Catalytic synthesis of vitamin E acetate using metal organic framework material ZIF-8

Vitamin E is an important fat soluble antioxidant, its acetate is the main derivative product of vitamin E. Using metal organic framework material ZIF-8 as a catalyst, vitamin E acetate (VEA) was prepared by catalyzing the esterification reaction of D-alpha-tocopherol and acetic anhydride in a solvent-free system. Firstly, the preparation conditions of metal organic framework materials were studied: different imidazole ligands, different zinc ion ligands, molar concentration ratio of Zn2+ to 2-methylimidazole(2-mIM), and preparation time. The results showed that the catalytic performance of ZIF-8 was optimal when Zn(CH3COO)2<middle dot>2H2O was used as the zinc source, 2-mIM was used as the imidazole ligand, the molar concentration ratio of Zn2+ / 2-mIM was 1:20, and the preparation time was 1 hour. The yield of vitamin E acetate was 86.85%. The synthesis process of VEA was optimized by single factor experiments such as substrate molar ratio, reaction time, dosage of nano enzyme, reaction temperature and so on. The results showed that the yield of vitamin E acetate reached 96.31% under the optimal conditions of n (D-alpha-tocopherol) =1mmol, [n (D-alpha-tocopherol) : n (Acetic anhydride)] =1:15, reaction time 24 h, ZIF-8 dosage 0.05 g, reaction temperature 50 degrees C.