A new emulsification technique for producing fine O/W emulsions, D phase emulsification, has been developed and elucidated the emulsification mechanism by using phase diagrams. The process of D phase emulsification begins with the formation of isotropic surfacatant solution, followed by formation of an oil-in-surfactant (O/D) gel emulsion by dispersion of oil in the surfactant solution, and finally formation of an O/W emulsion by the addition of an aqueous phase to the gel emision. The characteristics of D phase emulsification are as follows : (1) it is easy to produce submicron O/W emulsion in many types of oils and surfactants, (2) strict HLB adjustment is not necessary, (3) it is possible to reduce the emulsifier content. This emulsification method has been applied to develop new types of cosmetics.
The nitroso form of the entitled tautomer increases with water content in the medium. The rates of nitroso-oxime tautomerization of the tautomer of p-nitrosophenol and p-benzoquinoneoxime in the absence of catalyst in binary media of 40, 50, 60 and 80 vol% water and methanol at 1525°C were measured by means of UV spectrophotometry, using a calibration curve for the reaction prepared by wave analysis. The reaction followed reversible first-order kinetics : Rate=k1 (a-c-x) -k-1 (c+x). Here, k1 and k-1 are first-order rate constants for the nitrosozation and the oximization;a, c and x are the concentration of the whole tautomer, nitroso form at the initial time, and consumed oxime or formed nitroso form at time t, respectively. The entropy term is more predominant than the enthalpy term both for the forward and reverse reactions. The slopes of log k1 and log k-1 against log aH2O were 3 and 2 for the forward and reverse reactions, respectively. From these findings, a mechanism is presented, involving the intermediate hydrogen bonding perfect annular complex by three molecules of water between hydroxylamino hydrogen and ketonyl oxygen for nitrosozation and the imperfect annular complex by two water molecules with phenolic hydrogen and/or nitroso oxygen for oximization.
Carbonyl value (CV) of several edible oils were followed during autoxidation at 46°C by two procedures using 2, 4-dinitrophenylhydrazine, the conventional and triphenyl phosphine (TP) reduction procedures, in order to assess the contribution of hydroperoxides to the CV determination of oxidized oils. CV determined by the conventional procedure (Conv-CV) was always higher than that by the TP-reduction procedure (TP-CV). The discrepancy between these methods increased linearly with peroxide value. However, the ratio of Conv-CV/TP-CV reached a maximum, of around 3 to 4, at the end of the induction period. The time courses of Conv-CV in the initial stage of oxidation were basically the same as those of POV, because most carbonyls assayed by this method were produced by the decomposition of hydroperoxides. Therefore, a procedure, not affected by peroxides, should be established for CV measurement of autoxidized oils even in the early stage of autoxidation. The TP procedure is simple, and TP and TP oxides have no effect on CV determination. TP-CV was found closely correlated to the sensory evaluation of the odor and flavor of oxidized oils. The TP procedure was confirmed very useful for CV measurement of autoxidized oils.
To evaluate the stability of crown ether compounds with branched hydrocarbon chains differing in crown size (18-crown-6, 15-crown-5, and 12-crown-4) at the oil/water interface, monolayer properties (especially π-A curve) of the compunds were studied using various salts. A stable monolayer of each crown compound was noted to form at the interface under metal complexing conditions. However, in a system including a compound with small crown size such as 12-crown-4, ion selectivity and ability of complex formation decreased, due possibly to the high heat of hydration of small-size ions. This was also observed in the electrokinetic behavior of the O/W emulsion stabilized by the same crown ether compound. Ion transport of crown ether compounds was studied with different crown size compound-salt combinations. Ion selectivity by crown ethers in the ion transport was higher than that in complex formation. Only the specific metal ion, fitting to crown size among cations in the system was transported through the oil phase. The transportation rate of specific ions was strongly influenced by the number of counter ions picrate ions, i.e., the more picrate anions for a fixed number of specific cations, the faster was this rate by enhanced ion-pairing with the crown ether complex and metal cations.
GC-MS analysis of N-arylcarbonyl-O, O'-bis (TMS) derivatives (4) of synthetic dihydrosphingosines (1) was conducted to establish a convenien method for determining the erythro and threo isomers of (1) by mass spectrometry. The structures of fragment ions were determined by comparing the mass spectra of (4) with different substituents in the aryl group and carbon chain of (1). The structures were indicated based on differences in mass numbers of (4) -d18 and (4) h18 derivatives [N-arylcarbonyl-O, O'-bis (TMS) -d18 and O, O'-bis (TMS) -h18 derivatives of (1)]. One characteristic difference was relative intensity (RI) at m/z=M-103; the relative intensities of threo compounds (RI=30-70%) exceeded those of erythro isomers (RI<10%). The ratios, γ=RI (M-103) /RI (M-15), of threo compounds were greater than those of the erythro isomers. Values γ (threo) /γ (erythro) were from 3 to 7. From these results, it should be possible to determine the erythro and threo isomers of (1) by mass spectrometry in the form of (4).
Dynamic wetting was measured by moving a foam film in a glass tube. The apparatus con-sisted of (1) unit for placing the glass tube containing a foam film which was moved, (2) a gas flow controlling unit made of linear-head and syringe, (3) a pressure measuring unit consisting of a pressure sensor and amplifier, and (4) a data processing unit for calculating shear stress when the wetting glass tube by the foam film. The rate of film movement was controlled at 0.1 mm/s to 6.0 mm/s. A 0.5% SDS solution was used as the bulk liquid. Film movement was a function of the gas flow, confirmed by the finding that the inside diameter of the glass tube (48 mm) was independent from shear stress with film movement. The relation between shear stress and rate of film movement was determined from the equation, F=3.58 logR+8.35, where F is the shear stress with movement of the foam film (mN/m) and R, the rate of film movement (mm/s).
The rates of incorporation into triolein of eight free fatty acids [palmitic acid (16 : 0), linoleic acid (18 : 2), α-linolenic acid (18 : 3), γ-linolenic acid (18 : 3), octadecatetraenoic acid (18 : 4), arachidonic acid (20 : 4), icosapentaenoic acid (20 : 5) and docosahexaenoic acid (22 : 6)] by acidolysis were determined. Lipase TOYO (Chromobacterium viscosum) and Lipozyme (Mucor miehei) both as immobilized lipase were used for the reactions. Lipase TOYO incorporated each free fatty acid into triolein at more than 22%. Lipozyme incorporated each free fatty acid at above 15%, and showed especially high activity toward icosapentaenoic acid. These two lipases were thus concluded applicable to the acidolysis of fat with unsaturated fatty acids.