SO_4^(2-)/TiO_2合成维生素E亚油酸酯及抗氧化研究

Study on Optimization of Vitamin E Linoleic Acid Ester by SO_4^(2-)/TiO_2 Solid Super Acid and Antioxidant Activity in Edible Oil

利用新型催化剂固体超强酸SO_4^(2-)/TiO_2合成了维生素E亚油酸酯,研究了反应物配比(X_1)、反应温度(X_2)、催化剂用量(X_3)、反应时间(X_4)等因素对维生素E亚油酸酯产率的影响,利用Box-Benhnken中心组合试验和响应面分析法,进行工艺优化,并将维生素E亚油酸酯应用于食用油中。结果表明,维生素E亚油酸酯产率预测模型:Y_1=-301.198+35.634 62X_1+12.958 27X_2+6.625X_3-5.855 769X_1~2-0.137 231X_2~2。最优工艺条件为:亚油酸酰氯与维生素E摩尔比3︰1、反应温度45℃、SO_4^(2-)/TiO_2用量4.5%、反应时间3.5 h。此时产率达到95.6%。食用油抗氧化性研究表明维生素E亚油酸酯有较好的抗氧化性能,可以作为化学抗氧化剂替代品。

Synthesis of vitamin E linoleic acid ester was studied using SO_4^（2-）/TiO_2 solid super acid as the catalys. The influence of reaction condition on the yield of isopropyl chloroacetate was investigated, such as catalyst loading, molar ratio of linoleic acid chloride to vitamin E, reaction time, reaction temperature and repeated use of the catalyst. The mathematical regression model was established about the dependent variable（productivity of vitamin E linoleic acid ester） and independent variables（ratio of linoleicc acid chloride to vitamin E, reaction time, reaction temperature and repeated use of the SO_4^（2-）/TiO_2） through Box-Benhnken center composite design and response surface methodology. Moreover, vitamin E linoleic acid oleate was applied to edible oil. The results indicated that the optimal extraction condition was that the ratio of linoleic acid chloride to vitamin E of 3, reaction temperature of 45 ℃, repeated use of the SO_4^（2-）/TiO_2 of 4.5%, reaction time of 3.5 h. Under this condition, the validation value was 95.6%. The standardized regression equation was Y_1=-301.198＋35.634 62X_1＋12.958 27X_2＋ 6.625X_3-5.855 769X_1~2-0.137 231X_2~2. The results of experiment with vitamin E linoleic acid ester as edible oil antioxidants showed that vitamin E linoleic acid ester had good oxidation resistance as chemical antioxidants alternatives.