Note: This page contains sample records for the topic 1-pentanol 2-pentanol 3-pentanol from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

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

1996-11-01

2

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

1999-05-01

3

STUDIES ON THE PHASE DIAGRAM OF THE SURFACTANT\\/1PENTANOL \\/ WATER TERNARY SYSTEM II: THE LIQUID CRYSTALLINE PHASE  

Microsoft Academic Search

The phase behavior of liquid crystalline in the ternary system of dodecyl dimethyl ammonium hydroxyl propyl sulfonate(DDAHPS)\\/1pentanol(C5HnOH) \\/ water deuteron(D2O) has been investigated by polarizing optical microscopy, H NMR spectroscopy methods. The results indicate that two kinds of liquid crystals (the lamellar, and the hexagonal) exist in the liquid crystalline phase region. In this paper, we also use the polarized

Qiang Shen; Gan-Zuo Li; Yan-Zhang Huang; Li-Xia Li; Jun Xu

1999-01-01

4

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

5

Liquidliquidsolid equilibria for the quaternary system water+ethanol+1-pentanol+sodium chloride at 25C  

Microsoft Academic Search

Salting-out effect can be used to improve the extraction of some solutes by modifying the solute distribution between two liquid phases. In this work we report the results obtained for the quaternary system water+ethanol+1-pentanol+sodium chloride at 25C. All equilibrium regions (one liquid, two liquids, one liquid+one solid and two liquids+one solid zones) have been systematically studied. Tie lines and tie-triangles

M. M. Olaya; A. Botella; A. Marcilla

1999-01-01

6

Molecular interactions in 1-pentanol +2-methyl-2-butanol mixtures: Static dielectric constant, viscosity and refractive index investigations at 5, 25 and 45C  

Microsoft Academic Search

Static dielectric constants, refractive indices and viscosities of 1-pentanol +2-methyl-2-butanol mixtures were measured at 5, 25 and 45C. The results show that the mixing of the two isomers modifies the polarizability and the resistence of viscous flow of the system depending on the composition and temperature. Short range intermolecular interactions producing hetero-alcohol open dimers are considered.

Alessandro D'Aprano; Ines Dorina Donato; Vincenzo Turco Liveri

1989-01-01

7

Vaporliquid equilibrium of binary mixtures of trichloroethylene with 1-pentanol, 2-methyl-1-butanol and 3-methyl-1-butanol at 100 kPa  

Microsoft Academic Search

Isobaric vaporliquid equilibria (VLE) have been obtained for the systems trichloroethylene+1-pentanol, trichloroethylene+2-methyl-1-butanol and trichloroethylene+3-methyl-1-butanol at 100 kPa using a dynamic still. The experimental error in temperature is 0.1 K, in pressure 0.1 kPa, and in the liquid and vapor mole fraction 0.001. The three systems satisfy the point-to-point thermodynamic consistency test. All the systems show positive deviations from ideality. The

Ana Dejoz; Vicenta Gonzlez-Alfaro; Francisco J Llopis; Pablo J Miguel; M. Isabel Vzquez

1999-01-01

8

Phase behavior of water-in-supercritical carbon dioxide microemulsion with sodium salt of bis(2,2,3,3,4,4,5,5-octafluoro-1-pentanol) sulfosuccinate  

Microsoft Academic Search

The fluorinated analogues of AOT surfactant, sodium salt of bis(2,2,3,3,4,4,5,5-octafluoro-1-pentanol) sulfosuccinate, which has CO2-philic chains and a hydrophilic head group, was synthesized for forming water-in-CO2 microemulsion. The cloud point of this surfactant was measured and the supercritical fluid-phase behavior of water-in-CO2 microemulsion was investigated by using a variable-volume view cell apparatus. It was found that the phase behavior of microemulsion

Ji-Young Park; Jong Sung Lim; Youn Woo Lee; Ki-Pung Yoo

2006-01-01

9

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

10

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.; Dale, V.; Mellouki, A.

2013-09-01

11

ZrO 2 SiO 2 Mixed Oxides Xerogel and Aerogel as Solid Acid Catalysts for Solvent Free Isomerization of ?-Pinene and Dehydration of 4Methyl2Pentanol  

Microsoft Academic Search

\\u000a AbstractSulfated and non-sulfated ZrO2SiO2 mixed oxide xerogel and aerogel samples having varied Zr\\/Si molar ratio were evaluated as solid acid catalysts for the isomerization\\u000a of ?-pinene and dehydration of 4-methyl-2-pentanol. Sulfation resulted into enhancement in the catalytic activity of both\\u000a xerogel and aerogel samples towards the studied reactions. For example, sulfated catalysts showed 8698% conversion of ?-pinene\\u000a and 835% conversion

Kalpesh B. Sidhpuria; Beena Tyagi; Raksh V. Jasra

2011-01-01

12

Pseudo-ternary phase diagrams of lecithin-based microemulsions: influence of monoalkylphosphates.  

PubMed

The formation of macroscopically homogeneous, stable, fluid, optically transparent, isotropic solutions (microemulsions) was delineated, at 25 degrees C, for systems containing water, soybean lecithin, sodium monoalkylphosphate (hexyl or ocytl), alcohol and isopropyl myristate. Six straight or branched alcohols (1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, 3-pentanol) were investigated as co-surfactants. A constant lecithin/alcohol mixing ratio was used, while the aqueous phase consisted of a solution of alkylphosphates at different concentrations. An increase of the microemulsion domain was seen by increasing the concentration of the alkylphosphate. With 0.2m hexylphosphate, as aqueous phase, the microemulsion domain consisted of a single, region, that, in the presence of butylic alcohols, spanded the greater portion of the phase diagram. In the presence of amyl alcohols the area of this region was much smaller. With 0.2 m octylphosphate the realm of existence of the microemulsions, except for 1-pentanol, consisted of two regions separated by a liquid-crystal region. With all the alcohols examined, the liquid-crystal phase solubilized a larger amount of oil in the presence of octylphosphate than in the presence of hexylphosphate. The stability ranges of microemulsions in systems containing soybean, lecithin, alcohol, water, and isopropyl myristate can be greatly increased by using a second hydrophobic amphiphile, such as hexylphosphate, to adjust the hydrophilic-lipophilic balance or the spontaneous peaking properties of lecithin-alcohol systems. PMID:7674125

Trotta, M; Ugazio, E; Gasco, M R

1995-06-01

13

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

Microsoft Academic Search

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

Mary E. R. McHale; Ann-Sofi M. Horton; Sandra A. Padilla; Ashant L. Trufant; No U. De La Sancha; Ernesto Vela; Joyce R. Powell; William E. Acree

1997-01-01

14

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

1997-01-01

15

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

16

Preyssler catalyst, [NaP 5W 30O 110] 14?: A green, efficient and reusable catalyst for esterification of salicylic acid with aliphatic and benzylic alcohols  

Microsoft Academic Search

A series of eco-friendly solid acid catalysts, including H14[NaP5W30O110], H14P5, H14[NaP5W29MoO110], H14P5Mo, and silica supported H14[NaP5W30O110], H14P5\\/SiO2 have been used as catalysts for esterification of salicylic acid with aliphatic alcohols (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, t-butanol, 1-pentanol, and 2-pentanol) and benzylic alcohols (benzyl, 2-methylbenzyl, 2-chlorobenzyl, 4-bromobenzyl, 3-nitrobenzyl, and 4-methoxy benzyl) alcohol.The performance of different forms of Preyssler's anion in the

Fatemeh F. Bamoharram; Majid M. Heravi; Mina Roshani; Manochehr Jahangir; Ali Gharib

2006-01-01

17

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

18

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

19

Use of a chiral surfactant for enantioselective reduction of a ketone.  

PubMed

The influence of a chiral surfactant and a polymer-supported chiral additive on reduction of ketones using sodium borohydride will be described. Initial preparations involved methylation of (S)-leucinol to give (2S)-N , N-dimethyl-2-amino-4-methyl-1-pentanol (1) (67%). The chiral surfactant (2) was synthesized by reacting (1) with bromohexadecane (71%). The functionalized styrene for the polymer-supported chiral additive (5) was synthesized by reacting (1) with 4-vinylbenzyl chloride. Polymerization was carried out with 10% of the functionalized monomer (4), 5% cross-linking agent divinylbenzene, and 85% styrene with AIBN as the initiator. The activity of the chiral surfactant and polymeric additive were examined by using them as additives in a standard reduction of 2-pentanone with sodium borohydride to yield (R)- and (S)-2-pentanol (3) (20%). The resulting alcohol was analyzed by polarimetry (ee 9.5%) and also esterified with (2S)-methylbutyric acid prior to characterization by NMR. 13C NMR indicated an enantiomeric excess of 5.2% when the chiral surfactant was used, and 7% when the polymeric additive was used. PMID:15271578

Davidson, Tammy A; Mondal, Kalyan; Yang, Xiaoye

2004-08-15

20

Induction of suppressed ADH activity in Drosophila pachea exposed to different alcohols.  

