Study On The Synthesis Of Vitamin E Oleate And Simul-Taneously Determinate Multi-Component System

Vitamin E is easily oxidized to be VE quinine and lost the biological activity belonging to VE. So the products of VE are difficult to prepare and store. The paper presents the researches about the esterifiable modification to VE. The modification changes VE to its ramifications, so that the stability of VE products have been increased and surface activity of VE ramifications are also improved from the modification. In addition, a real-time analysis method for reaction kinetics study has been researched within the VE modification system.In the VE esterifiable modification, the Vitamin E oleate is synthetized by oleic chloride andα-tocopherol. The major four factors, the initial molar ratio of substrates, the amount of catalyst, reaction temperature and time, have been interested in this research. Using the Thin-Layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC) to analysis the transformation of each components in the system according to the L₁₆(4⁵) orthogonal experiment scheme, the optimum of reaction conditions were found. The reaction conditions is: at 45℃, vitamin E (α-tocopherol )/ oleic chloride (mol/mol) =3∶1, in the presence of 2.5% the pyridine as catalyst, vitamin E oleate yield reached 41.8% after 4hr of reaction.The apparent kinetics of catalytic esterification of oleic chloride and a-tocopherol was discussed at temperature 30℃to 60℃. Integral of these experiment data are gotten in four-step Runge-Kutta, and then the parameter of reaction kinetic are regressed at the nonlinear least square method. Within the esterifiable temperature, the reaction can be regarded as the second-order nearly. The A and E_αin Arrhenis equation were also determined, which are6.46×10⁴ dm³Â·mol^-1·s^-1 and 26.68 KJ.mol^-1 respectively.A pilot study of real-time analysis has been practiced for on-line kinetics research in this system. A three-component mixture system, mixed by vitamin-E, Oleic acid and vitamin-E Oleic acid ester, is designed to be a case. The directly measuring ultraviolet absorption spectrums are regressed in Principal component regression (PCR) of Chemometrics, and then a multivariable regression model of this system has been build for directly and simultaneously determining aid component. The whole of the relative error of predicted data result in this model was less than 5%, and the predicted-result is all right. At the same time the experimental result explain that Principal component regression is convenient, quickly, exactly and dispensed with pre-dissociation, and it can be widespread used in simultaneous determining multi-component mixture systems.