Preparation Of α-tocopherol And α-tocopheryl Acetate

Preparation ofα-tocopherol andα-tocopheryl acetate were studied in this paper. The preparation ofα-tocopherol related to two parts: the preparation of non-α-aminomethylated tocopherol salts and then subjected to hydrogenolysis.Non-α-aminomethylated tocopherol salts were produced from raw material of 52.3% tocopherols mixture. The following factors were considered in this process: reaction temperature, reaction time, selected of amic reagent, ratio of reactants and the separating method of non-α-aminomethylated tocopherol salts. And the optimal technological conditions were obtained: reaction temperature 80℃, reaction time 40min, amic reagent was dimethylamine, the molar ratio of tocopherols mixture, dimethylamine and formaldehyde were 1:3:3, translation rate was up to 98.20%, then the product was extracted by ethylacetate, and then phosphoric acid was added dropwise with stirring until pH value was 4.1, non-α-aminomethylated tocopherol salts were formed. The solution was heated to reflux, and cooled to 0℃,crystalline products were obtained.Hydroxymethylation-reduction was combined with aminoalkylation-reduction in the process of hydrogenolysis of non-α-aminomethylated tocopherol salts. Non-α-aminomethylated tocopherol salts was dissolved in n-heptane and charged to an autoclave with 5% Pd/C hydrogenolysis catalyst and hydroxymethylation catalyst toluene-p-sulfonic acid, the quality ratio of Pd/C, toluene-p-sulfonic acid, paraformaldehyde and non-α-aminomethylated tocopherol salts was 5.0:3.4:25.1:100. Hydrogenolysis was carried out at 170℃for 2 hours at 2.6MPa hydrogen pressure. The product was cooled, removed from the autoclave, filtered and the solvent removed under vacuum to yieldα-tocopherol, translation rate of non-α-aminomethylated tocopherol salts was 99.54%, purity ofα-tocopherol was 93.60%, yield was 90.58%.α-tocopheryl acetate was produced from raw material of 93.6%α-tocopherol, the following factors were considered: reaction time, reaction temperature, the molar ratio of acetate anhydride andα-tocopherol and the kinds of catalyst. The optimal technological conditions were obtained: reaction time was 1h, reaction temperature 95℃,the molar ratio of acetate anhydride andα-tocopherol was 1.8~2:1, the ratio of esterification catalyst toluene-p-sulfonic acid toα-tocopherol was 0.27g/100g, andα-tocopheryl acetate was formed,the reaction translation rate was up to 99.48%, selectivity was 98.81% and the yield 98.30%.