PubMed

Laboratory-reared males of the cactophilic Drosophila pachea exhibit a spontaneous and sex-specific suppression of alcohol dehydrogenase (ADH) activity within 4 days after eclosion. A lack of ADH activity also is usually seen in wild-caught males, although relatively high activity is always seen in female flies. In the present study we examined the effectiveness of different alcohols and related compounds, including several found naturally in necroses of the host cactus, to induce suppressed ADH activity in wild males of D. pachea and to serve as enzyme substrates. The primary alcohols (methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol), and the secondary alcohols (2-propanol and 2-butanol), each induced activity after 24 h exposure, although to different degrees. 1,2-Propanediol was usually effective as an inducer, but 2,3-butanediol usually was ineffective. Little or no induction was seen with 1-octanol, 2-pentanol, 3-methyl-1-butanol, 3-hydroxy-2-butanone, or acetaldehyde. Although the compounds tested varied in their ability to function as ADH substrates, methanol was the only alcohol that showed no activity staining. Ethanol induction of ADH activity was apparent after 3-6 h exposure and induced activity decreased dramatically within 1 week of flies being placed in an alcohol-free environment. Ethanol exposure did not induce ADH in adult female D. pachea, or in adult males and females of D. acutilabella in which control males show reduced ADH activity compared to females. The implications of the loss of ADH activity in adult males of D. pachea, as they relate to feeding ecology and fitness, are discussed. PMID:14994829

Pfeiler, Edward; Markow, Therese A

2003-12-01

21

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

22

In-situ Vapor-Phase Lubrication of MEMS  

Microsoft Academic Search

In-situ vapor-phase lubrication of sidewall MicroElectroMechanical System (MEMS) devices is investigated with 1-pentanol vapor.\\u000a The 1-pentanol vapor successfully maintains lubricating properties between silicon contacts of MEMS devices. This is attributed\\u000a to the ability of alcohol to adsorb on the silicon surface and sustain a lubricating layer, which prevents wear of the MEMS\\u000a surfaces and minimizes friction. In the presence of

David B. Asay; Michael T. Dugger; Seong H. Kim

2008-01-01

23

Thermodynamics of mixtures with strongly negative deviations from Raoults law. Part 8. Excess molar volumes at 298.15 K for 1-alkanol + isomeric amine (C 6H 15N) systems  

Microsoft Academic Search

Excess molar volumes, VE, at 298.15K and atmospheric pressure, over the entire composition range for binary mixtures of methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol and 1-octanol with hexylamine (HxA) and of 1-propanol, 1-pentanol, 1-hexanol, 1-heptanol and 1-octanol with triethylamine (TEA) are reported. They are calculated from densities measured with a vibrating-tube densimeter. All the excess volumes are large and

S Villa; N Riesco; I Garc??a de la Fuente; J. A Gonzlez; J. C Cobos

2004-01-01

24

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 38.0C and different pressures were determined. It was found that AOT (0.010.07M) could be solubilized in scCO2 with smaller amount of F-pentanol (0.200.30M) compared with ethanol (1.001.40M) and 1-pentanol (0.601.00M), because F-pentanol has CO2-philic fluorinated alkane chain. The phase behavior

Juncheng Liu; Zameer Shervani; Poovathinthodiyil Raveendran; Yutaka Ikushima

2005-01-01

25

Monitoring of exposure to methylpentanes by diffusive sampling and urine analysis for alcoholic metabolites.  

PubMed Central

OBJECTIVES--To investigate the possibilities of personal ambient monitoring and biological monitoring for methylpentane isomers. METHODS--The performance of activated carbon cloth to absorb 2- and 3-methylpentane was studied by experimental vapour exposure followed by solvent extraction and gas chromatography (GC). Urine from workers and rats exposed to 2- and 3-methylpentane was analysed by GC with or without acid or enzymatic hydrolysis. RESULTS--Carbon cloth absorbed 2- and 3-methylpentane linearly to exposures up to eight hours and to 400 ppm, and was sensitive enough to detect a 15 minute peak of exposure. The two isomers were clearly separated from hexane on a DB-1 column. For analysis of the urine, enzymatic hydrolysis was superior to acid hydrolysis. Exposure of rats to methylpentane vapours showed that 2-methyl-2-pentanol and 3-methyl-2-pentanol were excreted in urine in proportion to the dose of 2-methylpentane and 3-methylpentane, respectively. 2-Methyl derivatives of 1-, 3-, and 4-propanol, 2-methylpentane-2,4-diol, and 3-methyl-2-pentanol were minor metabolites. Analysis of urine from the exposed workers showed that 2-methyl- and 3-methyl-2-pentanol are leading urinary metabolites after exposure to the corresponding methylpentane. CONCLUSIONS--Diffusive sampling is applicable to monitor 2- and 3-methylpentane vapours as is the case for hexane vapour. 2-Methyl-2-pentanol and 3-methyl-2-pentanol will be markers of occupational exposure to 2-methylpentane and 3-methylpentane, respectively. Also, 2-methylpentane-2,4-diol might be a marker of exposure to 2-methylpentane.

Kawai, T; Mizunuma, K; Yasugi, T; Horiguchi, S; Iguchi, H; Mutti, A; Ghittori, S; Ikeda, M

1995-01-01

26

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

Microsoft Academic Search

Heat transfer coefficients in nucleate pool boiling of binary and ternary non-azeotropic hydrocarbon mixtures were obtained\\u000a experimentally using a vertical electrically heated cylindrical carbon steel surface at atmospheric pressure with several\\u000a surface roughness. The fluids used were Methanol\\/1-Pentanol and Methanol\\/1-Pentanol\\/1,2-Propandiol at constant 1,2-Propandiol\\u000a mole fraction of 30%. Heat fluxes were varied in the range 25235kW\\/m2. The cylindrical heater surface was

Ziad Nahra; Erling Nss

2009-01-01

27

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

28

Studies of Electrochemical Processes.  

National Technical Information Service (NTIS)

Salting effects are reported for 1-butanol, 1-pentanol, and cyclohexanol in KF, KCl, NaClO4 and Na2SO4. Adsorption-desorption potentials in these systems are interpreted in terms of specific adsorption of the electrolyte and competition with the surface-a...

B. L. Bruner E. B. Bradley E. V. Brown G. D. Christian H. H. Bauer

1970-01-01

29

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

30

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

31

Aggregation Pheromones and Host Kairomones of West Indian Sugarcane Weevil, Metamasius hemipterus sericeus  

Microsoft Academic Search

Coupled gas chromatographicelectroantennographic detection (GC-EAD) analyses and coupled GC-mass spectrometry (MS) of volatiles produced by male and female West Indian sugarcane weevils (WISW), Metamasius hemipterus sericeus (Oliv.), revealed eight male specific, EAD-active compounds: 3-pentanol (1), 2-methyl-4-heptanol (2), 2-methyl-4-octanol (3), 4-methyl-5-nonanol (4), and the corresponding ketones. In field experiments in Florida, alcohols 14 in combination with sugarcane were most attractive, whereas

A. L. Perez; Y. Campos; C. M. Chinchilla; A. C. Oehlschlager; G. Gries; R. Gries; R. M. Giblin-Davis; G. Castrillo; J. E. Pea; R. E. Duncan; L. M. Gonzalez; R. McDonald; R. Andrade

1997-01-01

32

Tetradecyltrimethylammonium bromide water-in-oil microemulsions: dependence of the minimum amount of alkanol required to produce a microemulsion with the alkanol and organic solvent topology  

Microsoft Academic Search

The amount of alcohol required to produce a microemulsion in a quaternary water-in-oil system was evaluated for a series of alcohols and hydrocarbon solvents of different size or topology. It was observed that the amount of n-hexanol and n-decanol required was similar in all the solvents considered. On the other hand, considerably higher concentrations of the branched alcohols (2,4-dimethyl-3-pentanol and

E Abuin; E Lissi; K Olivares

2004-01-01

33

Influence of surfactant conditions on the structure of an upward bubbly channel flow  

NASA Astrophysics Data System (ADS)

We investigated an upward bubbly channel flow and the effects of surfactant on its flow structure experimentally. 3-Pentanol and Triton X-100 are used as surfactants. By the addition of small amount of surfactant, bubble coalescences are prevented and mono-dispersed 1mm spherical bubbles are obtained. Under all of our experimental conditions, the added surfactants do not influence the single-phase turbulence. On the other hand, small amount of surfactant drastically changes the whole flow structure of bubbly flow. On the low concentration of 3-Pentanol (21-63ppm), bubbles strongly migrate towards the wall and these highly accumulated bubbles on the wall form crescent-like shaped horizontal bubble clusters of 10-40mm length. However, in 3-Pentanol solution of higher concentration (168ppm) or in the 2ppm Triton X-100 solution, the tendency of the lateral migration of bubbles is weaken and the bubbles are distributed uniformly in the channel. In the surfactant solution, the slip velocity on the bubble surface retards and the bubble rising velocity decreases (Marangoni effect). The change of boundary condition on the bubble surface affects not only drag force but shear-induced lift force. It is indicated that this change of shear-induced lift force greatly relates to the lateral migration of bubbles and the disaggregation of the bubble clusters. We also measured the turbulent properties using LDV and discuss the flow structure.

Ogasawara, Toshiyuki

2005-11-01

34

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

35

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; Nss, Erling

2009-05-01

36

Soybean lecithin hydrolysis using hog pancreas phospholipase A 2 influenced by the hydrophobic character of W\\/O microemulsion systems  

Microsoft Academic Search

Hydrolysis reactivity of soybean phosphatidylcholine (PC) catalyzed by hog pancreas phospholipase A2 in a W\\/O microemulsion was kinetically investigated by the hydrophobichydrophilic effect, using different alcohols as the co-solvent and water content in the organic phase. The desired solvent combinations were prepared by mixing isooctane (C8?) as the main solvent and 1-butanol (C4), 1-pentanol (C5), 1-hexanol (C6), and 1-octanol (C8)

Keiju Yamazaki; Masanao Imai; Isao Suzuki

2004-01-01

37

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

38

Promoting effect of wood vinegar compounds on fruit-body formation of Pleurotus ostreatus  

Microsoft Academic Search

The promoting effect of wood vinegar compounds on the fruiting ofPleurotus ostreatus (Japanese name, Hiratake) was investigated. Not only crude wood vinegar but its components, 3,5-dimethylphenol, 2-methoxyphenol, butanoic acid and 1-pentanol, had the ability to promote fruit-body formation on liquid medium. For use of these promoters industrially, a test for practical cultivation was carried out using a commercial sawdust medium.

Hisashi Yoshimura; Hisako Washio; Sadao Yoshida; Takao Seino; Mitsuho Otaka; Kazunori Matsubara; Matsutoshi Matsubara

1995-01-01

39

Naphthalene Complexation by ?-Cyclodextrin: Influence of Added Short Chain Branched and Linear Alcohols  

Microsoft Academic Search

Naphthalene forms 1 : 1 complexes with -cyclodextrin (-CD)in water. The binding constant is 377 35 M-1. Addition of linear or branched alcohols causes a reduction in the apparent strength of naphthalene binding (Kapp) compared to the value in the absence of additives. For example, 1% 1-pentanol reduces Kapp to 184 31 M-1. Branching does not alter Kapp

Christopher H. Evans; Morgan Partyka; Jan Van Stam

2000-01-01

40

Thermodynamics of transfer of non-ionic solutes between immiscible liquid phases. I. Transfer of normal alcohols from n -octane to water at 25C  

Microsoft Academic Search

A recently developed calorimetric method has been employed to estimate the thermodynamic functions for transfer of 1-propanol, 1-butanol, 1-pentanol, 1-hexanol and 1-heptanol from n-octane to water at 25C. A linear correlation for ?Gto as a function of the number of carbon atoms of the alchohol molecule has been found but for ?Hto and ?Sto the dependence gave well defined minima.

