethylammonium halide micelles has been ascertained by utilizing the solvatochromic acid-base indicator E\\/sub T\\/(30). The effective interfacial dielectric constant of a dodecyltrimethylammonium halide micelle has been found to increase slightly upon the addition of 1-pentanol. The micellar surface potential

Janine. Kibblewhite; Calum J. Drummond; Franz. Grieser; Thomas W. Healy

1987-01-01

88

Effect of coproduced alcohols and ketones on the extraction of 1-butanol from aqueous solution by the ethyl esters of soybean oil fatty acids  

SciTech Connect

Bacterial fermentations generally produce 1-butanol together wth acetone, ethanol, 2-propanol, or 1-pentanol. The effect of these materials on the extraction of 1-butanol from aqueous solution by the ethyl ester of soybean oil fatty acids was determined using a factorial experimental design. Concentrations of 1-butanol ranged from 0.1 to 4.1% w/v, while the concentrations of coproduced alcohols and ketones ranged up to 4.0% w/v. Acetone, ethanol, and 2-propanol had little effect on 1-butanol extraction, while a slight increase in extraction appeared with increasing 1-pentanol. The extraction of acetone, ethanol, 2-propanol, and 1-pentanol was not measured. 9 refs., 4 tabs.

Griffith, W.L.; Googin, J.M.; Compere, A.L.

1985-01-01

89

Micellization of sodium bis(2-ethylhexyl)sulfosuccinate in supercritical CO 2 with fluorinated co-surfactant and its solubilization of hydrophilic species  

Microsoft Academic Search

The solubilities of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in supercritical CO2 (scCO2) in the presence of ethanol, 1-pentanol and 2,2,3,3,4,4,5,5-octafluoro-1-pentanol (F-pentanol) at 38.0°C and different pressures were determined. It was found that AOT (0.01–0.07M) could be solubilized in scCO2 with smaller amount of F-pentanol (0.20–0.30M) compared with ethanol (1.00–1.40M) and 1-pentanol (0.60–1.00M), because F-pentanol has ‘CO2-philic’ fluorinated alkane chain. The phase behavior

Juncheng Liu; Zameer Shervani; Poovathinthodiyil Raveendran; Yutaka Ikushima

2005-01-01

90

Non-fermentation route to ethanol from biomass. Final report, September 1, 1979-August 31, 1980  

SciTech Connect

The purposes of this investigation were twofold: (1) to reduce furfural to ethanol via the lithium-amine system which we had previously shown to be capable of reducing other furan compounds; and (2) to determine whether it would be possible to essentially duplicate lithium-amine reduction of furfural by gamma radiolysis of amine solutions of furfural. Evidence that both ethanol and 2-pentanol were produced from the radiolysis of 2-methyfuran in ethylenediamine is presented. The magnitude of the effect of lithium salt on the radiolysis was not determined; however, ethanol and 2-pentanol were noted in a radiolysis in which lithium chloride was present. (MF)

Bedenbaugh, A.O.

1980-09-30

91

Fluorescence probe studies of the interactions between poly(oxyethylene) and surfactant micelles and microemulsion droplets in aqueous solutions  

SciTech Connect

The interaction between poly(ethylene oxide) (POE) and the aggregates present in micellar solutions of sodium dodecyl sulfate (SDS), mixed micellar solutions of SDS + 1-pentanol, and oil in water microemulsions made of SDS + 1-pentanol + oil (dodecane or toluene) has been investigated by means of fluorescence probing methods. It is shown that the addition of POE results in a decrease of the aggregation number of SDS in the aggregates present in all the systems investigated. Most likely this decrease is due to the adsorption of the POE chain in the micelle palisade layer and the ensuing increase of micelle ionization. 22 references, 5 figures, 2 tables.

Zana, R.; Lianos, P.; Lang, J.

1985-01-03

92

JASPERSE CHEM 360 TEST 1 VERSION 3 Reactions involving Alcohols  

E-print Network

1 JASPERSE CHEM 360 TEST 1 VERSION 3 Reactions involving Alcohols 1. 2-Methyl-3-pentanol is classified as: (3 points) a. a primary alcohol b. a secondary alcohol c. a tertiary alcohol d. none;6 10. Design syntheses of the following, starting from alcohols of 4 carbons. (7 points each) O #12;

Jasperse, Craig P.

93

Preparation of 2-Bromopentane.  

ERIC Educational Resources Information Center

Suggests that the preparation of 2-bromopentane from 2-pentanol might represent an instructive addition to a published description of pheromone synthesis in that it is economical, extends the synthetic nature of the problem, and amplifies the mechanistic vagaries of the substitution reaction. Theory, procedures used, and safety considerations are…

Howell, B. A.; Kohrman, R. E.

1984-01-01

94

Absolute and relative rate constants for the reactions of OH and Cl with Pentanols  

E-print Network

1 Absolute and relative rate constants for the reactions of OH and Cl with Pentanols M. Lendar ABSTRACT The rate constants for the reactions of OH with three pentanols have been determined in the range 267-373 K and P=100 Torr. The data obtained were (in units of cm3 molecule-1 s-1 ): k(1- pentanol

Boyer, Edmond

95

Development of a short-term assay based on the evaluation of the plasma membrane integrity of the alga Pseudokirchneriella subcapitata.  

PubMed

Membrane integrity has been used as a criterion for the definition of cell viability. In the present work, staining conditions (time and dye concentration) for the evaluation of membrane integrity in a fluorescence microplate reader, using the membrane-impermeant nucleic-acid dye SYTOX Green, were optimized. Incubating Pseudokirchneriella subcapitata algal cells with 0.5 ?mol/l SYTOX Green for 40 min allowed a clear discrimination between live (intact plasma membrane) and dead cells (with compromised plasma membrane). Algal cell suspensions, labelled with SYTOX Green, exhibited a green fluorescence proportional to the fraction of the cells with a permeabilized plasma membrane. The optimized staining conditions were used to assess the toxicity of 1-pentanol on P. subcapitata in a short-term exposure (6 h) assay. The loss of membrane integrity in the cell population increased with the concentration of 1-pentanol. The 6-h EC(10) and EC(50) values were 7,617 mg/l 1-pentanol (95 % confidence limits 4,670-9,327) and 12,818 mg/l 1-pentanol (95 % confidence limits 10,929-15,183), respectively. The developed microplate-based short-term assay can be useful in the high-throughput screening of toxics or environmental samples using the alga P. subcapitata. PMID:22660770

Machado, Manuela D; Soares, Eduardo V

2012-08-01

96

Mass action model for solute distribution between water and micelles. Partial molar volumes of butanol and pentanol in dodecyl surfactant solutions  

Microsoft Academic Search

The densities of 1-butanol and 1-pentanol were measured in aqueous solutions of dodecyltrimethylammonium bromide and dodecyldimethylamine oxide and the partial molar volumes at infinite dilution of the alcohols in aqueous surfactants solutions were obtained. The observed trends of this quantity as a function of the surfactant concentration were rationalized using a mass-action model for the alcohol distribution between the aqueous

R. De Lisi; V. Turco Liveri; M. Castagnolo; A. Inglese

1986-01-01

97

Phase behavior and properties of a petroleum sulfonate blend  

SciTech Connect

A sulfonate system composed of Stepan Petrostep 465, Petrostep 420, and 1-pentanol was investigated. The system was found to give ultralow interfacial tension against crude oil in a reasonable range of salinity and sulfonate concentrations. It also was found that sulfonate partitioned predominantly into the microemulsion phase. 15 refs.

Bae, J.H.; Petrick, C.B.

1981-10-01

98

Catalytic N-alkylation of primary amines by alcohols  

SciTech Connect

A study has been made of the vapor phase N-alkylation of cyclohexylamine by n-1-heptanol or n-1-pentanol on an industrial copper-zinc-aluminium oxide catalyst and a reduced, promoted sintered iron catalyst. Yields of amines are described.

Shuikin, A.N.; Glebov, L.S.; Kliger, G.A.; Zaikin, V.G. [A.V. Topchiyev Institute of Petrochemical Synthesis, Moscow (Russian Federation)

1993-12-31

99

New methodology for simultaneous volumetric and calorimetric measurements: Direct determination of {alpha}{sub p} and C{sub p} for liquids under pressure  

SciTech Connect

A new batch cell has been developed to measure simultaneously both isobaric thermal expansion and isobaric heat capacity from calorimetric measurements. The isobaric thermal expansion is directly proportional to the linear displacement of an inner flexible below and the heat capacity is calculated from the calorimetric signal. The apparatus used was a commercial Setaram C-80 calorimeter and together with this type of vessels can be operated up to 20 MPa and in the temperature range of 303.15-523.15 K, In this work, calibration was carried out using 1-hexanol and subsequently both thermophysical properties were determined for 3-pentanol, 3-ethyl-3-pentanol, and 1-octanol at atmospheric pressure, 5 and 10 MPa, and from 303.15 to 423.15 K in temperature. Finally experimental values were compared with the literature in order to validate this new methodology, which allows a very accurate determination of isobaric thermal expansion and isobaric heat capacity.

Casas, L. M. [Departamento de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Vigo, Lagoas Marcosende s/n, 36310 Vigo (Spain); Plantier, F.; Bessieres, D. [Laboratoire de Thermodynamique et Energetique des Fluides Complexes-UMR 5150, Universite de Pau et des Pays de l'Adour, BP 1155, 64013 Pau (France)

2009-12-15

100

New methodology for simultaneous volumetric and calorimetric measurements: Direct determination of ?p and Cp for liquids under pressure  

NASA Astrophysics Data System (ADS)

A new batch cell has been developed to measure simultaneously both isobaric thermal expansion and isobaric heat capacity from calorimetric measurements. The isobaric thermal expansion is directly proportional to the linear displacement of an inner flexible below and the heat capacity is calculated from the calorimetric signal. The apparatus used was a commercial Setaram C-80 calorimeter and together with this type of vessels can be operated up to 20 MPa and in the temperature range of 303.15-523.15 K, In this work, calibration was carried out using 1-hexanol and subsequently both thermophysical properties were determined for 3-pentanol, 3-ethyl-3-pentanol, and 1-octanol at atmospheric pressure, 5 and 10 MPa, and from 303.15 to 423.15 K in temperature. Finally experimental values were compared with the literature in order to validate this new methodology, which allows a very accurate determination of isobaric thermal expansion and isobaric heat capacity.

Casás, L. M.; Plantier, F.; Bessières, D.

2009-12-01

101

Neurotoxic metabolites of ''commercial hexane'' in the urine of shoe factory workers  

SciTech Connect

Urinary metabolites were tested in 41 shoe-factory workers exposed to a mixture of 10 solvents among which ''commercial hexane'' was the prevailing component. Cyclohexanol, 2-methyl-2-pentanol, 3-methyl-2-pentanol, and trichloroethanol were determined in connection with exposure to cyclohexane, 2-methylpentane, 3-methylpentane, and trichloroethylene, respectively. 2-Hexanol, 2,5-hexanedione, 2,5-dimethylfuran, and gamma-valerolactone were all determined in connection with n-hexane exposure only. 2,5-Hexanedione was the principal n-hexane metabolite found in the workers' urine. This finding of the experimentally proven neurotoxin 2,5-hexanedione in the urine of shoe-factory workers exposed to ''commercial hexane'' is consistent with the idea that this compound is responsible for the development of neuropathy in this group of individuals.

Perbellini, L.; Brugnone, F.; Gaffuri, E.

1981-12-01

102

Dehydration of alcohols over alumina: effect of sodium impregnation on the mode of elimination  

SciTech Connect

Dehydration of secondary alcohols has always been the key to studying reaction mechanisms of reactions catalyzed by oxides. The ..gamma..-alumina-promoted reactions always afforded a low S/sub 12/ (1-olefin/2-olefin) and high S/sub Ct/ (Cis/trans). These were shown to proceed by the anti mode of the elimination of elements of water. The effect of sodium impregnation has been studied, in detail, to understand the mode of elimination operative over these doped catalysts. Studies were conducted with 2-butanol and threo-3-methyl-2-pentanol over these catalysts. It appears that although sodium poisoning affected selectivity S/sub 12/, it did not show any variation in S/sub ct/, suggesting no variation in the mode of elimination. The studies conducted with threo-3-methyl-2-pentanol confirm that only the anti mode of elimination is operative on these catalysts.

Siddhan, S.; Narayanan, K.

1981-04-01

103

A silicon-containing resist for immersion lithography  

NASA Astrophysics Data System (ADS)

We have developed a new silicon-containing resist for 193-nm immersion lithography. This resist is compatible with topcoats used in the industry today for immersion lithography. Most of the current topcoats contain 4-methyl-2- pentanol as a solvent. Our evaluations indicated that the previously developed silicon-containing resists are not compatible with the current topcoats because of their solubility in 4-methyl-2-pentanol. In the new resist polymers, we have incorporated high percentage (> 60 mol%) of lactone monomers to prevent them from dissolving in this solvent. In order to increase the lactone content in a silicon polymer, we have incorporated lactone containing acidlabile functionalities in addition to widely used acid-inert lactone monomers. Utilizing these polymers, we have demonstrated a functional silicon-containing photoresist for immersion lithography.

Sooriyakumaran, Ratnam; Huang, Wu-Song; Swanson, Sally; Truong, Hoa; Brock, Phillip; Friz, Alexander; Chen, Kuang-Jung; Allen, Robert

2010-04-01

104

Heat transfer in pool boiling of binary and ternary non-azeotropic mixtures  

NASA Astrophysics Data System (ADS)

Heat transfer coefficients in nucleate pool boiling of binary and ternary non-azeotropic hydrocarbon mixtures were obtained experimentally using a vertical electrically heated cylindrical carbon steel surface at atmospheric pressure with several surface roughness. The fluids used were Methanol/1-Pentanol and Methanol/1-Pentanol/1,2-Propandiol at constant 1,2-Propandiol mole fraction of 30%. Heat fluxes were varied in the range 25-235 kW/m2. The cylindrical heater surface was polished to an average surface roughness of 0.2 ?m, and sandblasted yielding surface roughness of 2.98 and 4.35 ?m, respectively. The experimental results were compared to available prediction correlations, indicating that the correlations based on the boiling range are in better qualitative agreement than correlations based on the phase envelope. Increasing surface roughness resulted in an increase in the heat transfer coefficient, and the effect was observed to be dependent on the heat flux and fluid composition.

Nahra, Ziad; Næss, Erling

2009-05-01

105

Comparative Experiments of Protein Denaturation for Studying Structural Difference of Homologous Membrane Proteins: P-450scc and P-45011?  

NASA Astrophysics Data System (ADS)

The topological difference between two homologous membrane proteins, cytochromes P-450scc and P-45011 ? in the inner membrane of bovine adrenocortical mitochondria, was studied by denaturation experiments, using urea and 1-pentanol as denaturants. Both P-450s denatured at the urea concentration of about 2.5 M that is in the concentration range of the denaturation of soluble proteins. In contrast, P-45011 ? was denatured by 1-pentanol, which is an efficient denaturant of membrane proteins, at a much lower concentration than P-450scc. These results suggested that the membrane domain is more strongly coupled with the soluble functional domain in P-45011 ? than P-450scc. It was also indicated that the comparative experiments of protein denaturation by urea and alcohol provide a simple method to identify the structural difference of homologous membrane proteins.

Suzuki-Tomii, Keiko; Ohta, Yoshihiro; Kawato, Suguru; Mitaku, Shigeki

1999-01-01

106

Aklyl Chain Order Parameters and Phase Diagrams for Systems Containing Sodium n-Octanoate, Water, and Different Alcohols  

Microsoft Academic Search

Lamellar liquid crystalline phases containing sodium n-octanoate, water, and an alcohol have been studied by means of H NMR. Order parameters have been determined for the octanoate alkyl chain in systems containing ethanol, 1-propanol, 1-butanol, 1-pentanol, benzyl alcohol or 1, 8-octandiol. The straight chain alcohols yield decreasing octanoate order parameters with decreasing chain length. With 1, 8-octandiol the octanoate order

Torbjörn Wärnheim; Ulf Henriksson; Tomas Klason

1985-01-01

107

Enzymatic esterification and phase behavior in ionic microemulsions with different alcohols  

Microsoft Academic Search

The esterification of hexanoic acid and 1-pentanol catalyzed by the lipase fromChromobacterium viscosum was studied at 298.2 K using different Winsor systems as reaction medium. The microemulsion systems consisted of brine and alkane stabilized by the anionic surfactant sodium dodecylsulphate and a short-chained alcohol. The alcohol acts both as a reactant and as a part of the reaction medium. Therefore,

S. Backlund; F. Eriksson; S. Karlsson; G. Lundsten

1995-01-01

108

Enhancement of critical heat flux in subcooled flow boiling of water by use of a volatile additive  

SciTech Connect

The present investigation considers the effect of a 1-pentanol additive in water on the critical heat flux (CHF) and pressure drop in forced subcooled boiling. A small quantity of 1-pentanol was added to distilled water with the objective of getting an approximate 2% by weight mixture, which had been found to give superior performance in previous studies of pool and flow boiling. Experiments were performed using stainless steel tubes with internal diameters of 4.4 and 6.1 mm. Tests were conducted with mass fluxes of 4,400 kg/m{sup 2}s, exit pressures of 9 bar, length-to-diameter ratios of 25, and exit subcoolings from 65 to 90 C. Test sections were heated directly by DC power, and critical heat flux data were inferred from test-section burnout. The alcohol concentration was periodically checked by draining off a sample and performing a Proton Nuclear Magnetic Resonance scan on the mixture. At high subcoolings, the mixture exhibited an increase in the critical heat flux over that of pure water. However at low subcoolings there is a decrease in the critical heat flux. The increases in critical heat flux noted with the 1-pentanol mixture in this experiment were not as large as would be expected from saturated pool boiling results published by Van Stralen (1959). Pressure drop data for both the mixture and the pure water also were recorded. The 1-pentanol mixture, in general, exhibited larger pressure drops for the same conditions. Subcooled flow boiling has a wide array of commercial cooling applications, including blades in gas turbines, high power laser optics, plasma-facing components in fusion reactors, supercomputers, etc.

Pabisz, R.A. Jr.; Bergles, A.E. [Rensselaer Polytechnic Inst., Troy, NY (United States). Heat Transfer Lab.

1996-12-31

109

A rhodamine-deoxylactam based sensor for chromo-fluorogenic detection of nerve agent simulant.  

PubMed

N-(rhodamine B)-deoxylactam-5-amino-1-pentanol (dRB-APOH) was designed and prepared as the chromo-fluorogenic sensor for detection of a nerve agent simulant via analyte triggered tandem phosphorylation and opening of the intramolecular deoxylactam. The successful detection of diethyl chlorophosphate suggests the utility of rhodamine-deoxylactams as the chromo-fluorogenic signal reporting platform for design of sensors targeting reactive chemical species via various chemistries. PMID:22995618

Wu, Zhisheng; Wu, Xuanjun; Yang, Yuhui; Wen, Ting-bin; Han, Shoufa

2012-10-15

110

Pentanol as co-surfactant in polypyrrole actuators  

Microsoft Academic Search

Conducting polymers have been investigated for the use as active component in polymer actuators. Addition of 1-pentanol as co-surfactant to the polymerisation solution is shown to increase the reversible linear strain that can be achieved with polypyrrole films doped with dodecyl benzene sulfonate (PPy–DBS). When such films are prepared without pentanol, the length change between the oxidised and the reduced

Lasse Bay; Keld West; Steen Skaarup

2002-01-01

111

Do the interfacial fluidities of cationic reverse micelles enhance with an increase in the water content?  

NASA Astrophysics Data System (ADS)

The role of cosurfactant and water on the interfacial fluidities of reverse micelles formed with the cationic surfactant, cetyltrimethylammonium bromide (CTAB) has been examined by measuring the fluorescence anisotropies of two structurally similar ionic solutes, rhodamine 110 and fluorescein. For this purpose, reverse micellar systems with (CTAB/1-pentanol/cyclohexane/water) and without a cosurfactant (CTAB/chloroform-isooctane/water) have been chosen. In this study, the mole ratio of water to surfactant W has been varied in the region of 4-25. Experimental results indicate that the average reorientation time of the probe, which is a measure of the fluidity near the interfacial region, decreases by a factor of 1.5 and 1.4 for rhodamine 110 and fluorescein, respectively, as W goes up from 5 to 25 in CTAB/1-pentanol/cyclohexane/water reverse micellar system. In contrast, the average reorientation time, remains invariant for both the probe molecules in CTAB/chloroform-isooctane/water reverse micellar system despite an increase in W from 4 to 24. In case of CTAB/1-pentanol/cyclohexane/water reverse micellar system, the added water binds to bromide counter ions and also the hydroxyl groups of the cosurfactant, 1-pentanol, which results in an increase in the effective head group area. Such an increase in the effective head group area leads to a decrease in the packing parameter, and hence an increase in the interfacial fluidity. On the other hand, in CTAB/chloroform-isooctane/water system, the added water merely hydrates the bromide ions, thereby leaving the effective head group area unchanged. Thus, the interfacial fluidities remain invariant upon the addition of water in the absence of a cosurfactant.

Mali, K. S.; Dutt, G. B.

2009-11-01

112

Structure of microemulsions from magnetic and electric birefringence measurements  

E-print Network

'octylbenzène sulfonate de sodium-pentanol-décane-eau (à 0,3 % de NaCl) dans tout le domaine de solution homogène du (OBS)-pentanol-decane-water (with 0.3 % NaCl), in the homogeneous liquid region of the pseudo to [14]), - 1-pentanol as cosurfactant. We have used a constant ratio cosurfactant to sur- factant of 2

Boyer, Edmond

113

Polarizations in Irradiated Proton and Deuterated Materials  

NASA Astrophysics Data System (ADS)

Polarizations from a series of irradiations of deuterated and hydrogenous materials are presented. Irradiated deuterated butanol has the best performance with polarizations of 50.5% and -47.6% at 5.0 T, rising to 62.4% and -49.6% at 6.55 T. Deuterated 1-pentanol has a similar performance at 5 T. The results from hydrogenated materials are not as promising, giving values considerably less than obtained with standard chemical doping.

Crabb, D. G.

2007-04-01

114

Fluorescence probe study of oil-in-water microemulsions. 1. Effect of pentanol and dodecane or toluene on some properties of sodium dodecyl sulfate micelles  

Microsoft Academic Search

The analysis of the decay of the fluorescence of micelle-solubilized pyrene has been used to obtain for the first time the variation of the surfactant aggregation number n in micellar solutions of sodium dodecyl sulfate (SDS) upon addition of increasing amounts of 1-pentanol, and of oil (dodecane or toluene), thereby forming an oil-in-water (o\\/w) microemulsion. The polarity of the microenvironment

Panagiotis Lianos; Jacques Lang; Claude Strazielle; Raoul Zana

1982-01-01

115

Polyethersulfone hollow fiber gas separation membranes prepared from NMP\\/alcohol solvent systems  

Microsoft Academic Search

Polyethersulfone (PESf) asymmetric hollow fiber membranes were prepared by the dry\\/wet and the wet-phase inversion processes from spinning solutions containing N-methyl-2-pyrrolidone (NMP) and an alcohol as a nonsolvent-additive (NSA). Two grades of polyethersulfones. Victrex 4800P and Radel A-300, were used. The alcohols used in this study include five aliphatic alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol) and two polyhydric alcohols (ethylene

Dongliang Wang; K. Li; W. K. Teo

1996-01-01

116

Mechanistic studies of the pathways leading to ethers via coupling of alcohols  

SciTech Connect

The reaction mechanisms for the solid acid-catalyzed dehydrative coupling of methanol and ethanol with isobutanol and 2-pentanol to form ethers were examined by using isotope labelling and chiral inversion experiments. When the reactions were carried out it 110{degrees}C and 1 MPa with {sup 18}O-ethanol and {sup 16}O-isobutanol over the Amberlyst-35 resin catalyst, 95% of the major product ethyl isobutyl ether (EIBE) contained {sup 16}O, while 96% of the minor product ethyl tertiarybutyl ether (ETBE) contained {sup 18}O. Similar results were obtained with methanol and isobutanol over Nafion-H and Amberlyst-35 catalysts, with methyl isobutyl ether (MIBE) and methyl tertiarybutyl ether (MTBE) as the products. These results indicate that EIBE (MIBE) was produced by a surface-catalyzed S{sub N}2 reaction, while the ETBE (MTBE) product arose via a carbenium intermediate. The analogous reaction carried out over Nafion-H and HZSM-5 catalysts with chiral 2-pentanol verified the surface-mediated S{sub N}2 reaction, wherein chiral inversion of the product ether was observed relative to the S- and R-2-pentanol reactants.

Sun, Qun; Lietti, L.; Herman, R.G.; Klier, K. [Zettlemoyer Center for Surface Studies, Bethlehem, PA (United States)

1995-12-31

117

Mechanistic studies of the pathways leading to ethers via coupling of alcohols  

SciTech Connect

The reaction mechanisms for the solid acid-catalyzed dehydrative coupling of methanol and ethanol with isobutanol and 2-pentanol to form ethers were examined by using isotope labelling and chiral inversion experiments. When the reactions were carried out at 110{degrees}C and 1 MPa with Et{sup 18}OH and {sup 16}O-isobutanol over Amberlyst-35, 95% of the major product ethyl isobutyl ether (EIBE) contained {sup 16}O, while 96% of the minor product ethyl tertiarybutyl ether (ETBE) contained {sup 18}O. Similar results were obtained with methanol and isobutanol over Nafion-H and Amberlyst-35 catalysts, with MIBE and MTBE as the products. These results indicate that EIBE (MIBE) was produced by a surface-catalyzed S{sub N}2 reaction, while the ETBE (MTBE) product arose via a carbenium intermediate. The analogous reactions carried out over Nafion-H and H-ZSM-5 catalysts with chiral 2-pentanol verified the surface-mediated S{sub N}2 reaction, where in chiral inversion of the product ether was observed relative to the S- and R-2-pentanol reactants. In addition, a remarkable shape selectivity with chiral inversion was observed over the H-ZSM-5 zeolite to selectively form 2-ethoxypentane but not 3-ethoxypentane.

Sun, Qun; Lietti, L.; Herman, R.G. [Lehigh Univ., Bethlehem, PA (United States)] [and others

1995-12-01

118

Solvent extraction of tricyclic amines from blood plasma and liquid chromatographic determination.  

PubMed

The extraction of seven tricyclic antidepressant amines from human plasma at different pH values was investigated for dichloromethane, diethyl ether and hexane--1-pentanol (95:5). The amines were extracted as bases and back-extracted to sulphuric acid, 0.10 mol/l, prior to the separation by bonded-phase liquid chromatography. Ether and hexane--1-pentanol (95:5) were most suitable, tertiary amines being best extracted at pH 8, and secondary amines at pH 10. Using ether, both while 15 min ws sufficient for hexane--1-pentanol (95:5). UV detection allowed concentrations down to 10 ng in 1 ml of plasma to be determined. Three ammonium ions--octylammonium, dimethylammonium, and trimethylammonium--were added as modifiers to the mobile phase containing acetonitrile in phosphoric acid, 0.10 mol/l. In the concentration interval 0.010--0.030 mol/l all of the amine modifiers gave on Polygosil C8 peak asymmetry factors of sufficiently low magnitude, while on Li-Chrosorb RP-18 this was so only for di- and trimethylammonium in a concentration of 0.030 mol/l. PMID:6853644

Lagerström, P O; Marle, I; Persson, B A

1983-03-11

119

Behavioral and electrophysiological responses of Aedes albopictus to certain acids and alcohols present in human skin emanations.  

PubMed

Human skin emanations attract hungry female mosquitoes toward their host for blood feeding. In this study, we report the flight orientation and electroantennogram response of Aedes albopictus females to certain unsaturated acids and alcohols found in human skin. In the Y-tube olfactometer, odors of lactic acid and 2-methyl-3-pentanol attracted 54-65 % of Ae. albopictus females at all doses in a dose-dependent manner. However, at the highest dose (10(-2) g), the acids repelled 40-45 % females. Attractancy (ca. 62-68 %) at lower doses and repellency (ca. 30-45 %) at higher doses were recorded for 3-methyl-3-pentanol and 1-octen-3-ol, while 5-hexen-1-ol, cis-2-hexen-1-ol, and trans 2-hexen-1-ol odor repelled ca. 55-65 % of Ae. albopictus females at all doses. Antenna of female Ae. albopictus exhibited a dose-dependent EAG response up to 10(-3) g of L-lactic acid, trans-2-methyl-2-pentenoic acid, 2-octenoic acid, trans-2-hexen-1-ol and 1-octen-3-ol stimulations; however, the highest dose (10(-2) g) caused a little decline in the EAG response. EAG response of 9-10-fold was elicited by lactic acid, 2-octenoic acid, trans-2-hexenoic acid, and 3-methyl-3-pentanol, while cis-2-hexen-1-ol and trans-2-methyl pentenoic acid elicited 1-5-fold responses compared to solvent control. A blend of attractive compounds could be utilized in odor-baited trap for surveillance and repellent molecules with suitable formulation could be used to reduce the biting menace of mosquitoes. PMID:25049052

Guha, Lopamudra; Seenivasagan, T; Iqbal, S Thanvir; Agrawal, O P; Parashar, B D

2014-10-01

120

Alcohol dehydration: Mechanism of ether formation using an alumina catalyst  

SciTech Connect

Ether formation during the dehydration of secondary alcohols, namely, 2-butanol, 3-pentanol, and 1-cyclopentylethanol, was investigated. Using the proper reaction conditions, the yield of di-2-butyl ether during the dehydration of 2-butanol on alumina can be as high as 40%. That ether is formed by adding an alcohol to the alkene is ruled out by the results from deuterium tracer studies. Results from experiments using S(+)- 2-butanol suggest that the formation of di-2-butyl ether occurs by a S{sub N}2-type mechanism. 33 refs., 5 figs., 3 tabs.

Shi, B.; Davis, B.H. [Univ. of Kentucky, Lexington, KY (United States)] [Univ. of Kentucky, Lexington, KY (United States)

1995-12-01

121

Partial molal expansibilities of organic compounds in aqueous solution. I. Alcohols and ethers  

Microsoft Academic Search

The temperature dependence of limiting apparent molal volumes F°? in water for some alcohols (methanol, ethanol, 1-propanol, 2-butanol, 3-pentanol, 3-hexanol, 2,5-hexanediol, cyclopentanol, cyclohexanol, cycloheptanol, and 1,4-cyclohexanediol) and ethers (trimethylene oxide, tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, 1,3-dioxepane, 1,3,5-trioxane, dimethoxymethane, 1,2-dimethoxyethane, diethoxymethane, and diethyl ether) has been studied in the temperature range 10–50°C by means of an automatic digital-readout dilatometer. Values of

Sergio Cabani; Giovanni Conti; Enrico Matteoli

1976-01-01

122

Excess volumes of binary mixtures of benzene + 1-alkanols at 298. 15 and 308. 15 K  

SciTech Connect

Excess molar volumes V[sup E] of the binary mixtures of benzene + 1-butanol, + 1-pentanol, + 1-hexanol, + 1-heptanol, + 1-octanol, + 1-nonanol, or + 1-decanol are presented at 298.15 and 308.15 K. The values of V[sup E] are positive over the entire range of composition for these mixtures. All the measurements were made at constant temperature, employing a thermostat that could be maintained to [+-]0.01 K. The error in V[sup E] is estimated to be less than 0.02 cm[sup 3]/mol.

Yu, C.H.; Tsai, F.N. (National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Chemical Engineering)

1994-07-01

123

Unstable microemulsions  

SciTech Connect

Studies of certain microemulsion systems indicate that the manner of combining the components is important; that some microemulsions form only if the concentration gradient is large enough to allow diffusion of amphipathic materials across the oil/water interface; and that some clear oil/water dispersions are unstable (confirming earlier studies). Measurements of film pressure vs. area functions of duplex films show that oil penetrates the surfactant monolayer. 1-Pentanol also does so, increasing the film strength without changing the elasticity. This stabilizes the microemulsion droplets against coalescence. 33 references.

Rosano, H.L.; Lan, T.; Weiss, A.; Gerbacia, W.E.F.; Whittam, J.H.

1981-03-05

124

Molecular interactions in alcohol-ethyl methacrylate mixtures  

NASA Astrophysics Data System (ADS)

Molecular interaction between alcohols (1-propanol, 1-butanol, s-butanol, t-butanol, 1-pentanol, 1-heptanol, 1-octanol and 1-decanol) with ethyl methacrylate has been studied in n-heptane, CCl 4 and benzene at 298 K using FTIR spectroscopic and dielectric methods. The result obtained from both the methods indicates only the existence of most likely 1:1 complex formation between the alcohol and ethyl methacrylate in these systems. The alkyl chain length of alcohol and the solvent used play a significant role in the strength of hydrogen bond (O sbnd H:O dbnd C) determined on the basis of spectral and dielectric parameters.

Dharmalingam, K.; Ramachandran, K.; Sivagurunathan, P.; Kalamse, G. M.

2008-02-01

125

The Effect of Cavitating Ultrasound on the Heterogeneous Aqueous Hydrogenation of 3-buten-2-ol on Pd-black  

SciTech Connect

The effect of ultrasound at 20 kHz on the heterogeneous aqueous hydrogenation of 3-buten-2-ol employing a Pd-black catalyst has been studied isothermally at 295 K, forming 2-butanone and 2-butanol products. Our work here shows that adding 1-pentanol as an inert dopant had the effect of inducing cavitation in the ultrasound-treated reaction where it otherwise would not occur. The selectivity showed a 700% increase toward 2-butanol formation and the activity enhanced a factor of 10.8 compared to the noncavitating high-power ultrasound experiment. This study demonstrates that ''inert dopants'' may have use as synthetic tools in sonocatalysis.

Disselkamp, Robert S.; Chin, Ya-Huei; Peden, Charles HF.

2004-10-25

126

Complexation of a disulfide-linked ?-cyclodextrin dimer with 1-alkanols  

NASA Astrophysics Data System (ADS)

NMR titration experiments showed that a disulfide-linked ?-cyclodextrin dimer ( 1) stepwise forms 1:1 and 1:2 (host:guest) complexes with 1-alkanols. In the cases of ethanol and 1-propanol with short alkyl chains, the first and second guest molecules are included within the different CD cavities of 1. On the other hand, 1-pentanol and 1-hexanol with relatively long alkyl chains are bound to both of the CD cavities of 1 in their 1:1 complexes. The 1:1 complexes are less soluble in D 2O than their 1:2 complexes and slowly form precipitates.

