A green and simple preparation method of 2,3,5-trimethylbenzoquinone (tmbq)

Abstract

The invention discloses a preparation method for 2,3,5-trimethylbenzoquinone, which comprises the following steps of: dropwise adding a mixed solution of 50 percent of sulfuric acid and oxidant-glacial acetic acid at the temperature of 30 DEG C by taking 2,3,6-trimethylphenol as a raw material and petroleum ether as a solvent; standing after reaction is ended to separate out upper layer organic phases; extracting an aqueous phase by using the petroleum ether; merging the organic phases and then washing to be nearly neutral; evaporating to remove the organic phases; cooling; and performing vacuum drying to obtain the 2,3,5-trimethylbenzoquinone. The yield is higher than 86 percent, and the purity is higher than 98.5 percent. The preparation method for the 2,3,5-trimethylbenzoquinone has the advantages that the used raw materials are wide in source, the cost is low, the reaction time is short, the energy consumption is low, the post-processing operation is simple, and the product yield and the purity are higher. Meanwhile, reagents capable of polluting the environment, such as heavy metal and concentrated acid, used by a traditional method are omitted by the preparation method for the 2,3,5-trimethylbenzoquinone; the used solvent can also be repeatedly and mechanically used, therefore, the production cost is reduced, and meanwhile, the environmental pollution is avoided, and the requirement of the green and environmental protection of the modern industrial production is met. In a word, the preparation method has the advantages that the environment cannot be polluted, the requirement on reaction equipment is low and the production cost is low, and is extremely suitable for industrial large-scale production.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a green and simple preparation method of 2,3,5-trimethylbenzoquinone (TMBQ). Background technique [0002] 2,3,5-trimethylbenzoquinone (TMBQ for short) is an important intermediate in the synthesis of vitamin E—2,3,5-trimethylhydroquinone (2,3,5- Trimethylhydroquinone, referred to as TMHQ) precursor compound. Since vitamin E is an important fat-soluble biological antioxidant, it has been widely used in medicine, health products, food, cosmetics, animal husbandry and other fields, and the demand for vitamin E in domestic and foreign markets has increased sharply. However, my country's vitamin E mainly depends on imports, and 2,3,5-trimethylbenzoquinone is the key factor restricting the production of vitamin E. Therefore, the synthesis of its important intermediates has greater application value and higher economic benefits. [0003] The synthesis methods ...

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Problems solved by technology

We also tried to use this method to prepare TMBQ, and found that after the reaction was completed, orange-yellow needle crystals could not be obtained, and the product after evaporating the solvent was always oily, and the reaction was monitored by high-performance thin-layer chromatography (TLC). Shows a dark by-product point under the main spot, which is difficult to remove by conventional chemical methods, so the product cannot form a crystalline pure product

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