Preparation And Purification Of Alpha Linolenic Acid Ethyl Ester

Alpha-linolenic acid,which is necissary for human beings and can be obtained from the diet,is a kind of polyunsaturated fatty acids(PUFA) Alpha linolenic acid ethyl ester has the same physiological function with alpha linolenic acid and its stability is better than alpha linolenic acid.The catalytic reaction used solid base catalysts instead of the traditional homogeneous catalyst Can be effectively avoid shortcomings such as difficult separation after reaction, corrosion of equipment, environmental pollution etc. At the same time, the solid base catalyst can be recycled easily, and can be reused..In this study, we got high purity of alpha linolenic acid ethyl ester by three steps. 1:the preparation of solid base catalysts 2:prepared linseed oil fatty acid ethyl ester with the solid base catalyst prepared in the first step 3:obtained high purity of alpha linolenic acid ethyl ester by the separation and purification of the coarse fatty acid ethyl ester.The specific steps are as follows:The solid base catalyst CaO was prepared by high temperature calcination and optimized the solid base catalyst preparation conditions accroding to the characterization results :900℃ in the muffle furnace calcine for5 h,preparaed the solid base catalytic under the best conditions, and the esterification reaction of alpha-linolenic acid was catalysed.the optimal process reaction conditions was obtained by single factor experiments and orthogonal experiments: alcohol:oil was7:1,oil temperature was70℃,catalyst was2%(wt), catalytic time was2 h.the esterification rate reached 97.3% under the optimal conditions.Prepared Solid base catalyst KOH/TiO2 by solution impregnation,according to the characterization,optimized the best solid alkali preparation:load capacity of KOH 6.25mmol/g, calcination temperature is 600℃,toast for 5h.Prepared the solid base catalyst KOH/TiO2 under the optimal conditions, and then it was used in the esterification catalytic reaction,and obtained the optimal reaction conditions by single factor experiments and orthogonal experiments:the ratio of alcohol and oil is 8:1, 2.5%(wt)of catalyst and catalytic time 2h, catalytic temperature 75℃, the esterification rate reached 96.2%.Prepared Solid base catalyst KF/TiO2 by solution impregnation,optimized the solid base catalyst preparation conditions accroding to the characterization results:load capacity was 40%(w), in the muffle furnace calcine for 5h, calcination temperature is 500℃,prepared solid base catalyst KF/TiO2 under the conditions of optimum process and it was used to catalyse the esterification reaction of alpha-linolenic acid.Optimum reaction conditions: alcohol oil ratio of 9:1, the dosage of the catalyst was 3%, the reaction temperature was 80℃, reaction time was 3h, the esterification rate was 88.3%.At last the solid base catalyst CaO is the best catalyst through the comparison of the esterification rate.The coarse fatty acid ethyl ester was purified by molecular distillation and the relative content of alpha-linolenic ethyl ester reached 55.88%,then the purification obtained from the molecular distillation was subjected to freezing crystallization to obtain higher purity of alpha linolenic acid ethyl ester.The optimal conditions crystallization temperature-25 ℃,the crystallization time 12 h was obtained by examining the crystallization temperature and time,the relative content of alpha linolenic acid ethyl ester reached 61.78% under the optimal conditions finally.