• Applied Chemistry for Engineering
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• v.32 no.6
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• pp.679-683
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• 2021

Lecithin, a zwitterionic phospholipid, forms spherical reverse micelles in nonpolar organic solvents such as decane. The addition of monovalent ions like lithium chloride (LiCl) to lecithin organosols induces the transformation of organosols into organogels due to the entanglement of reverse cylindrical micelles. In this study, we investigate the effect of pentanol acting as co-surfactant on rheological properties of lecithin/LiCl mixtures. From rheological studies, we find that the viscosity and elastic property of organogels decreased upon the addition of pentanol to organogels. The decrease in viscosity and elastic property can be attributed to the shortening of reverse cylindrical micelles confirmed by small angle X-ray scattering (SAXS).

• Analytical Science and Technology
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• v.37 no.5
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• pp.306-314
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• 2024

This study describes the liquid chromatographic enantiomer separation of three typical chiral amines (α-methylbenzylamine, 2-amino-4-methyl-1-pentanol, and 1-methylheptylamine) as 2-hydroxynaphthaldimine derivatives using six amylose trisphenylcarbamates derived chiral stationary phases (CSPs). It was observed that the structural nature of three chiral amines and the structures of amylose chiral selectors can affect their chiral recognition ability. Among the three analytes as 2-hydroxynaphthaldimine derivatives, in general, the greatest enantioselectivities of aromatic amine analyte (α-methylbenzylamine) were achieved on amylose trisphenylcarbamate derived CSPs and were followed by amino alcohol analyte (2-amino-4-methyl-1-pentanol), and aliphatic amine analyte (1-methylheptylamine). Also, the enantiodiscrimination abilities obtained on the two CSPs, Chiralpak ID and Chiralpak IF, were selectively higher than the other four amylose trisphenylcarbamate derived CSPs for the studied analytes. The underlying chiral recognition mechanism between 2-amino-4-methyl-1-pentanol as 2-hydroxynaphthaldimine derivatives and amylose tris(3,5-dimethylphenylcarbamate) chiral selector of Chiralpak AD-H and Lux Amylose-1 was elucidated by molecular docking study, and it was observed that the intermolecular hydrogen bonding interactions by hydroxyl moiety on the amino alcohol analyte as 2-hydroxynaphthaldimine derivatives were the main interactive forces driving the chiral separation. The obtained binding energies between 2-amino-4-methyl-1-pentanol analyte as 2-hydroxynaphthaldimine derivative and amylose tris(3,5-dimethylphenylcarbamate) chiral selector were in agreement with the experimentally determined enantioseparation and elution order by chiral HPLC.

• Journal of the Korean Institute of Gas
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• v.16 no.5
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• pp.41-46
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• 2012

The flash point the lowest temperature at which the concentration of vapor of the substance in the air reaches the lower flammability limit(LFL), and is one of the most important physical properties used to determine the potential for fire and explosion hazards of industrial materials. The most published flash point data was for pure components and the flash points of the binary solutions that have flammable components, appear to be scarce in the literature. In the present study, the flash points of tert-pentanol+n-decane system were measured by Tag open-cup tester. The measured data were compared with the values calculated by the Raoult's law and the optimization methods based on the Wilson and NRTL equations. The calculated values by optimization methods were found to be better than those based on the Raoult's law.

• Korean Chemical Engineering Research
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• v.57 no.1
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• pp.73-77
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• 2019

Isothermal (vapor + liquid) equilibrium data measurements were undertaken for the binary mixtures of (propylene oxide + 1-pentanol) system at three different temperatures (303.15, 318.15, and 333.15) K. The Peng-Robinson-Stryjek-Vera equation of state (PRSV EOS) was used to correlate the experimental data. The van der Waals one-fluid mixing rule was used for the vapor phase and the Wong-Sandler mixing rule, which incorporates the non-random two liquid (NRTL) model, the universal quasi-chemical (UNIQUAC) model and the Wilson model, was used for the liquid phase. The experimental data were in good agreement with the correlation results.

• Journal of the Korean Chemical Society
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• v.37 no.3
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• pp.271-278
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• 1993

The hyperfine splitting constants of phenanthrenequinone anion radical have been determined for the solution of triethylamine with 2-propanol, 2-pentanol or benzene by cwESR and time-resolved ESR methods. The radical anion was produced by photolysis using a pulsed excimer laser. The resulting hyperfine splitting constant A$_{H1}$ and A$_{H2}$ are 1.662, 0.378 in 2-propanol, 1.602, 0.361 in 2-pentanol and 1.518 in benzene respectively. The hyperfine coupling constants decrease with the decreasing of polarity of the mixed solvent. The tendency of the variation depends on the polarity of the solvents, thus, making it in impossible to observe the magnetic equivalent proton in a mixed solvent of nonpolar benzene. Particularly, time-resolved ESR spectrum of triethylamine radical (TEA${\cdot}$) has been observed in 0.15∼0.30 ${\mu}s$ from the solvent of 3 : 1 with 2-pentanol and triethylamine. Thus from the results of solvent effect, we can suggest that the identification of the unstable short-lived spin polarized phenanthrenequinone anion radical(*PQ${\cdot}^-$) proceed through photochemistry.