Yoshikiyo, Keisuke; Ohta, Hideo; Matsui, Yoshihisa; Yamamoto, Tatsuyuki; Okabe, Yuji

2008-11-01

127

FTIR and dielectric studies of molecular interaction between alkyl methacrylates and primary alcohols  

NASA Astrophysics Data System (ADS)

The molecular interaction between alkyl methacrylates (methyl methacrylate, ethyl methacrylate and butyl methacrylate) and primary alcohols (1-propanol, 1-butanol, 1-pentanol, 1-heptanol, 1-octanol and 1-decanol) has been studied in carbon tetrachloride by FTIR spectroscopic and dielectric methods. The results show that the most likely association between alcohol and ester is 1:1 complex through the free hydroxyl group of the alcohol and the carbonyl group of ester, and the alkyl chain length of both the alcohols and esters plays an important role in the determination of the strength of hydrogen bond (O-H:O dbnd C) formed.

Dharmalingam, K.; Ramachandran, K.; Sivagurunathan, P.

2007-04-01

128

Regioselective alkane hydroxylation with a mutant CYP153A6 enzyme  

SciTech Connect

Cytochrome P450 CYP153A6 from Myobacterium sp. strain HXN1500 was engineered using in-vivo directed evolution to hydroxylate small-chain alkanes regioselectively. Mutant CYP153A6-BMO1 selectively hydroxylates butane and pentane at the terminal carbon to form 1-butanol and 1-pentanol, respectively, at rates greater than wild-type CYP153A6 enzymes. This biocatalyst is highly active for small-chain alkane substrates and the regioselectivity is retained in whole-cell biotransformations.

Koch, Daniel J.; Arnold, Frances H.

2013-01-29

129

Densities, molar volumes, cubic expansion coefficients, and isothermal compressibilities of 1-alkanols from 323. 15 K to 373. 15 K and pressures up to 10 MPa  

SciTech Connect

Densities of six alcohols, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-dodecanol, in the liquid state have been measured with a vibrating-tube densimeter from 323.15 to 373.15 K at pressures up to 10 MPa. Molar volumes (derived from the densities) have been fitted to polynomials as a function of temperature and pressure. Cubic expansion coefficients and isothermal compressibilities have been derived from molar volumes as a function of temperature and pressure. The results have also been compared with the available literature values.

Garg, S.K.; Banipal, T.S.; Ahluwalia, J.C. (Indian Inst. of Tech., New Delhi (India))

1993-04-01

130

Synergic effects in the extraction of paracetamol from aqueous NaCl solution by the binary mixtures of diethyl ether and low molecular weight primary alcohols  

NASA Astrophysics Data System (ADS)

Liquid-liquid extraction of paracetamol from aqueous NaCl solutions was performed with diethyl ether, 1-propanol, 1-butanol, isobutanol, 1-pentanol, and binary mixtures diethyl ether/1-propanol, diethyl ether/1-butanol, and diethyl ether/isobutanol. Among the pure solvents investigated in this study best extraction efficacy was obtained with 1-butanol. Synergic effects in the extraction with binary mixtures was investigated and compared with some other systems used for the extraction of poorly extractable compounds. Results obtained in this study may be of both fundamental and practical importance.

Nikoli?, G. M.; Živkovi?, J. V.; Atanaskovi?, D. S.; Nikoli?, M. G.

2013-12-01

131

Effect of release rate and enantiomeric composition on response to pheromones of Megaplatypus mutatus (Chapuis) in poplar plantations of Argentina and Italy.  

PubMed

Megaplatypus mutatus (=Platypus sulcatus Chapuis) is an Ambrosia beetle native to South America, which was recently introduced in Italy and its presence there is causing severe damage to the local poplar plantations. The male M. mutatus pheromone is composed of (S)-(+)-6-methyl-5-hepten-2-ol [(+)-sulcatol], 6-methyl-5-hepten-2-one (sulcatone) and 3-pentanol. A series of field trials testing dose, blend and enantiomer composition performed in Argentina and Italy evaluated attraction and found that the optimal release rate of pheromone components as baits in cross vane baited traps (CIPEIN-CV) was 6, 6 and 30 mg day?1 of sulcatone, (+)-sulcatol and 3-pentanol, respectively. It was also determined that racemic sulcatol is as effective as the pure (+)-isomer for the purpose of beetle catch, due to the inert nature of the (?)-isomer allowing the usage of low cost racemic sulcatol instead of highly expensive (+)-sulcatol. The results of our work contribute to the development of pheromone-based local technologies with low environmental impact and low cost for control or monitoring of an important pest. PMID:23590828

Funes, Hernán; Zerba, Eduardo; Gonzalez-Audino, Paola

2013-10-01

132

Using vertical circulation wells for partitioning tracer tests and remediation of DNAPLs  

SciTech Connect

Two different vertical circulation well (VCW) systems (Type A and Type B) were used to detect and subsequently remove tetrachloroethylene (PCE) spilled in a three-dimensional sand tank. The Type A system has one injection interval and one extraction interval. The Type B system has two injection intervals separated by an intermediate extraction interval. PCE was detected through partitioning tracer tests using ethanol and 2,2-dimethyl-3-pentanol as the non-partitioning and partitioning tracers, respectively. The concentration breakthrough curves for the tracers exhibited significant chromatographic separation due to partitioning of the 2,2-dimethyl-3-pentanol into the PCE. Because of the unique streamline distribution generated by the VCW systems, injected solutions did not sweep through the entire contaminated pore volume, which resulted in less than 100% detection of the spilled PCE. However, multiple tests along the borehole of the well were used to delineate the vertical profile of PCE residual saturation. Three food-grade surfactants were used to remediate the spilled PCE.

Chen, L.; Knox, R.C.

1997-12-01

133

The effect of alcohol structures on the interaction mode with the hexameric capsule of resorcin[4]arene.  

PubMed

After more than a century of research on resorcin[4]arenes (1) it is clear that such systems form spontaneously [1(6)(H(2)O)(8)]-type hexameric capsules in wet, non-polar, organic solvents. However, the interactions of these hexameric capsules with alcohols are far from being solved. Here we provide the results of an extensive study on the interaction of different alcohols with the hexameric capsules of resorcin[4]arene 1a by focusing on the exchange of magnetization manifested in diffusion NMR measurements of such capsular systems. We found that some alcohols such as 2-octyl-1-dodecanol and 1-octadecanol do not interact with the hexamers of 1a, whereas other alcohols such as 3-ethyl-3-pentanol, 2-ethyl-1-butanol and more act as simple guests and are simply encapsulated in the hexamers. Others alcohols such as 3-pentanol, 2-methyl-1-butanol and others, are part of the hexameric structure where they can exchange magnetization with alcohols in the bulk. The bulkier alcohols, due to an increase of the chain length or in branching, have a higher tendency to be encapsulated rather than being part of the hexameric capsule superstructure. This study demonstrate the unique information that diffusion NMR spectroscopy can provide on supramolecular systems in solution and on the precaution that should be exercised when analyzing diffusion NMR data of such dynamic supramolecular capsules. PMID:22639192

Slovak, Sarit; Cohen, Yoram

2012-07-01

134

Catalytic conversion of alcohols: the impact of inductive effect for secondary alcohol dehydration  

SciTech Connect

The use of linear free energy relationships (LFER) has become widespread in chemistry and correlations of product selectivity data for elimination reactions have resulted from application of LFER. A number of these correlations have involved heterogeneous catalysis. Dautzenberg and Knoezinger reported that the 1-alkene selectivity from the dehydration of 2-ols, with the general formula RCH/sub 2/CHOHCH/sub 3/, where R varied from methyl to tert-butyl, fit a LFER when correlated with Taft's inductive constant. Davis found that isomerization of the primary alkene products from 2-butanol and 2-pentanol could make a significant contribution in determining the slope of the LFER plot for an alumina catalyst. Davis contended that the inductive effect had little, if any, impact in determining the selectivity for terminal alkene. In view of the results with the alumina catalysts, it appeared desirable to extend the alcohol dehydration study to include other catalysts. Davis found that 2-octanol, because of its higher boiling point, provided a higher relative pressure and, as a consequence, a higher surface coverage than 2-butanol; thus, at low (less than ca. 20%) conversion 2-octanol effectively retarded secondary reactions of the primary butene and pentene products. Consequently, 2-butanol and 2-pentanol were converted in the presence of 2-octanol in these studies. Data are given for the following catalysts: aluminum oxide, thorium oxide, tungsten oxide, gallium oxide, indium oxide, and titanium oxide. 14 references.

Dabbagh, H.A.; Davis, B.H.

1988-04-01

135

Solubility of simvastatin: A theoretical and experimental study  

NASA Astrophysics Data System (ADS)

Solubility experimental data from Simvastatin in a family of alcohols were obtained at different temperatures. Simvastatin was characterized by using thermal analysis and X-ray diffraction. From the experimental solubility data an anomalous behavior was observed, since an increase the number of alcohol carbon atoms shows an increase in solubility only for the three first alcohols, ethanol, 1-propanol and 1-butanol. A decrease in solubility was obtained for 1-pentanol, 1-hexanol and 1-octanol. Van't·Hoff equation was used to obtain the theoretical solubility value and the ideal activity coefficient. Experimental error was very low and does not affect the plots and equations used. No polymorphic phenomenon was found from the Simvastatin characterization. Theoretical calculations were carried out in order to corroborate the experimental solubility data. Trends and results are similar in both cases. The geometry optimizations of Simvastatin was carried out using density functional theory with Becke's three parameter hybrid method and correlation functional of Lee, Yang and Parr (B3LYP) with 6-311++G?? basis set. The solvent effect was treated using a continuum model as modeled in water, methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol and 1-octanol. Moreover, dielectric constant, dipolar moment and solubility in the solvents were obtained for explaining the former behavior.

Aceves-Hernández, Juan M.; Hinojosa-Torres, Jaime; Nicolás-Vázquez, Inés; Ruvalcaba, Rene Miranda; García, Rosa María Lima

2011-05-01

136

Electron spin resonance and electron spin echo modulation studies of N,N,N',N'-tetramethylbenzidine photoionization in sodium dodecyl sulfate micelles: structural effects of alcohol addition  

SciTech Connect

Electron spin echo modulation (ESEM) and electron spin resonance (ESR) spectra of the photogenerated N,N,N',N'-tetramethylbenzidine cation radical (TMB/sup +/) in frozen micellar solutions of sodium dodecyl sulfate containing 2-propanol, 1-propanol, 1-pentanol, 1-octanol, 2-propanol-d/sub 7/, and 1-octanol-d/sub 17/ in H/sub 2/O and D/sub 2/O have been studied as a function of the alcohol concentration from 0 to 200 mM. Modulation effects due to the TMB/sup +/ interactions with deuteriums in D/sub 2/O and in 2-propanol-d/sub 7/ or 1-octanol-d/sub 17/ give direct evidence that 2-propanol is mainly located at the micellar interface whereas the alkyl chain of 1-octanol is located deeper into the micelle. Alcohol addition leads to an increase of water penetration into the micellar interface in the order 1-propanol < 2-propanol approx.= 1-pentanol < 1-octanol. The initial efficiency of charge separation upon potoionization of TMB as a function of alcohol concentration correlates with the degree of water penetration into the micelle, but the maximum photoionization efficiency seems more related to the degree of water organization at the micellar surface due to specific perturbing effects on the micellar structure dependent on the alcohol structure.

Baglioni, P.; Kevan, L.

1987-04-09

137

Copper(II) benzoate dimers coordinated by different linear alcohols - A systematic study of crystal structures  

NASA Astrophysics Data System (ADS)

Three new copper(II) benzoates coordinated by 1-propanol, [Cu2(PhCOO)4(1-PrOH)2] [Cu2(PhCOO)4(H2O)2] (3), 1-butanol, [Cu2(PhCOO)4(1-BuOH)2] (4) and 1-pentanol, [Cu2(PhCOO)4(1-PentOH)2] (5) at the available metal coordination sites, have been prepared and investigated with reference to their X-ray crystal structures. In all cases, dimeric paddle-wheel complexes where two copper(II) ions are held together by four benzoates were found. Moreover, the complexes show 1-propanol and water (3), 1-butanol (4) and 1-pentanol (5) coordinated to the free coordination sites of the Cu(II) ions. The dimeric complex units are connected with each other by strong OH⋯O hydrogen bonds to form strands linked together via weaker CH⋯O and CH⋯? interactions. Comparative discussion including the redetermined crystal structures obtained from copper(II) benzoate in the presence of methanol (1) or ethanol (2) allows to draw argumentation regarding the coordination of linear alcohols in corresponding crystals of paddle-wheel complexes.

Katzsch, Felix; Münch, Alexander S.; Mertens, Florian O. R. L.; Weber, Edwin

2014-05-01

138

Pairwise interaction enthalpies of enantiomers of ?-amino alcohols in DMSO + H2O mixtures at 298.15 K.  

PubMed

The dilution enthalpies of enantiomers of six ?-amino alcohols, namely (R)-(-)-2-amino-1-propanol versus (S)-(+)-2-amino-1-propanol, (R)-(-)-2-amino-1-butanol versus (S)-(+)-2-amino-1-butanol, and (R)-(-)-2-amino-1-pentanol versus (S)-(+)-2-amino-1-pentanol in dimethylsulfoxide (DMSO) + H(2)O mixtures (mass fractions of DMSO w = 0 to 0.3) have been determined respectively using an isothermal titration calorimeter (MicroCal ITC200, Northampton, MA, USA) at 298.15 K. According to the McMillan-Mayer theory, the corresponding homochiral enthalpic pairwise interaction coefficients (h(XX)) of the six amino alcohols have been calculated. It is found that across the whole studied composition range of mixed solvent, values of h(XX) for S-enantiomer are almost universally higher than those of R-enantiomer for each amino alcohol and that the variations of h(XX) depend largely on the composition of mixed solvent. The results were interpreted from the point of view of solute-solute interaction mediated by cosolvent DMSO, as well as competition equilibrium between hydrophobic-hydrophobic, hydrophilic-hydrophilic, and hydrophobic-hydrophilic interactions. PMID:22508362

Liang, Hongyu; Hu, Xingen; Fang, Guoyong; Shao, Shuang; Guo, Aidi; Guo, Zheng

2012-05-01

139

The role of the alcohol and carboxylic acid in directed ruthenium-catalyzed C(sp3)-H ?-alkylation of cyclic amines.  

PubMed

A general directed Ru-catalyzed C(sp(3))-H ?-alkylation protocol for piperidines (less-reactive substrates than the corresponding five-membered cyclic amines) has been developed. The use of a hindered alcohol (2,4-dimethyl-3-pentanol) as the solvent and catalyst activator, and a catalytic amount of trans-1,2-cyclohexanedicarboxylic acid is necessary to achieve a high conversion to product. This protocol was used to effectively synthesize a number of 2-hexyl- and 2,6-dihexyl piperidines, as well as the alkaloid (±)-solenopsin A. Kinetic studies have revealed that the carboxylic acid additive has a significant effect on catalyst initiation, catalyst longevity, and reverses the reaction selectivity compared with the acid-free reaction (promotes alkylation versus competing alkene reduction). PMID:22786664

Bergman, Sheba D; Storr, Thomas E; Prokopcová, Hana; Aelvoet, Karel; Diels, Gaston; Meerpoel, Lieven; Maes, Bert U W

2012-08-13

140

The Yang-Yang anomaly in liquid-liquid criticality: Experimental evidence from adiabatic scanning calorimetry  

NASA Astrophysics Data System (ADS)

Using adiabatic scanning calorimetry, we have found the first experimental evidence of the Yang-Yang anomaly in liquid-liquid criticality from high-resolution two-phase isobaric heat capacity measurements for the binary mixture 3-pentanol + nitromethane. The results suggest a rather strong effect. The critical amplitude of the partial molar heat capacity is higher for the component with larger molecular volume, in accordance with the predictions of complete scaling as obtained from the customary observed asymmetric behavior of the coexistence-curve diameter. This consolidates complete scaling as the true formulation of fluid-fluid criticality. The quantitative analysis indicates that molecular size is not the only microscopic factor at play in asymmetric liquid-liquid criticality.

Losada-Pérez, Patricia; Tripathi, Chandra Shekhar Pati; Leys, Jan; Cerdeiriña, Claudio A.; Glorieux, Christ; Thoen, Jan

2012-01-01

141

2,2,4-Trimethylpentane-induced nephrotoxicity. I. Metabolic disposition of TMP in male and female Fischer 344 rats  

SciTech Connect

2,2,4-Trimethylpentane (TMP), a component of unleaded gasoline, causes nephrotoxicity in male, but not in female, rats. In the present study, male and female Fischer 344 rats were treated with a single oral dose of (/sup 14/C)TMP (4.4 mmol/kg; 2 microCi/mmol). Radiolabeled material in kidney, liver, and plasma was determined at 4, 8, 12, 24, and 48 hr after dosing. Maximum concentration of TMP-derived radioactivity in kidney, liver, and plasma of male rats was found after 12 hr (1252, 1000, and 403 nmol eq/g, respectively), whereas those measured in females were found after 8 hr (577, 1163, and 317 nmol eq/g, respectively). A selective retention of the TMP-derived radiolabel in the kidneys of male rats was noted when peak tissue concentration was expressed as a percentage of administered dose. Kidney concentrations of TMP-derived radiolabel increased in a nonlinear, but dose-dependent, manner; the kidney to plasma ratio was greater at low doses than at higher doses. Increased retention of radiolabel material in the kidney was associated with a significant increase in renal concentration of the male-rat-specific protein, alpha 2u-globulin, 24 and 48 hr after TMP administration. Total radioactivity collected in urine 48 hr after TMP administration was similar in males and females (32 and 31% of dose). Identification and quantitation of the urinary metabolites of TMP showed that both male and female rats metabolize TMP via the same pathway and at a similar rate. Female rats, however, excreted more conjugates of 2,4,4-trimethyl-2-pentanol in urine than males. 2,4,4-Trimethyl-2-pentanol was the major metabolite present in the male rat kidney, but was absent in the female rat kidney. The renal retention of 2,4,4-trimethyl-2-pentanol appears to account for the delayed clearance observed in the disposition of (/sup 14/C)TMP-derived radiolabel.

Charbonneau, M.; Lock, E.A.; Strasser, J.; Cox, M.G.; Turner, M.J.; Bus, J.S.

1987-11-01

142

Characterization of an alcohol dehydrogenase from Thermoanaerobacter ethanolicus active with ethanol and secondary alcohols  

SciTech Connect

Thermoanaerobacter ethanolicus contains a NADP-dependent alcohol dehydrogenase. Ethanol is a substrate but secondary alcohols such as 2-propanol, 2-butanol and 2-pentanol are oxidized at a faster rate. The enzyme has a molecular weight of 172,000 and consists of 4 subunits. Each subunit contains 4 zinc atoms. With ethanol the kinetics are sigmoidal; however, in the presence of pyruvate a Michaelis-Menten kinetic pattern is approached. At 70/sup 0/C and pH 9 the purified enzyme oxidizes ethanol with NADP at a rate of 13 ..mu..mol min/sup -1/ mg/sup -1/, whereas it reduces acetaldehyde with NADPH two times that rate.

Bryant, F.; Ljungdahl, L.G.

1981-05-29

143

Unusual dielectric strength of Debye relaxation in monohydroxy alcohols upon mixing.  

PubMed

The dielectric strength of the Debye relaxation in the binary mixtures of two isomeric monohydroxy alcohols, 2-ethyl-1-butanol (2E1B) and 4-methyl-2-pentanol (4M2P), is studied at low temperature near glass transition. Enhanced dielectric strength is exhibited in the mixtures, remarkably different from the mixing behaviors of the structural (?-) relaxation of generic liquids. A similar result is observed when analyzing the dielectric data of the binary mixtures of 2-ethyl-1-hexanol and 2-methyl-1-butanol reported in an early study. The unusual behavior of the dielectric strength in the mixtures reveals a new feature of the Debye relaxation in monohydroxy alcohols. Yet, the calorimetric measurements of the glass transition temperature in 2E1B-4M2P mixtures show a distinct negative deviation from the ideal mixing law. The explanation of the Debye relaxation is discussed with the results. PMID:22913462

Gong, Hongxiang; Chen, Zeming; Bi, Dongyang; Sun, Mingdao; Tian, Yongjun; Wang, Li-Min

2012-09-20

144

Interplay of metalloligand and organic ligand to tune micropores within isostructural mixed-metal organic frameworks (M'MOFs) for their highly selective separation of chiral and achiral small molecules.  

PubMed

Four porous isostructural mixed-metal-organic frameworks (M'MOFs) have been synthesized and structurally characterized. The pores within these M'MOFs are systematically tuned by the interplay of both the metalloligands and organic ligands which have enabled us not only to direct their highly selective separation of chiral alcohols 1-phenylethanol (PEA), 2-butanol (BUT), and 2-pentanol (2-PEN) with the highest ee up to 82.4% but also to lead highly selective separation of achiral C(2)H(2)/C(2)H(4) separation. The potential application of these M'MOFs for the fixed bed pressure swing adsorption (PSA) separation of C(2)H(2)/C(2)H(4) has been further examined and compared by the transient breakthrough simulations in which the purity requirement of 40 ppm in the outlet gas can be readily fulfilled by the fixed bed M'MOF-4a adsorber at ambient conditions. PMID:22545712

Das, Madhab C; Guo, Qunsheng; He, Yabing; Kim, Jaheon; Zhao, Cong-Gui; Hong, Kunlun; Xiang, Shengchang; Zhang, Zhangjing; Thomas, K Mark; Krishna, Rajamani; Chen, Banglin

2012-05-23

145

Two new natural products from the fruits of Alpinia oxyphylla with inhibitory effects on nitric oxide production in lipopolysaccharide-activated RAW264.7 macrophage cells.  

PubMed

Chemical investigation of the fruits of Alpinia oxyphylla led to an isolation of the two new natural products, 9-hydroxy epinootkatol (1) and (S)-2-pentanol-2-O-?-D-glucopyranoside (2), in addition to the nine known compounds, pinocembrin (3), tectochrysin (4), izalpinin (5), nookatone (6), yakuchinone A (7), protocatechuic acid (8), ?-sitosterol (9), daucosterol (10) and ?-sitosterol palmitate (11). Their structures were elucidated on the basis of physicochemical constants and NMR spectral data analysis. The effects of the isolated components on nitric oxide production in LPS-induced RAW 264.7 macrophages were examined. The two new natural compounds showed inhibitory activities with IC(50) values of 21.8 and 32.8 ?g/mL, respectively. PMID:23263808

Qing, Zhang Jun; Yong, Wang; Hui, Li Yong; Yong, Lai Wei; Long, Li Hai; Ao, Duan Jin; Xia, Pei Li

2012-12-01

146

Liquid chromatographic analysis of coal surface properties  

SciTech Connect

Experiments on equilibrium adsorption of various alcohols on 60--200 mesh Illinois No. 6 coal (DECS-2; Randolph county) were performed during the July--September period. The alcohols include ethanol, methanol, isobutanol, t-butanol, 1-heptanol, 1-octanol, 1-hexadecanol, 4-methyl-2-pentanol, and 2-methyl-l-pentanol. Amounts of equilibrium adsorption of alcohols (ALCO) on 60--200 mesh Illinois No. 6 coal are 1 - 230 [times] 10[sup [minus]6] mg-ALCO/g-coal, whereas equilibrium concentrations of alcohols are 3--40 ppM. Relations between equilibrium loadings of alcohols on the coal and equilibrium concentrations of alcohols in aqueous solutions are shown to be linear.

Kwon, K.C.

1992-12-15

147

Liquid chromatographic analysis of coal surface properties. Quarterly progress report, July--September 1992  

SciTech Connect

Experiments on equilibrium adsorption of various alcohols on 60--200 mesh Illinois No. 6 coal (DECS-2; Randolph county) were performed during the July--September period. The alcohols include ethanol, methanol, isobutanol, t-butanol, 1-heptanol, 1-octanol, 1-hexadecanol, 4-methyl-2-pentanol, and 2-methyl-l-pentanol. Amounts of equilibrium adsorption of alcohols (ALCO) on 60--200 mesh Illinois No. 6 coal are 1 - 230 {times} 10{sup {minus}6} mg-ALCO/g-coal, whereas equilibrium concentrations of alcohols are 3--40 ppM. Relations between equilibrium loadings of alcohols on the coal and equilibrium concentrations of alcohols in aqueous solutions are shown to be linear.

Kwon, K.C.

1992-12-15

148

Experimental investigation of the atmospheric chemistry of aromatic hydrocarbons and long-chain alkanes. Final report  

SciTech Connect

The interaction of volatile organic compounds (VOCs) and oxides of nitrogen in the presence of sunlight leads to the formation of ozone and other manifestations of photochemical air pollution. There are, however, significant uncertainties in our knowledge of the products and mechanisms of the atmospheric reactions of alkanes and aromatic hydrocarbons, important constituents of ambient air in urban areas, with the hydroxyl (OH) radical. A series of product studies of the OH radical-initiated reactions of selected alkanes, ketones and alcohols have been carried out to obtain further insights into alkoxy radical isomerization. Product studies of the OH radical reaction with 4-methyl-2-pentanone, 2,6-dimethyl-4-heptanone, 2,4-dimethyl-2-pentanol and 3,5-dimethyl-3-hexanol in the presence of NOx have provided unambiguous evidence for alkoxy radical isomerization and these studies have provided rate constant ratios for the isomerization reaction versus alkoxy radical decomposition and reaction with O2.

Atkinson, R.; Arey, J.; Tuazon, E.C.; Aschmann, S.M.; Bridier, I.

1994-08-01

149

Temperature-dependent enantiospecificity of secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus  

SciTech Connect

An alcohol dehydrogenase reported from Thermoanaerobium brockii catalyzes the asymmetric reduction of aliphatic acyclic ketones. An interesting substrate size-induced reversal of stereoselectivity at 37/degree/C was observed by Keinan and co-workers in their studies of this latter enzyme. The smaller substrates (2-butanone, 3-methyl-2-butanone, or methyl cyclopropyl ketone) were reduced to (R)-alcohols, whereas 2-pentanone and the longer chain ketones provided the (S)-alcohols. In order to evaluate the mechanistic basis of this unusual stereochemical reversal, the authors have studied the kinetics of the reaction of SADH from T. ethanolicus with the (R)- and (S)-enantiomers of the simple secondary alcohols, 2-butanol and 2-pentanol.

Pham, V.T.; Phillips, R.S.; Ljungdahl, L.G.

1989-03-01

150

Synergism between microwave irradiation and enzyme catalysis in transesterification of ethyl-3-phenylpropanoate with n-butanol.  

PubMed

Lipase catalyzed transesterification was investigated to study the synergistic effect of microwave irradiation and enzyme catalysis. Transesterification of ethyl-3-phenylpropanoate with n-butanol was chosen as the model reaction using immobilized enzymes such as Novozyme 435, Lipozyme RMIM and Lipozyme TL IM with microwave irradiation. Novozyme 435 was the best catalyst. The effect of various parameters affecting the conversion and initial rates of transesterification were studied to establish kinetics and mechanism. There is synergism between enzyme catalysis and microwave irradiation. The analysis of initial rate data and progress curve data showed that the reaction obeys the Ping-Pong bi-bi mechanism with inhibition by n-butanol. The theoretical predictions and experimental data match very well. These studies were also extended to other alcohols such as 2-phenyl-1-propanol, n-octanol, benzyl alcohol, iso-amyl alcohol, 2-hexanol and 2-pentanol under otherwise similar conditions. PMID:22305539

Yadav, Ganapati D; Pawar, Sandip V

2012-04-01

151

Correlation and prediction of thermodynamic properties of binary mixtures from perturbed chain statistical associating fluid theory  

NASA Astrophysics Data System (ADS)

Densities and viscosities for binary mixtures of Diethanolamine (DEA) + 2 alkanol (2 propanol up to 2 pentanol) were measured over the entire composition range and temperature interval of 293.15-323.15 K. From the density and viscosity data, values of various properties such as isobaric thermal expansibility, excess isobaric thermal expansibility, partial molar volumes, excess molar volumes and viscosity deviations were calculated. The observed variations of these parameters, with alkanols chain length and temperature, are discussed in terms of the intermolecular interactions between the unlike molecules of the binary mixtures. The ability of the perturbed chain statistical associating fluid theory (PC-SAFT) to correlate accurately the volumetric behavior of the binary mixtures is demonstrated.

Almasi, Mohammad

2014-11-01

152

Ultrasonic relaxation studies of mixed micelles formed from alcohol-decyltrimethylammonium bromide-water  

SciTech Connect

This paper discusses how ultrasonic relaxation and conductance studies of alcohol (1-pentanol or 1-butanol)-DTAB-water mixed micelles reveal two relaxation frequencies related to the exchange of monomer surfactant and of alcohol between the micelles and the bulk phase. Conductance and time-resolved fluorescence measurements were used to obtain the alcohol distribution coefficients, micelle ionization, critical micellar concentration, and the alcohol and surfactant mean aggregation numbers. Using two models (Aniansson and Hall & Wyn-Jones), information about the forward and backward rate constants, polydispersity of the mixed micelles and the change in volumes of the two exchange processes are obtained and compared with 1-propanol-DTAB-water. Alcohol chain length influence on thermodynamics and kinetics is also discussed. 16 refs., 12 figs., 6 tabs.

Jobe, D.J.; Verrall, R.E. [Univ. of Saskatchewan, Saskatoon (Canada); Skalski, B. [A. Mickiewicz Univ., Poznan (Poland)] [and others

1992-08-06

153

High-pressure vapor-liquid equilibria for mixtures containing a supercritical fluid  

SciTech Connect

Supercritical fluid extraction has been proven as an efficient separation method for some specific industrial applications. The knowledge of the phase behavior of supercritical systems plays an important role in the process design. High pressure vapor-liquid phase equilibrium compositions were measured for the binary systems of carbon dioxide + 2-methyl-1-pentanol, carbon dioxide + 1-octanol, and carbon dioxide + 1-decanol over a temperature range between 348.15 and 453.15 K. In addition to the new data, a variety of supercritical fluid systems was used to test the validity of the Peng-Robinson and Patel-Teja equations of state accompanied by several types of mixing rules. In general, the Peng-Robinson equation incorporated with the cubic mixing rule yielded the best representation.

Weng, W.L. (Ming-Hsin Engineering College, Hsinchu (Taiwan, Province of China). Dept. of Chemical Engineering); Chen, J.T.; Lee, M.J. (National Taiwan Inst. of Technology, Taipei (Taiwan, Province of China). Dept. of Chemical Engineering)

1994-08-01

154

Interaction of poly(oxyethylene glycol) with cyclohexane-pentanol-sodium dodecyl sulfate water-in-oil microemulsions  

SciTech Connect

The interaction of poly(oxyethylene glycol) (MW 6000) with cyclohexane/1-pentanol/sodium dodecyl sulfate microemulsions was studied with dynamic light scattering and luminescence probing techniques. Some conductivity measurements have also been made. Particular weight has been given to luminescence. The authors have chosen to analyze luminescence decay profiles by using models obtained from the theory of random walk in fractal domains, in order to deal with percolation phenomena present in the above system and to underline new information obtained by fractal models. Ru(Bpy){sub 3}{sup 2+} has been used as the lumophore and Fe(CN){sub 6}{sup 3-} as the quencher. It was found that the polymer induces a structural reorganization of the dispersed phase so that the aggregates grow in size. The geometry of the dispersed phase becomes more restricted in the presence of polymer and the quenching efficiency decreases. The electric conductivity undergoes a limited decrease. 42 refs., 8 figs., 4 tabs.

Lianos, P.; Modes, S.; Staikos, G. [Univ. of Patras (Greece)] [and others

1992-04-01

155

Real-time feedback control using online attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy for continuous flow optimization and process knowledge.  

PubMed

The use of automated continuous flow reactors is described, with real-time online Fourier transform infrared spectroscopy (FT-IR) analysis to enable rapid optimization of reaction yield using a self-optimizing feedback algorithm. This technique has been applied to the solvent-free methylation of 1-pentanol with dimethyl carbonate using a ?-alumina catalyst. Calibration of the FT-IR signal was performed using gas chromatography to enable quantification of yield over a wide variety of flow rates and temperatures. The use of FT-IR as a real-time analytical technique resulted in an order of magnitude reduction in the time and materials required compared to previous studies. This permitted a wide exploration of the parameter space to provide process understanding and validation of the optimization algorithms. PMID:24067568

Skilton, Ryan A; Parrott, Andrew J; George, Michael W; Poliakoff, Martyn; Bourne, Richard A

2013-10-01

156

Bioethanol Production Optimization: A Thermodynamic Analysis  

NASA Astrophysics Data System (ADS)

In this work, the phase equilibrium of binary mixtures for bioethanol production by continuous extractive process was studied. The process is composed of four interlinked units: fermentor, centrifuge, cell treatment unit, and flash vessel (ethanol-congener separation unit). A proposal for modeling the vapor-liquid equilibrium in binary mixtures found in the flash vessel has been considered. This approach uses the Predictive Soave-Redlich-Kwong equation of state, with original and modified molecular parameters. The congeners considered were acetic acid, acetaldehyde, furfural, methanol, and 1-pentanol. The results show that the introduction of new molecular parameters r and q in the UNIFAC model gives more accurate predictions for the concentration of the congener in the gas phase for binary and ternary systems.

Álvarez, Víctor H.; Rivera, Elmer Ccopa; Costa, Aline C.; Filho, Rubens Maciel; Maciel, Maria Regina Wolf; Aznar, Martín

157

Chemoenzymatic solvent-free synthesis of 1-monopalmitin using a microwave reactor.  

