The granular crystals growing in palm oil were examined by means of GLC, DSC, and X-ray diffractometer. The polymorphic behaviors of palm oil mixed with 2-oleodipalmitin fraction (POP fraction) from palm oil or 2-oleopalmitostearin fraction (POS fraction) from cocoa butter were determined with X-ray diffractometer. (1) The granular crystals in palm oil consisted of symmetric monooleoyl disaturated triglycerides, mainly of 2-oleodipalmitin. (2) X-ray diffraction patterns of the granular crystals showed, in all cases, β form. (3) POP fraction and POS fraction transformed from unstable α form to stable β form at 30°C or higher temperature than 25°C, and grew into the granular crystals. (4) The transformation of symmetric monooleoyl disaturated triglycerides was promoted by liquid solid ratio, temperature, and tempered time. (5) In palm oil : POP fraction mixtures, a) all of the samples which were tempered at 10 and 15°C exhibited β' form. b) the granular crystals grew in the samples containing 80% or more of palm oil at 20°C. c) the granular crystals grew in the samples containing 40% or more of POP fraction at higher temperature than 25°C.
As previously reported, thermal reaction of fatty acid methyl ester and magnesium iodide resulted in the formation of magnesium soap and methyl iodide. In this paper, thermal reactions of oleic acid esters having various chain length of alkoxyl group with iodides of alkali and alkaline earth metals under various reaction temperatures were carried out. The longer the chain length of alkoxyl group in the oleates, the lower the yield of alkyl iodide except the case of magnesium iodide resulted. The higher the temperature in the reaction of methyl oleate with the metal iodides, the higher the maximum yield of methyl iodide and the faster the velocity which reached the maximum yield gained. The reaction of methyl oleate with calcium iodide at 200°C gave the maximum yield of alkyl iodide, 89% of methyl iodide.
In Germany oxidized fatty acid content that are insoluble in petroleum ether (below 0.7%), smoke point (above 170°C) and acid value (below 2.5) have been adopted as the criteria for the quality of frying oils and fats. Among these criteria oxidized fatty acid content should be preferably considered as an important index which reflects thermal oxidation of frying oils and fats. However the measurement of oxidized fatty acid content is a time consuming work. The authors therefore developed a new method for evaluation of the quality of frying oils and fats which is based on the change of relative interfacial tension about cyclohexane solution of frying oils and fats. The relative interfacial tension was measured with reference to the Japanese Industrial Standard (JIS). In measurement, instead of the standardized drop number tube, the authors used the original drop number tube which is composed of a injection needle and a measured glass tube. Indication of high correlation between relative interfacial tension and oxidized fatty acid content (=0.919) or carbonyl value (=0.929) was given through the measurement of such indices about a large number of frying oils and fats sampled from fried food manufactures. On the other hand, the correlation between relative interfacial tension and acid value was not so much high (=0.731). Relative interfacial tension should be considered as the index which reflects thermal oxidation of frying oils and fats more closely than hydrolysis of them.
Photolyses of phenol-alkylene oxide adducts as model compounds of nonionic surfactants in aqueous solution by sodium hypochlorite was studied. Alkylene oxides such as ethylene oxide, propylene oxide, 1, 2-butylene oxide, and styrene oxide were employed. In the presence of a large excess of hypochlorite, these compounds were completely photolyzed to give carbon dioxide. In the photolysis of an equimolar mixture of substrate and hypochlorite, the probable intermediates were analyzed by means of GC-MS. Irradiation of styrene oxide adduct with hypochlorite gave mainly phenol, arylalkylaldehyde, benzoic acid and monochlorobenzoic acid. In the cases of other alkylene oxide adducts, phenol, anisole, chlorophenol and small amounts of chlorinated compounds were detected.
The ζ-potential of polyamide fiber Nylon-6 was measured in aqueous acidic solution (pH 3) of anionic surfactants-sodium 2-sulfonatofatty acid methyl esters (abbr. SMSF, CnH2n+1CH (SO3Na) COOCH3; n=12 : SMSM, n=14 : SMSP and n=16 : SMSS) and sodium alkyl sulfates (abbr. SAS, CnH2n+1O·SO3Na; n=12 : SDS, n=14 : STS and n=16 : SHS). The amount adsorbed of surfactants per unit area of the fiber surface was calculated from these ζ-potential values. With increasing the concentration of surfactant, the sign of the ζ-potential value of the fiber changed from positive to negative and the amount adsorbed of surfactant (expressed in mol/cm2-fiber) increased because of the electrostatic attractive force and van der Waals' force between the fiber and those surfactants. The amount adsorbed of SMSF was higher than those of SAS. This result may possibly be attributed to the contribution of the methine group in SMSF molecule to the adsorption and the formation of the hydrogen bond between a carbonyl group of the surfactant and an amide group of the fiber. The free energy of adsorption for surfactant, ΔG, was calculated from the slope of the ζ-logCs (Cs : the concentration of surfactant) curve, etc. The negative values of ΔG for SMSF increased with rise of temperature and with increase of the chain length of the surfactant. Also the negative values of ΔG for SMSF were higher than those of SAS. The heat of adsorption ΔH and the entropy of adsorption ΔS for SMSM were -2.5kcal·mol-1 and 14.5cal·mol-1·deg-1, respectively. The corresponding parameters for SMSP were -2.0kcal·mol-1 and 18cal·mol-1·deg-1, respectively. The relatively high positive values of ΔS indicate the importance of entropic interaction and the formation of hydrophobic bond as a driving force to adsorption of SMSF on the fiber surface.
Lipophilic group analysis of a Nekal-type anionic surfactant was investigated. Highly purified potassium 1, 4-diisopropyl-6-naphthalenesulfonate (KDNS) (purity : >99mol%), prepared as a sample, was desulfonated with concentrated phosphoric acid, or fused with solid alkali hydroxides, and their reaction products were undertaken to GLC analysis. As a result, the desulfonation with concentrated phosphoric acid was recognized unsuitable for the lipophilic group analysis of such Nekal-type surfactants because of various side reaction products. On the contrary, the alkali fusion method with potassium hydroxide, carried out in a nickel crucible under nitrogen for 1h at 270280°C, produced only 1, 4-diisopropyl-6-naphthol from KDNS in good yield, as a reaction product, and moreover no side reaction products were found by GLC. Consequently, it was appreciated that the present method connected with GLC was adoptable for the lipophilic group analysis of the Nekal-type surfactants.
A convenient method for the preparation of methyl 1-chloro-2-oxocyclohexanecarboxylate (2a), which appears to be a versatile intermediate in organic syntheses, is described. Methyl 2-oxocyclohexanecarboxylate (1a) was chlorinated with sulfuryl chloride under mild conditions to give 1-chloro-2-oxoester (2a) in an excellent yield. Analogous compounds (2b) and (4) were also prepared by the same chlorination of 2-oxoesters (1b) and (3), respectively.