Mario Goffredi; Vincenzo Turco Liveri

1981-01-01

41

Excess molar volumes of an (1-alcohols+2,5-dioxahexane or 5,8,11-trioxapentadecane or 2-isopropoxyethanol) at 298.15 K  

Microsoft Academic Search

Excess molar volumes VE for binary liquid mixtures of an (1-alcohols+2,5-dioxahexane or 5,8,11-trioxapentadecane or 2-isopropoxy ethanol) have been measured as a function of compositions using a continuous-dilution dilatometer at 298.15 K and atmospheric pressure over the whole concentration range. The 1-alcohols were methanol, 1-propanol, and 1-pentanol. The VE for each of the mixtures studied are negative with the exception of

Amalendu Pal; Sanjay Sharma

1998-01-01

42

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

Microsoft Academic Search

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

S. J. Borghoff; A. B. Miller; J. P. Bowen; J. A. Swenberg

1991-01-01

43

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

44

Protonation and silver(I) complex-formation equilibria of some amino-alcohols  

Microsoft Academic Search

Formation constants of the silver(I) complexes with some amino-alcohols have been determined at 25C in 0.5 M KNO3 by means of two independent potentiometric measurements employing glass and silver electrode. The ligands considered are: sec-butylamine, 2-amino-1-propanol, 2-amino-1-methoxy-propane, 2-amino-2-methyl-1-propanol, 2-amino-1-butanol, 2-amino-1-pentanol, 2-amino-1-hexanol, 2-amino-1,3-propanediol, 2-amino-1,3-hexandiol, 2-amino-2-methyl-1,3-propanediol and Tris(hydroxymethyl)-aminomethane. Protonation constants of the selected ligands have also been determined. Calculations were made using

Silvia Canepari; Vincenzo Carunchio; Paola Castellano; Antonella Messina

1997-01-01

45

Use of labeled compounds to study the mechanism of flavor formation in oxidizing fats  

Microsoft Academic Search

2-14C-Hexanal,trans, trans-5-14C-2,4-decadienal, 4-14C-1-octen-3-ol, 4-14C-1-octen-3-one and 1-14C-1-pentanol were synthesized and added to freshly deodorized soybean oil in concentrations ranging from 7125 ppm. The soybean\\u000a oil was oxidized, and the fate of the labeled compounds was followed. Hexanal was converted to hexanoic acid especially at\\u000a 50 C or higher. The 2,4-decadienal was converted to 2,4-decadienoic acid at room temperature, and heptenal, 2-octanal,

S. T. Michalski; E. G. Hammond

1972-01-01

46

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

47

Regioselective alkane hydroxylation with a mutant CYP153A6 enzyme  

DOEpatents

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

48

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  

Microsoft Academic Search

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, and 1-octanol-d in HO and DO have been studied as a function of the alcohol concentration from 0 to 200 mM. Modulation effects due to the TMB\\/sup

Piero. Baglioni; Larry. Kevan

1987-01-01

49

Electron spin resonance and electron spin echo modulation studies of N,N,N?,N?-tetramethylbenzidine photoionization in sodium dodecylsulfate micelles: structural effects of alcohol and crown ether addition  

Microsoft Academic Search

Electron spin echo modulation (ESEM) and electron spin resonance (ESR) spectra of the photogenerated N,N,N?,N?-tetramethylbenzidine\\u000a cation radical (TMB+) in frozen micellar solutions of sodium dodecylsulfate containing 2-propanol, 1-propanol, 1-pentanol, 1-octanol, 2-propanol-d7, 1-octanol-d17 in D2O and H2O or 15-crown-5, 18-crown-6 ethers in D2O have been studied as a function of the alcohol or crown ether concentration from 0 to 200 mM.

P. Baglioni; L. Kevan

50

Separation of silicon isotopes by chemical exchange between silicon tetrafluoride and its complex compounds with aliphatic alcohols  

Microsoft Academic Search

Silicon tetrafluoride SiF4 reacted with aliphatic alcohols ROH to form liquid complex compounds SiF4 2ROH. The gas-liquid SiF4(g) -SiF4 2ROH(l) systems can be used for separating silicon isotopes. The hydrodynamics and mass transfer of the separation of silicon isotopes\\u000a in a countercurrent column were studied using SiF4-SiF4 2ROH systems based on butanol-1, pentanol-1, and hexanol-1 at 293

A. V. Khoroshilov; S. A. Cherednichenko; A. V. Lizunov; S. N. Fedorova

2010-01-01

51

The substrate binding cavity of particulate methane monooxygenase from Methylosinus trichosporium OB3b expresses high enantioselectivity for n-butane and n-pentane oxidation to 2-alcohol.  

PubMed

The particulate methane monooxygenase (pMMO) of Methylosinus trichosporium OB3b oxidized n-butane and n-pentane and mainly produced (R)-2-butanol and (R)-2-pentanol that comprised 78 and 89% of the product, respectively, indicating that the pro-R hydrogen of the 2-position carbon of n-butane and n-pentane is oriented toward a catalytic site within the substrate binding site of pMMO. The protein cavity adjacent to the catalytic center for pMMO has optimum volume for recognizing n-butane and n-pentane for enantioselective hydroxylation. PMID:21744144

Miyaji, Akimitsu; Miyoshi, Teppei; Motokura, Ken; Baba, Toshihide

2011-07-09

52

TBADH activity in water-miscible organic solvents: correlations between enzyme performance, enantioselectivity and protein structure through spectroscopic studies.  

PubMed

The enantioselective reduction of 2-pentanone to (R)- and (S)-2-pentanol by Thermoanaerobacter (formerly Thermoanaerobium) brockii alcohol dehydrogenase (TBADH) in mixtures of water and water-miscible organic solvents was investigated. Significant enzymatic activity was retained in up to 87% methanol, ethanol and acetonitrile. The changes in enzyme activity as a function of organic solvent were correlated to structural alterations of TBADH with a series of spectroscopic studies (fluorescence, fluorescence quenching and circular dichroism (CD)). Interestingly, this study shows that the tetrameric form of TBADH is not critical for catalytic performance. PMID:15731860

Olofsson, Linus; Nicholls, Ian A; Wikman, Susanne

2005-02-04

53

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, Hernn; Zerba, Eduardo; Gonzalez-Audino, Paola

2013-04-17

54

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

2012-04-16

55

Antagonists of alcohol inhibition of cell adhesion  

PubMed Central

Increasing evidence suggests that alcohols act within specific binding pockets of selective neural proteins; however, antagonists at these sites have not been identified. 1-Alcohols from methanol through 1-butanol inhibit with increasing potency the cellcell adhesion mediated by the immunoglobulin cell adhesion molecule L1. An abrupt cutoff exists after 1-butanol, with 1-pentanol and higher 1-alcohols showing no effect. Here, we demonstrate surprisingly strict structural requirements for alcohol inhibition of cellcell adhesion in L1-transfected NIH 3T3 fibroblasts and in NG10815 neuroblastoma glioma hybrid cells treated with BMP-7, an inducer of L1 and neural cell adhesion molecule. The target site discriminates the tertiary structure of straight-chain and branched-chain alcohols and appears to comprise both a hydrophobic binding site and an adjacent hydrophilic allosteric site. Modifications to the 2- and 3-carbon positions of 1-butanol increased potency, whereas modifications that restrict movement about the 4-carbon abolished activity. The effects of ethanol and 1-butanol on cellcell adhesion were antagonized by 1-pentanol (IC50 = 715 ?M) and 1-octanol (IC50 = 3.6 ?M). Antagonism by 1-octanol was complete, reversible, and noncompetitive. 1-Octanol also antagonized ethanol inhibition of BMP-7 morphogenesis in NG10815 cells. 1-Octanol and related compounds may prove useful in dissecting the role of altered cell adhesion in ethanol-induced injury of the nervous system.

Wilkemeyer, Michael F.; Sebastian, Anita B.; Smith, Sherri A.; Charness, Michael E.

2000-01-01

56

Determination of volatile metabolites originating from mould growth on wall paper and synthetic media.  

PubMed

Microbial volatile organic compounds (MVOCs) emitted from the mould species Penicillium expansum, P. chrysogenum, Aspergillus versicolor, A. fumigatus, A. niger and Cladosporium cladosporoides were analyzed by means of solid phase microextraction (SPME) and GCMS. The mould species were cultivated on the synthetic agar dichloran chloramphenicol (DG 18) and on wet wall paper. The production of MVOCs was monitored over several weeks to detect changes in the emission rates between the initial stage and later periods of growth. The cultivation on the synthetic agar resulted in MVOC patterns with a wide variety of signals. In contrast, the growth on wet wall paper led to changed MVOC patterns with less signals. The emission rates were drastically reduced. Components emitted by all six fungi species on wall paper were 2-pentanol and 2-pentanone. 1-Octen-3-ol was emitted by five fungi species. 2-Pentanol was only detected in considerable amounts during the first days of growth whereas 1-octen-3-ol had a more constant emission rate over the whole period of growth. On the basis of our studies some MVOCs could be proposed as specific for single fungi on wall paper, e.g. 1,3-dimethoxybenzene for A. versicolor and 2,4-pentandione for A. fumigatus. PMID:18577403

Matysik, Silke; Herbarth, Olf; Mueller, Andrea

2008-06-05

57

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; Prokopcov, Hana; Aelvoet, Karel; Diels, Gaston; Meerpoel, Lieven; Maes, Bert U W

2012-07-11

58

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

59

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

60

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

61

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; Ersland, E.K. [Bergen Technological College (Norway)

1996-05-10

62

Structure of biodiesel based bicontinuous microemulsions for environmentally compatible decontamination: A small angle neutron scattering and freeze fracture electron microscopy study.  

