For the purpose of a fundamental elucidation of the change of the taste of oils caused by heating, fractionation of components of heated oil has been carried out. The earlier part of the work was reported in the previous paper, and the present paper deals with the effect on the taste of free fatty acids resulting from the heated oil. Commercial soybean oil was blown with air at 180±3°C for 48 hours. The results of organoleptic test indicated that the original oil, added with free fatty acids separated from heated oil, increased not only the oily taste but the odour. From the profile-test, however, it was manifested that the contribution of free fatty acids was not essential to the change of the taste of oils caused by heating.
Heat of fusion of 1-monopalmitin was determined using Perkin-Elmer DSC-1 differential scanning calorimeter based on the heat of tin. The DSC analyses were done as follows; 510mg of the sample was placed in an aluminum pan which was placed in a sample holder. An empty pan was put in the reference holder. Heating rate and sensitivity were 10°C/min and range 16, respectively. 1-Monopal-mitin and 2-monopalmitin were prepared by the interesterification of methylpalmitate with glycerol or the acylation of 1, 3-benzylidene glycerol with palmitoyl chloride. The evident differences were observed between the initial melting curve and the repeated heating curves of pure 1-monopalmitin. The original melting curve shows the endotherm corresponding to the melting of β-form. The repeated heating curves had two endothermic peaks corresponding to sub-α-transformation and the melting of α-form.
The purification of mercaptans prepared from α-olefins and hydrogen sulfide by urea-adduction was investigated. Because α-olefin contains its isomers, the mercaptans prepared by radical addition of hydrogen sulfide to α-olefins are the mixture of straight-chain n-alkylmercaptans and their branched-chain isomers. As a result, it was found that the best method for separation of n-alkylmercaptans from these mixtures was the urea-adduction by reaction of solid urea with mercaptans dissolved in toluene containing a small amount of methanol. In various experimental conditions, the separations were carried out selectively, and the purified mercaptans contained over 98% of n-C10 or n-C12 mercaptan independently of the yields. The yields of n-alkylmercaptans were markedly dependent on the temperature of adduct-formation and on the solvent for the decomposition of urea-adduct. And it was suggested that the mercaptan itself might be an activator for the adduct-formation. In the case of this experimental condition, urea-adduct seemed to be not formed over 40°C and the urea-adduct of n-C8 mercaptan was hardly formed. And over the temperature range from -10°C to 30°C the rate of adduct-formation was accelerated almost linearly with lowering of temperature. The ratios of urea (moles) to the number of carbon atoms of n-mercaptans in the urea-adducts were not constant and decreased with increase of the number of carbon atoms of n-mercaptans from C8 to C18. This probably reflects the steric and polar effects of SH groups of n-mercaptans. Moreover, it was found that the formation of urea-adduct could be identified by IR spectrum. And it was qualitatively confirmed by NMR and mass spectra that the branched-chain isomers of n-mercaptans were derived from those of α-olefins.
It seems very interesting to study antioxidative effect of kojic acid and its related compounds which are non-toxic. As to the oxidation inhibiting activities of kojic acid and palmitoyl kojic acid, it was found that they were almost ineffective against oxidation of corn oil by Anderson et al. This report presents the results of oxidation inhibiting tests of O-acyl kojic acid and alkyl kojic acid obtained from the oxidation of lard, whale and soybean oils.Introduction of acyl or alkyl groups into kojic acid increases its solubility in oil. The tested acyl groups are butyroil, capryloyl and lauroyl while alkyl groups are butyl, capryl and lauryl (Table-1, 2). Their antioxidative effects for experimented oils are compared by the A.O.M. or Schaal oxidative tests as summarized in Fig.-1, 2.
Reaction between 2-octanol and triethylamine was carried out at the optimum condition, which was reported in our previous paper, but the yield in this reaction was only 36%. This may be due to steric hindrance effect of α-methyl group of 2-octanol. Authors then attempted the reaction after converting the sec-alcohol to primary alcohol by oxyethylation, and the resulted alcohol was reacted with triethylamine using Cu-Cr-Mn-O catalyst under moderate temperature and pressure of H2. In this reaction, it was confirmed that there was no decomposition of oxyethylene chain unless the reaction temperature was over 270°C and 72.2% yield of tertiary amine containing monoalkylether was obtained under the reaction temperature of 270°C. By applying this result for trioxyethylene glycol alkyl (C12C17, except C15) ether, five kind of tertiary amines having these alkyl group were obtained. By using these tertiary amines as the raw material, various new cationic surfactants and amine oxides were prepared. Of these surfactants, N, N-diethyl-N-trioxyethylene alkyl amine oxide (R(OCH2CH2)3N(C2H5)2) showed especially very interesting surface activity.
Intramolecular hydrogen bonding of the some terpenic cyclic unsaturated alcohols, such as 2-hydroxymethyl-6 (1) -p-menthene, 3-hydroxylmethyl-4 (5) -p-menthene, nopol, 1, 3, 6, 10, 10-pentamethyl-4-hydroxymethylbicyclo [4, 4, 0] decene-2, 3-hydroxymethyl-5-tert-butylcyclohexene and 3-hydroxym-ethylcyclooctene was measured by infrared absorption and nuclear magnetic resonance spectra.