PubMed

An environmentally friendly method for the synthesis of 1-monopalmitin has been developed. The procedure consists of a two-step, solvent-free chemoenzymatic reaction. In the first step, palmitic acid is esterified with solketal (4-hydroxymethyl-2,2-dimethyl-1,3-dioxolane) using Novozym 435 by both conventional heating and microwave irradiation. The use of a microwave reactor allows the enzymatic synthesis of the intermediate compound with a similar yield as that achieved using conventional heating. In the second step, 1,2-acetonide-3-palmitoyl glycerol is cleaved to yield 1-monopalmitin by means of a cation-exchange resin and water or aliphatic alcohols as hydrolytic reagent in solvent-free conditions. The hydrolysis was accomplished in 15 min at 85 degrees C. The best yield was obtained using 1-pentanol. We conclude that the yield achieved depends on the batch and nature of the cation-exchange resin used as catalyst. PMID:25233581

Torregrosa, Rubén; Balcells, Mercé; Torres, Mercé; Canela-Garayoa, Ramon

2014-08-01

158

Oil-in-water microemulsion globules as carriers of lipophilic substances across liquid membranes  

SciTech Connect

The carrier properties of microemulsion droplets were investigated by using biphasic systems of the Winsor I type (constituted of an oil-phase floating on the top of an oil-in-water microemulsion phase). The systems investigated were constituted of sodium dodecyl sulfate/1-pentanol/n-dodecane/ (or brine). The microemulsion was used as a liquid membrane between 2 oil phases (a source phase and a receiving phase) and the rate of transfer of neutral arenes (pyrene, perylene, and anthracene), practically insoluble in the water continuous phase of the microemulsion, was determined from ultraviolet spectrophotometric measurements. The influence of different parameters on the transported solutes was studied: initial concentration of solute in the source phase, composition of the microemulsion, salt concentration. The results are shown to be consistent with a model in which the diffusion of droplets is coupled with a fast solubilization-desolubilization process and other possible mechanisms are critically examined. 32 references.

Xenakis, A.; Tondre, C.

1983-11-10

159

Development of a new in-vial standard gas system for calibrating solid-phase microextraction in high-throughput and on-site applications.  

PubMed

In this work, an innovative, reproducible, and reusable standard generator vial is presented. The standard generator vial consists of vacuum-pump oil doped with McReynolds probes (benzene, 2-pentanone, pyridine, nitropropane, 1-pentanol, and n-octane) mixed with a polystyrene-divinylbenzene resin without functional groups. The evaluation of this vial was fully automated on a multifiber exchanger system and the extraction/desorption cycle, together with the programmed GC-qMS analysis, did not exceed 13 min. The results showed that after 160 extraction/injections cycles of the vial the relative SDs were smaller than 4% for all the standards. A randomized block design was used to evaluate the inter and intravial repeatability, and at 95% level of confidence nonstatistical differences among vials were found. Because of its compacted granular appearance this vial is easy to transport, and it is an ideal calibration standard for bench and field instruments and devices. PMID:23636846

Gómez-Ríos, German A; Reyes-Garcés, Nathaly; Pawliszyn, Janusz

2013-09-01

160

Dielectric relaxation study of mixtures of alkyl methacrylates and 1-alcohols using time-domain reflectometry  

NASA Astrophysics Data System (ADS)

Dielectric relaxation measurements on alkyl methacrylates (methyl methacrylate, ethyl methacrylate and butyl methacrylate) with 1-alcohols (1-propanol, 1-pentanol, 1-heptanol, 1-octanol and 1-decanol) have been carried out using time-domain reflectometry (TDR) over the frequency range 10?MHz to 20?GHz at 303?K for different concentrations of alcohols. The dielectric parameters, namely the static dielectric constant (?0), the dielectric constant at microwave frequencies (??) and the relaxation time (?) were determined. The Kirkwood correlation factor, which contains information regarding solute-solvent interaction and corresponding structural information, the excess permittivity and the excess inverse relaxation time were also determined. The values of the static dielectric constant and the relaxation time increase with the percentage of alkyl methacrylates in the alcohol, whereas the static dielectric constant decreases and the relaxation time increases with an increase in the alkyl chain length of both the methacrylates and the alcohols.

Sivagurunathan, P.; Dharmalingam, K.; Ramachandran, K.; Prabhakar Undre, B.; Khirade, P. W.; Mehrotra, S. C.

2006-05-01

161

Effect of five enological practices and of the general phenolic composition on fermentation-related aroma compounds in Mencia young red wines.  

PubMed

The effects of five technological procedures and of the contents of total anthocyanins and condensed tannins on 19 fermentation-related aroma compounds of young red Mencia wines were studied. Multifactor ANOVA revealed that levels of those volatiles changed significantly over the length of storage in bottles and, to a lesser extent, due to other technological factors considered; total anthocyanins and condensed tannins also changed significantly as a result of the five practices assayed. Five aroma compounds possessed an odour activity value >1 in all wines, and another four in some wines. Linear correlation among volatile compounds and general phenolic composition revealed that total anthocyanins were highly related to 14 different aroma compounds. Multifactor ANOVA, considering the content of total anthocyanins as a sixth random factor, revealed that this parameter affected significantly the contents of ethyl lactate, ethyl isovalerate, 1-pentanol and ethyl octanoate. Thus, the aroma of young red Mencia wines may be affected by levels of total anthocyanins. PMID:24262556

Añón, Ana; López, Jorge F; Hernando, Diego; Orriols, Ignacio; Revilla, Eugenio; Losada, Manuel M

2014-04-01

162

Solubility of anthracene in binary alcohol + 2-propoxyethanol solvent mixtures  

SciTech Connect

Solid-liquid equilibrium data of organic nonelectrolyte systems are becoming increasingly important in the petroleum industry, particularly in light of present trends toward heavier feedstocks and known carcinogenicity/mutagenicity of many of the larger polycyclic aromatic compounds. Experimental solubilities are reported for anthracene dissolved in seven binary mixtures containing 2-propoxyethanol with 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 1-octanol, and 3-methyl-1-butanol at 25 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the seven systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being on the order of 0.5%.

McHale, M.E.R.; Powell, J.R.; Kauppila, A.S.M.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry] [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry

1996-03-01

163

Characterisation of optically cleared paper by optical coherence tomography  

SciTech Connect

Due to the highly light scattering nature of paper, the imaging depth of optical methods such as optical coherence tomography (OCT) is limited. In this work, we study the effect of refractive index matching on improving the imaging depth of OCT in paper. To this end, four different refractive index matching liquids (ethanol, 1-pentanol, glycerol and benzyl alcohol) with a refraction index between 1.359 and 1.538 were used in experiments. Low coherent light transmission was studied in commercial copy paper sheets, and the results indicate that benzyl alcohol offers the best improvement in imaging depth, while also being sufficiently stable for the intended purpose. Constructed cross-sectional images demonstrate visually that the imaging depth of OCT is considerably improved by optical clearing. Both surfaces of paper sheets can be detected along with information about the sheet's inner structure. (laser applications and other topics in quantum electronics)

Fabritius, T; Alarousu, E; Prykaeri, T; Hast, J; Myllylae, Risto [Department of Electrical and Information Engineering, Optoelectronics and Measurement Techniques Laboratory, University of Oulu (Finland)

2006-02-28

164

Optical constants of alcohols in the infrared  

NASA Technical Reports Server (NTRS)

The spectral reflectances at near-normal incidence for methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol are reported for the spectral range 6700-350 kaysers. The real and imaginary parts of the complex index of refraction of these liquids are obtained in the range 4000-400 kaysers by use of Kramers-Kronig phase-shift analysis. For all of the alcohols studied, the strength for the OH-stretch bands is directly proportional to the number of OH groups per unit volume; similar relations are established for CH- and CO-stretch bands. Absorption cross sections for stretch vibrations of the three groups are considered, and the role of characteristic group intensities in intensity spectroscopy is discussed.

Sethna, P. P.; Williams, D.

1979-01-01

165

Solvent optimization for niacinamide adsorption on organo-functionalized SBA-15 mesoporous silica  

NASA Astrophysics Data System (ADS)

This work describes the application of organo-modified SBA-15 siliceous materials as the carrier for niacinamide. The surface functionalization of SBA-15 by a grafting strategy with triethoxyphenylsilane, triethoxy(4-methoxyphenyl)silane, triethoxymethylsilane and (3-mercaptopropyl)trimethoxysilane as modifying agents has been successfully achieved. The adsorption process was performed in acetonitrile, methanol, 2-propanol, 1-pentanol and ethyl acetate. The obtained results indicated a promote niacinamide adsorption on sulfopropyl-modified (119 mg/g) and non-modified (78 mg/g) SBA-15 from ethyl acetate. The pure and derivatized SBA-15 products have been characterized by elemental analysis, thermogravimetry, nitrogen adsorption and diffuse reflectance UV spectroscopy. After niacinamide adsorption the textural parameters of mesoporous carriers such as BET surface area, pore volume and microporosity were reduced. The mesoporous matrices loaded with niacinamide exhibited prolonged-release kinetics of this vitamin, especially from sulfopropyl-modified SBA-15 carrier.

Moritz, Micha?

2013-10-01

166

Characterization of a new mobility separation tool: HRIMS as differential mobility analyzer.  

PubMed

High resolution ion mobility spectrometer (HRIMS) is a new instrument that uses parallel plate Differential Mobility Analysis as principle of separation. Gas phase analysis of volatile organic compounds (VOCs) has been performed for the characterization of this new mobility system using an UV-lamp for ionization. Studies of the effect of temperature and the presence of a desiccant are detailed. Identification of the different peaks obtained with an electrometer was successfully carried out for a group of alcohols, aromatic compounds and ketones (ethanol, 1-propanol, isopropanol, 1-butanol, 1-pentanol, 1-heptanol, acetone, 2-butanone, 2-pentanone, 2-octanone, benzene, toluene, xylene and bromobenzene) following a modified Millikan equation. Moreover, the investigation of the discrimination capabilities within the different VOCs families as well as the mobility dependence with molecular mass was successfully achieved. PMID:25159427

Bouza, Marcos; López-Vidal, Silvia; Pisonero, Jorge; Bordel, Nerea; Pereiro, Rosario; Sanz-Medel, Alfredo

2014-12-01

167

Modification of the murakami retention model in reversed-phase high-performance liquid chromatography for micellar chromatographic separations  

NASA Astrophysics Data System (ADS)

A retention model for micellar liquid chromatography was tested based on the data of separation of three benzodiazepins and six ?-blockers. The model was obtained by analyzing changes in the microenvironment of a sorbate in transferring from the mobile to stationary phase. It can be used to describe the retention of benzodiazepins, which are neutral under the separation conditions, and the positively charged ?-blockers. The calculated model coefficients are indicative of an increase in the number of 1-pentanol molecules and sodium dodecyl sulfate monomers in the microenvironment of the sorbates in transferring from the mobile to stationary phase. The solvation of the positive ?-blockers by anionic surfactant monomers was higher than that of neutral benzodiazepins.

Loginova, L. P.; Boichenko, A. P.; Kulikov, A. Yu.

2008-09-01

168

Adsorption of sodium dodecyl sulfate on kaolin from different alcohol-water mixtures  

SciTech Connect

The adsorption of surfactants on solid/liquid interfaces is a subject of great interest especially for enhanced oil recovery processes. The adsorption of sodium dodecyl sulfate (SDS) onto kaolin from different alcohol-water mixtures has been studied. The alcohols used were 1-propanol, 1-butanol, 1-pentanol, and 1-decanol containing 3.5 or 7 wt% water. In all cases the adsorption isotherms show a rather steep rise at low surfactant concentrations. Thereafter, there is a more or less continuous leveling off. The plateau adsorption of SDS on kaolin is found to increase with increasing chain length of the alcohol in the alcohol-water solvent. The adsorption properties are discussed in relation to the dielectric constant of the solvents; the aggregation properties of the surfactant in the bulk phase and the molecular packing of the surfactant in the adsorbed state are also considered.

Blokhus, A.M.; Hoeiland, H.; Gjerde, M.I. [Univ. of Bergen (Norway). Dept. of Chemistry] [Univ. of Bergen (Norway). Dept. of Chemistry; Ersland, E.K. [Bergen Technological College (Norway)] [Bergen Technological College (Norway)

1996-05-10

169

Percolation transition in water-in-oil microemulsions. Electrical conductivity measurements  

SciTech Connect

The low-frequency (600 Hz) electric conductivity of water-in-oil microemulsions composed of water, cyclohexane, SDS, and 1-pentanol was measured. The structure of these microemulsions previously was described in the low water concentration range (water concentration approx. 10/sup -2/) as a suspension of minute droplets (diameter approx. 100 angstroms) with weak mutual interaction. Neutron scattering measurements show that the structure of droplets remains unchanged up to a water concentration of 0.30. At low water concentration, the electric conductivity is due to the mean charge of the droplets. The electric conductivity increases steeply over 5 orders of magnitude when the concentration of droplets increases. A second transition is observed at high water concentration: the microemulsion is inverted from water-in-oil to oil-in-water. The effect of both additional alcohol and ionic strength of water are discussed. 17 references.

Lagues, M.; Sauterey, C.

1980-12-25

170

The distribution of the anion and zwitterion forms of methyl orange between the disperse microemulsion pseudophase and continuous water phase  

NASA Astrophysics Data System (ADS)

A procedure is suggested for determining the distribution constants of methyl orange dye between water and direct microemulsion droplets (N-cetylpyridinium chloride + 1-pentanol + benzene in water) as the disperse phase, which allows one to circumvent difficulties associated with the formation of low-solubility salts and premicellar associates. Within the framework of the pseudophase model of equilibria, the distribution constants of the yellow monoanion and red zwitterion methyl orange forms between microscopic droplets and the continuous phase at an ionic strength of 0.2 mol/l (NaCl + HCl) were determined from the dependence of the apparent ionization constant of the indicator on the volume fraction of the disperse pseudophase. The constants on the molar concentration scale were P_{B^ - }^ ? = (253 ± 0.08) × 105 and P_{^ + HB^ - }^ ? = (1.7 ± 0.4) × 102.

Nikiforova, E. M.; Bryleva, E. Yu.; McHedlov-Petrosyan, N. O.

2008-09-01

171

Determination of C/sub 1/-C/sub 4/ alcohols in gasoline using multiple ion detection  

SciTech Connect

A method for the determination of C/sub 1/-C/sub 4/ alcohol content in gasoline by capillary column gas chromatography-ion trap detector system (GC-ITDS) is described. The method involves the direct injection of gasoline into the GC-ITDS, and subsequent detection of the alcohols using the multiple ion detection method. The detection method uses the mass-to-charge ratio peaks at 31 and 45 for the quantification of the alcohols. 1-Pentanol is used as an internal standard. The method was evaluated over the range of 0-20% for methanol and ethanol and 0-1% for 2-propanol, 1-propanol, 2-methyl-2-propanol, 1-methylpropanol, 2-methylpropanol, and 1-butanol. Detection limits for each of the alcohols are less than 0.1%.

Shofstahl, J.H.; Hardy, J.K.

1986-10-01

172

Photoionization in cationic micelles: Effect of alcohol or salt addition  

SciTech Connect

The photoionization of tetramethylbenzidine (TMB) in liquid cationic micelles of dodecyltrimethylammonium chloride (DTAC) has been studied in the presence of NaCl or 1-pentanol, so as to modulate the interfacial potential {Delta}{Psi}. The recording of the quantum yield of the photocation ({phi}{sub ion}) with the concentration of the additives indicates that {Delta}{Psi} variations do not control the charge separation efficiency. The results strongly suggest that, besides the water proximity correlated with the size and structure of the aggregate, the water organization at the interface could intervene and facilitate electron exit and its stabilization in the interface water shell. For both additives studied, a quantitative relationship was found between {phi}{sub ion} and the interfacial dielectric constant {epsilon}{sub eff}.

Grand, D. (Universite de Paris-Sud, Orsay (France))

1990-09-20

173

Monte Carlo simulation of optical clearing of paper in optical coherence tomography  

SciTech Connect

Signals of an optical coherence tomograph from paper samples are calculated by the Monte Carlo method before and after the action of different immersion liquids such as ethanol, glycerol, benzyl alcohol, and 1-pentanol. It is shown within the framework of the model used that all these liquids reduce the contrast of the inhomogeneity image in upper layers of the samples, considerably improving, however, the visibility of lower layers, allowing the localisation of the rear boundary of a medium being probed, which is important for precision contactless measuring a paper sheet thickness, for example, during the manufacturing process. The results of calculations are in well agreement with experimental data. (laser applications and other topics in quantum electronics)

Kirillin, M Yu; Priezzhev, A V [Department of Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation); Hast, J; Myllylae, Risto [Optoelectronics and Measurements Techniques Laboratory, Faculty of Technology, University of Oulu and Infotech Oulu (Finland)

2006-02-28

174

Binary mutual diffusion coefficients of aqueous alcohols. Methanol to 1-heptanol  

SciTech Connect

Mutual diffusion coefficients, measured by Taylor dispersion at 25 C, are reported for binary aqueous solutions of methanol, ethanol, isomeric propanols and butanols, 1-pentanol, 1-hexanol, and 1-heptanol. Limiting diffusion coefficients (D{sup 0}) for the 1-alkanols are found to decrease with alcohol molar volume V approximately as V{sup {minus}1/2}. Although values of D{sup 0} for aqueous 1-propanol and 2-propanol are nearly identical within experimental error, the limiting diffusion coefficients of the isomeric butanols differ by up to 10% and increase in the order D{sup 0}(2-methyl-2-propanol) < D{sup 0}(2-butanol) {approx} D{sup 0}(2-methyl-1-propanol) < D{sup 0}(1-butanol). The butanol results illustrate the difficulty of predicting accurate diffusion coefficients for aqueous solutions.

Hao, L.; Leaist, D.G. [Univ. of Western Ontario, London, Ontario (Canada). Dept. of Chemistry] [Univ. of Western Ontario, London, Ontario (Canada). Dept. of Chemistry

1996-03-01

175

Conductivity of molten salts in the presence of oil and surfactant  

SciTech Connect

The nonaqueous system of molten salts, sodium dodecyl sulfate (SDS), 1-pentanol, and decane is studied with electrical conductivity measurements in the molten salt rich emulsion phase. The molten salts are a nitrate mixture of ethylenediamine/ammonia/potassium in a ratio of 50/42.5/7.5 by weight. The addition of alcohol to a fixed ratio of salts/surfactant/oil initially causes the conductivity to decrease and then to increase; the solution also exhibits a change from turbid to clear to increasing turbidity. This may indicate a structural change from a globular droplet to a bicontinuous lamellar form. Other properties related to these measurements will be discussed in terms of microemulsion.

Chang, Do Ren (Averett College, Danville, VA (USA))

1990-06-01

176

Liquid chromatographic analysis of coal surface properties. Quarterly progress report, April--June 1993  

SciTech Connect

Experiments were performed on equilibrium adsorption of probes (2-methyl-1-pentanol (2M1P), 1-heptanol, benzene, toluene) on 60-200 mesh Illinois 6 coal, Adaville 1 coal, Wyodak coal, and Pittsburgh 8 coal. Equil. loadings of toluene are higher than those of benzene on the 4 coals. The aromatics (tolene, benzene) obey the Langmuir isotherm model for single-layer adsorption up to 100 ppM. Loadings of 2M1P and 1-heptanol do not follow both the Langmuir and the Freundlich empirical model. Flotation of the coals, equilibrated with aq. solns. of 2M1P and 1-heptanol, increase linearly with Equil. loadings. Equil. adsorption loadings of 1-heptanol on Illinois 6 coal increase with decreased adsorption temperature.

Kwon, K.C.; Rigby, R.

1993-11-01

177

Microemulsion systems studied by positron annihilation techniques  

SciTech Connect

The formation of thermalized positronium atoms is greatly reduced if increasing amounts of water become solubilized in reversed micelles formed by sodium bis(2-ethylhexyl) sulfosuccinate in apolar solvents. Similar observations have been made if the surfactant is Triton X-100. The application of the positron annihilation technique to the study of microemulsions consisting of potassium oleate-alcohol-oil-water mixtures indicates, consistent with previous results, that microemulsion formation requires a certain water/oil ratio if the oil is a long-chain aliphatic hydrocarbon such as hexadecane. This ratio is 0.4 in the case of a 1-pentanol- and 0.2 for a 1-hexanol-containing mixture. This minimum water content is strongly reduced if the oil is an aromatic hydrocarbon. The positron annihilation data also sensitively reflect structural rearrangements in these solutions occurring upon further addition of water, such as the transition of spherical aggregates to a disk-like lamellae structure.

Boussaha, A.; Djermouni, B.; Fucugauchi, L.A.; Ache, H.J.

1980-07-02

178

Effect of alcohol on the properties of micellar systems. Part 2. Chemical relaxation studies of the dynamics of mixed alcohol + surfactant micelles  

SciTech Connect

This work reports the first experimental evidence for the three relaxation processes obtained from systematic chemical relaxation investigation of the system, water/1-pentanol/tetradecyltrimethyl bromide. Less comprehensive results involving other alcohols and surfactants are given. The interpretation is on the basis of Aniansson's theory, and by making use of the quantities obtained in Part 1 in this series, a determination is made for the value of the rate constant of the reaction of dissociation of an alcohol (pentanol) from a mixed alcohol + surfactant micelle. It has been possible to estimate the variation of the rate constant of the reaction of dissociation of a surfactant from a mixed micelle, upon addition of alcohol. Finally, the variation of relaxation time upon addition of alcohol has been related to changes in the micelle size distribution curve. 35 references.

Yiv, S.; Zana, R.; Ulbricht, W.; Hoffmann, H.

1981-03-01

179

Quantum-chemical modeling of energy parameters and vibrational spectra of chain and cyclic clusters of monohydric alcohols  

NASA Astrophysics Data System (ADS)

The specific peculiarities of alcohols such as heightened viscosity, boiling temperature and surface tension can be explained by the capability of their molecules to form relatively stable associates named clusters due to hydrogen bonding. In present work the stability of different chain-like and cyclic clusters of methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol and 1-hexanol was investigated by means of quantum-chemical simulation and particular by recently developed DFT exchange-correlation functional M06-2X. The relative stability of the cluster structure was evaluated by the total energy per molecule at low temperatures (where all alcohols exist in solid state) and by the changing of the free Gibbs energy upon cluster formation at the room temperature. For the verification of revealed results the conformity of calculated IR spectra of the most stable cluster structures with the experimental IR spectra at different temperatures was analyzed.

Golub, P.; Doroshenko, I.; Pogorelov, V.

2014-05-01

180

Responses of the crucifer flea beetle to Brassica volatiles in an olfactometer.  

PubMed

A suite of commercially available volatile compounds was tested in an olfactometer bioassay for responses by the crucifer flea beetle (Phyllotreta cruciferae). Flea beetles were inhibited by exposure to hexane, pentane, and ethanol. Allyl-isothiocyanate, a crucifer-specific volatile, was moderately attractive to spring and early fall flea beetles, but inhibitory to late fall flea beetles. Spring flea beetles were most attracted to (+)-sabinene and E-beta-ocimene, and 1-hexanol, 1-pentanol, and Z-3-hexen-1-ol were stronger attractants than allyl-isothiocyanate. Spring beetles were strongly inhibited by (-)-E-caryophyllene, beta-ionone, indole, (+/-)-linalool, (+)-limonene, E-geraniol, and (-)-beta-pinene and moderately inhibited by (-)-verbenene and hexenal. Our study showed that older leaves and flowers of Brassica napus variety AC Excel contained small amounts of beta-ionone, but seedlings did not. beta-Ionone has not been documented previously in B. napus. PMID:19825302

Gruber, M Y; Xu, N; Grenkow, L; Li, X; Onyilagha, J; Soroka, J J; Westcott, N D; Hegedus, D D

2009-10-01

181

Direct quantitation of fatty acids present in bacteria and fungi: stability of the cyclopropane ring to chlorotrimethylsilane.  

PubMed

The stability of the cyclopropane ring and the fatty acid composition of microbial cells were determined using chlorotrimethylsilane as reagent with three different conditions 80 degrees C for 1 h, 60 degrees C for 1 h, and 60 degrees C for 2 h. Chlorotrimethylsilane permits a simultaneous extraction and derivatization of fatty acids. A basic method was used as reference. The bacteria, Escherichia coli, Burkholderia cepacia, and Lactobacillus brevis, and fungi Aspergillus niger and Gibberella fujikuroi were used. The stability of the cyclopropane ring on acidic conditions was tested using the cyclopropanecarboxylic acid and a commercial mixture of bacteria fatty acid methyl esters (BAME). Fisher's least significant difference test showed significant differences among the methods. The method using chlorotrimethylsilane and 1-pentanol for 1 h at 80 degrees C gave the best results in cyclopropane, hydroxyl, and total fatty acid recoveries. This procedure allows the fast and easy one-step direct extraction derivatization. PMID:18533660

Eras, Jordi; Oró, Robert; Torres, Mercè; Canela, Ramon

2008-07-01

182

Urinary excretion of 2,5-hexanedione and peripheral polyneuropathies in workers exposed to hexane  

SciTech Connect

Forty shoe factory workers who were exposed to hexane were investigated to see if there was a correlation between electroneuromyographic changes indicative of neuropathy and urinary excretion of 2,5-hexanedione. Urinary samples were analyzed for the presence of the metabolic products of n-hexane and its isomers. Electrodiagnostic examination was carried out following the urinary sampling. A rating scale was used to obtain a cumulative numeric index of electrodiagnostic findings. 2,5-Hexanedione and ..gamma..-valerolactone were discovered in all cases, while 2-hexanol was found in 11 cases. 2,5-Hexanedione was the main metabolite in most cases (39 of 40). Only in 1 case was a low level of 2-methyl-2-pentanol detected; 3-methyl-2-pentanol was never detected. Metabolic products of cyclohexane were present in about one-fifth of the cases, while trichloroethanol, a metabolic product of trichloroethylene, was nearly always present, all at very low concentrations. Electromyographic abnormalities significant for early detection of toxic polyneuropathy were found in 14 cases. A statistically significant correlation of the electroneuromyographic scoring on the urinary concentrations of measured metabolites was observed only with 2,5-hexanedione and ..gamma..-valerolactone, both derived from n-hexane. Since ..gamma..-valerolactone is probably not a true metabolite of n-hexane, the authors results support the hypothesis that polyneuropathies in shoemakers are due to 2,5-hexanedione. For practical purposes the urinary concentration of 2,5-hexanedione can serve as a predictive measurement for early detection of neurotoxic lesions at preclinical states.

Governa, M.; Calisti, R.; Coppa, G.; Tagliavento, G.; Colombi, A.; Troni, W.

1987-01-01

183

Atmospheric reactions Cl+CH3-(CH2)n-OH (n=0-4): A kinetic and theoretical study  

NASA Astrophysics Data System (ADS)

The reactions of Cl with a series of linear alcohols: methanol (k1), ethanol (k2), 1-propanol (k3), 1-butanol (k4), and 1-pentanol (k5) were investigated as a function of temperature in the range of 264-382 K by laser photolysis-resonance fluorescence. The obtained kinetic data were used to derive the following Arrhenius expressions: k1=(3.55+/-0.22)×10-10 exp[-(559+/-40)/T], k2=(5.25+/-0.52)×10-11 exp[(190+/-68)/T], k3=(2.63+/-0.21)×10-11 exp[(525+/-51)/T], k4=(3.12+/-0.31)×10-11 exp[(548+/-65)/T], and k5=(3.97+/-0.48)×10-11 exp[(533+/-77)/T] (in units of cm3 molecule-1 s-1). To our knowledge, these are the first absolute kinetic data reported for 1-butanol and 1-pentanol and also the first kinetic study as a function of temperature for these two compounds. Results, mechanism, and tropospheric implications are discussed and compared with the reported reactivity with OH radicals. Moreover, a theoretical insight into the mechanisms of these reactions has also been pursued through ab initio Möller-Plesset second-order perturbation treatment calculations with 6-311G** basis sets. Optimized geometries and vibrational frequencies have been obtained for transition states and molecular complexes appearing along the different reaction pathways. Furthermore, molecular energies have been calculated at quadratic configuration interaction with single, double, and triple excitations level in order to get an estimation of the activation energies.

Garzón, Andrés; Cuevas, Carlos A.; Ceacero, Antonio A.; Notario, Alberto; Albaladejo, José; Fernández-Gómez, Manuel

2006-09-01

184

Enhanced solubilization and desorption of organochlorine pesticides (OCPs) from soil by oil-swollen micelles formed with a nonionic surfactant.  

PubMed

The effect of oil-swollen micelles formed with nonionic surfactant polyoxyethylene sorbitan monooleate (Tween 80), cosurfactant 1-pentanol, and linseed oil on the solubilization and desorption of organochlorine pesticides (OCPs) including DDT and ?-HCH from both loam soil and clay soil were investigated. Results showed that the solubilizing capacities of oil-swollen micelles were dependent on the critical micelle concentration (CMC) of Tween 80. Once the concentrations of oil-swollen micelles exceeded the CMC of Tween 80, the oil-swollen micelles exhibited much higher solubilizing capacity than empty Tween 80 micelles for the two OCPs. Desorption tests revealed that oil-swollen micelles could successfully enhance desorption of OCPs from both loam soil and clay soil. However, compared with the efficiencies achieved by empty Tween 80 micelles, oil-swollen micelles exhibited their superiority to desorb OCPs only in loam soil-water system while was less effective in clay soil-water system. Distribution of Tween 80, 1-pentanol and linseed oil in soil-water system revealed that the difference in the sorption behavior of linseed oil onto the two soils is responsible for the different effects of oil-swollen micelles on the desorption of OCPs in loam soil and clay soil systems. Therefore, oil-swollen micelles formed with nonionic surfactant Tween 80 are better candidates over empty micelle counterparts to desorb OCPs from soil with relatively lower sorption capacity for oil fraction, which may consequently enhance the availability of OCPs in soil environment during remediation processes of contaminated soil. PMID:22998366

Zheng, Guanyu; Selvam, Ammaiyappan; Wong, Jonathan W C

2012-11-01

185

Preconcentration in micro-electromembrane extraction across free liquid membranes.  

PubMed

Preconcentration potential of micro-electromembrane extraction (?-EME) across free liquid membrane (FLM) was examined with an anionic and a cationic dye, 4,5-dihydroxy-3-(p-sulfophenylazo)-2,7-naphthalene disulfonic acid, trisodium salt (SPADNS) and phenosafranine, respectively. For the first time, it was shown that the spatial flexibility of FLMs enabled application of tailored extraction units with mutually different shapes and migration cross-sections for FLMs, donor and acceptor solutions. Thus, e.g. conical units enabled easy and reproducible formation of a three-phase extraction system (donor/FLM/acceptor) with sub-?L volumes of acceptor solutions as well as rapid and highly efficient preconcentration of the two dyes. Quantitative measurements of resulting solutions were carried out by UV-vis spectrophotometry and enrichment factors of up to 98 were achieved for ?-EMEs of 20?M SPADNS (50?L) preconcentrated into 0.5?L of pure water across 1-pentanol at -150V for 18min. Visual monitoring of the entire extraction process (with USB microscope camera) was possible across transparent extraction units, moreover, important extraction parameters, such as FLM dimensions and donor-to-acceptor solution volume ratio, which determine the mechanical stability of the membrane and maximum enrichment factor, respectively, were readily adjusted. Combination of ?-EME across FLMs with capillary electrophoresis (CE) was further shown suitable for preconcentration and determination of perchlorate in drinking water samples. Good repeatability of the ?-EME-CE method (RSD values better than 9.5%), linear relationship for the analytical signal vs. concentration (r(2) better than 0.997) and enrichment factors of up to 30 were achieved for ?-EMEs of perchlorate across 1-pentanol and 1-hexanol based FLMs. PMID:25263115

Kubá?, Pavel; Bo?ek, Petr

2014-10-27

186

Microbial Oxidation of Gaseous Hydrocarbons: Production of Secondary Alcohols from Corresponding n-Alkanes by Methane-Utilizing Bacteria  

PubMed Central

Over 20 new strains of methane-utilizing bacteria were isolated from lake water and soil samples. Cell suspensions of these and of other known strains of methane-utilizing bacteria oxidized n-alkanes (propane, butane, pentane, hexane) to their corresponding secondary alcohols (2-propanol, 2-butanol, 2-pentanol, 2-hexanol). The product secondary alcohols accumulated extracellularly. The rate of production of secondary alcohols varied with the organism used for oxidation. The average rate of 2-propanol, 2-butanol, 2-pentanol, and 2-hexanol production was 1.5, 1.0, 0.15, and 0.08 ?mol/h per 5.0 mg of protein in cell suspensions, respectively. Secondary alcohols were slowly oxidized further to the corresponding methylketones. Primary alcohols and aldehydes were also detected in low amounts (rate of production were 0.05 to 0.08 ?mol/h per 5.0 mg of protein in cell suspensions) as products of n-alkane (propane and butane) oxidation. However, primary alcohols and aldehydes were rapidly metabolized further by cell suspensions. Methanol-grown cells of methane-utilizing bacteria did not oxidize n-alkanes to their corresponding secondary alcohols, indicating that the enzymatic system required for oxidation of n-alkanes was induced only during growth on methane. The optimal conditions for in vivo secondary alcohol formation from n-alkanes were investigated in Methylosinus sp. (CRL-15). The rate of 2-propanol and 2-butanol production was linear for the 40-min incubation period and increased directly with cell protein concentration up to 12 mg/ml. The optimal temperature and pH for the production of 2-propanol and 2-butanol were 40°C and pH 7.0. Metalchelating agents inhibited the production of secondary alcohols. The activities for the hydroxylation of n-alkanes in various methylotrophic bacteria were localized in the cell-free particulate fractions precipitated by centrifugation between 10,000 and 40,000 × g. Both oxygen and reduced nicotinamide adenine dinucleotide were required for hydroxylation activity. The metal-chelating agents inhibited hydroxylation of n-alkanes by the particulate fraction, indicating the involvement of a metal-containing enzyme system in the oxidation of n-alkanes. The production of 2-propanol from the corresponding n-alkane by the particulate fraction was inhibited in the presence of methane, suggesting that the subterminal hydroxylation of n-alkanes may be catalyzed by methane monooxygenase. PMID:16345537

Patel, Ramesh N.; Hou, C. T.; Laskin, A. I.; Felix, A.; Derelanko, P.