PubMed

Most toxic industrial chemicals and chemical warfare agents are hydrophobic and can only be solubilized in organic solvents. However, most reagents employed for the degradation of these toxic compounds can only be dissolved in water. Hence, microemulsions are auspicious media for the decontamination of a variety of chemical warfare agents and pesticides. They allow for the solubilization of both the lipophilic toxics and the hydrophilic reagent. Alkyl oligoglucosides and plant derived solvents like rapeseed methyl ester enable the formulation of environmentally compatible bicontinuous microemulsions. In the present article the phase behavior of such a microemulsion is studied and the bicontinuous phase is identified. Small angle neutron scattering (SANS) and freeze fracture electron microscopy (FFEM) measurements are used to characterize the structure of the bicontinuous phase and allow for an estimation of the total internal interface. Moreover, also the influence of the co-surfactant (1-pentanol) on the structural parameters of the bicontinuous phase is studied with SANS. PMID:18571191

Wellert, S; Karg, M; Imhof, H; Steppin, A; Altmann, H-J; Dolle, M; Richardt, A; Tiersch, B; Koetz, J; Lapp, A; Hellweg, T

2008-06-05

63

Prediction of anthracene solubilities in binary alcohol+alcohol solvent mixtures using alcohol-specific mobile order theory stability constants  

NASA Astrophysics Data System (ADS)

Experimental solubilities are reported for anthracene dissolved in six binary mixtures containing 2-methyl-1-pentanol with 1-propanol, 2-propanol, 1-butanol, 2-butanol 2-methyl-1-propanol, and 1-octanol at 25C. Results of these measurements, along with previously published solubility data for anthracene in binary alcohol + alcohol solvent mixtures, are used to test the limitations and applications of expressions derived from mobile order theory and the Kretschmer-Wiebe association model. Alcohol-specific mobile order theory association constants are calculated from vapor-liquid equilibrium data for binary alkane + alcohol solvent mixtures and used in the solubility predictions. For the 57 systems considered, both models provided very accurate predictions of the anthracene solubilities, with an overall average absolute deviation between measured and calculated values being 1.7 and 1.2% for mobile order theory and the Kretschmer-Wiebe association model, respectively.

Powell, J. R.; Fletcher, K. A.; Coym, K. S.; Acree, W. E., Jr.; Varanasi, V. G.; Campbell, S. W.

1997-11-01

64

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.

lvarez, Vctor H.; Rivera, Elmer Ccopa; Costa, Aline C.; Filho, Rubens Maciel; Maciel, Maria Regina Wolf; Aznar, Martn

65

Dielectric Studies on Binary Mixtures of Tri-n-butyl Phosphate (TBP) and Long-Chain Primary Alcohols (Modifiers)  

NASA Astrophysics Data System (ADS)

Dielectric constant (\\varepsilon) of Tri-n-butyl phosphate (TBP), in binary mixtures with five long-chain primary alcohols viz; 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol and 1-octanol has been measured at ?{=}455 kHz and at temperature 302 K. The data is used to evaluate mutual correlation factor gab, excess molar polarization \\varDelta P and excess free energy of mixing \\varDelta Fab by using Winkelmann-Quitzsch eqn. for binary mixtures to assess the suitability of the alcohols as modifiers. The trend of variation of these parameters exhibit marked dependence on chain-length of the alcohols indicating 1-heptanol to be an efficient modifier.

Dash, Sarat Kumar; Swain, Bipin Behari

1993-06-01

66

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

67

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

68

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

2012-01-16

69

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

70

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

71

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

2012-05-11

72

The effects of maturity on chilli pepper volatile components determined by SDE, GC-MS and HPLC.  

PubMed

The volatile components of a Chinese chilli pepper (Capsicum annuum L. var. longum Sendt) were identified at different levels of ripeness. The peppers at the green, ripening, and full color stages were investigated by simultaneous distillation extraction (SDE) combined with gas chromatography and mass spectrometry (GC-MS). Principal component analysis (PCA) was used to analyze the main factors at each of the stages studied. Eighty-one volatile components were identified and quantified in this study. Twenty-two compounds were found at the green stage, forty-four at the ripening stage, and sixty-one at the full color stage. Qualitative and quantitative discrepancies were observed at the different levels of ripeness. Hexanal, 2-hexenal and propanoic acid-2-methyl-hexyl ester were the most abundant components at the green stage, while 2-pentanol was important at the ripening stage, and 3-hexen-1-ol was related to the full color stage. PMID:20614840

Liu, Rong; Xiong, Ke; Dai, Xiongze; Wang, Li; Liu, Zhimin; Xue, Wentong

2010-06-01

73

Oxidation of secondary alcohols to methyl ketones by yeasts.  

PubMed Central

Cell suspensions of yeasts, Candida utilis ATCC 26387, Hansenula polymorpha ATCC 26012, Pichia sp. NRRL-Y-11328, Torulopsis sp. strain A1, and Kloeckera sp. strain A2, grown on various C-1 compounds (methanol, methylamine, methylformate), ethanol, and propylamine catalyzed the oxidation of secondary alcohols to the corresponding methyl ketones. Thus, isopropanol, 2-butanol, 2-pentanol, and 2-hexanol were converted to acetone, 2-butanone, 2-pentanone, and 2-hexanone, respectively. Cell-free extracts derived from methanol-grown yeasts catalyzed an oxidized nicotinamide adenine dinucleotide-dependent oxidation of secondary alcohols to the corresponding methyl ketones, Primary alcohols were not oxidized. The effect of various environmental factors on the production of methyl ketones from secondary alcohols by methanol-grown Pichia sp. was investigated.

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

1979-01-01

74

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

75

Alcohol-vapor inclusion in single-crystal adsorbents [M(II)2(bza)4(pyz)]n (M = Rh, Cu): structural study and application to separation membranes.  

PubMed

The vapor absorbency of the series of alcohols methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol was characterized on the single-crystal adsorbents [M(II)2(bza)4(pyz)]n (bza = benzoate, pyz = pyrazine, M = Rh (1), Cu (2)). The crystal structures of all the alcohol inclusions were determined by single-crystal X-ray crystallography at 90 K. The crystal-phase transition induced by guest adsorption occurred in the inclusion crystals except for 1-propanol. A hydrogen-bonded dimer of adsorbed alcohol was found in the methanol- and ethanol-inclusion crystals, which is similar to a previous observation in 2 x 2EtOH (S. Takamizawa, T. Saito, T. Akatsuka, E. Nakata, Inorg. Chem. 2005, 44, 1421-1424). In contrast, an isolated monomer was present in the channel for 1-propanol, 1-butanol, and 1-pentanol inclusions. All adsorbed alcohols were stabilized by hydrophilic and/or hydrophobic interactions between host and guest. From the combined results of microscopic determination (crystal structure) and macroscopic observation (gas-adsorption property), the observed transition induced by gas adsorption is explained by stepwise inclusion into the individual cavities, which is called the "step-loading effect." Alcohol/water separation was attempted by a pervaporation technique with microcrystals of 2 dispersed in a poly(dimethylsiloxane) membrane. In the alcohol/water separation, the membrane showed effective separation ability and gave separation factors (alcohol/water) of 5.6 and 4.7 for methanol and ethanol at room temperature, respectively. PMID:17523183

Takamizawa, Satoshi; Kachi-Terajima, Chihiro; Kohbara, Masa-Aki; Akatsuka, Takamasa; Jin, Tetsuro

2007-07-01

76

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

PubMed

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 trichoroethylene, 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, our 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. PMID:3029393

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

1987-01-01

77

Simplification of a complex microbial antilisterial consortium to evaluate the contribution of its flora in uncooked pressed cheese.  

PubMed

A complex microbial consortium derived from raw milk and composed of populations classified in 4 groups (lactic acid bacteria (A), Gram positive catalase positive bacteria (B), Gram negative bacteria (C) and yeasts (D)) can contribute to the inhibition of Listeria monocytogenes in the core of an uncooked pressed cheese. To identify what groups may be involved in the inhibition, the consortium was simplified by successively omitting one group at a time. Pasteurized milk was inoculated with these more or less complex consortia and their effects on L. monocytogenes count, pH, acids and volatile compounds in the core of uncooked pressed cheese were evaluated. The growth of L. monocytogenes was the highest in cheeses prepared with pasteurized milk and only St. thermophilus. Inhibition in other cheeses was expressed by comparison with growth in these ones. All the consortia containing both lactic acid bacteria (group A) and Gram positive catalase positive bacteria (group B)--ABCD, ABD, ABC, AB--were more inhibitory than those containing lactic acid bacteria on its own (A) or associated only with yeasts (AD) or/and Gram negative (ADC). Consortia without lactic acid bacteria were weakly inhibitory or had no effect. Gram positive catalase positive bacteria alone were not inhibitory although most of the species became established in the cheeses. The Lactobacillus population (Lb. casei, Lb. plantarum, Lb. curvatus and Lb. farciminis) was predominant in cheeses (9 log CFU/g) with a higher count than Leuconostoc (7 log CFU/g) and Enterococcus (7 log CFU/g). Lactobacillus counts were negatively correlated with those of L. monocytogenes (r=-0.84 at 18 days) and with the level of D-lactic acid. There was no correlation between L. monocytogenes and Leuconostoc or Enterococcus counts. Complex consortium ABCD and AB not only had a stronger inhibitory power in cheeses than consortium AD, they were also associated with the highest levels of L-lactic and acetic acids. All cheeses inoculated with lactic acid bacteria differed from those without by higher levels of ethyl formiate, pentane and alcohols (2-butanol, 2-pentanol), and lower levels of ketones (2-hexanone, 2,3-butanedione) and aldehydes (2-methyl-butanal). Levels of 2-methyl-butanal, 2-butanol and 2-pentanol were higher in ABCD and AB cheeses than in AD cheeses. Beside their contribution to the inhibition, their effect on cheese flavour must be evaluated. PMID:21255857

Callon, Ccile; Saubusse, Marjorie; Didienne, Robert; Buchin, Solange; Montel, Marie-Christine

2010-12-31

78

Kinetics and products of the reactions of hydroxyl radicals with selected volatile organic compounds, including oxygenated compounds  

NASA Astrophysics Data System (ADS)

