In elucidating the mechanism by which silicone oil (SO) surpresses the thermal deterioration of frying oil, the following experiments were carried out. 1) The protective effects of SO on the thermal deterioration of various oils and esters were studied. SO showed protective effects on all non-conjugated unsaturated oils and esters, but none on tung oil. 2) The protective effects of various SOs on the thermal deterioration of soybean and linseed oil were compared. To determine the effects of SO, soybean oil and/or linseed oil were heated with various SO at 1ppm at 180°C for 4, 6 and 8h. The degree of deterioration of the heated oils was estimated in terms of viscosity and the acid and carbonyl values of each oil. Effective SOs, such as dimethylpolysiloxane (DMPS) and fluorine modified SO, were heatresistant and rather insoluble in glyceride. Fat-soluble SO, such as higher fatty acid modified SO, showed no protective effects. Among the DMPS tested, 100 and 20cSt SO were found to give greater protection. But, 0.65, 1 and 5cSt SO had no protective effect.
The oxidative dimerization and decomposition of dl-α-tocopherol (α-Toc) and d-δ-tocopherol (δ-Toc) during autoxidation of methyl laurate (Me-La) and methyl linoleate (Me-Li) were investi-gated. Twenty milliliters of fatty acid methyl esters, in which tocopherol had been dissolved at a concen-tration of 0.5%, were autoxidized under A.O.M. conditions. From the unsaponifiable matter obtained from the reaction mixture, the dimers of each tocopherol were confirmed by the same chromatographic techniques described in previous papers. The change in residual tocopherol and dimer content formed in oxidized Me-La and Me-Li, was followed by HPLC. Both α-Toc and δ-Toc showed good stability in Me-La, but α-Toc was rapidly and δ-Toc gradually oxidized in Me-Li (Figs.-3 and 5). 1, 2-Bis- (γ-tocopherol-5-yl) -ethane [α-TED] was obtained as an oxidation product of α-Toc, and two types of dimers were obtained from the reaction mixture of δ-Toc : 5- (δ-tocopheroxy) -δ-tocopherol [δ-TED], and 5- (δ-tocopherol-5-yl) -δ-tocopherol [δ-TBD (H) and (L)] as the atropisomers of each other. The dimers from α-Toc and δ-Toc were derived in small quantities and seemed stable in Me-La (Figs.-4, 6 and 7). The concentration of α-TED increased early during oxidation and then decreased after a reaction time of 2h in Me-Li (Figs.-3 and 4). Similarly, δ-Toc decom-posed gradually, and a small amount of δ-TBD and a large amount of δ-TED formed rapidly in Me-Li. The total content of δ-Toc and that of the dimers were generally constant during a reaction period of 10h, but decreased following this (Figs.-5, 6 and 7). These results suggest that the phe-noxy type radical from δ-Toc is more stalbe than the phenyl type radical in autoxidized Me-Li.
The synergistic antioxidant effects of tocopherol (Toc) and L-ascorbic or erythorbic acid on lard and palm oil were investigated by the oven test and AOM test. Both tests were carried out by the method previously described [Yukagaku, 32, 695 (1983)]. The antioxidant effects of those acids were also studied in the same manner. 1) In the oven test, L-ascorbic acid showed clear antioxidant effects on lard and palm oil. The same was observed for the AOM test. But, considering that the periods to attain POV 100 were almost equal between the system with L-ascorbic acid and that without it, no effects were observed on palm oil. 2) In the oven test, L-ascorbic acid contributed to a synergistic enhancement of antioxidant effects of a mixture of Tocs (m-Toc) and dl-α-Toc on lard, and remarkably controlled the increase in POV, particularly at the initial stage. Notably, when 50ppm of L-ascorbic acid were used in combination with dl-α-Toc (0.0050.01%), the effects were more marked than those due to m-Toc (0.02%) when used alone. However, no synergistic effects with Toc on palm oil were found. 3) In the AOM test, L-ascorbic acid showed synergistic effects with Toc on lard, Slight effects were observed by adding the acid together with m-Toc on the palm oil. 4) The synergistic and antioxidant effects of erythorbic acid on lard and palm oil were essentially the same as those of L-ascorbic acid,
Qualitative and quantitative analyses of commercial Nekal-type surfactants, the alkali salts of butyl- and propylnaphthalenesulfonic acids [BNS and PNS, respectively], were investigated by mass spectral pattern analysis, after converting them into their methyl esters quantitatively. According to mass spectra, measured by In-beam EI method (20eV) and direct inlet method (70eV), each component contained in these samples exhibited a characteristic spectral pattern consisting of both parent ions [M] + and their fragment ions, such as [M-29 (C2H5)] + and [M-15 (CH3)] + pro-duced by the fragmentation of the methyl esters of BNS and PNS, respectively. The fragmentation pattern of the alkyl group attached to the aromatic nuclei indicated each BNS and PNS to be a mixture of the sodium salts of homologous s-butylnaphthalene- and isopropylnaphthalene-monosulfonic acids, respectively. Moreover, each homologous component in the commercial Nekal-type surfactants was determined readily and quantitatively by the In-beam EI method, but only qualitatively by the direct inlet method.
