Preparation Of Natural Vitamin E Esters

The synthetic processes of natural vitamin E esters were studied in this work. Experiments were divided into two parts: one was primary research on the synthesis of d-α-tocopherol acetate; the other was primary research on the synthesis and crystallization of d-α-tocopherol succinate.With d-α-tocopherol and acetate anhydride as raw materials, n-hexane as the solvent, d-α-tocopherol acetate was prepared in the presence of the catalysts of hydrochloric acid and zinc oxide. Effects of various conditions were studied. The optimum conditions were molar ratio of d-α-tocopherol to acetate anhydride 1:2, the ratio of n-hexane volume to d-α-tocopherol 2.5 ml/g, the ratio of hydrochloric acid to d-α-tocopherol 0.0056 ml/g, the ratio of zinc oxide to d-α-tocopherol 0.56 g/100 g, reaction temperature 10-30 ℃ and reaction time 2 h. The conversion of d-α-tocopherol and the yield of d-α-tocopherol acetate were more than 98%.With d-α-tocopherol and succinate anhydride as raw materials, n-hexane as the solvent, d-α-tocopherol succinate was prepared in the presence of the catalyst of triethanolamine. Effects of various conditions were studied. The optimum conditions were molar ratio of d-α-tocopherol to succinate anhydride 1:2, the ratio of n-hexane volume to d-α-tocopherol 2.5 ml/g, the ratio of triethanolamine to d-α-tocopherol 0.06 ml/g, reaction temperature 100 ℃ and reaction time 3 h. The conversion of d-α-tocopherol was about 98%, and the yield of d-α-tocopherol succinate was about 95%.The optimum crystallization conditions of d-α-tocopherol succinate were the ratio of n-hexane to d-α-tocopherol succinate 8 ml/g, crystallization time 24 h and crystallization temperature 4℃. The purity of d-α-tocopherol succinate was more than 97% and the yield of d-α-tocopherol succinate was more than 80%.