1980-01-01

187

Development and evaluation of novel sensing materials for detecting food contamination  

NASA Astrophysics Data System (ADS)

Rapid detection of food-borne volatile organic compounds (VOCs) such as organic acids and alcohols released by bacterial pathogens is being used as an indicator for detecting bacterial contamination in food by our research group. One of our current research thrusts is to develop novel sensors that will be sensitive to specific compounds (at low operating temperature) associated with food safety. This study evaluates two approaches employed to develop sensors for detecting acid and alcohols at low concentrations. Chemoresistive and piezoelectric sensors were developed based on metal oxides and olfactory system based biomaterials, respectively to detect acetic acid, butanol, 3-methyl-1-butanol, 1-pentanol, and 1-hexanol. The metal oxide based sensors were developed by the sol-gel method. A zinc oxide (ZnO) sensor was found to be sensitive to acetic acid with lower detection limit ranging from 13-40 ppm. The three-layered dip-coated gold electrode based ZnO sensors had a LDL of 18 ppm for acetic acid detection. The ZnO-iron oxide (Fe2O3) based nanocomposite sensors were developed to detect butanol operating at 100°C. The 5% Fe/Zn mole ratio based ZnO-Fe2O3 nanocomposite sensors had high correlation coefficients (>0.90) of calibration curves, low butanol LDLs (26 +/- 7 ppm), and lower variation among the sensor responses. The ZnO and ZnO-Fe2O3 nanocomposite sensors showed potential to detect acetic acid and butanol at low concentrations, respectively at 100°C. QCM based olfactory sensors were developed from olfactory receptor and odorant binding protein based sequences to detect low concentrations of acetic acid and alcohols (3-methyl-1-butanol and 1-hexanol), respectively. The average LDLs for acetic acid as well as alcohols detection of the QCM sensors were < 5 ppm. The linear calibration curve based correlation coefficients of the QCM sensors were > 0.80. Finally, a computational simulation based peptide sequences was designed from olfactory receptors and evaluated as sensor material for the detection of alcohols at low concentrations. The results indicated that the QCM sensors exhibited a good sensitivity to 1-hexanol and 1-pentanol with the estimated LDLs in the range of 2-3 ppm and 3-5 ppm, respectively. This research work was successful in developing multiple novel sensing materials to detect alcohols and acid associated with meat contaminations at low concentrations.

Sankaran, Sindhuja

188

Aroma enhancement and enzymolysis regulation of grape wine using ?-glycosidase  

PubMed Central

Adding ?-glycosidase into grape wine for enhancing aroma was investigated using gas chromatography-mass spectrometry (GC-MS) and Kramer sensory evaluation. Compared with the extract from control wines, the extract from enzyme-treated wines increased more aromatic compounds using steam distillation extraction (SDE) and GC-MS analyses. Theses aromatic compounds were as follows: 3-methyl-1-butanol formate, 3-pentanol, furfural, 3-methyl-butanoic acid, 2-methyl-butanoic acid, 3-hydroxy-butanoic acid ethyl ester, hexanoic acid, hexanoic acid ethyl ester, benzyl alcohol, octanoic acid, octanoic acid ethyl ester, dodecanoic acid, and ethyl ester. The enzymolysis regulation conditions, including enzymolysis temperature, enzymolysis time, and enzyme amount, were optimized through L9(34) orthogonal test. Kramer sensory evaluation was performed by an 11-man panel of judges. The optimum enzymolysis regulation conditions were found to be temperature of 45°C, enzymolysis time of 90 min, and enzyme amount of 58.32 U/mL grape wine, respectively. The Kramer sensory evaluation supported that the enzyme-treated wines produced a stronger fragrance. PMID:24804072

Zhu, Feng-Mei; Du, Bin; Li, Jun

2014-01-01

189

Dislodgement effect of natural semiochemicals released by disturbed triatomines: a possible alternative monitoring tool.  

PubMed

The quick detection of domestic and peridomestic triatomines in their environments becomes difficult without the use of dislodgement substances that flush them out from their shelters. At present, tetramethrin 0.2% is being widely used in control programs. Although it is an efficient dislodging agent, its toxicity might affect the health of captured triatomines, of other insects and, to a lesser extent, of other animals, including humans. Here, we tested if semiochemicals released by disturbed adults of Triatoma infestans and/or Rhodnius prolixus can make larvae of the same species exit from their refuges. In a walking olfactometer we found that: 1) larvae of T. infestans were repelled by the odors released by disturbed adults of their own species and of R. prolixus, 2) larvae of R. prolixus did not change their behavior in the presence of odors released by adults of both species, and 3) activity levels were not modulated by these odors in any of both species. Besides, in pseudo-natural conditions we found an increased flushing-out activity of larvae of T. infestans when their shelters were sprayed with isobutyric acid or 3-pentanol, and of larvae of R. prolixus when sprayed with 3-methyl-1-butanol. We succeeded in this work to dislodge larvae of triatomines from artificial shelters using natural volatile compounds, allowing the capture of live bugs for further investigations (e.g., xenodiagnosis or genetic studies) and favoring ecological aspects (e.g., minimizing environmental insecticide-contamination and non-targeted mortality). PMID:24581366

Minoli, Sebastián; Palottini, Florencia; Crespo, Jose Guillermo; Manrique, Gabriel

2013-12-01

190

OH clock determination by proton transfer reaction mass spectrometry at an environmental chamber  

NASA Astrophysics Data System (ADS)

The hydroxyl free radical (OH) is the major oxidizing species in the lower atmosphere. Measuring the OH concentration is generally difficult and involves elaborate, expensive, custom-made experimental setups. Thus other more economical techniques, capable of determining OH concentrations at environmental chambers, would be valuable. This work is based on an indirect method of OH concentration measurement, by monitoring an appropriate OH tracer by proton transfer reaction mass spectrometry (PTR-MS). 3-pentanol, 3-pentanone and pinonaldehyde (PA) were used as OH tracers in ?-pinene (AP) secondary organic aerosol (SOA) aging studies. In addition we tested butanol-d9 as a potential "universal" OH tracer and determined its reaction rate constant with OH: kbutanol-d9 = 3.4(±0.88) × 10-12 cm3 molecule-1 s-1. In order to make the chamber studies more comparable among each other as well as to atmospheric measurements we suggest the use of a chemical (time) dimension: the OH clock, which corresponds to the integrated OH concentration over time.

Barmet, P.; Dommen, J.; DeCarlo, P. F.; Tritscher, T.; Praplan, A. P.; Platt, S. M.; Prévôt, A. S. H.; Donahue, N. M.; Baltensperger, U.

2012-03-01

191

Importance of the Debye interaction in organic solutions: Henry's law constants for polar liquids in nonpolar solvents and vice versa  

SciTech Connect

Henry's law constants have been determined for ..gamma..-butyrolactone (BL), ethyl acetate (EA), and 2-methyl-3-pentanol (MEP) in mixtures of iso-octane (ISO) and toluene (TOL), for BL, EA, TOL, and ISO in cinnamaldehyde (CIN) and for TOL and ISO in each other and in BL. From these data and published vapor pressures, the activity coefficients at infinite dilution and the standard molar Gibbs free energy of transfer, ..delta..G/sub 2/..pi.. of the solutes from dilute solution in ISO to dilute solution in each solvent medium have been calculated. The different behavior patterns of BL and EA are attributed to differences in their abilities to exist in different conformations possessing different dipole moments. For polar solutes, ..delta..G/sub 2//sup 0/ decreases with increasing polarizability of the solvent and with increasing dipole moment of the solute, suggesting increased contributions from dipole-induced dipole (Debye) interactions. The sigmoidal plot of ..delta..G/sub 2//sup 0/ against the change in pair potential energy calculated from the classical expressions suggests that ..delta..G/sub 2//sup 0/ seriously underestimates the strength of the Debye interactions in comparison with the London interactions.

Rytting, J.H.; McHan, D.R.; Higuchi, T.; Grant, D.J.W.

1986-08-01

192

Two Volatile Organic Compounds Trigger Plant Self-Defense against a Bacterial Pathogen and a Sucking Insect in Cucumber under Open Field Conditions  

PubMed Central

Systemic acquired resistance (SAR) is a plant self-defense mechanism against a broad-range of pathogens and insect pests. Among chemical SAR triggers, plant and bacterial volatiles are promising candidates for use in pest management, as these volatiles are highly effective, inexpensive, and can be employed at relatively low concentrations compared with agrochemicals. However, such volatiles have some drawbacks, including the high evaporation rate of these compounds after application in the open field, their negative effects on plant growth, and their inconsistent levels of effectiveness. Here, we demonstrate the effectiveness of volatile organic compound (VOC)-mediated induced resistance against both the bacterial angular leaf spot pathogen, Pseudononas syringae pv. lachrymans, and the sucking insect aphid, Myzus persicae, in the open field. Using the VOCs 3-pentanol and 2-butanone where fruit yields increased gave unexpectedly, a significant increase in the number of ladybird beetles, Coccinella septempunctata, a natural enemy of aphids. The defense-related gene CsLOX was induced by VOC treatment, indicating that triggering the oxylipin pathway in response to the emission of green leaf volatiles can recruit the natural enemy of aphids. These results demonstrate that VOCs may help prevent plant disease and insect damage by eliciting induced resistance, even in open fields. PMID:23698768

Song, Geun Cheol; Ryu, Choong-Min

2013-01-01

193

Two Volatile Organic Compounds Trigger Plant Self-Defense against a Bacterial Pathogen and a Sucking Insect in Cucumber under Open Field Conditions.  

PubMed

Systemic acquired resistance (SAR) is a plant self-defense mechanism against a broad-range of pathogens and insect pests. Among chemical SAR triggers, plant and bacterial volatiles are promising candidates for use in pest management, as these volatiles are highly effective, inexpensive, and can be employed at relatively low concentrations compared with agrochemicals. However, such volatiles have some drawbacks, including the high evaporation rate of these compounds after application in the open field, their negative effects on plant growth, and their inconsistent levels of effectiveness. Here, we demonstrate the effectiveness of volatile organic compound (VOC)-mediated induced resistance against both the bacterial angular leaf spot pathogen, Pseudononas syringae pv. lachrymans, and the sucking insect aphid, Myzus persicae, in the open field. Using the VOCs 3-pentanol and 2-butanone where fruit yields increased gave unexpectedly, a significant increase in the number of ladybird beetles, Coccinella septempunctata, a natural enemy of aphids. The defense-related gene CsLOX was induced by VOC treatment, indicating that triggering the oxylipin pathway in response to the emission of green leaf volatiles can recruit the natural enemy of aphids. These results demonstrate that VOCs may help prevent plant disease and insect damage by eliciting induced resistance, even in open fields. PMID:23698768

Song, Geun Cheol; Ryu, Choong-Min

2013-01-01

194

Aroma enhancement and enzymolysis regulation of grape wine using ?-glycosidase.  

PubMed

Adding ?-glycosidase into grape wine for enhancing aroma was investigated using gas chromatography-mass spectrometry (GC-MS) and Kramer sensory evaluation. Compared with the extract from control wines, the extract from enzyme-treated wines increased more aromatic compounds using steam distillation extraction (SDE) and GC-MS analyses. Theses aromatic compounds were as follows: 3-methyl-1-butanol formate, 3-pentanol, furfural, 3-methyl-butanoic acid, 2-methyl-butanoic acid, 3-hydroxy-butanoic acid ethyl ester, hexanoic acid, hexanoic acid ethyl ester, benzyl alcohol, octanoic acid, octanoic acid ethyl ester, dodecanoic acid, and ethyl ester. The enzymolysis regulation conditions, including enzymolysis temperature, enzymolysis time, and enzyme amount, were optimized through L9(3(4)) orthogonal test. Kramer sensory evaluation was performed by an 11-man panel of judges. The optimum enzymolysis regulation conditions were found to be temperature of 45°C, enzymolysis time of 90 min, and enzyme amount of 58.32 U/mL grape wine, respectively. The Kramer sensory evaluation supported that the enzyme-treated wines produced a stronger fragrance. PMID:24804072

Zhu, Feng-Mei; Du, Bin; Li, Jun

2014-03-01

195

Partitioning tracers for measuring residual NAPL: Field-scale test results  

SciTech Connect

The difficult task of locating and quantifying nonaqueous phase liquids (NAPLs) present in the vadose and saturated zones has prompted the development of innovative, nondestructive characterization techniques. The use of the interwell partitioning tracer`s (IWPT) test, in which tracers that partition into the NAPL phase are displaced through the aquifer, is an attractive alternative to traditional coring and analysis. The first field test of IWPT was conducted in a hydraulically isolated test cell to quantify the total amount of a complex NAPL (a mixture of JP-4 jet fuel and chlorinated solvents) trapped within a 1.5-m smear zone in a shallow, unconfined sand and gravel aquifer at Hill Air Force Base (AFB), Utah. Tracer breakthrough curves (BTCs) were measured in three extraction wells (EWs) following a tracer pulse introduction through four injection wells (IWs). The measured retardation of the partitioning tracer (2,2-dimethyl-3-pentanol) relative to the nonreactive tracer (bromide) was used to quantify the NAPL present. The EW data were used to estimate an average NAPL saturation of 4.6--5.4% within the test cell. NAPL saturations estimated by using measured concentrations in soil cores of two significant compounds present in the NAPL were 3.0 and 4.6%.

Annable, M.D.; Rao, P.S.C.; Hatfield, K.; Graham, W.D. [Univ. of Florida, Gainesville, FL (United States); Wood, A.L.; Enfield, C.G. [Environmental Protection Agency, Ada, OK (United States). National Risk Management Research Lab.

1998-06-01

196

Ruthenium-catalyzed ?-(hetero)arylation of saturated cyclic amines: reaction scope and mechanism.  

PubMed

Transition-metal-catalyzed sp(3) C-H activation has emerged as a powerful approach to functionalize saturated cyclic amines. Our group recently disclosed a direct catalytic arylation reaction of piperidines at the ? position to the nitrogen atom. 1-(Pyridin-2-yl)piperidine could be smoothly ?-arylated if treated with an arylboronic ester in the presence of a catalytic amount of [Ru3(CO)12] and one equivalent of 3-ethyl-3-pentanol. A systematic study on the substrate and reagent scope of this transformation is disclosed in this paper. The effect of substitution on both the piperidine ring and the arylboronic ester has been investigated. Smaller (pyrrolidine) and larger (azepane) saturated ring systems, as well as benzoannulated derivatives, were found to be compatible substrates with the ?-arylation protocol. The successful use of a variety of heteroarylboronic esters as coupling partners further proved the power of this direct functionalization method. Mechanistic studies have allowed for a better understanding of the catalytic cycle of this remarkable transformation featuring an unprecedented direct transmetalation on a Ru(II)-H species. PMID:23780756

Peschiulli, Aldo; Smout, Veerle; Storr, Thomas E; Mitchell, Emily A; Eliáš, Zden?k; Herrebout, Wouter; Berthelot, Didier; Meerpoel, Lieven; Maes, Bert U W

2013-07-29

197

Synthesis of short-chain diols and unsaturated alcohols from secondary alcohol substrates by the Rieske nonheme mononuclear iron oxygenase MdpJ.  

PubMed

The Rieske nonheme mononuclear iron oxygenase MdpJ of the fuel oxygenate-degrading bacterial strain Aquincola tertiaricarbonis L108 has been described to attack short-chain tertiary alcohols via hydroxylation and desaturation reactions. Here, we demonstrate that also short-chain secondary alcohols can be transformed by MdpJ. Wild-type cells of strain L108 converted 2-propanol and 2-butanol to 1,2-propanediol and 3-buten-2-ol, respectively, whereas an mdpJ knockout mutant did not show such activity. In addition, wild-type cells converted 3-methyl-2-butanol and 3-pentanol to the corresponding desaturation products 3-methyl-3-buten-2-ol and 1-penten-3-ol, respectively. The enzymatic hydroxylation of 2-propanol resulted in an enantiomeric excess of about 70% for the (R)-enantiomer, indicating that this reaction was favored. Likewise, desaturation of (R)-2-butanol to 3-buten-2-ol was about 2.3-fold faster than conversion of the (S)-enantiomer. The biotechnological potential of MdpJ for the synthesis of enantiopure short-chain alcohols and diols as building block chemicals is discussed. PMID:22752178

Schäfer, Franziska; Schuster, Judith; Würz, Birgit; Härtig, Claus; Harms, Hauke; Müller, Roland H; Rohwerder, Thore

2012-09-01

198

INVITED PAPER: Surfactant effect on the bubble motions and bubbly flow structures in a vertical channel  

NASA Astrophysics Data System (ADS)

It is well known that a small amount of surfactant can drastically change the motion of a single bubble and this causes a dramatic change of the whole bubbly flow structure. In our previous studies using upward vertical channel flows, it was shown that surfactant influences the shear-induced lift and the lateral migration of a bubble, which causes bubble accumulation and clustering near the wall. In this paper, the dependence of surfactant concentration on the motions of a 1 mm bubble rising through the laminar shear flow is investigated using 1-, 3-Pentanol and Triton X-100. The results are compared with the numerical ones, which show quantitative agreement on the lift and drag forces. Furthermore, we analyze the experimental data for the condition of bubble clustering in upward channel flows with the consideration of contaminant level in tap water. The results indicate that lower contaminant level and higher shear rate cause the significant bubble migration toward the wall, which leads to the formation of bubble clusters.

Takagi, Shu; Ogasawara, Toshiyuki; Fukuta, Masato; Matsumoto, Yoichiro

2009-12-01

199

OH clock determination by proton transfer reaction mass spectrometry at an environmental chamber  

NASA Astrophysics Data System (ADS)

The hydroxyl free radical (OH) is the major oxidizing species in the lower atmosphere. Measuring the OH concentration is generally difficult and involves elaborate, expensive, custom-made experimental setups. Thus other more economical techniques, capable of determining OH concentrations at environmental chambers, would be valuable. This work is based on an indirect method of OH concentration measurement, by monitoring an appropriate OH tracer by proton transfer reaction mass spectrometry (PTR-MS). 3-pentanol, 3-pentanone and pinonaldehyde (PA) were used as OH tracers in ?-pinene (AP) secondary organic aerosol (SOA) aging studies. In addition we tested butanol-d9 as potential "universal" OH tracer and determined its reaction rate constant with OH: kbutanol-d9 = 3.4(±0.88) · 10-12 cm3molecule-1s-1. In order to make the chamber studies more comparable among each other as well as to atmospheric measurements we suggest the use of a chemical (time) dimension:~the OH clock, which corresponds to the integrated OH concentration over time.

Barmet, P.; Dommen, J.; Decarlo, P. F.; Tritscher, T.; Praplan, A. P.; Platt, S. M.; Prévôt, A. S. H.; Donahue, N. M.; Baltensperger, U.

2011-12-01

200

Coupling of alcohols to ethers: The dominance of the surface S{sub N}2 reaction pathway  

SciTech Connect

Coupling of alcohols to ethers, important high value oxygenates, proceeds on acid catalysts via general pathways that uniquely control product composition, oxygen retention, chirality inversion, and kinetics. The dominant pathway is the S{sub N}2 reaction with competition of the alcohols for the surface acid sites. This is exemplified by formation of methyl(ethyl) isobutylether (M(E)IBE) from methanol(ethanol)/isobutanol mixtures, retention of oxygen ({sup 18}O) of the heavier alcohol, and optimum rate as a function of concentration of either reactant alcohol. The S{sub N}2 pathway in the confinement of zeolite pores exhibits additional features of a near-100% selectivity to dimethylether (DME) in H-mordenite and a near-100% selectivity to chiral inversion in 2-pentanol/ethanol coupling to 2-ethoxypentane in HZSM-5. A minor reaction pathway entails olefin or carbenium intermediates, as exemplified by the formation of methyl tertiarybutyl ether (MTBE) from methanol/isobutanol mixtures with oxygen retention of the lighter alcohol. Calculations of transition state and molecular modeling of the oxonium-involving pathways dramatically demonstrate how the reaction path selects the products.

Klier, K.; Feeley, O.C.; Johansson, M.; Herman, R.G. [Lehigh Univ., Bethlehem, PA (United States)

1996-12-31

201

Simultaneous convective heat and mass transfer in impingement ink drying  

SciTech Connect

Effective and economical drying of thin ink films is essential in the printing, packaging and coating industries. In evaporative drying, high heat and mass transfer rates are commonly achieved by means of high velocity impinging air jets. To provide data for dryer design a program of research has been implemented to study the heat and mass transfer processes which underlie the drying of thin ink films. The heat transfer situation under impinging air jets is outlined and some experimental results are presented. Optimization of nozzle arrays for impinging air jets is analyzed for practical applications. A non-contact infra-red technique for continuously monitoring the ink drying process is described and drying curves for an ink based on a single solvent (4-Methyl-2-pentanol-MIBC) are presented. Heat and mass transfer theory has been used to predict drying times in the constant rate drying period. These predictions have been compared with experimentally determined drying times. This research has served to confirm the fundamental importance of the drying curve as a basis for dryer design.

Can, M. [Univ. of Uldag, Bursa (Turkey)] [Univ. of Uldag, Bursa (Turkey)

1998-08-01

202

Studies on the interaction between ethanol and two industrial solvents (methyl isobutyl ketone) in mice  

SciTech Connect

Methyl n-butyl ketone (MnBK) and methyl isobutyl ketone (MiBK) prolong the duration of ethanol-induced loss of righting reflex (EILRR) in mice. MnBK was almost twice as potent in this regard. To explain this difference, the metabolism of both ketones was studied in male CD-1 mice using GC. MiBK was converted to 4-methyl-2-pentanol (4MPOL) and 4-hydroxy methyl isobutyl ketone (HMP). MnBK metabolites were 2-hexanol (2HOL) and 2,5-hexanedione (2,5HD). The effects of both ketones and metabolites on EILRR and ethanol (E) elimination were studied in mice. The ketones and their metabolites were dissolved in corn oil and injected intraperitoneally 30 min before E 4g/kg for EILRR and 2g/kg for E elimination. In the following doses: MnBK, 5; MiBK, 5; 2HOL, 2.5; 4MPOL, 2.5; and HMP 2.5, significantly prolonged EILRR. Concentrations of E in blood and brain upon return of the righting reflex were similar in solvent-treated and control animals. The mean elimination rate of E was slower in groups given MnBK or 2HOL than in control animals. No change in E elimination was observed with MiBK, HMP, 4MPOL, or 2, 5HD.

Granvil, C.P.; Sharkawi, M.; Plaa, G.L. (Univ. de Montreal, Quebec (Canada))

1991-03-11

203

Polymer-aggregate incompatability, phase behavior and electrophoretic laser light scattering investigations of microemulsions with ultralow interfacial tensions  

SciTech Connect

Enhanced oil recovery by surfactant-polymer flooding involves pumping surfactant solution underground followed by polymer solution for mobility control. This involves microemulsions which are stable dispersions of oil and water containing amphiphiles, and frequently electrolytes. Polymer addition induces phase separation in liquid crystalline surfactant solutions. Phase separation does not occur in isotropic solutions. Oil-in-water (lower phase) microemulsions are affected by the polymer which separates out. A microemulsion system containing a pure sulfonate (Texas 1) has been developed. It behaves like petroleum sulfonate microemulsions. Salinity and cosurfactant partitioning determine the formation, texture and viscosity of liquid crystalline phases formed before addition of oil. Microemulsion phase behavior depends on cosurfactant chain length through solubility and steric factors. A pH-dependent microemulsion system has been developed using oleic acid and 2-pentanol. At constant pH the phase transitions are lower ..-->.. middle ..-->.. upper with increasing salinity. The effects of pH and salinity on the electrostatic free energy were analyzed using Gouy-Chapman theory. The surface pressure is not very sensitive to salinity at constant bulk pH.

Qutubuddin, S.A.S.M.

1983-01-01

204

Characterization of the acidic and basic properties of [alpha]LiAlO[sub 2], [gamma]LiAlO[sub 2], and calcined [open quotes]HAlO[sub 2][close quotes] using isopropyl alcohol  

SciTech Connect

Characterization of both the acidic and basic sites of [alpha]LiAlO[sub 2], [gamma]LiAlO[sub 2], and calcined [open quotes]HAlO[sub 2][close quotes] was carried out with the isopropyl alcohol probe reaction. All three materials catalyzed the formation of both propylene and acetone. The formation of propylene is indicative of acidic-basic pair sites, while the presence of acetone is indicative of basic sites. In addition to the formation of both propylene and acetone, base-catalyzed acetone aldol condensation products were formed on both [alpha]LiAlO[sub 2], and calcined [open quotes]HAlO[sub 2][close quotes]. Both materials produced a C6DIENE (2-methyl-1,3-pentadiene or 4-methyl-1,3-pentadiene) aldol condensation product, while [alpha]M2PONE (4-methyl-2-pentanone) and 4M2POL (4-methyl-2-pentanol). The reaction pathways that describe the formation of the various C6 products were used to infer the nature of the basic sites on the materials. Additional information obtained from TPD and FTIR of chemisorbed CO[sub 2] demonstrate that the basic sites on [alpha]LiAlO[sub 2] are similar in strength and number to MgO. 35 refs., 9 figs., 6 tabs.

Tomczak, D.C.; Allen, J.L.; Poeppelmeier, K.R. (Northwestern Univ., Evanston, IL (United States))

1994-03-01

205

Interplay of Metalloligand and Organic Ligand to Tune Micropores within Isostructural Mixed-Metal Organic Frameworks (M MOFs) for Their Highly Selective Separation of Chiral and Achiral Small Molecules  

SciTech Connect

Four porous isostructural mixed-metal-organic frameworks (M'MOFs) have been synthesized and structurally characterized. The pores within these M'MOFs are systematically tuned by the interplay of both the metalloligands and organic ligands which have enabled us not only to direct their highly selective separation of chiral alcohols 1-phenylethanol (PEA), 2-butanol (BUT), and 2-pentanol (2-PEN) with the highest ee up to 82.4% but also to lead highly selective separation of achiral C{sub 2}H{sub 2}/C{sub 2}H{sub 4} separation. The potential application of these M'MOFs for the fixed bed pressure swing adsorption (PSA) separation of C{sub 2}H{sub 2}/C{sub 2}H{sub 4} has been further examined and compared by the transient breakthrough simulations in which the purity requirement of 40 ppm in the outlet gas can be readily fulfilled by the fixed bed M'MOF-4a adsorber at ambient conditions.

Madhab, Das [University of Texas at San Antonio (UTSA); He, Yabing [University of Texas at San Antonio (UTSA); Kim, Jaheon [Soongsil University, Korea; Guo, Qunsheng [University of Texas at San Antonio (UTSA); Zhao, Cong-Gui [University of Texas at San Antonio (UTSA); Hong, Kunlun [ORNL; Xiang, Sheng-Chang [University of Texas at San Antonio (UTSA); Zhang, Zhangjing [University of Texas at San Antonio (UTSA); Thomas, K Mark [University of Newcastle upon Tyne; Krishna, Rajamani [Universitate Amsterdam; Chen, Banglin [University of Texas at San Antonio (UTSA)

2012-01-01

206

Reactions of primary and secondary alkanols over platinum-, iridium-, and rhodium-silica (cab-o-sil) catalysts in the presence of hydrogen variables affecting ether formation  

SciTech Connect

The reaction of 3.1:1 hydrogen to 2-propanol, 2-butanol, or 2-pentanol over silica-supported 20% platinum, 18% iridium, or 10% rhodium in a flow reactor at 130/sup 0/-190/sup 0/C yielded ethers and alkenes. The alkenes were hydrogenated to alkanes under the reaction conditions. Under identical conditions, the conversion increased and the ether selectivity decreased with increasing carbons in the alkanols. In the reaction of 2-propanol over rhodium, the conversion increased and the ether selectivity decreased with increasing contact time. The reactions of n-butanol on supported iridium yielded 94.7 and 83.3% di-n-butyl ether at 13 and 60% conversion, respectively; yields were lower on platinum. The main product of neopentyl alcohol on platinum was isobutane, and on iridium, it was dineopentyl ether with 57.1% selectivity. The results were compared with previously published results obtained with silica-supported palladium and the reaction paths and relative rates of dehydroxylation-dehydroxymethylation and dehydration were discussed.

Licht, E. (Bar Ilan Univ.); Schaechter, Y.; Pines, H.

1980-01-01

207

Characterization of the most odor-active volatiles of orange wine made from a Turkish cv. Kozan (Citrus sinensis L. Osbeck).  

PubMed

The aroma-active compounds of cv. Turkish Kozan orange wine were analyzed by sensory and instrumental analyses. Liquid-liquid extraction with dichloromethane was used for extraction of volatile components. According to sensory analysis, the aromatic extract obtained by liquid-liquid extraction was representative of orange wine odor. A total of 63 compounds were identified and quantified in orange wine. The results of the gas chromatography-olfactometry analysis showed that 35 odorous compounds were detected by the panelists. Of these, 28 aroma-active compounds were identified. Alcohols followed by terpenes and esters were the most abundant aroma-active compounds of the orange wine. Among these compounds, ethyl butanoate (fruity sweet), 3-methyl-1-pentanol (roasty), linalool (floral citrusy), gamma-butyrolactone (cheesy burnt sugar), 3-(methylthio)-propanol (boiled potato, rubber), geraniol (floral citrusy), and 2-phenylethanol (floral rose) were the most important contributors to the aroma of the orange wine because they were perceived by all eight panelists. PMID:18078317

Selli, Serkan; Canbas, Ahmet; Varlet, Vincent; Kelebek, Hasim; Prost, Carole; Serot, Thierry

2008-01-01

208

Enantiomeric separation of imidazolinone herbicides using chiral high-performance liquid chromatography.  

PubMed

Chiral high-performance liquid chromatography (HPLC) is one of the most powerful tools to prepare enantiopure standards of chiral compounds. In this study, the enantiomeric separation of imidazolinone herbicides, i.e., imazethapyr, imazapyr, and imazaquin, was investigated using chiral HPLC. The enantioselectivity of Chiralpak AS, Chiralpak AD, Chiralcel OD, and Chiralcel OJ columns for the three analytes was compared under similar chromatographic conditions. Chiralcel OJ column showed the best chiral resolving capacity among the test columns. The resolved enantiomers were distinguished by their signs of circular dichroism detected at 275 nm and their structures confirmed with LC-mass spectrometric analysis. Factors affecting the chiral separation of imidazolinones on Chiralcel OJ column were characterized. Ethanol acted as a better polar modifier than the other alcohols including 2-propanol, 1-butanol, and 1-pentanol. Although the acidic modifier in the mobile phase did not influence chiral recognition, it was necessary for reducing the retention time of enantiomers and suppressing their peak tailing. Thermodynamic evaluation suggests that enantiomeric separation of imidazolinones on Chiralcel OJ column is an enthalpy-driven process from 10 to 40 degrees C. This study also shows that small amounts of pure enantiomers of imidazolinones may be obtained by using the analytical chiral HPLC approach. PMID:17167748

Lin, Kunde; Xu, Chao; Zhou, Shanshan; Liu, Weiping; Gan, Jay

2007-03-01

209

Absorption and emission characteristics of merocyanine 540 in microemulsions  

SciTech Connect

Cyanine dyes are heterocyclic chromophores that are extensively used in a number of areas. For example, they are used as photographic sensitizers, in photographic filter layers, for textiles, and in chemotherapy. Recently they have also been examined as possible candidates for solar energy conversion in the form of monolayers and thin films on glass substrates. The efficiency of the cyanine dyes as photosensitizers depends upon their emission properties and also on their photostability. Unfortunately, it is commonly observed that the cyanine dyes with a polymethine chain in the molecular framework degrade in light. In a recent communication, Humphrey-Baker et al. have shown that both the fluorescence yield and photostability of a cyanine dye are significantly enhanced in anionic micellar solution, and they have attributed it to a microviscosity effect. The absorption and fluorescence properties of merocyanine 540 in anionic and cationic microemulsion are reported. Measurements have also been performed in water, ethanol, 1-pentanol, and aqueous micellar solutions to serve as a basis of comparison.

Dixit, N.S.; Mackay, R.A.

1983-05-04

210

Surface Tension Characteristics of Aqueous Lithium Bromide Solution with Alcoholic Surfactant  

NASA Astrophysics Data System (ADS)

At present, the combination of aqueous lithium bromide (LiBr) solution as an absorbent and water as a refrigerant have widely been used as the working fluid for absorption refrigerating machines. In order to obtain absorption enhancement of water vapor into the LiBr solution by Marangoni convection, an alcoholic surfactant is being added in the LiBr solution. In that case, the surface tension of the LiBr solution with the surfactant plays an important role for the vapor absorption. In this study, the surface tensions of the LiBr solution with several alcoholic surfactants such as 1-butanol, 1-hexanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 1-heptanol, 1-octanol and 2-ethyl-1-hexanol were measured by Wilhelmy plate method. As a result, the surface tensions of 50 wt% LiBr solution with several surfactants were obtained over the LiBr solution temperature range from 298 K to 318 K and the surfactant concentration range from 0 to 104 ppm by mass. The measured surface tension has decreased with the increasing number of carbons included in the surfactant at constant concentration, and the surface tension has increased with the increasing temperature of 50 wt% LiBr solution. The surface tension increase of 1-octanol became greater than any other surfactant used in this work. The effective carbon number of the surfactant for the absorption enhancement was in the range from 7 to 8.

Sasaki, Naoe; Ogawa, Kiyoshi

211

Nucleation of ethanol, propanol, butanol, and pentanol: a systematic experimental study along the homologous series.  

PubMed

We present homogeneous vapor-liquid nucleation rates of the 1-alcohols (C(n)H(2n+1)OH, n = 2-4) measured in the well-established two-valve nucleation pulse chamber as well as in a novel one-piston nucleation pulse chamber at temperatures between 235 and 265 K. The nucleation rates and critical cluster sizes show a very systematic behavior with respect to the hydrocarbon chain length of the alcohol, just as their thermo-physical parameters such as surface tension, vapor pressure, and density would suggest. For all alcohols, except ethanol, predictions of classical nucleation theory lie several orders of magnitude below the experimental results and show a strong temperature-dependence typically found in nucleation experiments. The more recent Reguera-Reiss theory [J. Phys. Chem. B 108(51), 19831 (2004)] achieves reasonably good predictions for 1-propanol, 1-butanol, and 1-pentanol, and independent of the temperature. Ethanol, however, clearly shows the influence of strong association between molecules even in the vapor phase. We also scaled all experimental results with classic nucleation theory to compare our data with other data from the literature. We find the same overall temperature trend for all measurement series together but inverted and inconsistent temperature trends for individual 1-propanol and 1-butanol measurements in other devices. Overall, our data establishe a comprehensive and reliable data set that forms an ideal basis for comparison with nucleation theory. PMID:22894357

Manka, Alexandra A; Wedekind, Jan; Ghosh, David; Höhler, Kristina; Wölk, Judith; Strey, Reinhard

2012-08-01

212

Characterizing olfactory perceptual similarity using carbon chain discrimination in Fischer 344 rats.  