Kinetics, products and reaction mechanisms of the OH radical-initiated reactions of selected volatile organic compounds (VOCs) and oxygenated compounds were examined. These compounds are important smog forming chemicals that are found in gasoline and many consumer products. Smog is created by the interaction of these VOCs with oxides of nitrogen in the presence of sunlight. The hydroxyl (OH) radical is a daytime species and a key initiator of the VOC reactions which lead to photochemical smog formation. Chapter II investigates the OH radical-initiated reactions of p-xylene, 1,2,3-, and 1,2,4-trimethylbenzene which are components of gasoline fuels, vehicle exhaust and ambient air in urban areas. Experiments were conducted at varying NO2 concentrations in indoor environmental chambers in order to determine the dependence of the product yields as a function of NO2 concentrations. From these experiments and previous literature yields, a majority of the products from these reactions under atmospheric conditions have now been elucidated. Chapter III examines the OH radical-initiated reaction of 3-hexene-2,5-dione which is formed from the reactions of p-xylene and 1,2,4-trimethylbenzene (Chapter II). Due to its polar nature, 3-hexene-2,5-dione and its reaction products are difficult to handle experimentally. Products identified from this reaction through the use of in situ atmospheric pressure ionization tandem mass spectrometry were CH3C(O)CH(OH)CHO and CH 3C(O)CH(OH)CH(ONO2)C(O)CH3. Chapters IV, V, and VI examine the OH radical-initiated reactions of 6 different alcohols, including diols. The products examined in Chapters IV and V are those from 2-methyl-2,4-pentanediol and 1,2-, 1,3-, and 2,3-butanediol, which are found in various solvents. Reaction rates were determined using a relative rate method. Hydroxyaldehyde and hydroxyketone products from these reactions were also quantified. Chapter VI examined the reaction rates and products formed from the OH radical-initiated reactions of 2-methyl-2-pentanol and 4-methyl-2-pentanol. These compounds were studied in order to investigate the formation of alkoxy radicals (RO) and their subsequent reactions through isomerization, decomposition or reaction with O2 . Experiments of the type detailed here allow the determination of kinetics and products of the atmospheric reactions of VOCs and provide input for mechanistic models of photochemical smog formation.

Bethel, Heidi Lynn

79

Authentication of fattening diet of Iberian pigs according to their volatile compounds profile from raw subcutaneous fat.  

PubMed

The composition of volatile components of subcutaneous fat from Iberian pig has been studied. Purge and trap gas chromatography-mass spectrometry has been used. The composition of the volatile fraction of subcutaneous fat has been used for authentication purposes of different types of Iberian pig fat. Three types of this product have been considered, montanera, extensive cebo and intensive cebo. With classification purposes, several pattern recognition techniques have been applied. In order to find out possible tendencies in the sample distribution as well as the discriminant power of the variables, principal component analysis was applied as visualisation technique. Linear discriminant analysis (LDA) and soft independent modelling by class analogy (SIMCA) were used to obtain suitable classification models. LDA and SIMCA allowed the differentiation of three fattening diets by using the contents in 2,2,4,6,6-pentamethyl-heptane, m-xylene, 2,4-dimethyl-heptane, 6-methyl-tridecane, 1-methoxy-2-propanol, isopropyl alcohol, o-xylene, 3-ethyl-2,2-dimethyl-oxirane, 2,6-dimethyl-undecane, 3-methyl-3-pentanol and limonene. PMID:21072505

Narvez-Rivas, M; Pablos, F; Jurado, J M; Len-Camacho, M

2010-11-12

80

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; Eli, Zden?k; Herrebout, Wouter; Berthelot, Didier; Meerpoel, Lieven; Maes, Bert U W

2013-06-18

81

Electrophysiological and Behavioral Responses of Male Fall Webworm Moths (Hyphantria cunea) to Herbivory-Induced Mulberry (Morus alba) Leaf Volatiles  

PubMed Central

Volatile organic compounds (VOCs) were collected from damaged and intact mulberry leaves (Morus alba L., Moraceae) and from Hyphantria cunea larvae by headspace absorption with Super Q columns. We identified their constituents using gas chromatography-mass spectrometry, and evaluated the responses of male H. cunea antennae to the compounds using gas chromatography-flame ionization detection coupled with electroantennographic detection. Eleven VOC constituents were found to stimulate antennae of male H. cunea moths: ?-ocimene, hexanal, cis-3-hexenal, limonene, trans-2-hexenal, cyclohexanone, cis-2-penten-1-ol, 6-methyl-5-hepten-2-one, 4-hydroxy-4-methyl-2-pentanone, trans-3-hexen-1-ol, and 2,4-dimethyl-3-pentanol. Nine of these chemicals were released by intact, mechanically-damaged, and herbivore-damaged leaves, while cis-2-penten-1-ol was released only by intact and mechanically-damaged leaves and ?-ocimene was released only by herbivore-damaged leaves. Results from wind tunnel experiments conducted with volatile components indicated that male moths were significantly more attracted to herbivory-induced volatiles than the solvent control. Furthermore, male moths' attraction to a sex pheromone lure was increased by herbivory-induced compounds and ?-ocimene, but reduced by cis-2-penten-1-ol. A proof long-range field trapping experiment showed that the efficiency of sex pheromone lures in trapping male moths was increased by ?-ocimene and reduced by cis-2-penten-1-ol.

Tang, Rui; Zhang, Jin Ping; Zhang, Zhong Ning

2012-01-01

82

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

Schfer, Franziska; Schuster, Judith; Wrz, Birgit; Hrtig, Claus; Harms, Hauke; Mller, Roland H; Rohwerder, Thore

2012-06-29

83

Electrophysiological and behavioral responses of male fall webworm moths (Hyphantria cunea) to Herbivory-induced mulberry (Morus alba) leaf volatiles.  

PubMed

Volatile organic compounds (VOCs) were collected from damaged and intact mulberry leaves (Morus alba L., Moraceae) and from Hyphantria cunea larvae by headspace absorption with Super Q columns. We identified their constituents using gas chromatography-mass spectrometry, and evaluated the responses of male H. cunea antennae to the compounds using gas chromatography-flame ionization detection coupled with electroantennographic detection. Eleven VOC constituents were found to stimulate antennae of male H. cunea moths: ?-ocimene, hexanal, cis-3-hexenal, limonene, trans-2-hexenal, cyclohexanone, cis-2-penten-1-ol, 6-methyl-5-hepten-2-one, 4-hydroxy-4-methyl-2-pentanone, trans-3-hexen-1-ol, and 2,4-dimethyl-3-pentanol. Nine of these chemicals were released by intact, mechanically-damaged, and herbivore-damaged leaves, while cis-2-penten-1-ol was released only by intact and mechanically-damaged leaves and ?-ocimene was released only by herbivore-damaged leaves. Results from wind tunnel experiments conducted with volatile components indicated that male moths were significantly more attracted to herbivory-induced volatiles than the solvent control. Furthermore, male moths' attraction to a sex pheromone lure was increased by herbivory-induced compounds and ?-ocimene, but reduced by cis-2-penten-1-ol. A proof long-range field trapping experiment showed that the efficiency of sex pheromone lures in trapping male moths was increased by ?-ocimene and reduced by cis-2-penten-1-ol. PMID:23166622

Tang, Rui; Zhang, Jin Ping; Zhang, Zhong Ning

2012-11-14

84

Occurrence of polyfunctional thiols in fresh lager beers.  

PubMed

Polyfunctional thiols are known to have a strong impact on the overall aroma of many fermented foods. Surprisingly, very little data is available on their occurrence in beer. A specific extraction with p-hydroxymercuribenzoic acid was performed on four different fresh light-protected lager beers. gas chromatography-olfactometry, gas chromatography-mass spectrometry, and gas chromatography-pulsed-flame photometer detector analyses of the extracts revealed the presence of more than 10 polyfunctional thiols. All of them were absent from wort, suggesting a key role of the H(2)S excreted by yeasts. 3-Methyl-2-buten-1-thiol, 2-mercapto-3-methylbutanol, 3-mercapto-3-methylbutanol seem to be created from hop allylic alcohols via four different mechanisms: nucleophilic substitution, addition-elimination, and radical anti-Markovnikov or electrophilic Markovnikov additions. 1,4 Addition of hydrogen sulfide to wort alpha,beta-unsaturated aldehydes or ketones may explain the synthesis of 1-mercapto-3-pentanol, 3-mercaptohexanol, and 4-mercapto-4-methyl-2-pentanone through fermentation. Finally, 2-mercaptoethanol, 3-mercaptopropanol, and their corresponding acetates may derive from Ehrlich degradation of sulfur amino acids, while 2-methyl-3-furanthiol should be logically issued from Maillard reactions. PMID:16819917

Vermeulen, C; Lejeune, I; Tran, T T H; Collin, S

2006-07-12

85

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

86

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.

Song, Geun Cheol; Ryu, Choong-Min

2013-01-01

87

Synthesis of Short-Chain Diols and Unsaturated Alcohols from Secondary Alcohol Substrates by the Rieske Nonheme Mononuclear Iron Oxygenase MdpJ  

PubMed Central

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.

Schafer, Franziska; Schuster, Judith; Wurz, Birgit; Hartig, Claus; Harms, Hauke; Muller, Roland H.

2012-01-01

88

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.; Prvt, A. S. H.; Donahue, N. M.; Baltensperger, U.

2012-03-01

89

Synthesis and structures of zinc alkoxo, aryloxo and hydroxo complexes with an amidodiamine ligand  

Microsoft Academic Search

The synthesis and characterization of zinc complexes bearing an amidodiamine ligand, (EtO)4Zn3[N(CH2CH2NMe2)2]2 (1), [(Et3CO)ZnN(CH2CH2NMe2)2]2 (2) and [(2,6-iPr2C6H3O)ZnN(CH2CH2NMe2)2]2 (3), [(Me3Si)2N]Zn[N(CH2CH2NMe2)2] (4) and [(Me3Si)2N]2Zn2(OH)[N(CH2CH2NMe2)2] (5), are reported. Compounds 13 are synthesised in the reactions of {Zn[N(CH2CH2NMe2)2]2}2 with 2equiv. of ethanol, 3-ethyl-3-pentanol and 2,6-diisopropylphenol, respectively. Compound 4 is obtained by the reaction of Zn[N(SiMe3)2]2 with HN(CH2CH2NMe2)2, and compound 5 is synthesised by reacting

Bing Luo; Benjamin E. Kucera; Wayne L. Gladfelter

2010-01-01

90

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

91

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

92

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

93

Effect of stirring on the safety of flammable liquid mixtures.  