• Fire Science and Engineering
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• v.27 no.5
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• pp.70-74
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• 2013

The flash point is one of the most important physical properties to charaterize fire and explosion hazard of liquid solutions. The maximum flash point of liquid mixture is larger than those of the individual components. In this study, the flash points of 2-pentanol+acetic acid system were measured by Seta flash closed cup tester. This system exhibited the maximum flash point behavior. The flash points were estimated by the Raoult's law and the optimization methods using the van Laar and Wilson equations. The calculated values by optimization methods were found to be better than those based on the Raoult's law.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.3
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• pp.189-193
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• 1998

Volatile components were extracted from leaves of two Boxthorn (Lycium chinense M.) cultivars by using simultaneous distillation and extraction, analyzed by gas chromatography-mass spectrometry. Seventy components were identified : 13 acids, 15 alcohols, 18 hydrocarbons, 13 carbonyls, three esters, three ionones, and five others. The principal volatile components (and their peak area percentage) were n-pentanol (11.2～30.2%), phytol (14.5～28.3%), hexadecanoic acid (13.5～17.1%) 2,3-dihydrobenzofuran (1.5～4.2%), benzyl alcohol (1.9-4.8%), phenylacetaldehyde (1.8～3.2%), and octadecadienoic acid (1.7～10.7%). Fresh leaves showed much higher peak area than that of dried leaf in n-pentanol, n-hexanol, cis-2-penten-l-ol, cis-3-hexen-l-ol, benzyl alcohol, and $\beta$-phenylethyl alcohol, while dried leaves showed much higher content than that of fresh leaves in 9-hydroxytheaspran A, octadecanoic acid and octadecadienic acid.

• Proceedings of the Korean Vacuum Society Conference
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• 2001.07a
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• pp.139-139
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• 2001

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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• pp.3-18
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• 1997

This study was conducted to evaluate desorption efficiencies by types of desorption solvent for polar and non-polar organic compounds collected on activated charcoal tubes. Analytes tested were toluene, m-xylene, isobutyl alcohol, n-butyl alcohol, cellosolve acetate, and butyl cellosolve. Three different concentration levels of spiked sample were made. Types of cosolvent mixed with the main solvent, $CS_2$, were methanol, pentanol, and dimethylformamide (DMF) and the cosolvent for methylenechloride was methanol. The amounts of cosolvent added to the main solvent were 1, 5, and 10% by volume (v/v%), respectively. The results were as follows: 1. For all mixed solvents except 1% methanol and 1% pentanol with $CS_2$, desorption efficiency significantly increased, compared with that of $CS_2$ alone. 2. Desorption efficiency increased by increasing analyte loading on charcoal tube regardless of mixed solvents used and the material polarity. 3. For all cosolvents mixed with $CS_2$ by 1% and 5% volume, desorption efficiency for non-polar compound was significantly higher than that of polar compound. For the 10% mixed solvents and the methylenechloride mixed with methanol, the results were opposite. 4. The lowest mean percent bias of 4.79% was obtained from the 5% DMF-$CS_2$ mixed solvent, followed by 4.82% from the 10% DMF-$CS_2$ solvent while the highest bias of 23.26% was from the solvent of $CS_2$ alone. Based on the results of this study, in order to increase desorption efficiency, it is recommended to add such cosolvents as methanol, pentanol, and DMF to $CS_2$, preferably 5% by volume for analyzing polar compounds collected in charcoal tubes.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.229-234
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• 1989

Cooked soybeans were fermented with B. subtilis and B. natto for 48 hrs and 74 hrs. The odor concentrates of during these Chungkookjang fermentation were obtained with a simultaneous distillation and extraction system. The seperation and identification were carried out by GC and GC-MS. The main components of the cooked odor concentrate of soybeans were 3-methyl-1-butanol, 1-pentanol and 1-octen-3-ol etc.. In Chungkookjang (B. subtilis inoculation), 3-methyl-1-butanol, 1-pentanol and 1-octen-3-ol remained but alkyl pyrazines such as 2,5-dimethyl pyrazine, trimethyl pyrazine and tetramethyl pyrazine increased and those increased during the fermentation. In Chungkookjang(B. natto inoculation), 3-methyl-1-butanol, 1-pentanol and 1-octen-3-ol, main components of cooked soybeans decreased and alkyl pyrazines increased, especially, tetramethyl pyrazine remarkably increased during fermentation. From the result, it seems that alkyl pyrazines caused the characteristic odor of Chungkookjang and mask the beany odor.