Environmentally-friendly synthesis method of vitamin E

Abstract

The invention relates to the fine chemistry industry synthesis field, and especially relates to an environmentally-friendly synthesis method of vitamin E. The method comprises the following steps: adding 150-200 parts by weight of toluene into a reaction device, sequentially adding 40 parts by weight of 2,3,5-trimethylquinhydrone and 40-80 parts by weight of isophytol under mechanical stirring, slowly adding 1.5-2.5 parts by weight of magnesium chloride and 0.8-1.2 parts by weight of a magnesium oxide supported silica catalyst after the above obtained reaction system is fully dissolved and clear, closing the reaction system, allowing the reaction system to undergo a reaction under a vacuum degree of -0.07 - -0.05MPa at a temperature of 55-65DEG C for 1.5-2.5h, and allowing toluene reflux to be maintained and generated water to be distilled out with the toluene reflux in the reaction to be in favor of the implementation of the reaction; and recovering the catalyst and the above solvent, and carrying out reduced pressure distillation of the solvent-distilled reaction system to obtain a required pale-yellow oily vitamin E product. The method has the advantages of repeated use of the supported catalyst, high yield, low energy consumption and environmental protection.

Description

technical field [0001] The invention relates to the field of fine chemical synthesis, in particular to a green and environment-friendly synthesis method of vitamin E. Background technique [0002] Since vitamin E was first discovered by humans in 1922, the production and application of vitamin E has been a research hotspot in the field of vitamins. Vitamin E, referred to as tocopherol for short, has important effects on reproductive function, anti-aging and promoting metabolism, and is widely used in the fields of health care drugs and feed additives. [0003] The synthesis reaction mechanism of vitamin E is that under the catalysis of Lewis acid as a catalyst, enol forms alkene carbocation to attack the benzene ring in hydroquinone, and then dehydrates to form a six-membered ring, which belongs to electrophilic addition reaction, and the essence of the reaction belongs to Friedel-Crafts alkylation reaction. [0004] In terms of vitamin E synthesis research, most institu...

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Problems solved by technology

[0004] In terms of vitamin E synthesis research, most institutions use concentrated sulfuric acid, concentrated hydrochloric acid, methanesulfonic acid, p-toluenesulfonic acid and other acids that pollute the environment as catalysts for condensation reactions. Although the reaction conditions of this type of synthesis are relatively mild, but The disadvantage is that the amount of catalyst used is high, the recovery of the catalyst is difficult, and more importantly, the pollution to the environment is very serious during large-scale production

U.S. Patents US3444213 and US4634781 use boron trifluoride as the catalyst for the condensation reaction to react. The reaction is feasible, but the reaction equipment is highly corrosive and pollutes the environment.

[0005] Switzerland Dishman Company has recently studied the use of rare earth element compounds instead of the traditional Lewis acid and hydrochloric acid system as a catalyst. High, not suitable for industrial production

[0006] In order to improve the yield and purity of vitamin E, Makoto used iridium trifluorosulfonate and scandium trifluorosulfonate as catalysts, which improved the yield and purity of vitamin E, but the recovery of the catalyst was difficult and the production equipment was more corrosive. also cause serious environmental pollution

[0007] European patent EP603695 describes the production of vitamin E through the condensation of trimethylhydroquinone and isophytol in liquid or supercritical carbon dioxide in the presence of acidic catalyst hydrochloric acid, zinc chloride and ion exchangers. The operation of this method is relatively complicated. Catalysts cannot be recycled and reused, and the problem of equipment corrosion and environmental pollution is equally serious

[0008] The world patent WO9728151 describes the use of oxalic acid or citric acid as the catalyst for the condensation reaction in the solvent of cyclocarbonate, but there is also the problem that the catalyst cannot be recycled and the environment is seriously polluted.

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