Four types of racemic amphoteric surface active N-substituted amino acid derivatives containing a hydroxyl group and an ether group, ROCH2CH (OH) C2H4NHC2H4COOH ROCH2CH (OH) C2H4NHCH- (CH3) COOH ROCH2CH (OH) C2H4NHCH (CH3) CH2COOH ROCH2CH (OH) C2H4NHCH (C2H5) COOH were prepared, and racemic forms were optically resolved. Their antimicrobial and surface active properties were determined and the influence of optical and structural isomerism on these properties was examined. The difference in the surface active properties between racemate and optically active forms was not clear. It was confirmed that chirality had no influence on the cmc and surface active properties. The influence of the carbon chain length was clear, but the effects of the side methyl group situated between the ammonium and carboxylate group could not be definitely clarified. The N-substituted β-alanine derivatives were more antimicrobial than the corresponding α-alanine. The difference in antimicrobial properties between the racemate and optically active forms was recognized for a few fungi.
A simple and rapid method for the determination of carbonate was developed. A carbonate sample was decomposed in a hydrochloric acid solution and the evolved carbon dioxide was absorbed in a barium hydroxide solution. The absorption was carried out with apparatus consisting of two gas washing bottles with a circulating air pump (Fig.-1). The air pump was operated for 5min to fix carbon dioxide completely in the barium hydroxide solution to form BaCO3. Finally, the excess barium hydroxide was titrated with a standard solution of 1N hydrochloric acid using phenolphthalein as an indicator. Removal of precipitated barium carbonate during titration was unnecessary. The determination required about 10min per sample with a recovery of more than 99% and a coefficient of variation within 0.5%. The proposed method was applied to the determination of sodium carbonate in various commercial granulate detergents. The results were compared with those from an autoanalyzer method. Good agreement was obtained with both methods, thus concluding the content of sodium carbonate in a granulated detergent can be determined more conveniently by the proposed method.
The adsorption equilibria of benzene derivatives (phenol, benzoic acid, nitrobenzene, and aniline), 1-hexanol, and heptanoic acid on activated carbon in aqueous solutions was studied. The activated carbon used as the adsorbent was Pittsburgh Activated Carbon (Calgon Co.). The adsorption isotherms were in good agreement with the Freundlich-type isotherm. The adsorbed amount of adsorbate increased with decreasing its solubility in water, except for phenol. The adsorbed amount of phenol was particularly large. To clarify the relationship between the surface-chemical structure of the activated carbon and the adsorption character of phenol, the activated carbon was treated with hydrochloric acid, hydrofluoric acid, and hydrogen-gas, and the adsorbed amounts of the above-mentioned adsorbates on the activated carbon were determined. The surface-modified activated carbon had the same pore structure as the surface-unmodified activated carbon, but surface-chemical structures differed. The adsorption isotherms were in good agreement with the Freundlich-type isotherm. All adsorbed amounts of adsorbates were larger for HCl·HF·H2 treatment than without modification. It thus seems that there is no specific interaction between the phenol molecule and the surface-chemical structure of the activated carbon. To investigate the influence of the ionization of phenol, the adsorbed amounts of phenol, benzoic acid, and aniline on an activated carbon treated with HCl·HF·H2 were measured over a wide pH range of their solutions. The adsorbed amounts of phenol and benzoic acid decreased with increasing pH. The adsorbed amount of aniline decreased with decreasing pH. Thus the adsorbed amount of phenol, benzoic acid, or aniline decreased with an increase in the amount of adsorbate ionized. The ionization constant of phenol was smaller than those of other adsorbates. Consequently, it is thought that phenol is adsorbed specifically owing to its small ionization constant.