The solubilization of hydrocarbons in aqueous solutions of surfactant-cosurfactant mixtures has been studied to determine the influence of counter ions on the solubilization and the effects of changing the oxyethylene chain length in both the ionic surfactants and in the cosurfactants. A microemulsion of cyclohexane was produced using a mixture of calcium or magnesium dodecyl poly (oxyethylene) sulfate and octyl poly (oxyethylene) ether. The solubilization power of this mixture was about six to eight times greater than that which contains univalent ionic surfactant. The presence of 2wt% sodium chloride in the aqueous solution of sodium dodecylmonooxyethylene sulfate and octyl di (oxyethylene) ether increased the solubilization power to more than six times that without sodium chloride. In systems without cosurfactant, addition of the oxyethylene chain into the ionic surfactants caused on increase of their solubilization power. However, it was shown that lengthening the oxyethylenechain of the ionic surfactants might decrease the solubilization power of surfactant-cosurfactant mixtures and change the optimal mixing ratio. On the other hand, the addition of the oxyethylene chain into the cosurfactants turned them from lipophilic to hydrophilic like nonionic surfactants; e.g., octyl tetra (oxyethylene) ether dissolved in water at 25°C. Consequently, the optimal mixing ratio of the solubilizers for the solubili-zation varied with the oxyethylene chain length of the cosurfactants. The concentration of surfactant-cosurfactant mixtures in the aqueous solutions also affected the solubilization power. Experimentally it was observed that an increase in the concentration of sodium dodecyl sulfate-octyl poly (oxyethylene) ether systems by a factor of two (from 5 to 10wt%) increased the solubilization power 1.6 times. The properties of the hydrocarbon also had an effect on the optimal mixing ratio and the solubilization power. The surfactant-cosurfactant mixtures seemed to be particularly useful in solubilizing long chain hydrocarbons. For example, dodecane was solubilized by a calcium dodecylmono (oxyethylene) sulfate-octyl di (oxyethylene) ether system about twenty fold greater than in the system without cosurfactant.
The fundamental studies concerning the practical use of the microbial lipases have been reported in our laboratory. The availability of the lipases for determining the fatty acid dustribution in natural triglycerides (TG) was investigated. Rhizopus delemar lipase was found to be the most specific enzyme for both the nature of fatty acid and the positions of fatty acid in triglyceride. The condition of the reaction for TG hydrolysis was established. In this paper, we described the preferential hydrolysis of the primary ester linkage by the enzyme, the separation of the hydrolysis products by TLC, and the determination of the released fatty acids and the remained fatty acid in monoglyceride by GLC. From these results, it was confirmed that the Rhizopus delemer lipase could be available for analyzing most of natural vegetable oils and fats.
The removal of some polyoxyethylated nonionic surfactants in aqueous solution were studied by reverse osmosis process using cellulose acetate membrane. The results were as follows : 1) The permeability showed the high values when the carbon number of alkyl groups on the alkyl-phenyl ether and the alkyl ether surfactants was low, and as the carbon number of alkyl groups increases the permeability was tendencies to be lower. As the moles of ethylene oxide increases, the permeability comes to high, and the moles of ethylene oxide showed little difference in 20 to 40moles range. 2) The rejection of the alkylphenyl ether and the alkyl amine surfactants were observed better than that of alkyl ether. The relation between the moles of ethylene oxide and the rejection of surfactants were little.
Reverse osmosis separation of surfactants were investigated with various polymer membranes. The effect of physico-chemical characteristics of membranes and molecular structures of surfactants on membrane separation were examined. Ionic surfactants were rejected very well by cellulose acetate membrane and ionic membranes with the same fixed charged groups. Most of nonionic surfactants were rejected by neutral and ionic polymer membranes. The rejection level, however, was much lower than that of ionic surfactants, especially at low feed concentration. Permeability of surfactant through cellulose acetate membrane greatly increased with increase in number of ethylene oxide (520) of the nonionic surfactants. Rejection level of nonionic surfactants increased profoundly in the co-presence of ionic surfactant in the mixture. Rejection level of ionic surfactants dropped down with inorganic salt content in the feed solution.
The catalytic addition reaction of acrylic acid to castor fatty acids by a flow method was investi-gated. It was found that the addition of acrylic acid to castor fatty acids are easily carried out by continuously passing a mixture of acrylic acid and the fatty acids over the catalyst having phosphoric acid deposited on the synthetic silica-alumina composed of 70% of SiO2 and 29% of Al2O3. The adduct separated by column chromatography was analyzed by IR, NMR, and MS spectral measurement and found to have a cyclohexene ring structure. It was confirmed that the adduct was formed by the Diels-Alder addition of acrylic acid to the conjugated octadecadienoic acid produced by the dehydration of ricinoleic acid, the main component of the castor fatty acids. Moreover, the adduct was found to have the structure of 5-or 6-membered ring lactone formed after the Diels-Alder addition reaction.