PubMed

Performance on olfactory tests can be influenced by a number of stimulus characteristics including chemical structure, concentration, perceptual similarity, and previous experience with the test odorants. Few of these parameters have been extensively characterized in the Fischer 344 rat strain. To investigate how odor quality affects perception in this rat strain, we measured how graded perceptual similarity, created by varying carbon chain length across a series of homologous alcohol pairs, influenced odor discrimination using a liquid-motivated go/no-go task. We employed an automated, liquid-dilution olfactometer to train Fischer 344 rats (N = 8) on a 2-odor discrimination task. Six odorants (1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol) were arranged to produce 15 novel odorant pairs differing between 1 and 5 carbon atoms; testing sessions included presentation of only 1 pseudorandomly assigned pair daily (200 trials). Results show that although rats can learn to discriminate between any 2 odorant pairs, performance declines systematically as the pairs become more structurally similar and, therefore, more perceptually confusing. As such, the easier discrimination pairs produced reliable ceiling effects across all rats, whereas performance for the difficult discrimination pairs was consistently worse, even after repeated testing. These data emphasize the importance of considering odorant stimulus dimensions in experimental designs employing olfactory stimuli. Moreover, establishing baseline olfactory performance in Fischer 344 rats may be particularly useful for predicting age-related cognitive decline in this model. PMID:24488965

Yoder, Wendy M; Setlow, Barry; Bizon, Jennifer L; Smith, David W

2014-05-01

213

Experimental and computational study of the effect of alcohols on the solution and adsorption properties of a nonionic symmetric triblock copolymer.  

PubMed

This study investigates the effect of alcohols on the solution and adsorption properties of symmetric triblock nonionic copolymers comprising blocks of ethylene oxide (EO) and propylene oxide (PO) (EO(37)PO(56)EO(37)). The cloud point, surface tension, critical micelle concentration (CMC), and maximum packing at the air-water interface are determined, and the latter is compared to the amount of polymer that adsorbs from solution onto polypropylene (PP) and cellulose surfaces. The interaction energy and radius of micelles are calculated by using molecular dynamics (MD) simulations. Equivalent MD bead parameters were used in dynamic density functional theory (DDFT) simulations to study the influence of alcohols on the phase behavior of EO(37)PO(56)EO(37) and its adsorption on PP from aqueous solutions. The simulation results agree qualitatively with the experimental observations. Ethanol acts as a good cosolvent for EO(37)PO(56)EO(37) and reduces the amount of EO(37)PO(56)EO(37) that adsorbs on PP surfaces; however, little or no influence is observed on the adsorption on cellulose. Interestingly, longer chain alcohols, such as 1-pentanol, produce the opposite effect. Overall, the solution and adsorption properties of nonionic symmetric triblock copolymers in the presence of alcohols are rationalized by changes in solvency and the hydrophobic effect. PMID:22188471

Liu, Xiaomeng; He, Feng; Salas, Carlos; Pasquinelli, Melissa A; Genzer, Jan; Rojas, Orlando J

2012-02-01

214

Use of micellar liquid chromatography to analyze darunavir, ritonavir, emtricitabine, and tenofovir in plasma.  

PubMed

Danuravir, ritonavir, emtricitabine, and tenofovir are together prescribed against AIDS as a highly active antiretroviral therapy regimen. Micellar liquid chromatography has been applied to determine these four antiretroviral drugs in plasma. The sample preparation is shortened to the dilution of the sample in a micellar solution, filtration, and injection. Clean-up steps are avoided, due to the solubilization of plasma matrix in micellar media. The drugs were analyzed in <20 min using a mobile phase of 0.06 M sodium dodecyl sulfate/2.5% 1-pentanol (pH 7) running under isocratic mode through a C18 column at 1 mL/min at room temperature. Absorbance wavelength detection was set at 214 nm. The method was successfully validated following the ICH Harmonized Tripartite Guideline in terms of selectivity, limit of detection (0.080-0.110 ?g/mL), limit of quantification (0.240-0.270 ?g/mL), linearity between 0.25 and 25 ?g/mL (r(2) > 0.995), accuracy (89.3-103.2%), precision (<8.2%) and robustness (<7.5%). Real plasma sample from patients taking this therapy were analyzed. This is the first paper showing the simultaneous detection of this four drugs. Therefore, the methodology was proven useful for the routine analysis of these samples in a hospital laboratory for clinical purposes. PMID:25103282

Peris-Vicente, Juan; Villarreal-Traver, Mónica; Casas-Breva, Inmaculada; Carda-Broch, Samuel; Esteve-Romero, Josep

2014-10-01

215

Fractionation and identification of minor and aroma-active constituents in Kangra orthodox black tea.  

PubMed

The aroma constituents of Kangra orthodox black tea were isolated by simultaneous distillation extraction (SDE), supercritical fluid extraction and beverage method. The aroma-active compounds were identified using gas chromatography-olfactometry-mass spectrometry. Geraniol, linalool, (Z/E)-linalool oxides, (E)-2-hexenal, phytol, ?-ionone, hotrienol, methylpyrazine and methyl salicylate were major volatile constituents in all the extracts. Minor volatile compounds in all the extracts were 2-ethyl-5-methylpyrazine, ethylpyrazine, 2-6,10,14-trimethyl-2-pentadecanone, acetylfuran, hexanoic acid, dihydroactinidiolide and (E/Z)-2,6-nonadienal. The concentrated SDE extract was fractionated into acidic, basic, water-soluble and neutral fractions. The neutral fraction was further chromatographed on a packed silica gel column eluted with pentane and diethyl ether to separate minor compounds. The aroma-active compounds identified using gas chromatography-olfactometry-mass spectrometry were 2-amylfuran, (E/Z)-2,6-nonadienal, 1-pentanol, epoxylinalool, (Z)-jasmone, 2-acetylpyrrole, farnesyl acetone, geranyl acetone, cadinol, cubenol and dihydroactinidiolide. AEDA studies showed 2-hexenal, 3-hexenol, ethylpyrazine, (Z/E)-linalool oxides, linalool, (E/Z)-2,6-nonadienal, geraniol, phenylethanol, ?-ionone, hotrienol and dihydroactinidiolide to be odour active components. PMID:25148991

Joshi, Robin; Gulati, Ashu

2015-01-15

216

Sol-gel derived TiO[sub 2] microemulsion gels and coatings  

SciTech Connect

Microemulsion gels and coatings have been obtained by the sol-gel method using titanium(IV) isopropoxide. Three types of fine water dispersions have been used as the basis sol: reverse Triton X-100 micelles in cyclohexane; quaternary water-in-oil microemulsions containing cyclohexane, 1-pentanol, sodium dodecyl sulfate, and water; and dispersions of water in pentanol in the presence of sodium dodecyl sulfate. Titanium(IV) isopropoxide was dissolved in the continuous phase and hydrolyzed by the dispersed water. Gelation occurred in a few hours in the case of cyclohexane, as the solvent of the continuous phase, and in few days in the case of pentanol. The gelation processes and the obtained microenvironment were probed with fluorescent probes. Films of thickness of the order of a hundred nanometers can be obtained by dipping glass, plastic, or aluminum plates into the solutions at their early stage of gelation. The absorption spectra of the films were characteristic of TiO[sub 2] absorption. X-ray analysis of films heated to 400-500[degree]C revealed a rutile structure. 44 refs., 8 figs., 2 tabs.

Papoutsi, D.; Lianos, P.; Yianoulis, P.; Koutsoukos, P. (Univ. of Patras (Greece))

1994-06-01

217

Mechanism of promotion of iron Fischer-Tropsch catalysts: Quarterly report for the period ending March 31, 1987  

SciTech Connect

The Fischer-Tropsch reaction is a complex combination of many reactions. Among those that have been demonstrated to occur on the catalyst surface are CO dissociation, build-up of carbon chains by a polymerization process, desorption of products such as olefins and oxygen-containing compounds, water formation and its subsequent shift reaction to form CO/sub 2/, olefin hydrogenation, isomerization and reincorporation in the synthesis and, probably, other reactions yet to be identified and studied. The tracer technique, involving the feeding of /sup 14/C-labeled compounds to the synthesis, is being used here in an effort to learn how catalyst additives and supports influence these reactions and determine the final product distribution. The results presented in this paper utilized (1-/sup 14/C)-1-pentanol as the label. Product separations were utilized in order to evaluate the /sup 14/C distribution in alkene and alkane components over a range of carbon numbers. Results pertaining to the two alpha values are presented in this paper. 21 refs., 13 figs.

Not Available

1987-01-01

218

The effect of medium chain length alcohols on the micellar properties of sodium dodecyl sulfate in sodium chloride solutions  

SciTech Connect

The effect of medium chain length alcohols on the micellar size and shape of sodium dodecyl sulfate in electrolyte solutions has been investigated by means of small angle neutron scattering (SANS), dynamic light scattering (DLS), and viscosity measurements. The surfactant content was kept constant throughout, at 0.04 m, and the alcohols used were 1-butanol, 1-pentanol, and 1-hexanol. The data from the various techniques are qualitatively in agreement. The SANS data generally fit a model for prolate ellipsoids with varying ratios of the major to minor axis. Addition of butanol first leads to a decrease in micellar size, the major to minor axis ratio decreases from about 6 to less than 2. However, as the butanol concentration exceeds 0.5 m, the micelles starts to grow again. The same can be seen from the diffusion coefficient as measured by DLS. Addition of pentanol or hexanol do not bring about this minimum in micellar size. The minor axis decreases and the major axis increases as these alcohols are added. Thus these alcohols make the prolate ellipsoidal micelles grow continuously towards large rod-like structures. The viscosity data are less detailed, but confirm the general trend upon alcohol addition.

Foerland, G.M.; Hoeiland, H. (Bergen Univ. (Norway). Dept. of Chemistry); Samseth, J. (Institute for Energy Technology, Kjeller (Norway)); Mortensen, K. (Risoe National Lab., Roskilde (Denmark))

1994-04-01

219

Removal of acrylic coatings from works of art by means of nanofluids: understanding the mechanism at the nanoscale  

NASA Astrophysics Data System (ADS)

Conservation of works of art often involves the inappropriate application of synthetic polymers. We have proposed the use of alternative methodologies for conservation and formulated innovative cleaning nanostructured systems to remove previously applied polymer films and grime from painted surfaces. In particular, a novel ``micellar system'' composed of water, SDS, 1-pentanol, ethyl acetate and propylene carbonate was recently formulated and successfully used to remove acrylic and vinyl/acrylic copolymers from Mesoamerican wall paintings in the archeological site of Cholula, Mexico. This contribution reports on the mechanism of the interaction process that takes place between the nanostructured fluid and the polymer coating at the nanoscale. The structural properties of the ``micellar solution'' and of the polymer film are investigated before, during and after the interaction process using several surface and solution techniques. Rather than a classical detergency mechanism, we demonstrate that micelles act as solvent containers and interact with the polymer film leading to its swelling and detachment from the surface and to its segregation in a liquid droplet, which phase-separates from the aqueous bulk. After the removal process the micelles become smaller in size and undergo a structural re-arrangement due to the depletion of the organic solvents. These findings can be framed in an interaction mechanism which describes the removal process, opening up new perspectives in the design and formulation of new cleaning systems specifically tailored for intervention on particular conservation issues.

Baglioni, Michele; Rengstl, Doris; Berti, Debora; Bonini, Massimo; Giorgi, Rodorico; Baglioni, Piero

2010-09-01

220

Validation of techniques for the destruction of dimethyl sulfate  

SciTech Connect

It has been reported that dimethyl sulfate (DMS) can be degraded with sodium hydroxide solution (1 mol/L), sodium carbonate solution (1 mol/L), or ammonium hydroxide solution (1.5 mol/L). This has now been confirmed. Complete destruction of undiluted DMS or DMS in solvents miscible with water (methanol, ethanol, DMSO, DMF, acetone) or solvents partially miscible or immiscible with water (toluene, p-xylene, benzene, 1-pentanol, ethyl acetate, chloroform, carbon tetrachloride, acetonitrile) could be obtained using any of the above methods. Reaction times were 15 min after homogeneity was obtained for undiluted DMS, 15 min for solutions in methanol, ethanol, DMSO, and DMF, one hour for solutions in acetone, three hours for acetonitrile, and one day for the other solvents listed above. The final reaction mixtures were tested for mutagenicity, and when the solutions were not cytotoxic, no mutagenic response was obtained. DMS in solution was determined by a colorimetric method. The products of the reactions were found to be methanol when NaOH and Na/sub 2/ CO/sub 3/ were used and methylamine, dimethylamine, trimethylamine, and methanol when ammonium hydroxide was used. The stability of DMS in various solvents was also determined.

Lunn, G.; Sansone, E.B.

1985-03-01

221

Oil-in-water microemulsions enhance the biodegradation of DDT by Phanerochaete chrysosporium.  

PubMed

A novel approach was developed using oil-in-water (O/W) microemulsions formed with non-ionic surfactant, cosurfactant (1-pentanol) and linseed oil, at the cosurfactant to surfactant ratio (C/S ratio, w/w) of 1:3 and oil to surfactant ratio (O/S ratio, w/w) of 1:10, to enhance the biodegradation of DDT by the white rot fungus Phanerochaete chrysosporium. Results showed that microemulsions formed with Tween 80 effectively enhanced the biodegradation of DDT by P. chrysosporium and the enhancement was about two times that of Tween 80 solution, while microemulsion formed with Triton X-100 exhibited negative effect. Further studies revealed that microemulsion formed with Tween 80 enhanced the biodegradation of DDT through transporting DDT from crystalline phase to mycelium as well as their positive effect on the growth of P. chrysosporium; of these, the former is likely the most important and pre-requisite for the biodegradation of DDT by P. chrysosporium. PMID:22520221

Zheng, Guanyu; Selvam, Ammaiyappan; Wong, Jonathan W C

2012-12-01

222

Dependence of local void fraction distribution on turbulent structure of upward bubbly flow in vertical channel  

NASA Astrophysics Data System (ADS)

Turbulent structure of upward dilute bubbly flow with 1 mm bubbles in a vertical channel is investigated experimentally. Small amount of surfactant is added to water to avoid bubble coalescence and to control local void fraction distribution. Liquid phase velocity is measured using two-dimensional Laser Doppler Velocimetry. In 1-Pentanol solution of 20 ppm, bubbles have half-slip surface and migrate strongly toward the channel wall due to the shear-induced lift force which leads to wall-peaked distribution of local void fraction. On the other hand, in Triton X-100 solution of 2 ppm, bubbles become fully-contaminated and do not migrate toward the wall or the channel centre due to near-zero lift force, causing uniform distribution of local void fraction in the wall-normal direction. Once bubbles accumulate near the wall, transport of turbulent energy produced by the wall shear towards the channel centre is blocked. Then turbulence induced by the bubble motion becomes dominant in a wide core region (so-called pseudo turbulence). By contrast, in the case of uniform distribution of bubbles, a mechanism of a turbulent energy transport which is the same as that of a single-phase turbulence still exists and furthermore the bubble-induced turbulence is added on it.

Ogasawara, Toshiyuki; Takagi, Shu; Matsumoto, Yoichiro

2008-11-01

223

Nucleation of ethanol, propanol, butanol, and pentanol: A systematic experimental study along the homologous series  

NASA Astrophysics Data System (ADS)

We present homogeneous vapor-liquid nucleation rates of the 1-alcohols (CnH2n+1OH, n = 2-4) measured in the well-established two-valve nucleation pulse chamber as well as in a novel one-piston nucleation pulse chamber at temperatures between 235 and 265 K. The nucleation rates and critical cluster sizes show a very systematic behavior with respect to the hydrocarbon chain length of the alcohol, just as their thermo-physical parameters such as surface tension, vapor pressure, and density would suggest. For all alcohols, except ethanol, predictions of classical nucleation theory lie several orders of magnitude below the experimental results and show a strong temperature-dependence typically found in nucleation experiments. The more recent Reguera-Reiss theory [J. Phys. Chem. B 108(51), 19831 (2004)] achieves reasonably good predictions for 1-propanol, 1-butanol, and 1-pentanol, and independent of the temperature. Ethanol, however, clearly shows the influence of strong association between molecules even in the vapor phase. We also scaled all experimental results with classic nucleation theory to compare our data with other data from the literature. We find the same overall temperature trend for all measurement series together but inverted and inconsistent temperature trends for individual 1-propanol and 1-butanol measurements in other devices. Overall, our data establishe a comprehensive and reliable data set that forms an ideal basis for comparison with nucleation theory.

Manka, Alexandra A.; Wedekind, Jan; Ghosh, David; Höhler, Kristina; Wölk, Judith; Strey, Reinhard

2012-08-01

224

Initial spectra of trapped electrons in alcohol glasses from 12 to 115 K  

SciTech Connect

Glassy 1-propanol (PrOH), 1-butanol (BuOH), and 1-pentanol (PenOH) were studied by pulse radiolysis from 6 to 115 K. Spectra were measured from 100 ns after the start of a 40-ns pulse. The temperature of samples irradiated at 6 K rose to 12 K due mostly to the electron pulse. At a nominal 6 K, the 100-ns spectra have maxima at approx. 2000 nm. At higher temperatures the spectra shift to the blue until, at 115 K, maxima in the range 1300 to 1700 nm are found with shoulders at approx. 800 nm. However, the midpulse spectrum for each alcohol was almost independent of temperature, both in shape and in absolute intensity. Hence, on the 20-ns time scale, the initial spectra of trapped electrons are essentially the same between 12 and 115 K. This is in direct contradiction to one current model of electron trapping which presents the view that initial trapping in these glasses occurs at different sites depending on the temperature because of higher activation energies for trapping in deep traps. Our measurements, combined with published results, strongly suggest that the spectrum of the initially trapped electrons in 1-propanol undergoes only a small change between 12 and 261 K. 2 figures, 1 table.

Klassen, N.V.; Teather, G.G.

1983-09-29

225

Control over the color transition behavior of polydiacetylene vesicles using different alcohols.  

PubMed

In this contribution, we investigate the color transition behavior of polydiacetylene (PDA) vesicles upon exposure to different chemical stimuli. A series of linear and branched alcohols are used as model additives, allowing systematic control of their molecular shape and polarity. The PDA vesicles are fabricated by using three monomers, 10,12-pentacosadiynoic acid (PCDA), 10,12-tricosadyinoic acid (TCDA), and N-(2-amino ethyl)pentacosa-10,12-dyinamide (AEPCDA). When a series of linear alcohols is used, the longer alcohol length causes color transition of all PDA vesicles. In this system, the penetration of linear alcohols into the inner layer of PDA vesicles is dictated by their polarity. The change of -OH position within the alcohol molecule also affects the degree of penetration. It requires a higher amount of the 2-propanol to induce color transitions of the PDAs compared to that of the 1-propanol. The addition of methyl branches into the hydrophobic tail of alcohols causes an increase in steric effect, which hinders the penetration as well. When the 2,2-dimethyl-1-propanol is used as a stimulus, the color transition of PDAs occurs at much higher alcohol concentration compared to 2-methyl-1-butanol, 3-methyl-1-butanol, and 1-pentanol. The variation of PDA structures also affects their ability to interact with the alcohols. The modified head group of poly(AEPCDA) promotes the ability to distinguish between 1-propanol and 2-propanol or 1-propanol and ethanol. PMID:23123029

Pattanatornchai, Thanutpon; Charoenthai, Nipaphat; Wacharasindhu, Sumrit; Sukwattanasinitt, Mongkol; Traiphol, Rakchart

2013-02-01

226

Temperature and viscosity dependence of the nonradiative decay rates of auramine-O and thioflavin-T in glass-forming solvents.  

PubMed

Both auramine-O (AuO) and thioflavin-T (ThT) behave as fluorescent molecular rotors, meaning that their (non)radiative properties are markedly affected by the intramolecular rotation of the molecule. In this article, steady-state and time-resolved fluorescence of AuO and ThT were measured in three alcohols, 1-propanol, 1-butanol, and 1-pentanol, over a wide range of temperatures (86-260 K). These solvents are glass-forming liquids, and their viscosity and dielectric relaxation time increase by more than 10 orders of magnitude as the temperature is lowered from room temperature to ~100 K. Accordingly, the fluorescence nonradiative rates constants of AuO and ThT in these solvents decrease by about 3 orders of magnitude at the latter temperature range. We found very good correspondence between the temperature dependence of the nonradiative rate constant, k(nr), of both molecules and the dielectric relaxation rate of the solvents. The k(nr) values of AuO are twice those of ThT along the whole temperature range. The temperature dependence of k(nr) is consistent with the nonradiative model suggested by Glasbeek and co-workers. PMID:23176313

Erez, Yuval; Amdursky, Nadav; Gepshtein, Rinat; Huppert, Dan

2012-12-13

227

Dielectric barrier discharge carbon atomic emission spectrometer: universal GC detector for volatile carbon-containing compounds.  

PubMed

It was found that carbon atomic emission can be excited in low temperature dielectric barrier discharge (DBD), and an atmospheric pressure, low power consumption, and compact microplasma carbon atomic emission spectrometer (AES) was constructed and used as a universal and sensitive gas chromatographic (GC) detector for detection of volatile carbon-containing compounds. A concentric DBD device was housed in a heating box to increase the plasma operation temperature to 300 °C to intensify carbon atomic emission at 193.0 nm. Carbon-containing compounds directly injected or eluted from GC can be decomposed, atomized, and excited in this heated DBD for carbon atomic emission. The performance of this new optical detector was first evaluated by determination of a series of volatile carbon-containing compounds including formaldehyde, ethyl acetate, methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol, and absolute limits of detection (LODs) were found at a range of 0.12-0.28 ng under the optimized conditions. Preliminary experimental results showed that it provided slightly higher LODs than those obtained by GC with a flame ionization detector (FID). Furthermore, it is a new universal GC detector for volatile carbon-containing compounds that even includes those compounds which are difficult to detect by FID, such as HCHO, CO, and CO2. Meanwhile, hydrogen gas used in conventional techniques was eliminated; and molecular optical emission detection can also be performed with this GC detector for multichannel analysis to improve resolution of overlapped chromatographic peaks of complex mixtures. PMID:24328147

Han, Bingjun; Jiang, Xiaoming; Hou, Xiandeng; Zheng, Chengbin

2014-01-01

228

High efficiency solution processed fluorescent yellow organic light-emitting diode through fluorinated alcohol treatment at the emissive layer/cathode interface  

NASA Astrophysics Data System (ADS)

We compare solvent treatments using fluorinated alcohol (2,2,3,3,4,4,5,5-octafluoro- 1-pentanol) and ethanol in improving the efficiency of a polymer organic light-emitting diode (OLED) by spin coating the solvent on top of the emissive layer. The presence of fluorinated alcohol is confirmed using x-ray photoelectron spectroscopy. The electron current is found to be significantly enhanced following solvent treatment while the hole current remains the same. The solvent treatment by fluorinated alcohol on top of a ‘super-yellow’ poly-(p-phenylenevinylene) (SY-PPV) based OLED results in efficiency as high as 19.2 lm W-1 (20.9 cd A-1) at a brightness of 1000 cd m-2. The improvement of device efficiency through the use of fluorinated alcohol treatment can be attributed to its large dipole, which lowers the electron injection barrier. This work also suggests that fluorinated alcohol might be a better trap passivator for electrons than ethanol.

Ng, Calvin Yi Bin; Yeoh, Keat Hoe; Whitcher, Thomas J.; Azrina Talik, Noor; Woon, Kai Lin; Saisopa, Thanit; Nakajima, Hideki; Supruangnet, Ratchadaporn; Songsiriritthigul, Prayoon

2014-01-01

229

From sample processing to quantification: a full electrochemical approach for neutral analyte derivatization, capillary electrophoresis separation, and contactless conductivity detection.  

PubMed

A thin-layer electrochemical flow cell coupled to capillary electrophoresis with contactless conductivity detection (EC-CE-C(4)D) was applied for the first time to the derivatization and quantification of neutral species using aliphatic alcohols as model compounds. The simultaneous electrooxidation of four alcohols (ethanol, 1-propanol, 1-butanol, and 1-pentanol) to the corresponding carboxylates was carried out on a platinum working electrode in acid medium. The derivatization step required 1 min at 1.6 V vs. Ag/AgCl under stopped flow conditions, which was preceded by a 10 s activation at 0 V. The solution close to the electrode surface was then hydrodynamically injected into the capillary, and a 2.5 min electrophoretic separation was carried out. The fully automated flow system operated at a frequency of 12 analyses per hour. Simultaneous determination of the four alcohols presented detection limits of about 5 × 10(-5) mol L(-1). As a practical application with a complex matrix, ethanol concentrations were determined in diluted pale lager beer and in nonalcoholic beer. No statistically significant difference was observed between the EC-CE-C(4)D and gas chromatography with flame ionization detection (GC-FID) results for these samples. The derivatization efficiency remained constant over several hours of continuous operation with lager beer samples (n = 40). PMID:22931091

Santos, Mauro Sérgio Ferreira; Lopes, Fernando Silva; Vidal, Denis Tadeu Rajh; do Lago, Claudimir Lucio; Gutz, Ivano Gebhardt Rolf

2012-09-18

230

Effect of paper porosity on OCT images: Monte Carlo study  

NASA Astrophysics Data System (ADS)

Non-invasive measurement of paper porosity is an important problem for papermaking industry. Presently used techniques are invasive and require long time for processing the sample. In recent years optical coherence tomography (OCT) has been proved to be an effective tool for non-invasive study of optically non-uniform scattering media including paper. The aim of present work is to study the potential ability of OCT for sensing the porosity of a paper sample by means of numerical simulations. The paper sample is characterized by variation of porosity along the sample while numerical simulations allow one to consider the samples with constant porosity which is useful for evaluation of the technique abilities. The calculations were performed implementing Monte Carlo-based technique developed earlier for simulation of OCT signals from multilayer paper models. A 9-layer model of paper consisting of five fiber layers and four air layers with non-planar boundaries was considered. The porosity of the samples was varied from 30 to 80% by varying the thicknesses of the layers. The simulations were performed for model paper samples without and with optical clearing agents (benzyl alcohol, 1-pentanol, isopropanol) applied. It was shown that the simulated OCT images of model paper with various porosities significantly differ revealing the potentiality of the OCT technique for sensing the porosity. When obtaining the images of paper samples with optical clearing agents applied, the inner structure of the samples is also revealed providing additional information about the samples under study.

Kirillin, Mikhail Yu.; Priezzhev, Alexander V.; Myllylä, Risto

2008-06-01

231

Monitoring of HAART regime antiretrovirals in serum of acquired immunodeficiency syndrome patients by micellar liquid chromatography.  

PubMed

A methodology based on micellar liquid chromatography to monitor five antiretroviral drugs (lamivudine, stavudine, tenofovir, zidovudine and efavirenz) was proposed. Antiretrovirals were studied in sets of three, corresponding to each highly active antiretroviral therapy (HAART) regime, prescribed to acquired immunodeficiency syndrome (AIDS)-infected patients. Four aqueous micellar mobile phases buffered at pH 7 were optimized to separate these compounds, using sodium dodecyl sulfate as the tensioactive, and 1-propanol or 1-pentanol as the organic modifier. The composition of each mobile phase was optimized for each antiretroviral. The common separation conditions were: C18 apolar column (125 × 4.6 mm, 5 ?m particle size), UV detection set at 214 nm, and mobile phase running at 1 mL min(-1) without controlling the temperature. The finally suggested method was validated for five analysed antiretroviral drugs following the US Food and Drug Administration guidelines in terms of: linearity between 0.5 and 50 ppm (r(2) > 0.9995), sensitivity (LOD lower than 0.25 ppm), intra- and inter-day precision (<7.1 and <5.2%, respectively) and accuracy (recovery 88.5-105.3% and 93.5-101.3%, respectively), as well as robustness (<6.5%). The proposed method was used to monitor the level of antiretrovirals in the serum of AIDS patients. The suggested methodology was found to be useful in the routine analysis of antiretrovirals in serum samples. PMID:22858583

Casas-Breva, I; Peris-Vicente, J; Rambla-Alegre, M; Carda-Broch, S; Esteve-Romero, J

2012-09-21

232

Detection of radicals in microemulsions using spin trapping techniques  

SciTech Connect

The technique of spin trapping has been successfully applied to a photochemical study of microemulsions. An oil-soluble derivative of phthalocyanine (tetra-tert-butyl) was incorporated into the hydrocarbon phase of an oil-in-water, nonionic microemulsion. It was demonstrated that the phthalocyanine molecules can photochemically mediate the hydrogen atom abstraction of 1-penthanol which is present as the cosurfactant. In the presence of O/sub 2/, the carbon-centered radical derived initially from the 1-pentanol undergoes further reaction to form a peroxy radical. In addition, singlet oxygen is generated and this reacts with the spin trap to yield a diamagnetic product. Optical studies demonstrated that the phthalocyanine is undergoing photodegradation under these conditions and O/sub 2/ uptake measurements confirm the consumption of oxygen. Finally, the generation of both OH and SO/sub 4/ radicals was accomplished independently in this microemulsion. The formation of what appears to be the same carbon-centered radical confirms the proposed mechanisms. 18 references.

Harbour, J.R.; Hair, M.L.

1980-06-12

233

Gas-liquid solubilities of carbon monoxide, carbon dioxide, hydrogen, water, 1-alcohols (1 [<=] n [<=] 6), and n-paraffins (2 [<=] n [<=] 6) in hexadecane, octacosane, 1-hexadecanol, phenanthrene, and tetraethylene glycol at pressures up to 5. 5 MPa and temperatures from 293 to 553 K  

SciTech Connect

At temperatures between 473 and 673 K and pressures between 2 and 10 MPa, synthesis gas can be converted toward methanol, fuel-methanol (a mixture of methanol and higher alcohols), or a mixture of hydrocarbons (Fischer-Tropsch synthesis), depending on the type of heterogeneous catalyst applied. The gas-liquid solubilities of the solutes carbon monoxide, carbon dioxide, hydrogen, water, ethane, propane, pentane, hexane, methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, and 1-hexanol in the solvents tetraethylene glycol, hexadecane, octacosane, 1-hexadecanol, and phenanthrene were measured as a function of temperature. The solutes are all reactants or products relevant for synthesis gas conversion into alcohols and/or hydrocarbons. The solvents are seen as potentially attractive for synthesis gas conversion via gas-slurry processes. Experimental conditions varied between 293 and 553 K and 0.06 and 5.5 MPa, covering typical process conditions for synthesis gas conversion. The total set of experimental results consists of 1,533 gas-liquid solubilities divided over 60 binary systems. As far as the authors know hardly any of the gas-liquid solubilities from this set have been reported previously in the literature. Where literature data are available, a comparison is made with their data. This comparison always shows an agreement within the calculated experimental errors with an average deviation of 7.6% and a maximal deviation of 15.0%.

Breman, B.B.; Beenackers, A.A.C.M.; Rietjens, E.W.J.; Stege, R.J.H. (Univ. of Groningen (Netherlands). Dept. of Chemical Engineering)

1994-10-01

234

Improvement of the Dimensional Stability of Powder Injection Molded Compacts by Adding Swelling Inhibitor into the Debinding Solvent  

NASA Astrophysics Data System (ADS)

Defects are frequently found in powder injection molded (PIM) compacts during solvent debinding due to the swelling of the binders. This problem can be alleviated by adjusting the composition of the debinding solvent. In this study, 10 vol pct swelling inhibitors were added into heptane, and the in-situ amounts of swelling and sagging of the specimen in the solvent were recorded using a noncontacting laser dilatometer. The results show that the addition of ethanol, 2-propanol, 1-butanol, and 1-pentanol reduced the amounts of swelling by 31, 21, 17, and 11 pct, respectively. This was because the small molecule alcohols, which do not dissolve paraffin wax (PW) or stearic acid (SA) in the binder system, could diffuse easily into the specimen and increased the portion of the swelling inhibitor inside. The amount of the extracted PW and SA also decreased, but only by 8.3, 6.1, 4.3, and 2.4 pct, respectively. The solubility parameters of 1-bromopropane (n-PB) and ethyl acetate (EA) are between those of heptane and alcohols, and they also yielded a slight reduction in the amounts of swelling by 6 and 11 pct, respectively. These results suggest that to reduce defects caused by binder swelling during solvent debinding, alcohols with high solubility parameters can be added into heptane without sacrificing significantly on the debinding rate.

Fan, Yang-Liang; Hwang, Kuen-Shyang; Su, Shao-Chin

2008-02-01

235

Micro-electromembrane extraction across free liquid membranes. Instrumentation and basic principles.  

PubMed

A micro-electromembrane extraction (?-EME) technique using electrically induced transfer of charged analytes across free liquid membranes (FLMs) was presented. A disposable extraction unit was proposed and it was made of a short segment of transparent perfluoroalkoxy tubing, which was successively filled with three liquid plugs serving as acceptor solution, FLM and donor solution. These plugs formed a three-phase extraction system, which was precisely defined, that was stable and required ?L to sub-?L volumes of all respective solutions. Basic instrumental set-up and extraction principles of ?-EME were examined using an anionic and a cationic dye, 4,5-dihydroxy-3-(p-sulfophenylazo)-2,7-naphthalene disulfonic acid trisodium salt (SPADNS) and crystal violet, respectively. Transfers of the charged dyes from donor into acceptor solutions across FLMs consisting of 1-pentanol were visualized by a microscope camera and quantitative measurements were performed by UV-vis spectrophotometry. The effects of operational parameters of ?-EME system were comprehensively investigated and experimental measurements were accompanied with theoretical calculations. Extraction recoveries above 60% were achieved for 5min ?-EME of 1mM SPADNS at 100V with repeatability values below 5%. Selectivity of FLMs was additionally examined by capillary electrophoretic analyses of acceptor solutions and the potential of FLMs for ?-EME pretreatment of samples with artificial complex matrices was demonstrated. PMID:24792701

Kubá?, Pavel; Bo?ek, Petr

2014-06-13

236

The solubility of hydrophobic aromatic chemicals in organic solvent/water mixtures  

SciTech Connect

The influence of dissolved organic solvents on the aqueous phase solubility of hydrophobic aromatic chemicals was investigated. To provide a basis for a comprehensive evaluation of the importance of cosolvent properties on solubility, the effects of several different organic cosolvents on the solubility of a model hydrophobic solute, naphthalene, were determined. Naphthalene solubility was measured in binary, ternary, and quaternary alcohol/water (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol) mixtures, binary ketone/water (acetone, methylethylketone, diethylketone), and aromatic organic solvent/water (benzene, toluene) mixtures. The solubility data were statistically evaluated and used to obtain an estimate of the overall accuracy of solubility measurements of hydrophobic chemicals in organic solvent/water mixtures. An accurate data base for mixed solvent solubility was established by combining the solubility data with additional solubility data obtained experimentally and from the literature. Thermodynamic models for predicting solubility in organic solvent/water mixtures were tested against the experimental data. The effects of organic cosolvent properties and solute hydrophobicity on solubility behavior and model predictive capability were evaluated. The results were used to evaluate the accuracy of existing models for predicting solubility and to explore possible molecular interactions in organic solvent/water mixtures.

