The synergistic effects of several aliphatic amines and their oxides on the antioxidative activity of tocopherols in inhibiting the oxidation of lard were investigated and compared with those of trimethylamine oxide (TMAO). As for amines, the lower the volatility and the larger the molecular weight of amines become, the more effective they are, and tri-n-octylamine (TOA) showed the most excellent synergism with tocopherols. As for oxides, however, TMAO having the lowest molecular weight was found to be most effective. A distinct difference between TOA and TMAO was recognized in their synergistic mechanism.
d-γ-Tocopherol (γ-Toc), which was dissolved in saturated and unsaturated triglycerides, was oxidized in air. Experimental conditions were the same as those described in Part I of this series. After the oxidation of γ-Toc in trilaurin at 180°C for 10h, the reaction mixtures were separated by chromatography on a silicic acid column eluted with n-hexane-diethyl ether mixtures and three main products were isolated (Table-1). Products [I] and [III] were identified as the dimers of γ-Toc, 5-(γ-tocopheroxy)-γ-tocopherol (γ-TED) and 5-(γ-tocopherol-5-yl)-γ-tocopherol (γ-TBD), respectively, by means of UV absorption, IR absorption, NMR and MS spectroscopy (Table-2). These compounds were also confirmed by TLC and HSLC (Figs.-1 and 2). Product [II] was confirmed as the atropisomer of γ-TBD only by TLC and HSLC, for this compound could not be satisfactorily purified by chromatographic techniques. The oxidative dimerization of γ-Toc during the course of thermal oxidation in trilaurin (Tri-La), in triolein (Tri-Ol) and in trilinolein (Tri-Li) was followed by HSLC. The concentrations of these dimers in reaction mixtures increased with the oxidation time, and reached maximum by the oxidation for 5h. The quantities of formed γ-TED were greatly affected by the species of triglyceride molecules and were in the order of Tri-La>Tri-Ol>Tri-Li (Fig.-5), but the difference between the amount of γ-TBD formed in Tri-La and those in Tri-Li was not so remarkable (Fig.-6). This fact shows that the phenoxy radical of γ-Toc is more stable in saturated triglyceride than in unsaturated one under the condition of thermal oxidation.
Various kinds of anionic oligosoaps were synthesized from alternating cooligomers of alkyl vinyl ethers with maleic anhydride or diethyl maleate. The variations of apparent (φυ) and partial base molal volumes (φυ0) of these oligosoaps in aqueous solution were investigated to discuss the degrees of the formation of their hydrophobic regions. 1) The observed dependence of φυ on the concentration of oligosoaps indicated that the cooligomer derivatives with shorter alkyl ethers behaved as polyelectrolytes (remarkable extension of molecules due to electrostatic repulsion), while those with longer alkyl ethers formed hydrophobic regions. 2) The values of φυ0 depended on saponification degrees and the kind of gegen ions (K or Na). This may be interpreted by the difference of the effective bulkiness of gegen ions fixed by oligomer anions. 3) It was found that increments of φυ0 (Δφυ0) per methylene group of alkyl chain in the vinyl ethers scattered in the range of 1617 ml/methylene, while those of various monosoaps were found to be almost the same. These results seem to reflect the variety of hydrophobic region of oligosoaps in water. 4) Effects of chemical structures and the number of repeating-units of the alternating cooligomers on φυ, φυ0 and Δφυ0 have also been discussed.
Surface active properties of anionic oligosoap homologues prepared from alternating cooligomers of maleic acid derivatives and alkyl vinyl ethers having C2C16 alkyl groups were measured and classified by the differences of their partial molal volumes in aqueous solutions, that is, the ratios (R) of the observed partial base molal volumes (φυ0) to the calculated ones (the summation of atomic volume) were introduced as an index for the classification, and this idea was applicable especially to the oligosoaps having C10C16 side chain while the corresponding C2 and C4 derivatives were not fitted owing to their polyelectrolyte behaviors. It was ascertained that solubilizing and emulsifying powers of aqueous oligosoap solutions were colligatively estimated by R values, independently on their chemical structures. Furthermore, it was found that there was a minimum in the plot of surface tension vs. alkyl side chain length of oligosoaps, and such phenomenon was attributed to the inhibition of surface adsorption of originally bulky and immobile oligosoap molecules in aqueous solution owing to the strong trend of their intermolecular aggregation. Namely, C16 derivative seems to give a high surface tension (68 dyn/cm) near that of water in aqueous solutions, as the result that their surface adsorptions at the air-solution interface competed with their own intermolecular aggregations. Furthermore, wetting, dispersing, and flocculating behaviors of oligosoaps were also examined.
The structure of a Nekal-type surfactant, which was prepared by sulfonation in the β-position of naphthalene followed by alkylation with isopropyl alcohol, was determined on the basis of an analysis on an NMR spectrum of its sulfonamide derivative. The pattern of the NMR spectrum observed in the lower magnetic field than 7 ppm (δ) showed characteristic substitutions of the alkyl and sulfonic acid groups on the naphthalene nucleus. From these results, this sulfonic acid was identified as 1, 4-diisopropyl-6-naphthalene sulfonic acid.
Various allyl ketones were prepared from esters via two steps : Grignard reaction of allylmagnesium chloride with esters and thermolysis of the resulted diallyl alcohol. For example, 4-allyl-1-decen-4-ol (2) was prepared from methylheptanate (1) and allylmagnesium chloride. At 440°C and atmospheric pressure, compound (2) thermally decomposes to 1-decen-4-one (3).