In order to find the most effective use of tocopherol (Toc) in practice, relationship between the antioxidant effect and the addition level of Toc was investigated using oven test (30 and 60°C) and the AOM test with refined lard and palm oil added commercial concentrated natural Tocs (m-Toc) and synthetic α-Toc (dl-α-Toc). 1) In antioxidative tests of lard, an optimal addition level of Toc had a tendency to increase with the rise of reaction temperature and of the POV level for evaluating the stability. 2) It was found that m-Toc showed a slight antioxidant effect on palm oil, but dl-α-Toc had no effect. 3) After 30d in the oven test at 60°C, the remnant portion of Toc in the same fat had a tendency to be higher with the increase of addition level, and the residual amount of Toc in palm oil was more than that in lard at the same addition level. During the oven test, each Toc had a tendency to be consumed in order of α>γ>δ. 4) In comparing POV after 30d in the oven at 60°C, the addition level of m-Toc in the sample showing the lowest was 0.020.05% in lard and 0.050.1% in palm oil. Also, that of dl-α-Toc was 0.02% in palm oil. But, any lard sample that had dl-α-Toc added showed remarkably high POV under the same condition.
The five kinds of α, ω-type amphoteric surfactants were synthesized from 1, 12-dibromododecane. The chemical formula and abbreviation of these surfactants are as follows. α, ω-NB : R=CH2COO-α, ω-NP : R=CH2CH2COO-α, ω-SB : R=CH2CH2CH2SO3- Critical micelle concentration (cmc), surface tension at cmc (γcmc), area/molecule at air-water interface, anti-static power and catalytic activity on the reaction of octyl bromide with saturated aqueous potassium iodide were determined. The cmc values increased in the order α, ω-TB<α, ω-PB<α, ω-SB<α, ω-NP<α, ω-NB. The order of the increase in the ability of lowering γcmc was α, ω-SB<α, ω-PB<α, ω-TB<α, ω-NP<α, ω-NB. The area/molecule increased in the order α, ω-TB≈α, ω-NB<α, ω-NP<α, ω-PB<α, ω-SB. No significant difference in anti-static power and the catalytic activity was observed among the surfactants. These results were discussed by comparison with α-type amphoteric surfactants such as alkylthiobetaine, N-alkylammoniumbetaine and N-alkylpyridinium-3-carboxylate.
Copolymerizations of maleic anhydride (MAn) with vinyl acetate (VAc), allyl alcohol (AAlc) with methyl acrylate (MA), and MA with VAc in the presence of 1-dodecanethiol yielded, respectively, cotelomers Ls-MAn-VAc, Ls-MA-AAlc and Ls-MA-VAc with Pn of 9.616.6, which were treated with hydroxylamine, giving the corresponding hydroxamic acid derivatives, LMV-Hx, LAA-Hx and LAV-Hx, respectively. A copolymer of maleic anhydride with vinyl acetate (MAn-VAc) and its adduct with dodecylamine (MAn-VAc-P) were also converted into the hydroxamic acid derivatives, MV-Hx and MVP-Hx, respectively. The aqueous solutions of LMV-Hx, LAA-Hx and LAV-Hx showed surface tensions of 35.548dyn·cm-1 with cmcs of O.0020.69wt% and phase transition points at 1526°C. Electron micrograph of Cu (II) complex of LMV-Hx demonstrated the formation of vesicle and lamellar structures. As to the dissociation of the hydroxamic acid groups, LMV-Hx, MV-Hx and MVP-Mx showed lower pKa values than other cotelomers. A difference in the ultraviolet spectra was also found between the MV series compounds and other cotelomers. The hydroxamic acid derivatives catalyzed the hydrolysis of p-nitrophenyl acetate, where LMV-Hx gave the lower second order rate constant than other cotelomers. These remarkable features in MV series were considered to be derived from an interaction between the hydroxamic acid groups and the neighboring carboxyl groups.
Enzymes are known to be unstable in the absence of any stabilizing agents. Especially, lipase (EC 188.8.131.52) is more unstable than others. Generally, enzymes are said to be stabilized by its substrate or polyols. Glycerol or the substrate such as olive oil is found to stabilize lipase (from Candida cylindracea) in aqueous solution. For example, lipase is completely inactivated at 50°C for 4h in aqueous solution (100U/ml), however 80% of the lipase activity is preserved in the presence of 3.6M glycerol under the same conditions. We have investigated the series of glycerol derivatives which would stabilize the lipase in aqueous solution, and found that glycerol poly (oxypropylene) ethers could stabilize lipase more effectively than glycerol. Actually, 97% of the lipase activity was preserved in the presence of 1.05M glycerol poly (oxypropylene) ether (TG-300) under the above conditions. Poly (oxypropylene) groups as well as hydroxyl groups seem to stabilize lipase cooperatevely. We believe that hydroxyl groups hold some parts of the enzyme, while poly (oxypropylene) groups hold other parts of the enzyme by the hydrophobic bond simultaneously. This type of complex makes lipase to be stabilized in the aqueous solution.
2-Phenylthioallyl alcohol and its derivatives (1) are selectively rearranged to the corresponding aldehydes or ketones (2) in the presence of phosphorus tribromide, triphenylphosphine dibromide, or thionyl chloride without the formation of halogenated products. Similarly, the carbonyl compounds, (4), (5) and (6) are obtained from 2-ethoxypropenol (3), being different from the 2-trimethylsilylpropenol (8) which is readily halogenated to (9).