PubMed

Flash point is the most important variable employed to characterize fire and explosion hazard of liquids. The models developed for predicting the flash point of partially miscible mixtures in the literature to date are all based on the assumption of liquid-liquid equilibrium. In real-world environments, however, the liquid-liquid equilibrium assumption does not always hold, such as the collection or accumulation of waste solvents without stirring, where complete stirring for a period of time is usually used to ensure the liquid phases being in equilibrium. This study investigated the effect of stirring on the flash-point behavior of binary partially miscible mixtures. Two series of partially miscible binary mixtures were employed to elucidate the effect of stirring. The first series was aqueous-organic mixtures, including water+1-butanol, water+2-butanol, water+isobutanol, water+1-pentanol, and water+octane; the second series was the mixtures of two flammable solvents, which included methanol+decane, methanol+2,2,4-trimethylpentane, and methanol+octane. Results reveal that for binary aqueous-organic solutions the flash-point values of unstirred mixtures were located between those of the completely stirred mixtures and those of the flammable component. Therefore, risk assessment could be done based on the flammable component flash-point value. However, for the assurance of safety, it is suggested to completely stir those mixtures before handling to reduce the risk. PMID:20116168

Liaw, Horng-Jang; Gerbaud, Vincent; Chen, Chan-Cheng; Shu, Chi-Min

2010-01-13

94

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

Galn, Abraham; Moreno, Laura; Prraga, Javier; Serrano, ngel; Sanz, Ma Jess; Cortes, Diego; Cabedo, Nuria

2013-04-02

95

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

2012-03-14

96

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.

97

Aliphatic carboxylic acids and alcohols as efficiency and elution strength enhancers in micellar liquid chromatography.  

PubMed

Micellar liquid chromatography (MLC) uses surfactant solutions as mobile phases with added organic additives to enhance both the elution strength and the chromatographic efficiency. Two aliphatic carboxylic acids (1-butanoic and 1-pentanoic) were used as MLC additives and compared with the two corresponding alcohols (1-butanol, 1-pentanol) in terms of elution strength, efficiency and selectivity. A set of 11 phenol derivatives was used as probe compounds. All micellar mobile phases were prepared with sodium dodecylsulfate (SDS) with concentration ranging from 0.05 to 0.15M and the modifier content within 1.0 and 5.0% (v/v). The elution strength of different mobile phases containing a constant amount of SDS and different amounts of modifiers; and mobile phases containing a constant amount of modifier and different SDS concentration were determined and discussed. The effect of the acid modifiers on efficiency was studied constructing van Deemter plots that showed no minimum within the 0.01-0.7mL/min flow rate range studied. Temperature effects were also studied constructing the classical van't Hoff plots. The slight curvature of the plots in the 25-70 degrees C range may indicate some modification of the surfactant-bonded moiety layer on the stationary phase surface. Since no definitive advantage of the use of aliphatic acids were established compared to their alcohol counterpart, their terrible smell will probably preclude their use as MLC organic modifiers. PMID:20673901

Boichenko, Alexander P; Berthod, Alain

2010-07-31

98

Aroma profiles of vegetable oils varying in fatty acid composition vs. concentrations of primary and secondary lipid oxidation products.  

PubMed

The aroma compositions of oxidised sunflower oil, linseed oil and a blend thereof (85/15) were compared with frequently used indicators for primary and secondary lipid oxidation. Primary lipid oxidation was followed by the formation of conjugated dienes, secondary lipid oxidation by proponal and hexanal formation. Highest concentrations of conjugated dienes and propanal were measured in the linseed oil, followed by the blend and sunflower oil, respectively. Highest concentrations of hexanal were determined in the blend. At similar primary oxidation levels, volatile compounds of the oils were isolated in a model mouth system and subsequently analysed by gas chromatography/sniffing port analysis. Propanal, pentanal, 1-penten-3-one, hexanal, 1-pentanol, octanal, 1-octen-3-one, 1-octen-3-ol and (E,Z)-2,4-heptadienal possessed detectable odours. Comparing the three oils, most aroma compounds and greatest intensities were determined in the blend. Conjugated diene concentrations did not predict the formation of aroma compounds adequately. Although propanal and hexanal concentrations were reasonable indicators for aroma development in linseed and sunflower oil, respectively, neither of the indicators predicted aroma development in all three oils sufficiently. PMID:11075372

van Ruth, S M; Roozen, J P; Jansen, F J

2000-10-01

99

Microemulsion-enhanced remediation of soils contaminated with organochlorine pesticides.  

PubMed

Soil contaminated by organic pollutants, especially chlorinated aromatic compounds such as DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane), is an environmental concern because of the strong sorption of organochlorine pesticide onto the soil matrix and persistence in the environment. The remediation of organochlorine pesticide contaminated soils through microemulsion is an innovative technology to expedite this process. The remediation efficiency was evaluated by batch experiments through studying the desorption of DDT and hexachlorocyclohexane (y-HCH) and sorption of microemulsion composed of Triton X-100, 1-pentanol and linseed oil in the soil-surfactant-water suspension system. The reduction of desorption efficiency caused by the sorption loss of microemulsion components onto the soil could be corrected by the appropriate adjustment of C/S (Cosurfactant/Surfactant) and O/S (Oil/Surfactant) ratio. The C/S and O/S ratios of 1:2 and 3:20 were suitable to desorb DDT and gamma-HCH from the studied soils because of the lower sorption of Triton X-100 onto the soil. Inorganic salts added in microemulsion increased the pesticides desorption efficiency of pesticides and calcium chloride has a stronger ability to enhance the desorption of DDT than sodium chloride. From the remediation perspective, the balance of surfactant or cosurfactant sorbed to soil and desorption efficiency should be taken into consideration to enhance the remediation of soils contaminated by organochlorine pesticides. PMID:22439580

Zhang, Yanlin; Wong, Jonathan W C; Zhao, Zhenyong; Selvam, Ammaiyappan

2011-12-01

100

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; Hhler, Kristina; Wlk, Judith; Strey, Reinhard

2012-08-01

101

The relationship between terminal functionalization and molecular weight of a gene delivery polymer and transfection efficacy in mammary epithelial 2-D cultures and 3-D organotypic cultures  

PubMed Central

Non-viral gene delivery vectors were developed for efficient gene transfer to hard to transfect mouse mammary epithelial cells. Ten modified versions of the same base poly(beta-amino ester), poly(1,4-butanediol diacrylate-co-5-amino-1-pentanol), were tested in both traditional 2-D monolayer and in 3-D organotypic cultures. The polymers self-assembled with plasmid DNA encoding enhanced green fluorescent protein to form nanoparticles (~100 nm) used to transfect the cells. Nanoparticle transfection efficacy was tuned by changes in synthesis and fabrication conditions and the transfection efficacy was analyzed using confocal microscopy and flow cytometry. The best performing polymeric nanoparticles transfected 576% of the cells in 2-D culture and 61% of the cells in 3-D culture. Small modifications to the polymer end-capping molecules and tuning of polymer molecular weight could either significantly enhance the transfection efficacy up to 6-fold or instead abolish efficacy completely. The efficacy of leading polymers was higher than that of the commercial transfection agent FuGENE HD by a factor of 13 in 2-D and 2 in 3-D. These non-viral nanoparticles may be useful as delivery reagents or targeted therapeutics for breast cancer. This gene delivery strategy is also a promising approach for studying the normal development of the mammary gland.

Bhise, Nupura S.; Gray, Ryan S.; Sunshine, Joel C.; Htet, Soe; Ewald, Andrew J.

2011-01-01

102

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

2012-01-23

103

Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and characterisation of its blend with oil palm empty fruit bunch fibers.  

PubMed

Poly(3-hydroxybutyrate-co-38 mol%-3-hydroxyvalerate) [P(3HB-co-38mol%-3HV)] was produced by Cupriavidus sp. USMAA2-4 in the presence of oleic acid and 1-pentanol. Due to enormous production of empty fruit bunch (EFB) in the oil palm plantation and high production cost of P(3HB-co-3HV), oil palm EFB fibers were used for biocomposites preparation. In this study, maleic anhydride (MA) and benzoyl peroxide (DBPO) were used to improve the miscibility between P(3HB-co-3HV) and EFB fibers. Introduction of MA into P(3HB-co-3HV) backbone reduced the molecular weight and improved the thermal stability of P(3HB-co-3HV). Thermal stability of P(3HB-co-3HV)/EFB composites was shown to be comparable to that of commercial packaging product. Composites with 35% EFB fibers content have the highest tensile strength compared to 30% and 40%. P(3HB-co-3HV)/EFB blends showed less chemicals leached compared to commercial packaging. PMID:21115240

Salim, Yoga Sugama; Abdullah, Amirul Al-Ashraf; Nasri, Coswald Stephen Sipaut Mohd; Ibrahim, Mohamad Nasir Mohamad

2010-11-12

104

Factors determining the formation of complexes between alpha-cyclodextrin and alkylated substances in aqueous solutions: a calorimetric study at 25 degrees C.  

PubMed

The formation of complexes of alpha-cyclodextrin with cycloalkanediols, monoalkylamines and 1-alkanols has been studied calorimetrically at 25 degrees C in water, in phosphoric acid, pH 1.3, and in phosphate buffer, pH 5.5, respectively. When a complex is formed, calorimetry enables the calculation of both the enthalpy and the association constant, from which the free energy and the entropy of the process can be obtained. A model is proposed to explain the unusual trend of the association parameters for substances having alkyl chains longer than six-seven carbon atoms. The main role played by the different functional groups, and the forces involved in the association process, are discussed in the light of the signs and values of the thermodynamic parameters obtained. The effect of the variation of the aqueous medium on the hydration of the interacting substances and the consequent changes in the association parameters have been investigated. To this end, the thermodynamic parameters for the formation of the complexes between the cyclodextrin and 1-pentanol were determined at increasing concentrations of phosphate buffer. There is an increase in the association constant due to a positive entropy contribution originating from the relaxation of water molecules from the hydrophobic hydration cosphere of the alkanol to an increasingly disordered bulk. Deaquation of the interacting substances is the main factor determining the stability of the inclusion complex. PMID:10839121

Castronuovo, G; Elia, V; Iannone, A; Niccoli, M; Velleca, F

2000-05-01

105

Determination of trimebutine and desmethyl-trimebutine in human plasma by HPLC.  