Dickhut, R.M.

1989-01-01

237

Influence of local void fraction distribution on turbulent structure of upward bubbly flow in vertical channel  

NASA Astrophysics Data System (ADS)

Turbulent structure of upward dilute bubbly flow with 1 mm bubbles in a vertical channel is investigated experimentally. Small amount of surfactant is added to water to avoid bubble coalescence and to control local void fraction distribution. Liquid phase velocity is measured using two-dimensional laser Doppler Velocimetry. In 1-Pentanol solution of 20 ppm, bubbles have half-slip surface and migrate strongly toward the channel wall due to the shear-induced lift force which leads to wall-peaked distribution of local void fraction. On the other hand, in Triton X-100 solution of 2 ppm, bubbles become fully-contaminated and do not migrate toward the wall or the channel centre due to near-zero lift force, causing uniform distribution of local void fraction in the wall-normal direction. Once bubbles accumulate near the wall, transport of turbulent energy produced by the wall shear towards the channel centre is blocked. Then turbulence induced by the bubble motion becomes dominant in a wide core region (so-called pseudo turbulence). By contrast, in the case of the uniform distribution of bubbles, a mechanism of a turbulent energy transport which is the same as that of a single-phase turbulence still exists and furthermore the bubble-induced turbulence is added on it.

Ogasawara, T.; Takagi, S.; Matsumoto, Y.

2009-02-01

238

Mass action model for solute distribution between water and micelles. Partial molar volumes of butanol and pentanol in dodecyl surfactant solutions  

SciTech Connect

Water-surfactant-solubilizate systems have attracted much attention in recent years since these systems in the presence of oil can lead to microemulsions that have important applications in oil recovery. In this light, the densities of 1-butanol and 1-pentanol were measured in aqueous solutions of dodecyltrimethylammonium bromide and dodecyldimethylamine oxide, and the partial molar volumes at infinite dilution of the alcohols in aqueous surfactant solutions were obtained. The observed trends of this quantity as a function of the surfactant concentration were rationalized using a mass-action model for the alcohol distribution between the aqueous and the micellar phase. At the same time, the model was revised to account for the alcohol effect on the surfactant micellization equilibrium. The partial molar volume of alcohols in the aqueous and in the micellar phases and the ratios between the binding constant and the aggregation number were calculated. These thermodynamic quantities are nearly the same in the two surfactants analyzed but differ appreciably from those in sodium dodecylsulfate. The apparent molar volume of surfactants in some hydroalcoholic solutions at fixed alcohol concentration were also calculated. In the micellization region the trend of this quantity as a function of the surfactant concentration shows a hump, which depends on the alcohol concentration and on the alcohol alkyl chain length. The alcohol extraction from the aqueous to the micellar phase due to the addition of the surfactant can account for the observed trends.

De Lisi, R.; Castagnolo, M.; Inglese, A.; Liveri, V.T.

1986-01-01

239

Effect of possible interferences on the extraction of 1-butanol from aqueous solution by the ethyl esters of soybean oil fatty acids  

SciTech Connect

The methyl, ethyl, propyl and butyl esters of vegetable and tree oils are effective solvent extractants for 1-butanol from aqueous solution. Early applications of this process will probably involve bacterial mixed solvent fermentations of relatively impure waste and low-valued carbohydrates. Two types of materials, salts and solvents, could be expected to affect the extraction of 1-butanol from such industrial fermentation systems. The effect of four salts, three alcohols, and a ketone were evaluated using factorial experiments. Variations in NaCl, Na2SO4, Na2SO3, and KHPO4 from 0 to 0.15 M on the extraction of 0.1 to 4.1% 1-butanol from aqueous solutions at 25, 40, and 55 C gave small changes in distribution coefficient. Mild in creases occurred with increasing temperature and increasing NaCl, Na2SO4, and KH2PO4. Mild decreases in 1-butanol extraction occurred with increasing Na2SO3. Variations in acetone, ethanol, and 2-propanol concentrations ranging between 0 and 4% w/v at 25, 40 and 55 C gave small changes in distribution coefficient at 1-butanol concentrations ranging between 0.1 and 4.1% w/v had little effect. A slight increase in 1-butanol extraction was observed with increasing 1-pentanol under similar conditions.

Compere, A.L.; Googin, J.M.; Griffith, W.L.

1987-01-01

240

Molecular Interaction Study of N-Benzylformamide with 1-ALCOHOLS Using X-Band Microwave  

NASA Astrophysics Data System (ADS)

The secondary amide unit is a subject of particular interest, because of its occurrence in peptides and proteins. Molecular interaction between N-benzylformamide (NBF) with 1-alcohols (1-propanol, 1-butanol, 1-pentanol) has been studied in carbon tetrachloride by using X-band microwave bench at 936 GHz. Dielectric constant (?') and dielectric loss (??) of alcohol and NBF and their binary mixture for different mole fractions of NBF have been determined. Dielectric relaxation time (?) of the binary system is obtained by both Higasi's method and the Gopalakrishna single-frequency concentration variational method. The results show that the most likely interaction between alcohols and NBF is 1:1 complex for binary mixture through the free hydroxyl group of the alcohol and the carbonyl group of NBF. The alkyl chain-length of both alcohol and amide plays an important role in the determination of the strength of hydrogen bond (O-H: C=O) formed. The variation of relaxation time of NBF+1-alcohol mixtures in CCl4 indicates a weak solute-solvent type of molecular association. The result shows that as the relaxation time of the proton acceptor increases, the donating ability of the solute environment increase.

Manjunath, M. S.; Sannappa, J.

241

Chlorophyll a sensitized redox processes in microemulsion systems  

SciTech Connect

A chlorophyll-containing microemulsion was prepared on 80% water w/w and sodium hexadecyl sulfate, hexadecane, 1-pentanol, and chlorophyll a. The droplet radius as determined by autocorrelated Rayleigh scattering is 130 angstroms. Using a pulsed ruby laser the chl-a triplet spectrum was measured. It peaks at approximately 465 nm and shows minima due to ground-state bleaching at 430 and 420 nm. Chl-a reduces methyl viologen (MV/sup 2 +/) with a specific rate of 4 x 10/sup 8/ M/sup -1/ sec./sup -1/. At 5 x 10/sup -3/ M MV/sup 2 +/ concentration the efficiency of this process is unity. The cation radical Chl-a/sup +/ reacts with both ascorbate and NADh. In the latter case Chl-a can sensitize irreversible electron transfer from NADh to MV/sup 2 +/. If this system is coupled with a suitable hydrogenation catalyst, hydrogen evolution from water is observed. 34 references.

Kiwi, J.; Gratzel, M.

1980-06-12

242

Alcohol partition in a water-in-oil microemulsion from small-angle neutron scattering  

SciTech Connect

It is often necessary to add a cosurfactant, typically an alcohol of medium chain length, to water oil, and surfactant for a microemulsion to form. To gain information on the role of alcohols, we have measured small-angle neutron scattering (SANS) from microemulsions comprised of n-hexadecane, potassium oleate, and water, plus several concentrations of 1-pentanol, 1-hexanol, and 1-octanol, in two regions of the phase diagram. Several models, including polydisperse spheres interpreted by recently developed equations for the structure function, were tested. Experimental data could be fit successfully with the core-plus-shell monodisperse-oblate-ellipsoids model previously used for similar compositions. Variation of the alcohol-to-surfactant molar ratios, particle dimensions increase with alcohol chain length in both regions of the phase diagrams. The water phase volume can reasonably by assumed constant, and estimates of the amount of alcohol at the water-surfactant interface were made from the parameters obtained from the fits. At fixed alcohol-to-surfactant molar ratios, we found a lower fraction of larger alcohols at the interface, in agreement with the increase of hydrophobicity. For a given alcohol, increasing the alcohol-to-surfactant ratio increased the amount of alcohol at the interface, although the fraction of total alcohol in the particles decreases. 32 refs., 14 figs., 9 tabs.

Caponetti, E.; Lizzio, A.; Triolo, R. [Dipartimento Chimica Fisica, Palermo (Italy); Griffith, W.L.; Johnson, J.S. Jr. [Oak Ridge National Lab., TN (United States)

1992-06-01

243

Pentynyl dextran as a support matrix for immobilization of serine protease subtilisin Carlsberg and its use for transesterification of N-acetyl-L-phenylalanine ethyl ester in organic media.  

PubMed

In this study, serine protease (subtilisin Carlsberg) was immobilized on pentynyl dextran (PyD, O-alkynyl ether of dextran, 1) and used for the transesterification of N-acetyl-L-phenylalanine ethyl ester (2) with different aliphatic (1-propanol, 1-butanol, 1-pentanol, 1-hexanol) and aromatic (benzyl alcohol, 2-phenyl ethanol, 4-phenyl-1-butanol) alcohols in tetrahydrofuran (THF). The effect of carbon chain length in aliphatic and aromatic alcohols on initial and average transesterification rate, transesterification activity of immobilized enzyme and yield of the reaction under selected reaction conditions was investigated. The transesterification reactivity of the enzyme and yield of the reaction increased as the chain length of the alcohols decreased. Furthermore, almost no change in yield was observed when the immobilized enzyme was repeatedly used for selected alcohols over six cycles. Intrinsic fluorescence analysis showed that the catalytic activity of the immobilized enzyme in THF was maintained due to retention of the tertiary structure of the enzyme after immobilization on PyD (1). PMID:23978850

Tahir, Muhammad Nazir; Cho, Eunae; Mischnick, Petra; Lee, Jae Yung; Yu, Jae-Hyuk; Jung, Seunho

2014-04-01

244

Phase separation phenomena of polysulfone/solvent/organic nonsolvent and polyethersulfone/solvent/organic nonsolvent systems  

SciTech Connect

The precipitation values (PVs) of several organic nonsolvents in polysulfone (PSf)/solvent and polyethersulfone (PESf)/solvent systems were measured in temperatures ranging from 10 to 80 C by the direct titration method and compared with those of water in the same systems. The solvents used were N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAC); the organic nonsolvents employed were methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, ethylene glycol, and diethylene glycol as well as acetic acid and propionic acid. The compositions of nonsolvent, polymer, and solvent at the precipitation points for different polymer concentrations up to 10 wt% were also determined at 30 C with respect to both the polymers and six nonsolvents presented. These results were used to obtain the polymer precipitation curves in the polymer-solvent-nonsolvent triangular phase diagrams and to determine the theta composition of solvent-nonsolvent triangular phase diagrams and to determine the theta composition of solvent-nonsolvent for a polymer. The effect of temperature on the precipitation value was observed to be dramatically different for different polymer/solvent/nonsolvent systems. These results were explained on the basis of polar and nonpolar interactions of the polymer, solvent, and nonsolvent system.

Wang, Dongliang; Li, K.; Sourirajan, S.; Teo, W.K. (National Univ. of Singapore, Kent Ridge Crescent (Singapore). Dept. of Chemical Engineering)

1993-12-10

245

Density gradient theory combined with the PC-SAFT equation of state used for modeling the surface tension of associating systems  

NASA Astrophysics Data System (ADS)

The density gradient theory (GT) combined with a SAFT-type (Statistical Associating Fluid Theory) equation of state has been used for modeling the surface tension of associating fluids represented by a series of six alkanols ranging from methanol to 1-pentanol. The effect of nonzero dipole moment of the selected alkanols on the predicted surface tension was investigated in this study. Results of the GT + non-polar Perturbed Chain (PC) SAFT equation of state were compared to predictions of GT combined with the PC-polar-SAFT, i.e. PCP-SAFT, equation. Both GT + PC-SAFT and GT + PCP-SAFT give reasonable prediction of the surface tension for pure alkanols. Results of both models are comparable as no significant difference in the modeled saturation properties and in the predicted surface tension using GT was found. Consideration of dipolar molecules of selected alkanols using PCP-SAFT had only minor effect on the predicted properties compared to the non-polar PC-SAFT model.

Vinš, Václav; Planková, Barbora; Hrubý, Jan; Celný, David

2014-03-01

246

Novel isoquinoline derivatives as antimicrobial agents.  

PubMed

The wide variety of potent biological activities of natural and synthetic isoquinoline alkaloids encouraged us to develop novel antimicrobial isoquinoline compounds. We synthesized a variety of differently functionalized 1-pentyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines (THIQs), including dihydroisoquinolinium salts (2 and 5), methyl pentanoate-THIQ (6), 1-pentanol-THIQ (7), ester derivatives (8-15) and carbamate derivatives (16-23). We employed classic intramolecular Bischler-Napieralski cyclodehydration to generate the isoquinoline core. All the structures were characterized by nuclear magnetic resonance and mass spectrometry. The bactericide and fungicide activities were evaluated for all the synthesized compounds and structure-activity relationships were established. Many compounds exhibited high and broad-range bactericidal activity. Fluorophenylpropanoate ester 13 and the halogenated phenyl- (17, 18) and phenethyl carbamates (21, 22) exerted the most remarkable bactericidal activity. However, few compounds displayed antifungal activity against most of the fungi tested. Among them, chlorinated derivatives like chlorobenzoate and chlorophenylpropanoate esters (10 and 14, respectively) and chlorophenethyl carbamate 22, exhibited the greatest antifungal activity. PMID:23601815

Galán, Abraham; Moreno, Laura; Párraga, Javier; Serrano, Ángel; Sanz, Ma Jesús; Cortes, Diego; Cabedo, Nuria

2013-06-01

247

Enthalpies of solutions and dilution of butanol and pentanol in dodecyltrimethylammonium bromide micellar solutions  

SciTech Connect

The enthalpies of solution and of dilution of 1-butanol and 1-pentanol were measured in micellar solutions of dodecyltrimethylammonium bromide by systematically changing the concentration of alcohols and surfactant. The enthalpies of solution at infinite dilution of alcohols at each surfactant concentration were evaluated from a linear plot. This quantity increases with surfactant concentration (up to 0.8m) with a curvature which depends on the alcohol alkyl chain length. The difficulties arising for a quantitative treatment of both the enthalpies of dilution and of solution at finite alcohol concentrations are discussed. The dependence on the surfactant concentration of the standard enthalpies of solution and the enthalpies of dilution for m ..-->.. 0 are rationalized. From the resulting equations the distribution constant, standard enthalpy of transfer, standard enthalpy of solution, and the alcohol-alcohol interaction parameter in the micellar phase are evaluated. The enthalpies of transfer obtained using this technique agree well with those previously reported from enthalpies of mixing. The distribution constants also agree with those reported in the literature from several approaches: mixing enthalpies, partial molar volumes, and the dependence of the cmc on added alcohol.

De Lisi, R.; Milioto, S.; Castagnolo, M.; Inglese, A.

1987-05-01

248

Determination of paroxetine in blood and urine using micellar liquid chromatography with electrochemical detection.  

PubMed

Paroxetine is a potent selective serotonin reuptake inhibitor used for the treatment of depression and related mood disorders. A micellar liquid chromatographic method was developed for the determination of paroxetine in serum and urine. Detection of paroxetine was carried out using a C18 column and a mobile phase of 0.15 M sodium dodecyl sulfate, 6% 1-pentanol at pH 3 (buffer salt 0.01 M NaH2PO4) running under isocratic mode at 1.0 mL/min and electrochemical detection at 0.8 V. The analyte was eluted without interferences in <15 min. The proposed methodology was validated under the guidelines of the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use in matrix in terms of specificity, linearity (r(2) > 0.9999; 0.5-5 ?g/mL range), accuracy (88-97.5%, recovery), repeatability (RSD < 0.54%), intermediate precision (RSD < 0.54%), limit of detection and quantification (0.001 and 0.005 ?g/mL, respectively) and robustness (RSD < 3.63%). Developed method was successfully applied to real blood and urine samples as well as in spiked serum and urine samples. The developed method was specific, rapid, precise, reliable, accurate, inexpensive and then suitable for routine analysis of paroxetine in monitorized samples. PMID:24448669

Agrawal, Nitasha; Marco-Peiró, Sergio; Esteve-Romero, Josep; Durgbanshi, Abhilasha; Bose, Devasish; Peris-Vicente, Juan; Carda-Broch, Samuel

2014-11-01

249

First total synthesis of the (?)-2-methoxy-6-heptadecynoic acid and related 2-methoxylated analogs as effective inhibitors of the leishmania topoisomerase IB enzyme  

PubMed Central

The fatty acids (±)-2-methoxy-6Z-heptadecenoic acid (1), (±)-2-methoxy-6-heptadecynoic acid (2) and (±)-2-methoxyheptadecanoic acid (3) were synthesized and their inhibitory activity against the Leishmania DNA topoisomerase IB enzyme (LdTopIB) determined. Acids 1 and 2 were synthesized from 4-bromo-1-pentanol, the former in ten steps and in 7% overall yield, while the latter in seven steps and in 14% overall yield. Acid 3 was prepared in six steps and in 42% yield from 1-hexadecanol. Acids 1–3 inhibited the LdTopIB enzyme following the order 2 > 1 ? 3, with 2 displaying an EC50 = 16.6 ± 1.1 ?M and 3 not inhibiting the enzyme. Acid 1 preferentially inhibited the LdTopIB enzyme over the human TopIB enzyme. Unsaturation seems to be a prerequisite for effective inhibition, rationalized in terms of weak intermolecular interactions between the active site of LdTopIB and either the double or triple bonds of the fatty acids. Toxicity towards Leishmania donovani promastigotes was also investigated resulting in the same order 2 > 1 > 3, with 2 displaying an EC50 = 74.0 ± 17.1 ?M. Our results indicate that ?-methoxylation decreases the toxicity of C17:1 fatty acids towards L. donovani promastigotes, but improves their selectivity index. PMID:23118491

Carballeira, Nestor M.; Cartagena, Michelle; Li, Fengyu; Chen, Zhongfang; Prada, Christopher F.; Calvo-Alvarez, Estefania; Reguera, Rosa M.; Balana-Fouce, Rafael

2012-01-01

250

Analysis of volatile compounds and triglycerides of seed oils extracted from different poppy varieties (Papaver somniferum L.).  

PubMed

Poppy seed oil (Oleum Papaveris Seminis) is used for culinary and pharmaceutical purposes, as well as for making soaps, paints, and varnishes. Astonishingly, hardly anything was yet known about the volatile compounds of this promising comestible. Likewise, there are no current published data about the triglyceride (TAG) composition of poppy seed oils available. In this investigation solid-phase microextraction (SPME) with DVB/Carboxen/PDMS Stable-Flex fiber was applied to the study of volatile compounds of several seed oil samples from Papaver somniferum L. (Papaveraceae). 1-Pentanol (3.3-4.9%), 1-hexanal (10.9-30.9%), 1-hexanol (5.3-33.7%), 2-pentylfuran (7.2-10.0%), and caproic acid (2.9-11.5%) could be identified as the main volatile compounds in all examined poppy seed oil samples. Furthermore, the TAG composition of these oils was analyzed by MALDI-ReTOF- and ESI-IT-MS/MS. The predominant TAG components were found to be composed of linoleic, oleic, and palmitic acid, comprising approximately 70% of the oils. TAG patterns of the different poppy varieties were found to be very homogeneous, showing also no significant differences in terms of the applied pressing method of the plant seeds. PMID:16218681

Krist, Sabine; Stuebiger, Gerald; Unterweger, Heidrun; Bandion, Franz; Buchbauer, Gerhard

2005-10-19

251

On the Investigation of Coarse-Grained Models for Water: Balancing Computational Efficiency and the Retention of Structural Properties  

PubMed Central

Developing accurate models of water for use in computer simulations is important for the study of many chemical and biological systems, including lipid bilayer self-assembly. The large temporal and spatial scales needed to study such self-assembly have led to the development and application of coarse-grained models for the lipid-lipid, lipid-solvent and solvent-solvent interactions. Unfortunately, popular center-of-mass-based coarse-graining techniques are limited to modeling water with one-water per bead. In this work, we have utilized the K-means algorithm to determine the optimal clustering of waters to allow the mapping of multiple waters to single coarse-grained beads. Through the study of a simple mixture between water and an amphiphilic solute (1-pentanol), we find a 4-water bead model has the optimal balance between computational efficiency and accurate solvation and structural properties when compared to water models ranging from 1 to 9 waters per bead. The 4-water model was subsequently utilized in studies of the solvation of hexadecanoic acid and the structure, as measured via radial distribution functions, for the hydrophobic tails and the bulk water phase were found to agree well with experimental data and their atomistic targets. PMID:20230012

Hadley, Kevin R.; McCabe, Clare

2010-01-01

252

Bacterial degradation of tert-amyl alcohol proceeds via hemiterpene 2-methyl-3-buten-2-ol by employing the tertiary alcohol desaturase function of the Rieske nonheme mononuclear iron oxygenase MdpJ.  

PubMed

Tertiary alcohols, such as tert-butyl alcohol (TBA) and tert-amyl alcohol (TAA) and higher homologues, are only slowly degraded microbially. The conversion of TBA seems to proceed via hydroxylation to 2-methylpropan-1,2-diol, which is further oxidized to 2-hydroxyisobutyric acid. By analogy, a branched pathway is expected for the degradation of TAA, as this molecule possesses several potential hydroxylation sites. In Aquincola tertiaricarbonis L108 and Methylibium petroleiphilum PM1, a likely candidate catalyst for hydroxylations is the putative tertiary alcohol monooxygenase MdpJ. However, by comparing metabolite accumulations in wild-type strains of L108 and PM1 and in two mdpJ knockout mutants of strain L108, we could clearly show that MdpJ is not hydroxylating TAA to diols but functions as a desaturase, resulting in the formation of the hemiterpene 2-methyl-3-buten-2-ol. The latter is further processed via the hemiterpenes prenol, prenal, and 3-methylcrotonic acid. Likewise, 3-methyl-3-pentanol is degraded via 3-methyl-1-penten-3-ol. Wild-type strain L108 and mdpJ knockout mutants formed isoamylene and isoprene from TAA and 2-methyl-3-buten-2-ol, respectively. It is likely that this dehydratase activity is catalyzed by a not-yet-characterized enzyme postulated for the isomerization of 2-methyl-3-buten-2-ol and prenol. The vitamin requirements of strain L108 growing on TAA and the occurrence of 3-methylcrotonic acid as a metabolite indicate that TAA and hemiterpene degradation are linked with the catabolic route of the amino acid leucine, including an involvement of the biotin-dependent 3-methylcrotonyl coenzyme A (3-methylcrotonyl-CoA) carboxylase LiuBD. Evolutionary aspects of favored desaturase versus hydroxylation pathways for TAA conversion and the possible role of MdpJ in the degradation of higher tertiary alcohols are discussed. PMID:22194447

Schuster, Judith; Schäfer, Franziska; Hübler, Nora; Brandt, Anne; Rosell, Mònica; Härtig, Claus; Harms, Hauke; Müller, Roland H; Rohwerder, Thore

2012-03-01

253

Can volatile organic metabolites be used to simultaneously assess microbial and mite contamination level in cereal grains and coffee beans?  

PubMed

A novel approach based on headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-ToFMS) was developed for the simultaneous screening of microbial and mite contamination level in cereals and coffee beans. The proposed approach emerges as a powerful tool for the rapid assessment of the microbial contamination level (ca. 70 min versus ca. 72 to 120 h for bacteria and fungi, respectively, using conventional plate counts), and mite contamination (ca. 70 min versus ca. 24 h). A full-factorial design was performed for optimization of the SPME experimental parameters. The methodology was applied to three types of rice (rough, brown, and white rice), oat, wheat, and green and roasted coffee beans. Simultaneously, microbiological analysis of the samples (total aerobic microorganisms, moulds, and yeasts) was performed by conventional plate counts. A set of 54 volatile markers was selected among all the compounds detected by GC×GC-ToFMS. Principal Component Analysis (PCA) was applied in order to establish a relationship between potential volatile markers and the level of microbial contamination. Methylbenzene, 3-octanone, 2-nonanone, 2-methyl-3-pentanol, 1-octen-3-ol, and 2-hexanone were associated to samples with higher microbial contamination level, especially in rough rice. Moreover, oat exhibited a high GC peak area of 2-hydroxy-6-methylbenzaldehyde, a sexual and alarm pheromone for adult mites, which in the other matrices appeared as a trace component. The number of mites detected in oat grains was correlated to the GC peak area of the pheromone. The HS-SPME/GC×GC-ToFMS methodology can be regarded as the basis for the development of a rapid and versatile method that can be applied in industry to the simultaneous assessment the level of microbiological contamination and for detection of mites in cereals grains and coffee beans. PMID:23613710

Salvador, Angelo C; Baptista, Inês; Barros, António S; Gomes, Newton C M; Cunha, Angela; Almeida, Adelaide; Rocha, Silvia M

2013-01-01

254

Can Volatile Organic Metabolites Be Used to Simultaneously Assess Microbial and Mite Contamination Level in Cereal Grains and Coffee Beans?  

PubMed Central

A novel approach based on headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC–ToFMS) was developed for the simultaneous screening of microbial and mite contamination level in cereals and coffee beans. The proposed approach emerges as a powerful tool for the rapid assessment of the microbial contamination level (ca. 70 min versus ca. 72 to 120 h for bacteria and fungi, respectively, using conventional plate counts), and mite contamination (ca. 70 min versus ca. 24 h). A full-factorial design was performed for optimization of the SPME experimental parameters. The methodology was applied to three types of rice (rough, brown, and white rice), oat, wheat, and green and roasted coffee beans. Simultaneously, microbiological analysis of the samples (total aerobic microorganisms, moulds, and yeasts) was performed by conventional plate counts. A set of 54 volatile markers was selected among all the compounds detected by GC×GC–ToFMS. Principal Component Analysis (PCA) was applied in order to establish a relationship between potential volatile markers and the level of microbial contamination. Methylbenzene, 3-octanone, 2-nonanone, 2-methyl-3-pentanol, 1-octen-3-ol, and 2-hexanone were associated to samples with higher microbial contamination level, especially in rough rice. Moreover, oat exhibited a high GC peak area of 2-hydroxy-6-methylbenzaldehyde, a sexual and alarm pheromone for adult mites, which in the other matrices appeared as a trace component. The number of mites detected in oat grains was correlated to the GC peak area of the pheromone. The HS-SPME/GC×GC–ToFMS methodology can be regarded as the basis for the development of a rapid and versatile method that can be applied in industry to the simultaneous assessment the level of microbiological contamination and for detection of mites in cereals grains and coffee beans. PMID:23613710

Salvador, Angelo C.; Baptista, Ines; Barros, Antonio S.; Gomes, Newton C. M.; Cunha, Angela; Almeida, Adelaide; Rocha, Silvia M.

2013-01-01

255

Field evaluation of interfacial and partitioning tracers for characterization of effective NAPL-water contact areas  

SciTech Connect

The use of surface-active tracers for measuring the interfacial area between nonaqueous phase liquids (NAPLs) and water was evaluated in a hydraulically isolated test cell installed in a surficial aquifer located at Hill Air Force Base (AFB), Utah. Interfacial tracers were developed at the University of Florida for quantifying immiscible fluid-fluid interfaces (air-water or NAPL-water) in porous media. Sodium dodecyl benzene sulfonate (SDBS) was used as the interfacial tracer to measure the effective NAPL-water interfacial area (a{sub Nw}), while 2,2-dimethyl-3-pentanol (DMP) was used as the partitioning tracer to estimate the NAPL saturation (S{sub N}). The observed retardation of SDBS and DMP when compared to a nonreactive tracer (bromide or methanol) at eight multi-level sampling locations and one extraction well, was used to quantify the a{sub Nw} and S{sub N} values averaged over the interval between the injection wells and each monitoring point. The NAPL morphology index, defined here as H{sub N} = a{sub Nw}/{psi}S{sub N} ({psi} = porosity), varied significantly within the test cell. In locations where the magnitude of H{sub N} was large, the NAPL was assumed to be more or less uniformly spread, providing good contact with the mobile fluid. In contrast, regions with low H{sub N} values were assumed to have NAPL that was more heterogeneously distributed as isolated patches providing poor contact with the mobile fluid. The index H{sub N}, provided by the combined use of interfacial and partitioning tracers, has important implications for NAPL source region remediation employing in situ flushing technologies.

Annable, M.D.; Jawitz, J.W.; Rao, P.S.C.; Dai, D.P.; Kim, H. [Univ. of Florida, Gainesville, FL (United States); Wood, A.L. [Environmental Protection Agency, Ada, OK (United States). National Risk Management Research Lab.

1998-05-01

256

Surface studies of dry and solid lubricants under different environmental conditions  

NASA Astrophysics Data System (ADS)

Advanced lubrication schemes depend on the presence of specific solids at or the continuous delivery of a gas to the sliding interface to manage friction and wear, and are known to have a strong environmental dependence. An in-vacuo pin-on-disc tribometer was designed to allow controlled environmental testing of the solid lubricants in order to determine the role of atmospheric components on their frictional behavior. Solid lubrication testing of highly oriented pyrolytic graphite, MoS2-Sb2O 3-Au, and MoS2-Sb2O3-C films was carried out under environments of 760 Torr air (50% relative humidity), 150 Torr oxygen, 8 Torr water, 610 Torr nitrogen, and 10-7 Torr vacuum. Dry lubrication testing of the native oxide of silicon (100) surfaces was carried out under environments of 760 Torr air (50% relative humidity), 1 Torr pentanol, and 10-7 Torr vacuum. Pin-on-disc tribometry revealed a strong dependence of friction and wear as a function of sliding environment. MoS2-Sb2O3-Au and MoS2-Sb 2O3-C films were strongly affected by the presence of water molecules. Friction and wear were observed to increase in the presence of partial pressures of water when compared to vacuum, oxygen, and nitrogen environmental testing. Spectroscopic analysis of the MoS2-Sb2O 3-Au and MoS2-Sb2O3-C films showed a general trend of MoS2 expression at the surface of low friction wear tracks. However, high friction could not be directly linked to the expression of a specific species within the wear track. X-ray photoelectron spectroscopy of the tracks created under ambient and water environments yielding high friction showed no clear relationship between the two conditions, even though their frictional behavior was similar. As revealed by atomic force microscopy measurements, the microstructure of the wear tracks of MoS2-Sb2O3-Au films produced under vacuum were predominantly low friction MoS2. The vacuum wear tracks of MoS2-Sb2O3-C films showed a mixed microstructure with both low friction MoS2, and moderate friction C. Ambient wear tracks for MoS2-Sb2O 3-Au films contained a minor, higher friction constituent, identified as Au, in the presence of the major constituent, MoS2. Ambient wear tracks for MoS2-Sb2O3-C films were more complex, expressing a majority of higher friction Sb2O3 and graphite constituents, with a reduced fraction of MoS2. These micro-tribometry measurements correlated well with those made by the pin-on-disc tribometer and X-ray photoelectron spectroscopy characterization. Dry or vapor-phase lubrication methods employing 1-pentanol were effective in reducing the friction of silicon (100) compared to sliding under ambient or vacuum environments. A continuous supply of 1-pentanol served to lubricate silicon surfaces through the formation of a tribochemical film which was composed primarily of (CH2)x species. However, the presence of a tribofilm was not responsible for the lowered friction coefficient, but it did enable the extreme wear protection previously reported for this lubrication technique.

Dudder, Gregory James

257

Intensely luminescent homoleptic alkynyl decanuclear gold(I) clusters and their cationic octanuclear phosphine derivatives.  

PubMed

Treatment of Au(SC(4)H(8))Cl with a stoichiometric amount of hydroxyaliphatic alkyne in the presence of NEt(3) results in high-yield self-assembly of homoleptic clusters (AuC(2)R)(10) (R = 9-fluorenol (1), diphenylmethanol (2), 2,6-dimethyl-4-heptanol (3), 3-methyl-2-butanol (4), 4-methyl-2-pentanol (4), 1-cyclohexanol (6), 2-borneol (7)). The molecular compounds contain an unprecedented catenane metal core with two interlocked 5-membered rings. Reactions of the decanuclear clusters 1-7 with gold-diphosphine complex [Au(2)(1,4-PPh(2)-C(6)H(4)-PPh(2))(2)](2+) lead to octanuclear cationic derivatives [Au(8)(C(2)R)(6)(PPh(2)-C(6)H(4)-PPh(2))(2)](2+) (8-14), which consist of planar tetranuclear units {Au(4)(C(2)R)(4)} coupled with two fragments [AuPPh(2)-C(6)H(4)-PPh(2)(AuC(2)R)](+). The titled complexes were characterized by NMR and ESI-MS spectroscopy, and the structures of 1, 13, and 14 were determined by single-crystal X-ray diffraction analysis. The luminescence behavior of both Au(I)(10) and Au(I)(8) families has been studied, revealing efficient room-temperature phosphorescence in solution and in the solid state, with the maximum quantum yield approaching 100% (2 in solution). DFT computational studies showed that in both Au(I)(10) and Au(I)(8) clusters metal-centered Au ? Au charge transfer transitions mixed with some ?-alkynyl MLCT character play a dominant role in the observed phosphorescence. PMID:22686420

Koshevoy, Igor O; Chang, Yuh-Chia; Karttunen, Antti J; Selivanov, Stanislav I; Jänis, Janne; Haukka, Matti; Pakkanen, Tapani; Tunik, Sergey P; Chou, Pi-Tai

2012-07-01

258

High extraction efficiency fiber coated with calix[4] open-chain crown ether for solid-phase microextraction of polar aromatic and aliphatic compounds.  

