About 50 kinds of new tocopherol derivatives have been synthesized, and the rates of scavenging of substituted phenoxyl radical (PhO ·), k2, and quenching of singlet oxygen (1O2), kQ, by these tocopherols have been measured spectrophotometrically in ethanol. Both the log of the rate constants, k2 and kQ, were found to correlate with their peak oxidation potential, Ep. The quenching rates, kQ, were found to be related linearly to the rates k1 and k2 of scavenging of peroxyl (LOO ·) (reported by Burton et al.) and phenoxyl (PhO ·) radicals by these tocopherols, respectively. Vitamin K1-chromanol and K1-chromenol were found to be 6.9 and 4.5 times more active than α-tocopherol, respectively, which has the highest antioxidant activity among natural tocopherols. Further, the second-order rate constants, k-1, k3, k4, and k6 for the reaction of vitamin E radical with i) lipid hydroperoxides (LOOH), ii) vitamin C, iii) ubiquinol, and iv) unsaturated fatty acid esters (LH), respectively, in solution have been measured. By comparing these rate constants, the mechanism of antioxidant and prooxidant actions of tocopherols in biomembranes and edible oils has been discussed.
Assessment was made of the thermal stability of long-chain alkyl phosphate by thermal analysis (TG/DTA/DSC). Several monoalkyl phosphates (Cn-MAP) differing in chain length (C12, C14, C16) showed essentially the same thermal stability. The decomposition temperature of didodecyl phosphate (C12-DAP) was 257.8°C [40-50°C higher than that of monododecyl phosphate (C12-MAP)]. C12-MAP·2 Na salt was thermally more stable than C12-MAP, but C12-MAP·Na salt was less stable than this. Gas chromatographic analysis of the decomposition gas indicated dodecene to be mainly formed from C12-MAP, whereas 1-dodecanol from C12-MAP·Na salt and C12-MAP·2 Na salt. 31P-NMR analysis of C12-MAP decomposition mixtures revealed that the disproportionation of C12-MAP to phosphoric acid (PA) and C12-DAP and condensed phosphate formation fromC12-MAP were competetive with the elimination of olefin from C12-MAP. The elimination of olefins from monoalkyl pyrophosphate [Py- (1.0)] and dialkyl pyrophosphate [Py- (1, 1)] besides from C12-MAP thus must be taken into consideration for assessement of the thermostability of long-chain alkyl phoshates. The formation of [PA+ Py- (0, 0)] from [MAP+DAP +Py- (1, 0) +Py- (1, 1)] appears to be a zero order reaction with an activation energy of 26.2kcal/mol.
An analytical procedure was established for the identification and quantitative determination of salts of polyacrylate, acrylate-methacrylate copolymer and acrylate-maleate copolymers in household granular detergents. The metal salts of these polymers were converted to their methyl esters by diazomethane treatment followed by extraction with chloroform to isolate them from the other components in the detergents. Quantitative determination was conducted by weighing chloroform extracts, with recovery exceeding 90%. A 1H-NMR and pyrolysis GC-MS spectroscopy conducted in conjunction was found to be an adequate means for identifications.
Various mixtures of soy lysophospholipids (SLPs) and fatty acid monoglycerides (MGs) were examined for properties and surface activities of their aqueous solutions. The SLPs used were mixtures of mono-and diacylphospholipid (MDPL) and the lysophosphatidylcholine (LPC) purified form of SLP. (1) MGs were solubilized with SLPs, and their solubility increased with lysophospholipid content. Monostearin was solubilized to the greatest extent among the C18 fatty acid MGs examined. An aqueous solution of an SLP/MG mixture was relatively stable under acidic and salt conditions. (2) The water solubility of LPC/monostearin mixtures was altered by incubation at room temperature, and micellar transformation was observed to occur under an electron microscope. (3) Decrease in surface tension of the mixture was proportional to the extent of unsaturation of the C18 fatty acid of MG, and for mixtures containing the medium chain acid MG, maximum decrease in surface tension (25.5 mN/m) was observed. (4) Aqueous solutions of SLP/MG mixtures showed significant immersion and adhesion wettability when MGs consisted of polyunsaturated and/or medium chain fatty acids. (5) Mixtures of SLP/MG were more effective for O/W emulsification of vegetable oil compared to ordinary soy phospholipids/MG. Emulsions with SLP/MG mixtures were stable under acidic and salt conditions when SLP contained over 50% (wt/wt) LPC. (6) Aqueous solutions of MDPL/MG mixtures showed excellent dispersibility when MDPL contained more than 40% lysophospholipids. The betha-carotene solubilizing ability of SLP decreased on adding monostearin. The above results show that suitable blend of SLP/MG can be prepared using various mixtures for specific purposes as a safe and natural surfactant.
The surface characteristics of polystyrene-films having various fluoroalkylated ratios (Rf-ratio) were studied by contact angle and Electron Spectroscopy for Chemical Analysis (ESCA) measurements. The fluoroalkylation agents used were perfluoroalkanoyl peroxides [bis (heptafluorobutyryl) peroxides]. Critical surface tension (γc) of the polystyrene films decreased with increase in Rf-ratio, but remained constant above an Rf-ratio of 26%. Decrease in γc was found due to that in the London dispersion force (γcd) and polar force (γcp) in the components of γc. The effects of fluorine atoms in fluoroalkyl groups on surface characteristics (water-repellent and oil-repellent) of polystyrene were maximized even when the atoms were relatively few in number.
An analytical method was developed for N, N-bis (2-hydroxyethyl) dodecanamide and N- (2-hydroxyethyl) dodecanamide in mixtures with dodecyl poly (oxyethylene) ethers using alumina column chromatography. HPLC data for the mobile phase systems of the ethyl acetate with water and with methanol were found to indicate linear relationships between log k' and log (concentration of water [or methanol]) except when dodecyl poly (oxyethylene) ethers were used for methanol. An abrupt change in retention time was noted for dodecyl poly (oxyethylene) ether at a methanol concentration of about 3% in ethyl acetate. They virtually ceased to be retained regardless of the added numbers of ethylene oxide. This elution behavior should be applicable to the development of suitable methods for the objective analysis.