The technical problem to be solved by the present invention is to overcome the shortcomings such as low conversion rate, serious environmental pollution, and high energy consumption in the chemical synthesis method of the above-mentioned Tocopheryl Acetate Ewg, and provide a method with high conversion rate, mild production reaction conditions, low energy consumption, and environmental protection. Synthesis method of natural α-tocopheryl acetate with low pollution.
The technical solution adopted to solve the above-mentioned technical problems comprises the following steps:
1, prepare immobilized lipase  The lipase measured by the addition of every gram of natural α-tocopherol 700 ~ 900U is dissolved in pure water, and the lipase solution that is made into a concentration of 8.5mg/ml is measured. Textile carrier, the quality of textile carrier is 5 times of lipase quality, 4 ℃ is soaked in the lipase solution, soaks 16 hours, dries, repeats above steps until lipase solution absorbs completely, obtains immobilized lipase.
2. Modified immobilized lipase
The prepared immobilized lipase is soaked in dimethyl sulfoxide, the mass ratio of immobilized lipase and dimethyl sulfoxide is 1: 1.5~5, 28~45 DEG C are incubated 1~3 hour, carry out modification treatment .
3. Immobilized lipase catalyzed reaction
Mix the natural α-tocopherol with the acetyl donor in a molar ratio of 1: 1.5~55, add the modified immobilized lipase in the mixture, 28~45°C, 180~200 rpm in a shaker React for 12 to 24 hours.
4. Filtration and purification
Filtration and recovery of immobilized lipase, vacuum distillation at -0.09MPa, 95 to 160°C to recover the acetyl donor until no condensate is generated, and film evaporation and dehydration at a vacuum of 200Pa and 170 to 180°C Degassing, vacuum tightness is 1～3Pa, 250～260 ℃ carries out molecular distillation with molecular distillation device, gets natural α-tocopheryl acetate.
The above-mentioned acetyl donor is 25% acetic acid-n-hexane solution in mass percent concentration, and the molar ratio of natural α-tocopherol to acetic acid is 1: 1.5~3; the acetyl donor is ethyl acetate or acetic acid Methyl ester, the mol ratio of natural α-tocopherol and ethyl acetate or methyl acetate is: 1: 25～55.
The lipase of the present invention is Candida lipolytica lipase or Candida plicata lipase.
In step 2 of the modified immobilized enzyme of the present invention, the prepared immobilized enzyme is soaked in dimethyl sulfoxide, the optimum mass ratio of immobilized lipase and dimethyl sulfoxide is 1: 3, 28 ~ 35 ° C Insulated for 1 to 3 hours for modification.
In step 2 of the modified immobilized lipase of the present invention, the prepared immobilized lipase is soaked in dimethyl sulfoxide, and the optimum temperature is kept at 30° C. for 2 hours to perform modification treatment.
The fabric carrier of the present invention is cotton fabric, silk, hemp fabric, nylon fabric.
The synthetic method of natural α-tocopherol acetate of the present invention carries out esterification or transesterification under the catalysis of modified immobilized lipase through natural α-tocopherol and acetyl donor, and reaction product is filtered, reduced pressure Distillation and molecular distillation to obtain Tocopheryl Acetate Ewg, the amount of catalyst used is less, no corrosion to equipment, easy to recycle, less chemical reagents are introduced in the reaction process, no side reactions occur, and the conversion rate of reactants is high, up to 90%, making the separation It is simple, does not generate a large amount of waste water, and does not need to recover a large amount of extraction solvents, is environmentally friendly and energy-saving, and meets the requirements of large-scale continuous industrial production.