PubMed

The calix[4] open-chain crown ether, 5,11,17,23-tetra-tert-butyl-25,27-di(2-allyloxyethoxyl)-26,28-dihydroxycalix[4]arene was synthesized and used for preparation of solid-phase microextraction (SPME) fibers of enhanced extraction efficiency. The new SPME coating made from calix[4] open-chain crown ether and hydroxyl-terminated silicone oil was developed with the aid of vinyltriethoxylsilane as bridge using sol-gel method and cross-linking technology. The efficiency of the novel fiber in the extraction of polar aromatic and aliphatic compounds, such as phenols, alcohols, and volatile fatty acids, was also investigated. Due to the introduction of the polar open-chain crown ether in calix[4]arene molecules, the calix[4] open-chain crown ether fiber showed much better selectivity and sensitivity to these polar compounds in comparison with calix[4]arene fiber. It also had superior extraction efficiency when compared to commercial poly(dimethylsiloxane)-divinylbenzene and polyacrylate fibers. Parts per billion to parts per trillion level detection limits were achieved for most of the analytes through SPME in conjunction with GC and flame ionization detector. The linear ranges were two to four orders of magnitude, and the RSD values were below 7% for all analytes. The novel fiber was applied to determine volatile alcohols and fatty acids in wine samples. The volatile-free wine prepared in this work was used to assure similar chemical environment for analytes in both calibration solutions and in real wine samples, thus compensating for possible matrix interferences. The established internal standard method using 4-methyl-2-pentanol as internal standard showed satisfactory accuracy and precision. PMID:16342796

Liu, Mingming; Zeng, Zhaorui; Lei, Yun; Li, Haibing

2005-11-01

259

Physicochemical studies of mixed surfactant microemulsions with isopropyl myristate as oil.  

PubMed

The present study is focused on evaluation of interfacial compositions and thermodynamic properties of w/o mixed surfactant [(sodium dodecylsulfate, SDS/polyoxyethylene (23) lauryl ether, Brij-35)/1-pentanol (Pn)/isopropyl myristate (IPM)] microemulsions under various physicochemical conditions by the dilution method. The number of moles of Pn at the interface (n(a)(i)) and bulk oil (n(a)(o)), and various thermodynamic parameters [viz. standard Gibbs free energy (?G(o?i)(0)), standard enthalpy (?H(o?i)(0)), and standard entropy (?S(o?i)(0)) of the transfer of Pn from bulk oil to the interface] have been found to be dependent on the molar ratio of water to surfactant (?), concentration of Brij-35 (X(Brij-35)), and temperature. Temperature-insensitive microemulsions with zero specific heat capacity (?C(p)(0))(o?i) have been formed at specific compositions. The intrinsic enthalpy change of the transfer process (?H(0))(o?i)* has been evaluated from linear correlation between ?H(o?i)(0) and ?S(o?i)(0) at different experimental temperatures. The present report also aims at a precise characterization on the basis of molecular interactions between the constituents and provides insight into the nature of the oil/water interfaces of these systems by conductivity and dynamic light scattering studies as a function of ? and X(Brij-35). Conductivity studies reveal that incorporation of Brij-35 in non-percolating water/SDS/Pn/IPM systems makes them favorable for ?-induced percolation behavior up to X(Brij-35) ? 0.5. But further addition of Brij-35 causes a decrease in conductivity with increasing ?. Furthermore, the hydrodynamic diameters of the microemulsion droplets increase with increase in both X(Brij-35) and ?. Correlations of the results in terms of the evaluated physicochemical parameters have been attempted. PMID:23664388

Bardhan, Soumik; Kundu, Kaushik; Saha, Swapan K; Paul, Bidyut K

2013-07-15

260

Gas-Phase Reactivity of Protonated 2-, 3-, and 4-Dehydropyridine Radicals Toward Organic Reagents  

NASA Astrophysics Data System (ADS)

To explore the effects of the electronic nature of charged phenyl radicals on their reactivity, reactions of the three distonic isomers of n-dehydropyridinium cation (n = 2, 3, or 4) have been investigated in the gas phase by using Fourier-transform ion cyclotron resonance mass spectrometry. All three isomers react with cyclohexane, methanol, ethanol, and 1-pentanol exclusively via hydrogen atom abstraction and with allyl iodide mainly via iodine atom abstraction, with a reaction efficiency ordering of 2 > 3 > 4. The observed reactivity ordering correlates well with the calculated vertical electron affinities of the charged radicals (i.e., the higher the vertical electron affinity, the faster the reaction). Charged radicals 2 and 3 also react with tetrahydrofuran exclusively via hydrogen atom abstraction, but the reaction of 4 with tetrahydrofuran yields products arising from nonradical reactivity. The unusual reactivity of 4 is likely to result from the contribution of an ionized carbene-type resonance structure that facilitates nucleophilic addition to the most electrophilic carbon atom (C-4) in this charged radical. The influence of such a resonance structure on the reactivity of 2 is not obvious, and this may be due to stabilizing hydrogen-bonding interactions in the transition states for this molecule. Charged radicals 2 and 3 abstract a hydrogen atom from the substituent in both phenol and toluene, but 4 abstracts a hydrogen atom from the phenyl ring, a reaction that is unprecedented for phenyl radicals. Charged radical 4 reacts with tert-butyl isocyanide mainly by hydrogen cyanide (HCN) abstraction, whereas CN abstraction is the principal reaction for 2 and 3. The different reactivity observed for 4 (as compared to 2 and 3) is likely to result from different charge and spin distributions of the reaction intermediates for these charged radicals.

Adeuya, Anthony; Price, Jason M.; Jankiewicz, Bart?omiej J.; Nash, John J.; Kenttämaa, Hilkka I.

2009-11-01

261

Fluorescence probe study of oil-in-water microemulsions. 1. Effect of pentanol and dodecane or toluene on some properties of sodium dodecyl sulfate micelles  

SciTech Connect

The analysis of the decay of the fluorescence of micelle-solubilized pyrene has been used to obtain for the first time the variation of the surfactant aggregation number n in micellar solutions of sodium dodecyl sulfate (SDS) upon addition of increasing amounts of 1-pentanol, and of oil (dodecane or toluene), thereby forming an oil-in-water (o/w) microemulsion. The polarity of the microenvironment of the micelle-solubilized pyrene, the intramicellar rate constant k/sub E/ for pyrene excimer formation, and the microviscosity eta sensed by dipyrenylpropane (DPyP) upon intramolecular excimer formation have been also investigated. The results indicate that the addition of pentanol to concentrated (> 0.2 M) SDS solutions results in an increase of n and a decrease of k/sub E/, eta, and microenvironment polarity. These effects have been associated with the transformation of the initially spherical SDS micelles into anisotropic (disk-shaped) large micelles upon dissolution of pentanol in the micelles. Upon addition of dodecane, eta goes through a minimum in the case of concentrated SDS + pentanol systems, but only shows a monotonous increase for less concentrated SDS + pentanol systems. For the former the variation of n has been attributed to a change of micelle shape from nonspherical to spherical, whereas for the latter the initially spherical micelles remain spherical upon dodecane solubilization. Similar variations of n are observed when dodecane is replaced by toluene in the case of dilute SDS + pentanol systems, whereas large differences are noted for concentrated SDS + pentanol systems. In the case where the results suggest the formation of oil-in-water microemulsion droplets, the calculations indicate that the oil core permeates part of the surfactant alkyl chains.

Lianos, P.; Lang, J.; Strazielle, C.; Zana, R.

1982-03-18

262

Kinetic limitations on tracer partitioning in ganglia dominated source zones  

NASA Astrophysics Data System (ADS)

Quantification of the relationship between dense nonaqueous phase liquid (DNAPL) source strength, source longevity and spatial distribution is increasingly recognized as important for effective remedial design. Partitioning tracers are one tool that may permit interrogation of DNAPL architecture. Tracer data are commonly analyzed under the assumption of linear, equilibrium partitioning, although the appropriateness of these assumptions has not been fully explored. Here we focus on elucidating the nonlinear and nonequilibrium partitioning behavior of three selected alcohol tracers — 1-pentanol, 1-hexanol and 2-octanol in a series of batch and column experiments. Liquid-liquid equilibria for systems comprising water, TCE and the selected alcohol illustrate the nonlinear distribution of alcohol between the aqueous and organic phases. Complete quantification of these equilibria facilitates delineation of the limits of applicability of the linear partitioning assumption, and assessment of potential inaccuracies associated with measurement of partition coefficients at a single concentration. Column experiments were conducted under conditions of non-equilibrium to evaluate the kinetics of the reversible absorption of the selected tracers in a sandy medium containing a uniform entrapped saturation of TCE-DNAPL. Experimental tracer breakthrough data were used, in conjunction with mathematical models and batch measurements, to evaluate alternative hypotheses for observed deviations from linear equilibrium partitioning behavior. Analyses suggest that, although all tracers accumulate at the TCE-DNAPL/aqueous interface, surface accumulation does not influence transport at concentrations typically employed for tracer tests. Moreover, results reveal that the kinetics of the reversible absorption process are well described using existing mass transfer correlations originally developed to model aqueous boundary layer resistance for pure-component NAPL dissolution.

Ervin, Rhiannon E.; Boroumand, Ali; Abriola, Linda M.; Ramsburg, C. Andrew

2011-11-01

263

Determination of volatile compounds in wine by gas chromatography-flame ionization detection: comparison between the U.S. Environmental Protection Agency 3sigma approach and Hubaux-Vos calculation of detection limits using ordinary and bivariate least squares.  

PubMed

A capillary GC-flame ionization detection (FID) method to determine volatile compounds (ethyl acetate, 1,1-diethoxyethane, methyl alcohol, 1-propanol, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 1-butanol, and 2-butanol) in wine was investigated in terms of calculation of detection limits and calibration method. The main objectives were: (1) calculation of regression coefficient parameters by ordinary least-squares (OLS) and bivariate least-squares (BLS) regression models, taking into account errors in both axes; (2) estimation of linear dynamic range (LDR) according to International Conference on Harmonization recommendations; (3) performance evaluation of a method by using three different internal standards (ISs) such as acetonitrile, acetone, and 1-pentanol; (4) evaluation of LODs according to the U.S. Environmental Protection Agency (EPA) 3sigma approach and the Hubaux-Vos (H-V) method; (5) application of H-V theory to a gas chromatographic analytical method and to a food matrix; and (6) accuracy assessment of the method relative to methyl alcohol content through a Unione Italiana Vini (UIV) interlaboratory proficiency test. Calibration curves calculated via BLS and OLS show similar slopes, while intercepts are closer to zero in the first case, independent of the chosen IS. The studied ISs show a substantially equivalent behavior, even though the IS closer to the analyte retention time seems to be more appropriate in terms of LDR and LOD. Results indicate an underestimation of LODs using the EPA 3sigma approach instead of the more realistic H-V method, both with OLS and BLS regression models. Methanol contents compared with UIV average values indicate recovery between 90 and 110%. PMID:22649934

Caruso, Rosario; Scordino, Monica; Traulo, Pasqualino; Gagliano, Giacomo

2012-01-01

264

Phase Behavior of Liquid Crystals Formed in [C12mim]CI/H2O and [C12mim]CI/Alcohols Systems  

NASA Astrophysics Data System (ADS)

Phase behaviors of different binary systems involving 1-dodecyl-3-methylimidazolium chloride ([C12mim]Cl) and H2O, [C12mim]Cl and different alcohols (1-butanol, 1-pentanol, 1-hexanol and 1-octanol) are investigated at 25 °C. Hexagonal liquid crystal phase (H1) is identified in [C12mim]Cl/H2O system, and lamellar liquid-crystalline (L?) phase is found in [C12mim]Cl/alcohols systems by using polarized optical microscopy and small-angle X-ray scattering techniques. The formation of such phases is considered as a synergetic result of the solvatophobic force and the hydrogen-bonded network comprising an imidazolium ring, chloride ion and water (or alcohols), which can be confirmed by Fourier transform infrared spectra. It is noticeable that in [C12mim]Cl/1-octanol system, the lattice spacings of lamellar phase increase with increasing C12mimCl concentration, which is opposite to the results of [C12mim]Cl/H2O system. This may result mainly from stronger static repulsion among hydrophilic headgroups of imidazolium salts arranged in the bilayers of lamellar structures. Further measurements by differential scanning calorimetry indicate that the lamellar phase is stable within a wide temperature range above room temperature. However, the lattice spacings decrease with the increase of temperature, which may be due to the softening of the hydrocarbon chain of [C12mim]Cl molecules. In different alcohols systems, it is found that the lamellar lyotropic liquid crystal structure is easier to be formed when the carbon chain length becomes longer.

Pei, Mei-shan; Wu, Zhi-yan; Wang, Lu-yan; Wu, Xin-zhou; Tao, Xu-tang

2009-10-01

265

Floatabilities of treated coal in water at room temperature  

SciTech Connect

Experiments on equilibrium adsorption loadings of various probe compounds on 60-200 mesh Illinois No. 6 coal (PSOC-1539), Adaville No. 1 coal (PSOC-1544), Wyodak coal (PSOC-1545), and Pittsburgh No. 8 coal (PSOC-1549) were performed. The probe compounds include 2-methyl-1-pentanol (2M1P), 1-heptanol, benzene, and toluene. Equilibrium adsorption loadings of aromatic compounds such as toluene and benzene on the four chosen coals obey the Langmuir isotherm model up to 100 ppm in concentrations of probe compounds. Equilibrium adsorption loadings of higher aliphatic alcohols such as 2M1P and 1-heptanol on the four chosen coals do not follow both the Langmuir isotherm model and the Freundlich empirical adsorption model. Flotation of the coals, equilibrated with aqueous solutions of 2M1P and 1-heptanol, increases linearly with equilibrium adsorption loadings of these probe compounds on the coals. The chosen coals were treated with nitrogen and air at 1 atm and 125-225{degrees}C for 24 h. Flotation experiments of the treated coals were conducted at room temperature, using distilled water only as a flotation medium. Flotation of Adaville No. 1 coal and Wyodak coal treated with nitrogen gas is higher than that of the untreated coals and increases with treatment temperatures. Flotation of Adaville No. 1 coal treated with air at 125-225{degrees}C is not significantly different from that of untreated coal. Flotation of Pittsburgh No. 8 coal treated with air is lower than that of untreated coal and decreases with treatment temperatures. Flotation of Illinois No. 6 coal treated with nitrogen with nitrogen only is higher than that of untreated coal. Flotation of Illinois No. 6 coal treated with nitrogen at 125-175{degrees}C increases with treatment temperatures, whereas flotation of Illinois No. 6 coal treated with nitrogen at 174-225{degrees}C decreases with treatment temperatures.

Kwon, K.C. [Tuskegee Univ., Tuskegee, AL (United States); Rohrer, R.L.; Lai, R.W. [DOE, Pittsburgh, PA (United States)] [and others

1995-04-01

266

Physicochemical investigation of mixed surfactant microemulsions: water solubilization, thermodynamic properties, microstructure, and dynamics.  

PubMed

In this contribution, we report on a systematic investigation of phase behavior and solubilization of water in water-in-heptane or decane aggregates stabilized by mixtures of polyoxyethylene (20) cetyl ether (Brij-58) and cetyltrimethylammonium bromide (CTAB) surfactants with varying compositions in conjugation with 1-pentanol (Pn) at fixed surfactant(s)/Pn ratio and temperature. Synergism in water solubilization was evidenced by the addition of CTAB to Brij-58 stabilized system in close proximity of equimolar composition in both oils. An attempt has been made to correlate composition dependent water solubilization and volume induced conductivity studies to provide insight into the solubilization mechanism of these mixed systems. Conductivity studies reveal the ascending curve in water solubilization capacity-(Brij-58:CTAB, w/w) profile as the interdroplet interaction branch indicating percolation of conductance and the descending curve is a curvature branch due to the rigidity of the interface in these systems. The microstructure of these systems as a function of surfactant composition has been determined by dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR) measurements. FTIR study reveals increase and decrease in relative population of bound and bulk-like water, respectively, with increase in Brij-58:CTAB (w/w). DLS measurements showed that the droplet hydrodynamic diameter (Dh) decreases significantly with the increase in Brij-58:CTAB (w/w). Further, the interfacial composition and energetic parameters for the transfer of Pn from bulk oil to the interface were evaluated by the dilution method. Formation of temperature-insensitive microemulsions and temperature invariant droplet sizes are evidenced in the vicinity of the equimolar composition. The results are interpreted in terms of a proposed mechanism. PMID:24064004

Bardhan, Soumik; Kundu, Kaushik; Saha, Swapan K; Paul, Bidyut K

2013-12-01

267

Isoform selectivity of adenylyl cyclase inhibitors: characterization of known and novel compounds.  

PubMed

Nine membrane-bound adenylyl cyclase (AC) isoforms catalyze the production of the second messenger cyclic AMP (cAMP) in response to various stimuli. Reduction of AC activity has well documented benefits, including benefits for heart disease and pain. These roles have inspired development of isoform-selective AC inhibitors, a lack of which currently limits exploration of functions and/or treatment of dysfunctions involving AC/cAMP signaling. However, inhibitors described as AC5- or AC1-selective have not been screened against the full panel of AC isoforms. We have measured pharmacological inhibitor profiles for all transmembrane AC isoforms. We found that 9-(tetrahydro-2-furanyl)-9H-purin-6-amine (SQ22,536), 2-amino-7-(furanyl)-7,8-dihydro-5(6H)-quinazolinone (NKY80), and adenine 9-?-d-arabinofuranoside (Ara-A), described as supposedly AC5-selective, do not discriminate between AC5 and AC6, whereas the putative AC1-selective inhibitor 5-[[2-(6-amino-9H-purin-9-yl)ethyl]amino]-1-pentanol (NB001) does not directly target AC1 to reduce cAMP levels. A structure-based virtual screen targeting the ATP binding site of AC was used to identify novel chemical structures that show some preference for AC1 or AC2. Mutation of the AC2 forskolin binding pocket does not interfere with inhibition by SQ22,536 or the novel AC2 inhibitor, suggesting binding to the catalytic site. Thus, we show that compounds lacking the adenine chemical signature and targeting the ATP binding site can potentially be used to develop AC isoform-specific inhibitors, and discuss the need to reinterpret literature using AC5/6-selective molecules SQ22,536, NKY80, and Ara-A. PMID:24006339

Brand, Cameron S; Hocker, Harrison J; Gorfe, Alemayehu A; Cavasotto, Claudio N; Dessauer, Carmen W

2013-11-01

268

Nanostructured surfactant-based systems for the removal of polymers from wall paintings: a small-angle neutron scattering study.  

PubMed

Nanostructured soft matter systems represent effective and long-lasting solutions with respect to traditional and often obsolete methodologies for the conservation of works of art. In particular, complex fluids such as micelles and microemulsions are the most performing media for the removal of organic materials from porous supports, like wall paintings or stones. In this Article, we report on the characterization of two systems, EAPC and XYL, which have shown good to optimal performances in the removal of organic polymers from wall paintings. EAPC is a five-components fluid composed of water, sodium dodecylsulfate (SDS), 1-pentanol (PeOH), propylene carbonate (PC), and ethyl acetate (EA), while XYL is a "classical" o/w microemulsion, where p-xylene droplets are stabilized in water by SDS and PeOH. Small-angle neutron scattering (SANS) with contrast variation is used to infer a detailed picture of the structure of these complex fluids, with a particular focus on the partition of the components between the bulk phase and the nanocompartments. We found that, differently from XYL, the EAPC system is neither a microemulsion nor a simple micellar solution, with the cosolvents partitioned between the dispersing phase and the disperse droplets. These different structural features play a key role in defining the cleaning effectiveness and specifically the kinetics of interaction between the nanofluid and the polymeric coating to be removed, which is of paramount importance for the application in the field. Both of these nanofluids are effective in polymer removal, but EAPC is considerably more efficient and versatile. The composition and the structure at the nanoscale determine the capability of removing a broad range of different polymer coatings from porous materials. A representative case study is here described, addressing a particularly challenging conservative issue, which is the removal of a multilayered aged coating that was irreversibly damaging the pictorial layer of the Annunciation Basilica in Nazareth. PMID:23025287

Baglioni, Michele; Berti, Debora; Teixeira, José; Giorgi, Rodorico; Baglioni, Piero

2012-10-30

269

Interfacial stoichiometry of a microemulsion system  

SciTech Connect

An o/w emulsion (4 g of sodium dodecyl sulfate (SDS); 4 mL of n-hexadecane (n-C{sub 16})/20 mL of H{sub 2}O) was titrated to clarity with 1-pentanol (n-C{sub 5}OH). When (1) n-C{sub 5}OH volume versus H{sub 2}O volume and (2) n-C{sub 16} volume versus n-C{sub 5}OH volume were plotted, two straight lines were obtained. The microdroplet is assumed to be an interfacial sheath with a n-C{sub 16} core and n-C{sub 5}OH distributed between three phases, oil, water, and the interface. The amount of n-C{sub 5}OH in the oil core and in the continuous phase was determined. The minimum volume of n-C{sub 16} required to form a microemulsion was also determined. From the experiments the calculated molar interfacial stoichiometry was found to be 2 n-C{sub 5}OH/3.5 SDS/1 n-C{sub 16}. To substantiate the proposed model, DSC curves of frozen microemulsion containing various volumes on n-C{sub 5}OH were investigated. Peak temperatures were found to be n-C{sub 16} (18.33{degree}C), H{sub 2}O ({minus}2.04{degree}C), and the interfacial sheath ({minus}9.65{degree}C). In these systems the microdroplets may be considered as oil spheres encapsulated by an interfacial sheath of constant interfacial composition.

Rosano, H.L.; Nixon, A.L. (City College of the City Univ. of New York, NY (USA)); Cavallo, J.L. (General Foods USA, Tarrytown, NY (USA))

1989-06-01

270

Manipulating volatile emission in tobacco leaves by expressing Aspergillus nigerbeta-glucosidase in different subcellular compartments.  

PubMed

Expression of the Aspergillus nigerbeta-glucosidase gene, BGL1, in Nicotiana tabacum plants (cv. Xanthi) had a profound effect on the volatile emissions of intact and crushed leaves. BGL1 was expressed under the control of the cauliflower mosaic virus (CaMV) 35S promoter and targeted to the cytoplasm, cell wall, lytic vacuole (LV), chloroplast or endoplasmic reticulum (ER). Subcellular localization was confirmed by gold immunolabelling, followed by transmission electron microscopy (TEM). Significant beta-glucosidase activity was observed in transgenic plants expressing BGL1 in the cell wall, LV and ER. Compared with controls, all intact transgenic leaves were found to emit increased levels of 2-ethylhexanol, as determined by gas chromatography-mass spectrometry (GC-MS) analysis of the headspace volatiles. Plants expressing BGL1 in the cell wall (Tcw) emitted more trans-caryophyllene than did non-transgenic controls, whereas plants expressing BGL1 in the ER (Ter) and LV (Tvc) emitted more cembrene than did non-transgenic controls. Volatiles released from crushed transgenic leaves and collected with solid-phase microextraction (SPME) polydimethylsiloxane fibre were distinctly enhanced. Significant increases in linalool, nerol, furanoid cis-linalool oxide, 4-methyl-1-pentanol, 6-methyl-hept-5-en-2-ol and 2-ethylhexanol were detected in transgenic plants when compared with wild-type controls. 3-Hydroxyl-beta-ionone levels were increased in crushed Tcw and Ter leaves, but were undetectable in Tvc leaves. The addition of glucoimidazole, a beta-glucosidase inhibitor, abolished the increased emission of these volatiles. These results indicate that the expression of a fungal beta-glucosidase gene in different subcellular compartments has the potential to affect the emission of plant volatiles, and thereby to modify plant-environment communication and aroma of agricultural products. PMID:17134395

Wei, Shu; Marton, Ira; Dekel, Mara; Shalitin, Dror; Lewinsohn, Efraim; Bravdo, Ben-Ami; Shoseyov, Oded

2004-07-01

271

Gas-Phase Reactivity of Protonated 2-, 3- and 4-Dehydropyridine Radicals Toward Organic Reagents  

PubMed Central

In order to explore the effects of the electronic nature of charged phenyl radicals on their reactivity, reactions of the three distonic isomers of ndehydropyridinium cation (n = 2, 3 or 4) have been investigated in the gas phase by using Fourier-transform ion cyclotron resonance mass spectrometry. All three isomers react with cyclohexane, methanol, ethanol and 1-pentanol exclusively via hydrogen atom abstraction, and with allyl iodide mainly via iodine atom abstraction, with a reaction efficiency ordering: 2 > 3 > 4. The observed reactivity ordering correlates well with the calculated vertical electron affinities of the charged radicals (i.e., the higher the vertical electron affinity, the faster the reaction). Charged radicals 2 and 3 also react with tetrahydrofuran exclusively via hydrogen atom abstraction, but the reaction of 4 with tetrahydrofuran yields products arising from nonradical reactivity. The unusual reactivity of 4 is likely to result from the contribution of an ionized carbene-type resonance structure that facilitates nucleophilic addition to the most electrophilic carbon atom (C-4) in this charged radical. The influence of such a resonance structure on the reactivity of 2 is not obvious, and this may be due to stabilizing hydrogen-bonding interactions in the transition states for this molecule. Charged radicals 2 and 3 abstract a hydrogen atom from the substituent in both phenol and toluene, but 4 abstracts a hydrogen atom from the phenyl ring – a reaction that is unprecedented for phenyl radicals. Charged radical 4 reacts with tert-butyl isocyanide mainly by hydrogen cyanide (HCN) abstraction while CN abstraction is the principal reaction for 2 and 3. The different reactivity observed for 4 (compared to 2 and 3) is likely to result from different charge and spin distributions of the reaction intermediates for these charged radicals. PMID:19902945

Adeuya, Anthony; Price, Jason M.; Jankiewicz, Bartlomiej J.; Nash, John J.; Kenttamaa, Hilkka I.

2009-01-01

272

Isoform Selectivity of Adenylyl Cyclase Inhibitors: Characterization of Known and Novel Compounds  

PubMed Central

Nine membrane-bound adenylyl cyclase (AC) isoforms catalyze the production of the second messenger cyclic AMP (cAMP) in response to various stimuli. Reduction of AC activity has well documented benefits, including benefits for heart disease and pain. These roles have inspired development of isoform-selective AC inhibitors, a lack of which currently limits exploration of functions and/or treatment of dysfunctions involving AC/cAMP signaling. However, inhibitors described as AC5- or AC1-selective have not been screened against the full panel of AC isoforms. We have measured pharmacological inhibitor profiles for all transmembrane AC isoforms. We found that 9-(tetrahydro-2-furanyl)-9H-purin-6-amine (SQ22,536), 2-amino-7-(furanyl)-7,8-dihydro-5(6H)-quinazolinone (NKY80), and adenine 9-?-d-arabinofuranoside (Ara-A), described as supposedly AC5-selective, do not discriminate between AC5 and AC6, whereas the putative AC1-selective inhibitor 5-?[[2-?(6-?amino-?9H-?purin-?9-?yl)?ethyl]?amino]?-?1-?pentanol (NB001) does not directly target AC1 to reduce cAMP levels. A structure-based virtual screen targeting the ATP binding site of AC was used to identify novel chemical structures that show some preference for AC1 or AC2. Mutation of the AC2 forskolin binding pocket does not interfere with inhibition by SQ22,536 or the novel AC2 inhibitor, suggesting binding to the catalytic site. Thus, we show that compounds lacking the adenine chemical signature and targeting the ATP binding site can potentially be used to develop AC isoform–specific inhibitors, and discuss the need to reinterpret literature using AC5/6-selective molecules SQ22,536, NKY80, and Ara-A. PMID:24006339

Brand, Cameron S.; Hocker, Harrison J.; Gorfe, Alemayehu A.; Cavasotto, Claudio N.

2013-01-01

273

Sensory and physicochemical evolution of tropical cooked peeled shrimp inoculated by Brochothrix thermosphacta and Lactococcus piscium CNCM I-4031 during storage at 8°C.  

PubMed

This study investigated the sensory quality and physicochemical evolution (pH, glucose, l-lactic acid, biogenic amine, free amino-acids and volatile compounds) during storage at 8°C of cooked peeled shrimp inoculated with the specific spoilage bacteria Brochothrix thermosphacta alone or mixed with the protective strain Lactococcus piscium CNCM I-4031. Growth of both bacteria was monitored at regular intervals during storage by microbial counts and the thermal temperature gradient gel electrophoresis (TTGE) technique. Bacterial counts showed that L. piscium and B. thermosphacta inoculated at 7 log CFU/g and 3 log CFU/g were well adapted to shrimp, reaching a maximum level of 9 log CFU/g after 4days and 10days respectively. In mixed culture, the growth of B. thermosphacta was reduced by 3.2±0.1 log CFU/g. The TTGE technique allowed monitoring the colonisation of the strains on the shrimp matrix and confirming the dominance of L. piscium in mixed culture throughout the experiment. Sensory analysis confirmed that B. thermosphacta spoiled the product after 11days, when its cell number attained 8 log CFU/g with the emission of strong butter/caramel off-odours. This sensory profile could be linked to the production of 2,3 butanedione, cyclopentanol, 3-methylbutanol, 3-methylbutanal, 2-methylbutanal, 4-methyl-3-chloro-3-pentanol and ethanol, which were produced in more significant quantities in the B. thermosphacta batch than in the batches in which the protective strain was present. On the contrary, TVBN and TMA were not suitable as quality indicators for B. thermosphacta spoilage activity. In the products where the protective L. piscium strain was present, no adverse effect on sensory quality was noted by the sensory panels. Moreover, biogenic amine assessment did not show any histamine or tyramine production by this strain, underlining its safety profile. Both strains produced lactic acid (1850mg/kg in L. piscium and B. thermosphacta batch on days 3 and 10 respectively; 3830mg/kg on day 7 in mixed culture) and the pH decrease from 6.6±0.0 to 5.9±0.1 was similar in all batches. Lactic acid production or competition for free amino-acid was not involved in the inhibition mechanism; however rapid glucose consumption by L. piscium could partially explain the growth limitation of the spoilage micro-organism. This study demonstrated the spoilage characteristic of B. thermosphacta and the usefulness of L. piscium as a bioprotective culture for tropical cooked peeled shrimp without any adverse effect on the sensory quality of the product. PMID:21835482

Fall, Papa Abdoulaye; Pilet, Marie France; Leduc, François; Cardinal, Mireille; Duflos, Guillaume; Guérin, Camille; Joffraud, Jean-Jacques; Leroi, Françoise

2012-01-16

274

An examination of the H/D isotope substitution effect on selectivity and activity in the cavitating ultrasound hydrogenation of aqueous 3-buten-2-ol and 1,4-pentadien-3-ol on Pd-black  

SciTech Connect

An H/D isotope effect study of the (H2 versus D2) hydrogenation of the aqueous substrates 3-buten-2-ol (3B2OL) and 1,4-pentadien-3-ol (14PD3OL) was performed using Pd-black catalyst. Either H2O or D2O solvents were employed (for alcohol H/D isotope substitution). Two experimental processing conditions of cavitating ultrasound (CUS) and stirred/silent (SS) methods were used. Products formed include 2-butanol and 2-butanone for the former, and 3-pentanol and 3-pentanone for the latter. The observed selectivity and pseudo-first order reaction rate coefficients (e.g., activity) to these products enabled a mechanistic interpretation of the various reaction conditions to be proposed. Experiments utilized a 50 mL batch reactor maintained at 298 K, employed 5.4 atm of H2 or D2 gas, while seven aliquots were collected during the course of the reaction. We have utilized 1-propanol as an inert dopant in all experiments to enable the rapid onset of cavitation in the CUS systems as described earlier [R.S. Disselkamp et al., J. Catal., 227, 552 (2004)]. The following conclusions were noted. First, the activity of the CUS compared to SS processing were ~100-fold larger. Second, variable catalyst loading experiments for stirred/silent D2 hydrogenation processing indicated that mass transfer of hydrogen gas to the Pd-surface played a role such that higher catalyst loading reduced surface D-atom concentrations and reduced saturated alcohol formation (e.g., via reduced H-addition to surface alkyl radicals). Third, for CUS processing the ketone selectivities for experiments employing water compared to D2O indicated that 3B2OL were twice as large, whereas for 14PD3OL they were comparable. This suggests, somewhat surprisingly, that for 3B2OL enol tautomerization to ketone is a slow, and possibly rate-controlling, process. Finally, again for CUS processing, the similarity in ketone selectivities (all ~17%) for H2 compared to D2 hydrogenation for both 3B2OL and 14PD3OL suggest that both H/D isotopes have rapid surface diffusion and hence give rise to nearly equal selectivies. Restated, the thermal or cavitating ultrasound activation is much greater than the surface H/D diffusion barrier.

Boyles, Kelly R.; Chajkowski, Sarah M.; Disselkamp, Robert S.; Peden, Charles HF

2006-05-24

275

Airborne molds and bacteria, microbial volatile organic compounds (MVOC), plasticizers and formaldehyde in dwellings in three North European cities in relation to sick building syndrome (SBS).  

