Fatty thiohydroxamic acids (FTAs) have been successfully synthesized from palm olein and thiohydroxamic acid by a one-step lipase catalyzed reaction. The use of immobilized lipase (Lipozyme RMIM) as the catalyst for the preparation reaction provides an easy isolation of the enzyme from the products and other components in the reaction mixture. The FTAs were characterized using Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR) technique and elemental analysis. The highest conversion percentage (95 %) was obtained when the process was carried out for 30 hours using urea to palm oil ratio of 6.0: 1.0 at 40 °C. The method employed offers several advantages such as renewable and abundant of the raw material, simple reaction procedure, environmentally friendly process and high yield of the product.
The relatively high cost of refined oils render the resulting fuels unable to compete with petroleum derived fuel. In this study, biodiesel is prepared from palm fatty acid (PFA) which is a by-product of palm oil refinery. The process conditions were optimized for production of palm fatty acid methyl esters. A maximum conversion of 94.4% was obtained using two step trans-esterification with 1:10 molar ratio of oil to methanol at 65°C. Sulfuric acid and Sodium hydroxide were used as acid and base catalyst respectively. The composition of fatty acid methyl esters (FAME) obtained was similar to that of palm oil. The biodiesel produced met the established specifications of biodiesel of American Society for Testing and Materials (ASTM). The kinetics of the trans-esterification reaction was also studied and the data reveals that the reaction is of first order in fatty acid and methanol (MeOH) and over all the reaction is of second order.
Phase behavior in lysophospholipid/long-chain alcohol/water system at 80°C was investigated using hexanol and oleyl alcohol as the long-chain alcohol. Similarly to hydrophilic surfactant, a micellar phase in a lysophospholipid/water system transitioned to a lamellar liquid-crystalline phase by the addition of long-chain alcohol. In the oleyl alcohol system the lamellar liquid-crystalline phase was observed in wider region compared to the hexanol system. The effect of cholesterol addition on the phase behavior was also studied. The region of liquid-crystalline phase and (reverse micellar + liquid-crystalline + water) phase shifted towards higher lysophospholipid concentrations. The structure of hydrated solid as well as the transition between lamellar liquid-crystalline phase and hydrated solid was analyzed by X-ray scattering measurement and differential scanning calorimetry measurement. It was revealed that the hydrated solid was α-type crystals with lamellar structure. The hydrated solid (gel)-liquid crystal transition temperature gradually decreased with increasing oleyl alcohol concentration and the decrement was enhanced by the addition of cholesterol.
The purpose of this study was to discuss the effects of surface activity on the aquatic toxicity of binary surfactant mixtures comprising anionic, nonionic, and cationic surfactants. Surface tension was measured to determine the cmc (critical micelle concentration), and acute aquatic toxicity tests were conducted on Daphnia magna to obtain 24h-EC50 (24h 50% effective concentration). TU (toxic unit) was calculated to evaluate the toxicity of the mixture. Most of the surfactant mixtures showed no synergistic increase in the aquatic toxicity. The mixture of anionic/nonionic surfactants showed synergistic interfacial activity with decreasing cmc, but the toxicity did not increase. The surface tension of the mixture at 24h-EC50 (γtox), which was used as an indicator of the toxic concentration, decreased considerably and TU was >1, indicating decreased toxicity. γtox of the anionic/anionic surfactant mixture decreased when tested with hard water (hardness of 625 ppm). γtox could not be used as a toxic indicator for the anionic/cationic surfactant mixtures because they showed aquatic toxicity before their surface tension began to decrease.
The potential production of biosurfactant was investigated with a strain of Pseudomonas aeruginosa OCD1, which was isolated from air in our laboratory. The degradation of different hydrocarbons was studied with this microorganism. The values of surface tension and emulsification index of culture broth were very promising when n-octadecane was used as substrate. Characterization of biosurfactant revealed that the biosurfactant was rhamnolipid in nature. The surface tension of water was reduced to 31.5 mN/m from 72 mN/m with the critical micelle concentration of 35 mg/L. A low rhamnolipid concentration (< 5 mg/L) had a strong effect on reduction of surface tension.
The reactions of alcohols with nitriles under solvent-free conditions, using molecular iodine as a catalyst, were investigated. The reaction of 1-phenylethanol with propanenitrile produced the amide N-(1-phenylethyl)propanamide, by dehydration and tautomerization, in 71% yield, under the following conditions: temperature=90°C, alcohol:iodine molar ratio=1:0.2, alcohol:nitrile molar ratio=1:5, and reaction time=5 h. The amidation reactivity depended on the stability of the cationic intermediate formed from the alcohol. The reaction of (–)-borneol with benzonitrile produced a racemic amide in 83% yield.
N,N’-bis (1-naphthylmethyl)-diaza-18-crown-6 (1) showed weak emissions, suggesting that photoinduced electron transfer (PET) from the amine group to the excited naphthalene occurs. The PET fluoroionophore (1) was found to display unique photophysical properties in the presence of a guest cation. Single crystals of the HNCS salt of 1 were grown from 1 and NH4SCN. The crystal structure of the HNCS salt of 1 was elucidated by X-ray crystallographic analysis. The HNCS salt of 1 consists of a 1·2H+ and 2NCS– ion pair. The 1·2HNCS salt gave an emission band at 332 nm. Complexation of 1 with HNCS increased the fluorescence intensity of the host by a factor of 29. The emission enhancement of 1 with HNCS was caused by the proton which dissociates from HNCS.
In the screening of selective DNA polymerase (pol) inhibitors, we isolated an acylated steryl glycoside, β-sitosteryl (6’-O-linoleoyl)-glucoside (compound 1), from the waste extract of soybean (Glycine max L.) oil. This compound exhibited a marked ability to inhibit the activities of eukaryotic Y-family pols (pols η, ι and κ), which are repair-related pols. Among mammalian Y-family pols, the activity of mouse pol κ was most strongly inhibited by compound 1, with an IC50 value of 10.2 μM. On the other hand, compound 1 had no effect on the activities of other eukaryotic pols such as A-family (pol γ), B-family (pols α, δ, and ε), or X-family (pols β, λ and terminal deoxynucleotidyl transferase) pols. In addition, compound 1 had no effect on prokaryotic pols or other DNA metabolic enzymes such as calf primase of pol α, T7 RNA polymerase, T4 polynucleotide kinase, or bovine deoxyribonuclease I. Compound 1 consists of 3 groups: β-sitosteryl (compound 2), linoleic acid (compound 3), and D-glucose (compound 4). Compound 3 inhibited the activities of all mammalian pols tested, but compounds 2 and 4 did not have any effect on the tested pols. Kinetic studies showed that the inhibition of pol κ activity by compound 1 was noncompetitive with both the DNA template-primer and nucleotide substrate, whereas compound 3-induced inhibition was competitive with the DNA template-primer and noncompetitive with the nucleotide substrate. The relationship between the structure of compound 1 and the selective inhibition of eukaryotic Y-family pols is discussed.