PubMed

A simple and sensitive HPLC method has been developed to measure trimebutine (CAS 39133-31-8, maleate: CAS 34140-59-5) and its main metabolite desmethyl-trimebutine in human plasma. The method was validated according to the Washington Consensus Conference on the Validation of Analytical Methods. It involved extraction of the plasma with n-hexane containing 2-pentanol, followed by reversed-phase HPLC using a Partisil ODS2 10 microns column and UV detection at 265 nm. The retention times of the internal standard (procaine), desmethyl-trimebutine and trimebutine were 2.4, 4.3 and 6.5 min, respectively. The standard curves were linear from 20 ng.ml-1 (limit of quantitation) to 5000 ng.ml-1 for both compounds. The coefficient of variation for all the criteria of validation were less than 15%. The extraction recoveries obtained for trimebutine and desmethyl-trimebutine were about 90%. Both compounds were very stable upon storage in plasma. The method was tested by measuring the plasma concentrations following oral administration to humans during a bioequivalence study and was shown suitable for pharmacokinetic studies. PMID:10965422

Lavit, M; Saivin, S; Boudra, H; Michel, F; Martin, A; Cahiez, G; Labaune, J P; Chomard, J M; Houin, G

2000-07-01

106

Production and Characterization of a Thermostable Alcohol Dehydrogenase That Belongs to the Aldo-Keto Reductase Superfamily  

PubMed Central

The gene encoding a novel alcohol dehydrogenase that belongs to the aldo-keto reductase superfamily has been identified in the hyperthermophilic archaeon Pyrococcus furiosus. The gene, referred to as adhD, was functionally expressed in Escherichia coli and subsequently purified to homogeneity. The enzyme has a monomeric conformation with a molecular mass of 32 kDa. The catalytic activity of the enzyme increases up to 100C, and a half-life value of 130 min at this temperature indicates its high thermostability. AdhD exhibits a broad substrate specificity with, in general, a preference for the reduction of ketones (pH optimum, 6.1) and the oxidation of secondary alcohols (pH optimum, 8.8). Maximal specific activities were detected with 2,3-butanediol (108.3 U/mg) and diacetyl-acetoin (22.5 U/mg) in the oxidative and reductive reactions, respectively. Gas chromatrography analysis indicated that AdhD produced mainly (S)-2-pentanol (enantiomeric excess, 89%) when 2-pentanone was used as substrate. The physiological role of AdhD is discussed.

Machielsen, Ronnie; Uria, Agustinus R.; Kengen, Serve W. M.; van der Oost, John

2006-01-01

107

Production and characterization of a thermostable alcohol dehydrogenase that belongs to the aldo-keto reductase superfamily.  

PubMed

The gene encoding a novel alcohol dehydrogenase that belongs to the aldo-keto reductase superfamily has been identified in the hyperthermophilic archaeon Pyrococcus furiosus. The gene, referred to as adhD, was functionally expressed in Escherichia coli and subsequently purified to homogeneity. The enzyme has a monomeric conformation with a molecular mass of 32 kDa. The catalytic activity of the enzyme increases up to 100 degrees C, and a half-life value of 130 min at this temperature indicates its high thermostability. AdhD exhibits a broad substrate specificity with, in general, a preference for the reduction of ketones (pH optimum, 6.1) and the oxidation of secondary alcohols (pH optimum, 8.8). Maximal specific activities were detected with 2,3-butanediol (108.3 U/mg) and diacetyl-acetoin (22.5 U/mg) in the oxidative and reductive reactions, respectively. Gas chromatrography analysis indicated that AdhD produced mainly (S)-2-pentanol (enantiomeric excess, 89%) when 2-pentanone was used as substrate. The physiological role of AdhD is discussed. PMID:16391048

Machielsen, Ronnie; Uria, Agustinus R; Kengen, Serv W M; van der Oost, John

2006-01-01

108

Preparation of passion fruit-typical 2-alkyl ester enantiomers via lipase-catalyzed kinetic resolution.  

PubMed

The preparation of ester enantiomers (acetates, butanoates, hexanoates and octanoates) of the secondary alcohols 2-pentanol, 2-heptanol and 2-nonanol via lipase-catalyzed kinetic resolutions was investigated. Conversion rates and stereochemical courses of esterification and hydrolysis reactions catalyzed by commercially available enzyme preparations were followed for the homologous series of these passion fruit-typical 2-alkyl esters by capillary gas chromatography using heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin as chiral stationary phase. An efficient method was developed to prepare the ester enantiomers via lipase-catalyzed esterifications: optically pure (R)-2-alkyl esters (ee > 99.9%) were obtained by esterification of the racemic alcohols with enantioselective Candida antarctica lipase B (immobilized) as catalyst. The subsequent esterification of the unreacted alcohols using lipase from Candida cylindracea yielded the optically enriched (S)-esters (ee > 81.4%). The separation of the products via liquid solid chromatography using a mixture of silica gel and aluminum oxide (basic) resulted in high chemical purities and yields (> 40 mol %). PMID:20415422

Strohalm, Hedwig; Dold, Susanne; Pendzialek, Kathrin; Weiher, Monika; Engel, Karl-Heinz

2010-05-26

109

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

110

Characterisation of whiskeys using solid-phase microextraction with gas chromatography-mass spectrometry.  

PubMed

The application of solid-phase microextraction and gas chromatography-mass spectrometry to the detection of flavour volatiles present in Irish and Scottish whiskeys was investigated. A method was developed to characterise these volatiles which included the extraction, identification and quantification of 17 congeners which included fusel alcohols, acetates and esters. The method validation produced the optimum fibre [85 microm poly(acrylate)], extraction time (35 min), sample volume size (3 ml) and desorption time (5 min). The impact of salt on the absorption process was also studied. Characteristic profiles were determined for each whiskey and the flavour congeners were quantified using 4-methyl-2-pentanol as the internal standard. Calibration ranges were determined for each of the congeners with coefficients of linearity ranging from 0.993 (butan-1-ol) to 0.999 (ethyl laurate) and relative standard deviations ranging from 2.5% (2-methylbutan-1-ol) to 21% (furfural) at a concentration of 18.2 mg/l. Detection limits ranged from 0.1 mg/l (ethyl caprate) to 21 mg/l (butan-2-ol). PMID:11093670

Fitzgerald, G; James, K J; MacNamara, K; Stack, M A

2000-10-27

111

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

112

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 chromatographytime-of-flight mass spectrometry (GCGCToFMS) 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 GCGCToFMS. 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/GCGCToFMS 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.

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

2013-01-01

113

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 (GCGC-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 GCGC-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/GCGC-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, Ins; Barros, Antnio S; Gomes, Newton C M; Cunha, Angela; Almeida, Adelaide; Rocha, Silvia M

2013-04-16

114

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 Central

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.

Schuster, Judith; Schafer, Franziska; Hubler, Nora; Brandt, Anne; Rosell, Monica; Hartig, Claus; Harms, Hauke; Muller, Roland H.

2012-01-01

115

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.

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

2009-01-01

116

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

117

Role of non-ionic surfactants and plant oils on the solubilization of organochlorine pesticides by oil-in-water microemulsions.  

PubMed

Screening low-cost, high efficacy and environmentally safe surface active agents is critical for achieving successful surfactant-enhanced remediation (SER) of soil contaminated with hydrophobic organic compounds. This study reports the solubilization of organochlorine pesticides (DDT or gamma-HCH) in oil-in-water (Winsor I) microemulsions (microE) composed of non-ionic surfactant (Tween 80 or Triton X-100), plant oil (linseed oil or soybean oil), and the cosurfactant (1-pentanol). Results show that the cosurfactant to surfactant ratio (C/S ratio, w/w) is the major factor influencing the microemulsion formation, and C/S ratios of 1:3 and 1:6 are superior to 1:1 for microemulsion formation. 66.9-95.6% and 51.9-80.9% of DDT solubilization enhancements were achieved by microemulsions based respectively on Tween 80 or Triton X-100 as compared to their respective surfactant solution alone, indicating the higher solubilizing capacities of microemulsion systems. The solubilization of gamma-HCH also increased by 40.6-57.5% in microemulsion formed with Tween 80 and 43.0-65.8% in microemulsion formed with Triton X-100, compared with that in corresponding surfactant solutions only. Further studies revealed that both cosurfactant content and oil content could influence the solubilizing capacity of microemulsions system, and higher solubilizing capacity could be obtained when more cosurfactant or oil were emulsified in microemulsion system. Between the two, oil content is more influential than cosurfactant content. The present results affirm the effective role of microemulsions formed with Tween 80 and Triton X-100 in enhancing the solubilization of DDT and gamma-HCH which would facilitate remediation of soils contaminated with these compounds. PMID:21780695

Zheng, Guanyu; Zhao, Zhenyong; Wong, Jonathan W C

118

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

119

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

2013-09-04

120

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

2013-09-03

121

Purification and Properties of Primary and Secondary Alcohol Dehydrogenases from Thermoanaerobacter ethanolicus  

PubMed Central

Thermoanaerobacter ethanolicus (ATCC 31550) has primary and secondary alcohol dehydrogenases. The two enzymes were purified to homogeneity as judged from sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration. The apparent Mrs of the primary and secondary alcohol dehydrogenases are 184,000 and 172,000, respectively. Both enzymes have high thermostability. They are tetrameric with apparently identical subunits and contain from 3.2 to 5.5 atoms of Zn per subunit. The two dehydrogenases are NADP dependent and reversibly convert ethanol and 1-propanol to the respective aldehydes. The Vm values with ethanol as a substrate are 45.6 ?mol/min per mg for the primary alcohol dehydrogenase and 13 ?mol/min per mg for the secondary alcohol dehydrogenase at pH 8.9 and 60C. The primary enzyme oxidizes primary alcohols, including up to heptanol, at rates similar to that of ethanol. It is inactive with secondary alcohols. The secondary enzyme is inactive with 1-pentanol or longer chain alcohols. Its best substrate is 2-propanol, which is oxidized 15 times faster than ethanol. The secondary alcohol dehydrogenase is formed early during the growth cycle. It is stimulated by pyruvate and has a low Km for acetaldehyde (44.8 mM) in comparison to that of the primary alcohol dehydrogenase (210 mM). The latter enzyme is formed late in the growth cycle. It is postulated that the secondary alcohol dehydrogenase is largely responsible for the formation of ethanol in fermentations of carbohydrates by T. ethanolicus. Images

Bryant, Frank O.; Wiegel, Juergen; Ljungdahl, Lars G.