PubMed

There are few studies on associations between airborne microbial exposure, formaldehyde, plasticizers in dwellings and the symptoms compatible with the sick building syndrome (SBS). As a follow-up of the European Community Respiratory Health Survey (ECRHS II), indoor measurements were performed in homes in three North European cities. The aim was to examine whether volatile organic compounds of possible microbial origin (MVOCs), and airborne levels of bacteria, molds, formaldehyde, and two plasticizers in dwellings were associated with the prevalence of SBS, and to study associations between MVOCs and reports on dampness and mold. The study included homes from three centers included in ECRHS II. A total of 159 adults (57% females) participated (19% from Reykjavik, 40% from Uppsala, and 41% from Tartu). A random sample and additional homes with a history of dampness were included. Exposure measurements were performed in the 159 homes of the participants. MVOCs were analyzed by GCMS with selective ion monitoring (SIM). Symptoms were reported in a standardized questionnaire. Associations were analyzed by multiple logistic regression. In total 30.8% reported any SBS (20% mucosal, 10% general, and 8% dermal symptoms) and 41% of the homes had a history of dampness and molds There were positive associations between any SBS and levels of 2-pentanol (P=0.002), 2-hexanone (P=0.0002), 2-pentylfuran (P=0.009), 1-octen-3-ol (P=0.002), formaldehyde (P=0.05), and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (Texanol) (P=0.05). 1-octen-3-ol (P=0.009) and 3-methylfuran (P=0.002) were associated with mucosal symptoms. In dwellings with dampness and molds, the levels of total bacteria (P=0.02), total mold (P=0.04), viable mold (P=0.02), 3-methylfuran (P=0.008) and ethyl-isobutyrate (P=0.02) were higher. In conclusion, some MVOCs like 1-octen-3-ol, formaldehyde and the plasticizer Texanol, may be a risk factor for sick building syndrome. Moreover, concentrations of airborne molds, bacteria and some other MVOCs were slightly higher in homes with reported dampness and mold. PMID:23280302

Sahlberg, Bo; Gunnbjörnsdottir, Maria; Soon, Argo; Jogi, Rain; Gislason, Thorarinn; Wieslander, Gunilla; Janson, Christer; Norback, Dan

2013-02-01

276

Catalytic characterization of lithium aluminum oxides: Including a study of both the cation replacement chemistry and the structure of the [alpha]LiAlO[sub 2]/[open quotes]HAlO[sub 2][close quotes] system  

SciTech Connect

Cation replacement is a low temperature synthetic technique used to replace most of the lithium cations in [alpha]LiAlO[sub 2] with protons without significantly modifying the structure of the reactant. Lauric acid worked well as a proton source because it was capable of 90% replacement without significant dissolution of [alpha]LiAlO[sub 2]. High pressure CO[sub 2]/H[sub 2]O treatment of the cation replaced product resulted in the decomposition of the reactant to form boehmite and Li[sub 2]CO[sub 3]. The XRD characterization of a series of partially replaced samples from the [alpha]LiAlO[sub 2]/HAlO[sub 2] system was used to develop an understanding of the cation replacement mechanism. A two phase mechanism is proposed, which consists of particles with an outer shell of lithiated HAlO[sub 2] and an inner core of [alpha]LiAlO[sub 2] (for 0.0 < x < 0.90). A model for the structure of HAlO[sub 2] was developed to describe the location of the protons and the lithium cations. The 3,3-dimethyl-1-isomerization reaction did not detect any intrinsic acidity on HAlO[sub 2] and detected only small amounts on calcined HAlO[sub 2] at 350[degrees]C. Lithium free [gamma]-alumina was extremely active for 3,3-dimethyl-1-butene isomerization demonstrating that the small concentration of lithium in both HAlO[sub 2] and calcined HAlO[sub 2] is sufficient to neutralize strong acid sites. The conversion of isopropyl alcohol produces propylene on acid-base sites and acetone on basic sites. [alpha]LiAlO[sub 2], [gamma]LiAlO[sub 2], and calcined HAlO[sub 2], produced varying amounts of propylene and acetone. [alpha]LiAlO[sub 2] and calcined HAlO[sub 2] produced a C6 diene, which indicates the presence of basic sites stronger than those needed for acetone formation. [alpha]LiAlO[sub 2] was the only sample that produced 4-methyl-2-pentanone and 4-methyl-2-pentanol.

Tomczak, D.C.

1993-01-01

277

Kinetics of n-butoxy and 2-pentoxy isomerization and detection of primary products by infrared cavity ringdown spectroscopy.  

PubMed

The primary products of n-butoxy and 2-pentoxy isomerization in the presence and absence of O(2) have been detected using pulsed laser photolysis-cavity ringdown spectroscopy (PLP-CRDS). Alkoxy radicals n-butoxy and 2-pentoxy were generated by photolysis of alkyl nitrite precursors (n-butyl nitrite or 2-pentyl nitrite, respectively), and the isomerization products with and without O(2) were detected by infrared cavity ringdown spectroscopy 20 ?s after the photolysis. We report the mid-IR OH stretch (?(1)) absorption spectra for ?-HO-1-C(4)H(8)•, ?-HO-1-C(4)H(8)OO•, ?-HO-1-C(5)H(10)•, and ?-HO-1-C(5)H(10)OO•. The observed ?(1) bands are similar in position and shape to the related alcohols (n-butanol and 2-pentanol), although the HOROO• absorption is slightly stronger than the HOR• absorption. We determined the rate of isomerization relative to reaction with O(2) for the n-butoxy and 2-pentoxy radicals by measuring the relative ?(1) absorbance of HOROO• as a function of [O(2)]. At 295 K and 670 Torr of N(2) or N(2)/O(2), we found rate constant ratios of k(isom)/k(O(2)) = 1.7 (±0.1) × 10(19) cm(-3) for n-butoxy and k(isom)/k(O(2)) = 3.4(±0.4) × 10(19) cm(-3) for 2-pentoxy (2? uncertainty). Using currently known rate constants k(O(2)), we estimate isomerization rates of k(isom) = 2.4 (±1.2) × 10(5) s(-1) and k(isom) ? 3 × 10(5) s(-1) for n-butoxy and 2-pentoxy radicals, respectively, where the uncertainties are primarily due to uncertainties in k(O(2)). Because isomerization is predicted to be in the high pressure limit at 670 Torr, these relative rates are expected to be the same at atmospheric pressure. Our results include corrections for prompt isomerization of hot nascent alkoxy radicals as well as reaction with background NO and unimolecular alkoxy decomposition. We estimate prompt isomerization yields under our conditions of 4 ± 2% and 5 ± 2% for n-butoxy and 2-pentoxy formed from photolysis of the alkyl nitrites at 351 nm. Our measured relative rate values are in good agreement with and more precise than previous end-product analysis studies conducted on the n-butoxy and 2-pentoxy systems. We show that reactions typically neglected in the analysis of alkoxy relative kinetics (decomposition, recombination with NO, and prompt isomerization) may need to be included to obtain accurate values of k(isom)/k(O(2)). PMID:22530669

Sprague, Matthew K; Garland, Eva R; Mollner, Andrew K; Bloss, Claire; Bean, Brian D; Weichman, Marissa L; Mertens, Laura A; Okumura, Mitchio; Sander, Stanley P

2012-06-21

278

Bulk activity measurements of organic compounds in aqueous electrolyte solutions and their implication in electrosorption studies  

SciTech Connect

Bulk activity measurements of the slightly soluble aliphatic alcohols 1-butanol, 2-butanol, 1-pentanol, 3-methyl-1-butanol, and 1-hexanol in various aqueous electrolyte solutions were made using the gas chromatographic method of Mohilner et al. a[sub A], x[sub A], m[sub A], and f[sub A] are the alcohol activity, mole fraction, molality, and activity coefficient with f[sub A] defined by a[sub A] = f[sub A]x[sub A] and standard state defined by a[sub A] = 1 when x[sub A] = 1. Representation of data by lnf[sub A] = ln f[degrees][sub A]-k[prime][sub A]m[sub A] + k[double prime][sub A]m[sub A][sup 2], with k[prime][sub A] and k[double prime][sub A] adjustable parameters expected to depend on both alcohol and electrolyte, was investigated. Plots of lnf[sub A] vs m[sub A] were found to be linear within experimental error up to saturation value of m[sub A] in all cases investigated; i.e., the k[double prime][sub A]m[sub A][sup 2] contributed negligibly in all cases and concentrations investigated and could be omitted. Semiquantitative models, based on the principle of independent surface action (for water-alcohol interactions) and dependence of electrolyte activities on dielectric constant, were developed and found to provide reasonable qualitative and semiquantitative interpretation of parameter trends and basis for semiquantitative estimation of parameters for other similar systems. In electrosorption studies involving measurement of the dependence of interfacial tension on organic solute concentration at fixed polarization with respect to a fixed reference electrode (e.g., a saturated calomel electrode), the activity coefficients of both alcohol and electrolyte will change as the organic solute concentration changes. Bases for calculating these changes and their effect on the estimation of organic solute surface excess are given and discussed. 23 refs., 3 figs., 1 tab.

Baikerikar, K.G.; Hansen, R.S. (Iowa State Univ., Ames (United States))

1993-01-01

279

Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage.  

PubMed

Nutrient composition and organoleptic properties of milk can be influenced by cow diets. The objective of this study was to evaluate the forage type effects on volatile organic compounds, fatty acid (FA) profile, and organoleptic properties of milk. Timothy grass was fed as hay, pasture, or silage during a period of 27 d to a group of 21 cows in a complete block design based on days in milk. Each cow also received 7.2 kg/d of a concentrate mix to meet their nutrient requirements. Forage dry matter intake averaged 13.9 kg/d and was not different among treatments. Milk yield was higher for cows fed pasture, intermediate for cows fed silage, and lowest for cows fed hay. However, milk fat content was higher for cows fed hay and silage, compared with cows fed pasture. As a result, fat-corrected milk and fat yield were not different among treatments. Increasing the supply of dietary cis-9,cis-12 18:2 (linoleic acid) and cis-9,cis-12,cis-15 18:3 (?-linolenic acid) when feeding pasture enhanced the concentration of these 2 essential FA in milk fat compared with feeding hay or silage. Moreover, the ratio of 16:0 (palmitic acid) to cis-9 18:1 (oleic acid), which is closely related to the melting properties of milk fat, was lower in milk from cows on pasture than in milk from cows fed hay or silage. Cows fed hay produced milk with higher levels of several free FA and ?-lactones, but less pentanal and 1-pentanol. More dimethyl sulfone and toluene were found in milk of cows on pasture. Cows fed silage produced milk with higher levels of acetone, 2-butanone, and ?-pinene. Results from a sensory evaluation showed that panelists could not detect a difference in flavor between milk from cows fed hay compared with silage. However, a significant number of assessors perceived a difference between milk from cows fed hay compared with milk from cows fed pasture. In a sensory ranking test, the percentage of assessors ranking for the intensity of total (raw milk, fresh milk, and farm milk), sweet (empyreumatic, vanilla, caramel, and sugar), and grassy (grass, leafy vegetable, and plant) flavors was higher for milk from cows fed pasture compared with hay and silage. Using timothy hay, pasture, or silage harvested at a similar stage of development, the current study shows that the taste of milk is affected by the forage type fed to cows. More research is, however, needed to establish a link between the sensory attributes of milk and the observed changes in volatile organic compounds and FA profile. PMID:24035021

Villeneuve, M-P; Lebeuf, Y; Gervais, R; Tremblay, G F; Vuillemard, J C; Fortin, J; Chouinard, P Y

2013-11-01

280

Hydrido (1,4,8,11,15,18,22,25-octa-n-pentylphthalocyaninato)-rhodium dimers: Single-crystal X-ray structure and the isomerization of the four isomers  

SciTech Connect

The hydrido(phthalocyaninato)rhodium dimer [(R{sub 8}Pc)RhH]{sub 2} (1; R{sub 8}Pc{sup 2-} = dianion of 1,4,8,11,15,18,22,25-octa-n-pentylphthalocyanine) was synthesized from the reaction of [(R{sub 8}Pc)(MeOH){sub 2}Rh]Cl with H{sub 2} at 110{degree}C in 1-pentanol. A single-crystal X-ray diffraction study shows that 1 is a dimer. Our belief that protonation occurs on a meso (or peripheral) nitrogen, rather than a pyrrolic nitrogen, is derived from X-ray structural data and {sup 1}H NMR results. (1) No uniquely long Rh-N bond is present, and all four pyrrolic nitrogens remain on the same plane, along with the Rh atom. (2) The chemical shift of {delta} 11.6 ppm for the N-H proton indicates that it is highly deshielded and, therefore, lies outside the extended ring currents of the Pc ligand. Therefore, the hydride-bridged isomer (R{sub 8}PcH)Rh({mu}-H)Rh(R{sub 8}Pc) (1a), in which the proton of R{sub 8}PcH{sup -} resides on a meso nitrogen, is proposed for 1 in the solid state and in benzene solution. Variable-temperature {sup 1}H NMR studies of 1 in toluene-d{sub 8} indicate that when T >= 115{degree}C, 1 dissociates into the monomeric hydride complex (R{sub 8}Pc)RhH (2); when T <= -25{degree}C, four isomers of 1, all of which have one Rh-H and one N-H moiety, are reversibly formed. Two isomers (1b and 1c), which exhibit fine structure in the hydride resonance due to their coupling to two inequivalent Rh nuclei, are assigned to two rotamers of the terminal hydride dimer (R{sub 8}PcH)RhRh(R{sub 8}Pc)H. 20 refs., 6 figs., 2 tabs.

Chen, M.J.; Nunez, L.; Rathke, J.W. [Argonne National Lab., IL (United States)] [Argonne National Lab., IL (United States); Rogers, R.D. [Northern Illinois Univ., DeKalb, IL (United States)] [Northern Illinois Univ., DeKalb, IL (United States)

1996-04-30

281

The effect of cavitating ultrasound on the aqueous phase hydrogenation of cis-2-buten-1-ol and cis-2-penten-1-ol on Pd-black  

SciTech Connect

We have studied the effect of cavitating ultrasound on the heterogeneous aqueous hydrogenation of cis-2-buten-1-ol (C4 olefin) and cis-2-penten-1-ol (C5 olefin) on Pd-black to form the trans-olefins (trans-2-buten-1-ol and trans-2-penten-1-ol) and saturated alcohols (1-butanol and 1-pentanol, respectively). Silent (and magnetically stirred) experiments served as control experiments. As described in an earlier publication by our group, we have added an inert dopant, 1-propanol, in the reaction mixture to ensure the rapid onset of cavitation in the ultrasound-assisted reactions that can lead to altered selectivity compared to silent reaction systems [R.S. Disselkamp, Ya-Huei Chin, C.H.F. Peden, J. Catal. 227 (2004) 552]. The motivation for this study is to examine whether cavitating ultrasound can reduce the [trans-olefin/saturated alcohol] molar ratio during the course of the reaction. This could have practical application in that it may offer an alternative processing methodology of synthesizing healthier edible seed oils by reducing trans-fat content.We have observed that cavitating ultrasound results in a [(trans-olefin/saturated alcohol)ultrasound/(trans-olefin/saturated alcohol)silent] ratio quantity less than 0.5 at the reaction mid-point for both the C4 and C5 olefin systems. This indicates that ultrasound reduces trans-olefin production compared to the silent control experiment. Furthermore, there is an added 30% reduction for the C5 versus C4 olefin compounds again at reaction mid-point. We attribute differences in the ratio quantity as a moment of inertia effect. In principle, the C4 versus C5 olefins has a {approx}52% increase in moment of inertia about C2 C3 double bond slowing isomerization. Since seed oils are C18 multiple cis-olefins and have a moment of inertia even greater than our C5 olefin here, our study suggests that even a greater reduction in trans-olefin content may occur for partial hydrogenation of C18 seed oils.

Disselkamp, Robert S.; Denslow, Kayte M.; Hart, Todd R.; White, James F.; Peden, Charles HF.

2005-07-15

282

The Effect of Cavitating Ultrasound on the Aqueous Phase Hydrogenation of Cis-2-buten-1-ol and Cis-2-penten-1-ol on Pd-black  

SciTech Connect

We have studied the effect of cavitating ultrasound on the heterogeneous aqueous hydrogenation of cis-2-buten-1-ol (C4 olefin) and cis-2-penten-1-ol (C5 olefin) on Pd-black to form the trans-olefins (trans-2-buten-1-ol and trans-2-penten-1-ol) and saturated alcohols (1-butanol and 1-pentanol, respectively). Silent (and magnetically stirred) experiments served as control experiments. As described in an earlier publication by our group, we have added an inert dopant, 1-propanol, in the reaction mixture to ensure the rapid onset of cavitation in the ultrasound-assisted reactions that can lead to altered selectivity compared to silent reaction systems [Disselkamp et al., J. Catal., 227 (2004) 552]. The motivation for this study is to examine whether cavitating ultrasound can reduce the [trans-olefin/saturated alcohol] molar ratio during the course of the reaction. This could have practical application in that it may offer an alternative processing methodology of synthesizing healthier edible seed oils by reducing trans-fat content. We have observed that cavitating ultrasound results in a [(trans-olefin/saturated alcohol)ultrasound/(trans-olefin/saturated alcohol)silent] ratio quantity less than 0.5 at the reaction mid-point for both the C4 and C5 olefin systems. This indicates that ultrasound reduces trans-olefin production compared to the silent control experiment. Furthermore, there is an added 30% reduction for the C5 versus C4 olefin compounds again at reaction mid-point. We attribute differences in the ratio quantity as a moment of inertia effect. In principle, the C4 versus C5 olefins has a {approx}52% increase in moment of inertia about C2=C3 double bond slowing isomerization. Since seed oils are C18 multiple cis olefins and have an moment of inertia even greater than our C5 olefin here, our study suggests that even a greater reduction in trans-olefin content may occur for partial hydrogenation of C18 seed oils.

Disselkamp, Robert S.; Denslow, Kayte M.; Hart, Todd R.; White, James F.; Peden, Charles HF.

2005-07-15

283

Enzymes and microemulsions. Activity and kinetic properties of liver alcohol dehydrogenase in ionic water-in-oil microemulsions.  

PubMed

The activity and the kinetic properties of horse liver alcohol dehydrogenase have been studied in water-in-oil microemulsions containing sodium dodecyl sulfate (SDS) or hexadecyl trimethylammonium bromide (CTAB), 1-butanol or 1-pentanol or 1-hexanol or t-butanol, water and cyclohexane alone or with octane. In the anionic microemulsions (i.e. containing sodium dodecyl sulfate), the enzyme quickly lost its activity, but was efficiently protected by the coenzyme and some adenine nucleotides. In the cationic microemulsions (i.e. containing hexadecyl trimethylammonium bromide), the enzyme activity was more stable and with higher alcohols was stable for at least 20 min. The Michaelis constant of NAD+ calculated with respect to the water content was nearly constant and higher than in water. The maximum velocity in anionic microemulsions depends on the water content whereas in cationic microemulsions, the maximum velocity did not show a clear dependence on the water content and was close to the maximum velocity found in water. The pH dependence of Km and Vmax in these microemulsions was similar to that observed in water. The kinetic data for a hydrophobic substrate, cinnamyl alcohol, showed that this alcohol partitions between the pseudo-phases and thus the apparent Michaelis constant and the concentration at which substrate-excess inhibition appeared were increased. The catalytic properties of the enzyme in microemulsions were illustrated by the preparative reduction of cinnamaldehyde with cofactor recycling. The rate determination of NAD+ reduction and of 1-butanol/cinnamaldehyde redox reaction showed that at low water content (2.8%), the NAD+ reduction rate was close to zero whereas the redox reaction rate was about half of the rate at higher water content. Probably at low water content the coenzyme binding-dissociation rates are reduced much more than the binding-dissociation rates of the substrates and the rates of the ternary complex interconversion. The cationic microemulsions seemed to be very favorable medium for enzyme activity, the tetraalkyl ammonium surfactant causing less denaturation than the anionic detergent dodecyl sulfate. PMID:3830176

Samama, J P; Lee, K M; Biellmann, J F

1987-03-16

284

Experimental study of the effect of test-well arrangement for partitioning interwell tracer test on the estimation of NAPL saturation  

NASA Astrophysics Data System (ADS)

Partitioning interwell tracer test (PITT) is a method to quantify and qualify a contaminated site with NAPLs through a degree of retardation of partitioning tracers compared to a conservative one. Although PITT is known to be a more effective method to measure the saturation of spatially-distributed NAPL contaminant than the point investigation method, the saturation estimation from PITT is reported to be underestimated due to various factors including heterogeneity of the media, adsorption, source zone NAPL architecture, and long tailing in breakthrough curves of partitioning tracers. Analytical description of PITT assumes that the injection-pumping well pair is on the line of ambient groundwater flow direction, but the test-well pair could easily be off the line in the field site, which could be another erroneous factor in analyzing PITT data. The purpose of this work is to study the influence of the angle of the test-well pair to ambient groundwater flow direction based on the result from PITT. The experiments were conducted in a small-scale 3D sandbox with dimensions of 0.5 m × 0.4 m × 0.15 m (LWH) of stainless steel. The surface is covered and sealed with a plexiglass plate to make the physical model a confined aquifer. Eight full-screened wells of Teflon material were installed along the perimeter of a 50 mm circle with 45 degree intervals in the middle of the physical model. Both ends of the sand box are connected to constant head reservoirs. The physical model was wet-packed with sieved and washed sand. Trichloroethylene (TCE) and bromide were used as the contaminant and the conservative tracer, respectively. Hexanol, 2,4-dimethyl-3-pentanol and 6-methyl-2-heptanol were used as partitioning tracers. Before the injection of TCE, a PITT was conducted to measure adsorption coefficient of partitioning tracers to the sand material. TCE of 4.5 mL, dyed with Sudan IV, was injected into the inner part of the circle of the wells. PITTs using the test-well pair parallel and with angles of 45 and 90 degrees to ambient flow direction were performed. Another PITT was conducted at an increased pumping rate with the test-well pair at a 45 degree angle to examine the effect of pumping rate. From the experiments, it was found that as the angles of the test-well pair to ambient groundwater flow direction increased, the estimated NAPL saturation decreased. Although the increase in pumping rate in this experiment reduces the effect of the obliqueness of the test-well arrangement, the effect of rate-limited transfer of partitioning tracers due to the increased pumping rate on the PITT should be examined in the interpretation. The results of these experiments revealed that the arrangement of the test-well pair is another controlling factor in performing and interpreting PITT in the field, in addition to the factors such as heterogeneity, source zone architecture, and tailing. Key words: PITT, test-well arrangement, ambient groundwater flow direction, NAPL saturation Acknowledgements: This research was supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Knowledge Economy of Korea. 11-3414

Kim, B.; Kim, Y.; Yeo, I.; Yongcheol Kim, In Wook Yeo

2011-12-01

285

Methanomassiliicoccus luminyensis gen. nov., sp. nov., a methanogenic archaeon isolated from human faeces.  

PubMed

During attempts to obtain novel, human-associated species of the domain Archaea, a coccoid micro-organism, designated strain B10(T), was isolated in pure culture from a sample of human faeces collected in Marseille, France. On the basis of its phenotypic characteristics and 16S rRNA and mcrA gene sequences, the novel strain was classified as a methanogenic archaeon. Cells of the strain were non-motile, Gram-staining-positive cocci that were approximately 850 nm in diameter and showed autofluorescence at 420 nm. Cells were lysed by 0.1% (w/v) SDS. With hydrogen as the electron donor, strain B10(T) produced methane by reducing methanol. The novel strain was unable to produce methane when hydrogen or methanol was the sole energy source. In an atmosphere containing CO(2), strain B10(T) could not produce methane from formate, acetate, trimethylamine, 2-butanol, 2-propanol, cyclopentanol, 2-pentanol, ethanol, 1-propanol or 2,3-butanediol. Strain B10(T) grew optimally with 0.5-1.0% (w/v) NaCl, at pH 7.6 and at 37 °C. It required tungstate-selenite for growth. The complete genome of the novel strain was sequenced; the size of the genome was estimated to be 2.05 Mb and the genomic DNA G+C content was 59.93 mol%. In phylogenetic analyses based on 16S rRNA gene sequences, the highest sequence similarities (98.0-98.7%) were seen between strain B10(T) and several uncultured, methanogenic Archaea that had been collected from the digestive tracts of a cockroach, a chicken and mammals. In the same analysis, the non-methanogenic 'Candidatus Aciduliprofundum boonei' DSM 19572 was identified as the cultured micro-organism that was most closely related to strain B10(T) (83.0% 16S rRNA gene sequence similarity). Each of the three treeing algorithms used in the analysis of 16S rRNA gene sequences indicated that strain B10(T) belongs to a novel order that is distinct from the Thermoplasmatales. The novel strain also appeared to be distinct from Methanosphaera stadtmanae DSM 3091(T) (72.9% 16S rRNA gene sequence similarity), another methanogenic archaeon that was isolated from human faeces and can use methanol in the presence of hydrogen. Based on the genetic and phenotypic evidence, strain B10(T) represents a novel species of a new genus for which the name Methanomassiliicoccus luminyensis gen. nov., sp. nov. is proposed. The type strain of the type species is B10(T) (?=?DSM 24529(T)?=?CSUR P135(T)). PMID:22859731

Dridi, Bédis; Fardeau, Marie-Laure; Ollivier, Bernard; Raoult, Didier; Drancourt, Michel

2012-08-01

286

A Unique Equation to Estimate Flash Points of Selected Pure Liquids Application to the Correction of Probably Erroneous Flash Point Values  

NASA Astrophysics Data System (ADS)

A simple empirical equation is presented for the estimation of closed-cup flash points for pure organic liquids. Data needed for the estimation of a flash point (FP) are the normal boiling point (Teb), the standard enthalpy of vaporization at 298.15 K [?vapH°(298.15 K)] of the compound, and the number of carbon atoms (n) in the molecule. The bounds for this equation are: -100?FP(°C)?+200; 250?Teb(K)?650; 20??vap H°(298.15 K)/(kJ mol-1)?110; 1?n?21. Compared to other methods (empirical equations, structural group contribution methods, and neural network quantitative structure-property relationships), this simple equation is shown to predict accurately the flash points for a variety of compounds, whatever their chemical groups (monofunctional compounds and polyfunctional compounds) and whatever their structure (linear, branched, cyclic). The same equation is shown to be valid for hydrocarbons, organic nitrogen compounds, organic oxygen compounds, organic sulfur compounds, organic halogen compounds, and organic silicone compounds. It seems that the flash points of organic deuterium compounds, organic tin compounds, organic nickel compounds, organic phosphorus compounds, organic boron compounds, and organic germanium compounds can also be predicted accurately by this equation. A mean absolute deviation of about 3 °C, a standard deviation of about 2 °C, and a maximum absolute deviation of 10 °C are obtained when predictions are compared to experimental data for more than 600 compounds. For all these compounds, the absolute deviation is equal or lower than the reproductibility expected at a 95% confidence level for closed-cup flash point measurement. This estimation technique has its limitations concerning the polyhalogenated compounds for which the equation should be used with caution. The mean absolute deviation and maximum absolute deviation observed and the fact that the equation provides unbiaised predictions lead to the conclusion that several flash points have been reported erroneously, whatever the reason, in one or several reference compilations. In the following lists, the currently accepted flash points for bold compounds err, or probably err, on the hazardous side by at least 10 °C and for the nonbolded compounds, the currently accepted flash points err, or probably err, on the nonhazardous side by at least 10 °C: bicyclohexyl, sec-butylamine, tert-butylamine, 2-cyclohexen-1-one, ethanethiol, 1,3-cyclohexadiene, 1,4-pentadiene, methyl formate, acetonitrile, cinnamaldehyde, 1-pentanol, diethylene glycol, diethyl fumarate, diethyl phthalate, trimethylamine, dimethylamine, 1,6-hexanediol, propylamine, methanethiol, ethylamine, bromoethane, 1-bromopropane, tert-butylbenzene, 1-chloro-2-methylpropane, diacetone alcohol, diethanolamine, 2-ethylbutanal, and formic acid. For some other compounds, no other data than the currently accepted flash points are available. Therefore, it cannot be assessed that these flash point data are erroneous but it can be stated that they are probably erroneous. At least, they need experimental re-examination. They are probably erroneous by at least 15 °C: 1,3-cyclopentadiene, di-tert-butyl sulfide, dimethyl ether, dipropyl ether, 4-heptanone, bis(2-chloroethyl)ether, 1-decanol, 1-phenyl-1-butanone, furan, ethylcyclopentane, 1-heptanethiol, 2,5-hexanediol, 3-hexanone, hexanoic acid methyl ester, 4-methyl-1,3-pentadiene, propanoyl chloride, tetramethylsilane, thiacyclopentane, 1-chloro-2-methyl-1-propene, trans-1,3-pentadiene, 2,3-dimethylheptane, triethylenetetramine, methylal, N-ethylisopropylamine, 3-methyl-2-pentene, and 2,3-dimethyl-1-butene.

Catoire, Laurent; Naudet, Valérie

2004-12-01

287

Influence of Mass Transfer Kinetics on Interpretation of Push-Pull Partitioning Tracer Tests  

NASA Astrophysics Data System (ADS)

There is now considerable interest in predicting plume response to various levels of treatment applied within a DNAPL source zone. An important component to the development of this predictive capability is the ability to characterize the distribution of DNAPL within the source zone. Metrics developed for description of source zone architecture are frequently based upon some combination of downgradient contaminant concentrations and in source testing. One option for in source testing is the use of partition tracers in either interwell or push-pull test configurations. Push-pull tracer tests are advantageous for obtaining more localized information that can be integrated with other observations to reduce the uncertainty related the links between the architecture of a source and its associated plume. Here we examined push-pull tracer tests in a series of aquifer cell experiments to evaluate the potential of this type of test to quantify metrics of the DNAPL distribution at the local-scale (i.e., 1 m flow path). Three DNAPL architectures were characterized by conducting push-pull tracer tests using a solution which comprised three partitioning tracers (1-pentanol, 1-hexanol, and 2-octanol) and one non-partitioning tracer (bromide). Each architecture was characterized using three flow regimes that employed combinations of fast (~30 cm/hr) and slow (~2 cm/hr) velocities. Production curves (i.e., tracer concentrations during the pull phase of the test) for the partitioning tracers were found to be asymmetric. This asymmetry severely degraded the ability of an analytical solution employing the local equilibrium assumption to predict the overall saturations. Saturation estimates from the analytical solution were found to be improved when the application of the model was restricted to later time data (Vext/Vinj >1). This observation suggests it is important to better understand the factors influencing the early time data. Experiments were also simulated using a numerical model containing a linear driving force expression to describe the tracer mass transfer. Mass transfer coefficients in all simulations were produced using available correlations for pool dissolution. Perfect knowledge of the DNAPL and permeability distributions, as well as relative permeability effects enabled the numerical model to better capture the asymmetry observed in the production curves. We then began to systematically simplify the numerical model to explore which assumptions associated with the analytical solution cause its poor performance. These assumptions include: uniform packing distribution, uniform DNAPL distribution, equilibrium partitioning, and no permeability reduction due to the presence of the DNAPL. Results suggest only limited degradation in model performance when the medium permeability and DNAPL saturation are assumed to be uniform, and relative permeability effects are neglected. In contrast, model performance was considerably poorer when mass transfer kinetics were neglected. These results highlight the importance of including mass transfer kinetics when characterizing local-scale DNAPL architecture.

Ervin, R. E.; Boroumand, A.; Abriola, L. M.; Ramsburg, C. A.

2012-12-01

288

Decontamination of Tritiated-Water Using Super-hydrophobic Pt-Catalyst Synthesized with Water-in-Supercritical CO{sub 2}  

SciTech Connect

Tritium, {sup 3}H, is one of the hydrogen isotopes, created in coolant of a fission reactor and to be utilized as fuel for nuclear fusion reactors. Since a large amount of tritium will be contained in a fusion reactor or in a fission reactor, a small fraction of the tritiated chemical species, in most cases, tritiated water, may leak to the environment. Tritium is, however, a radioactive isotope whose specific radioactivity is 4 x 10{sup 17} Bq kg{sup -1}, and easy to transfer in human body, its confinement is very important from the safety aspect. One of the problems of tritium confinement and decontamination of tritiated chemical species is related with necessity of its isotope separation from lighter hydrogen isotopes, {sup 2}H and {sup 1}H. Most of principles for the isotope separations are based on fractionations of isotopes in different chemical species. A large fractionation for hydrogen isotopes is observed in a chemical exchange of hydrogen atoms between water, Q{sub 2}O, and hydrogen gas, Q{sub 2}, where 'Q' denotes one of the hydrogen isotopes. Heavier isotopes are enriched significantly into Q{sub 2}O rather than Q{sub 2}. Therefore practical method of tritium removal would be established by hydrogen isotope separation with chemical exchange of water and hydrogen gas. At first, we prepared a catalyst, by reducing Pt{sup 4+} in reversed micelles where the reducing agent, aqueous solution of sodium tetra borohydrate, NaBH{sub 4} was also contained in reversed micelles prepared separately. In this situation, micelles containing Pt{sup 4+} and reducing reagent collided and produced Pt nanoparticles, which were expected to be impregnated in the hydrophobic structure after depressurization. After this type of earlier experiment we determined a mass of impregnated Pt by total dissolution of gauze with aqua regia followed by concentration measurement of Pt with ICP-AES. We performed several trials, unfortunately, however, the mass of Pt deposited on the gauze was very small to detect, and this approach turns to be not successful. As the second approach, we utilize CO{sub 2} soluble Pt precursor, CODMe{sub 2}Pt purchased from Sigma-Aldrich Co. and H{sub 2} gas as reducing agent, which could be completely mixed with SC-CO{sub 2}. This system was well-known for Pt particle formation by auto-catalytic growth. The second approach was aiming at increasing Pt amount deposited in the gauze. This approach was successful in increasing Pt amount, but the Pt particle size also increased to be more than 50 nm, which was not suitable for catalyst. Finally, we synthesized the catalyst by the following procedure: firstly, a reducing agent of NaBH{sub 4} was deposited on the nano-textured hydrophobic layer on the gauze. This step was realized by forming reversed micelles of aqueous NaBH{sub 4} solution using a surfactant AOT and a co-surfactant 2,2,3,3,4,4,5,5,-octafluoro-1-pentanol (F-pentanol) in SC-CO{sub 2}. This system of surfactant combination of AOT and F-pentanol has been found to work successfully in recent studies. In the second step, the gauze was contacted with CODMe{sub 2}Pt dissolved in SC-CO{sub 2} to synthesize seeds of Pt particles for the auto-catalytic reaction proceeding by CODMe{sub 2}Pt with hydrogen. The seeds were formed by the reaction between deposited NaBH{sub 4} and CODMe{sub 2}Pt in SC-CO{sub 2}. The physical characterization of this catalyst was performed by SEM-EDS. By this procedure, the Pt hydrophobic catalyst where Pt nanoparticle of 10 nm in diameter was locally deposited in the nano-textured layer was successfully prepared. Hydrophobicity after the chemical Pt deposition was tested by measurement of water absorbed on the gauze and the catalyst performance was evaluated by {sup 1}H{sup 2}H formation through the scrambling reaction from {sup 1}H{sub 2} and {sup 2}H{sub 2} and the reaction was successfully observed. We demonstrated a new hydrophobic catalyst preparation using SC-CO{sub 2} effectively. We can conclude that the approach of creating Pt nanoparticles in SC-CO{sub 2} and depositing them in

Youichi Enokida; Kayo Sawada [EcoTopia Science Institute (Japan)]|[Graduate School of Engineering, Nagoya University, 1 furo-cho, Nagoya 463-8603, Aichi-ken (Japan); Ryosuke Shimizu [EcoTopia Science Institute (Japan); Ichiro Yamamoto [Graduate School of Engineering, Nagoya University, 1 furo-cho, Nagoya 463-8603, Aichi-ken (Japan)

2008-01-15