1988-01-01

122

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; Jnis, Janne; Haukka, Matti; Pakkanen, Tapani; Tunik, Sergey P; Chou, Pi-Tai

2012-06-11

123

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

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 8C 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 3.20.1 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 6.60.0 to 5.90.1 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, Franois; Cardinal, Mireille; Duflos, Guillaume; Gurin, Camille; Joffraud, Jean-Jacques; Leroi, Franoise

2011-07-23

124

Structural and Functional Models for the Dinuclear Copper Active Site in Catechol Oxidases: Syntheses, X-ray Crystal Structures, Magnetic and Spectral Properties, and X-ray Absorption Spectroscopic Studies in Solid State and in Solution.  

PubMed

Two novel tridentate dinucleating ligands containing benzimidazole were prepared, 1,3-bis(2-benzimidazolyl)-2-propanol (Hbbp, 1) and 1,5-bis(2-benzimidazolyl)-3-pentanol (Hbbpen, 2). Their complexing properties toward copper were studied in order to obtain structural and functional models for catechol oxidases. Syntheses and crystal structures of dinuclear Cu(II) complexes derived from these ligands are reported. [Cu(2)bbp(2)](ClO(4))(2).2MeOH, 3, crystallizes in the triclinic space group P&onemacr; with the following unit cell parameters: a = 7.702(3) , b = 10.973(6) , c = 12.396(6) , alpha = 100.59(4) degrees, beta = 99.02(4) degrees, gamma = 98.90(4) degrees, V = 998.7(8) (3), and Z = 1. [Cu(2)bbpen(2)](ClO(4))(2).3MeOH, 4, crystallizes in the orthorhombic space group Pccn, with the following unit cell parameters: a = 17.478(9) , b = 18.795(8) , c = 13.888(6) , V = 4562.2(4) (3), and Z = 4. Magnetic susceptibility measurements in the temperature ranges 4.6-459 K (3) and 4.6-425 K (4) indicate an antiferromagnetic coupling between the Cu(II) centers of both complexes. In order to determine the structures of the complexes in solution, XAS spectra (EXAFS and XANES) were recorded in the solid state and in solution. The interpretation of these data, including multiple scattering calculations, together with UV-vis titrations, shows that the complexes have the same structure in the crystalline state as well as in methanolic solution. Complex 4 is able to oxidize 3,5-di-tert-butylcatechol (3,5-DTBC) to the quinone (catecholase activity). This reaction was also studied by XAS and UV-vis spectroscopy. These measurements reveal the reduction of Cu(II) to Cu(I) accompanied by a decrease of the coordination number. PMID:11666546

Zippel, Frank; Ahlers, Friedhelm; Werner, Rdiger; Haase, Wolfgang; Nolting, Hans-Friedrich; Krebs, Bernt

1996-05-22

125

A Combinatorial Polymer Library Approach Yields Insight into Nonviral Gene Delivery  

PubMed Central

CONSPECTUS The potential of gene therapy to benefit human health is tremendous because almost all human diseases have a genetic component, from untreatable monogenic disorders to cancer and heart disease. Unfortunately, a method for gene therapy that is both effective and safe has remained elusive. It has been said that there are only three problems in gene therapy - delivery, delivery, and delivery. (quote from I. M. Verma in Jaroff, L. TIME, 1999; Jan 11). This Account describes an alternative strategy to viral gene delivery: the design of biodegradable polymers that are able to deliver DNA like a synthetic virus. Using high-throughput synthesis and screening techniques, we have created libraries of over 2000 structurally unique poly(?-amino esters) (PBAEs). PBAEs are formed by the conjugate addition of amines to diacrylates. These biomaterials are promising for nonviral gene delivery due to their ability to condense plasmid DNA into small and stable nanoparticles and their ability to promote cellular uptake and endosomal escape. Our laboratory has iteratively improved PBAE nanoparticles through polymer end modifications and nanoparticle coatings. Lead PBAEs have high gene delivery efficacy and low cytotoxicity both in vitro and in vivo. Certain polymer structural characteristics are important for effective gene delivery. The best PBAEs are linear polymers of ~10 kDa that contain hydroxyl side chains and primary amine end groups. These polymers bind DNA to form nanoparticles that are small (<200 nm) and stable and have near-neutral ?potential in the presence of serum-containing media. Lead PBAEs also contain tertiary amines that can buffer the low pH environment of endosomes and facilitate escape of polymer/DNA particles into the cytoplasm. Diamine end-modified 1,4-butanediol diacrylate-co-5-amino-1-pentanol polymers (C32) bind DNA more tightly and form smaller nanoparticles than other PBAEs. These nanoparticles also have higher cellular uptake and the best gene expression of all gene delivery polymers in the library. These polymers are more effective for gene delivery than top commercially available nonviral vectors including jet-PEI and Lipofectamine 2000 and are comparable to adenovirus for in vitro gene delivery to human primary cells. In vivo, these PBAE/ DNA particles are promising as cancer therapeutics. This Account summarizes the results of our laboratory in using a combinatorial polymer library approach to elucidate polymer structure/function relationships and enable the development of polymeric gene delivery nanoparticles with viral-like efficacy.

GREEN, JORDAN J.; LANGER, ROBERT; ANDERSON, DANIEL G.

2012-01-01

126

Volatile metabolite production of spoilage micro-organisms on a mixed-lettuce agar during storage at 7 degrees C in air and low oxygen atmosphere.  

PubMed

This paper describes the volatile metabolite production of spoilage bacteria (Pantoea agglomerans and Rahnella aquatilis) and spoilage yeasts (Pichia fermentans and Cryptococcus laurentii), previously isolated from mixed lettuce, on a simulation medium of shredded mixed lettuce (mixed-lettuce agar) both under air conditions and modified atmosphere (MA)-conditions at 7 degrees C. These latter conditions simulated the equilibrium modified atmosphere packaging, which is used to extend the shelf-life of shredded mixed lettuce. Besides volatile metabolites, organic acid metabolites and consumption of sugars were measured. Microbiological growth on the mixed-lettuce agar resulted in metabolite production and consumption of sugars. Bacteria and yeasts produced a range of volatile organic compounds both under air conditions and MA-conditions: ethanol, ethyl acetate, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2,3-butanedione, 3-methyl-1-pentanol, 1-butanol and 1-hexanol. Under MA-conditions, 2-methyl-1-butanol, 3-methyl-1-butanol and ethanol were the first compounds that were detected in the headspace as being produced by the inoculated micro-organisms. In the case of the yeast P. fermentans, production of these compounds was detected from a count of 5.0+/-0.1 log cfu/cm(2) with a fast increase when exceeding 6.0-6.5 log cfu/cm(2). Unlike P. fermentans, the yeast C. laurentii showed a slow metabolism under MA-conditions, compared to air conditions. In the case of the bacteria, production of 2-methyl-1-butanol and 3-methyl-1-butanol was detected starting from a count of 6.7+/-0.1 log cfu/cm(2) in the case of R. aquatilis and from a count of 7.1+/-0.4 log cfu/cm(2) in the case of P. agglomerans with a fast increase when exceeding 8 log cfu/cm(2). No production of ethanol by the bacteria under MA-conditions was detected in contradiction to air conditions. It could be concluded that, if these counts are reached on the cut surfaces of shredded mixed lettuce which are simulated by the mixed-lettuce agar, sensorial quality of shredded mixed lettuce could be influenced by the microbiological production of metabolites. PMID:16860421

Ragaert, P; Devlieghere, F; Devuyst, E; Dewulf, J; Van Langenhove, H; Debevere, J

2006-07-21

127

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

128

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

129

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 7.2kg/d of a concentrate mix to meet their nutrient requirements. Forage dry matter intake averaged 13.9kg/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

2013-09-12

130

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

2012-05-16

131

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

132

Initial Studies Using Aliphatic ?-Nitro Alcohols for Therapeutic Corneal Cross-Linking  

PubMed Central

Purpose Corneal collagen cross-linking through UVA-riboflavin photochemistry (UVAR) has been shown to be an effective treatment for keratoconus and related keratectasias. In recent studies using sclera, the authors observed that short-chain aliphatic ?-nitro alcohols can cross-link collagenous tissue under physiologic conditions. Thus, this study was undertaken to evaluate these agents as potential pharmacologic alternatives to UVAR. Methods Porcine corneal strips (8 4 mm) and corneoscleral complexes were cross-linked using 1 to 100 mM 2-nitroethanol (2ne), 2-nitro-1-propanol (2nprop), and 3-nitro-2-pentanol (3n2pent) at pH 7.4, 34C. Cross-linking by UVAR was carried out for comparison. Thermal shrinkage temperature analysis was used to evaluate cross-linking effects, and changes in corneal light transmission were determined with a fiber-optic spectrophotometer. Results At 10 and 100 mM for 96 hours, initial shrinkage temperature (Ti) was shifted by 3.3C (P < 0.001) and 9.8C (P < 0.001) for 2ne, 2.9C (P = 0.008) and 4.9C (P < 0.001) for 2nprop, and 3.8C (P = 0.003) and 4.9C (P < 0.001) for 3n2pent. Reacting at 1 mM through daily exchange of fluid over 7 days shifted Ti by 3.8C (P < 0.001), 4.4C (P = 0.002), and 3.2C (P = 0.005), for 2ne, 2nprop, and 3n2pent, respectively. These shifts were greater than cross-linking using UVAR (Ti = 1.9C; P = 0.012). In the blue light region (400?500 nm), transmission was decreased by 5.6% (P = 0.003), 2.1% (P = 0.260), and 0% (P = 0.428) for 2ne, 2nprop, and 3n2pent, respectively. Conclusions ?-Nitro alcohols can induce corneal cross-linking in vitro better than the UVAR technique and can induce negligible effects on light transmission. These early results suggest that such compounds could be used as topical stiffening agents for keratoconus and related disorders.

Paik, David C.; Wen, Quan; Braunstein, Richard E.; Airiani, Suzanna; Trokel, Stephen L.

2009-01-01

133

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