Study On The Synthesis Of2,3,5-trimethylbenzoquinone

2,3,5-Trimethylbenzoquinone is an important pharmaceutical intermediates. Itcan be through catalytic hydrogenation synthesized2,3,5-trimethylhydroquinone, and2,3,5-trimethylhydroquinone is an important intermediate for the synthesis of vitaminE. In this article,2,3,5-trimethylbenzoquinone were prepared by catalytic oxidationreaction step using1,2,4-trimethylbenzene,2,3,6-trimethylphenol as raw materials.The main content and the results were as follows:In the process of1,2,4-trimethylbenzene as a raw material for the preparation of2,3,5-trimethylbenzoquinone, using glacial acetic acid as the solvent, hydrogenperoxide as an oxidizing agent. The catalyst was prepared by supporting differentquantity of Fe3+on silicic acid, silica, γ-Al2O3, β-Al2O3;compounding differentquantity copper phthalocyanine and silicic acid, silica, γ-Al2O3, β-Al2O3; putting thecompounds of copper phthalocyanine and silicate, silica, γ-Al2O3, β-Al2O3calcined ina muffle furnace. The catalyst was used the reaction for the preparing the2,3,5-trimethylbenzoquinone by catalytic oxidation using the1,2,4-trimethylbenzeneas a raw material. The conversion of1,2,4-trimethylbenzene and yield of2,3,5-trimethylbenzoquinone were measured by the external standard method for GCanalysis in the process of the reaction to give the best catalyst is catalyst J which isprepared by componding10g γ-Al2O3and3g copper phthalocyanine.The catalyst J was used in the catalytic reaction. The conditions of catalystamount, reaction time, reaction temperature, the dropwise addition of H2O2wereparticularly studied for the preparing the2,3,5-trimethylbenzoquinone by catalyticoxidation using the1,2,4-trimethylbenzene as a raw material. The study found that,the1,2,4-trimethylbenzene conversion was72.8%,2,3,5-trimethylbenzoquinone yieldup to65.3%in the case of in the reflux temperature the catalyst J:1,2,4-trimethylbenzene=0.083:1(wt: wt), the reaction time was2h, the H2O2wasadded drop by drop.In the process of2,3,6-trimethylphenol as a raw material for the preparation of2,3,5–trimethylbenzoquinone. The technology used oxygen as an oxidizing agent.The catalyst was prepared by taking one of the ionic liquids, such as:[Bmin][Br],[Bmin][BF4],[Bmin][NO3] and adding one or more of the copper halide, the alkaline earth metal halide. The catalyst was used in the catalytic reaction. The conditions ofthe reaction temperature, reaction time, degree of the oxidation liquid washing, theion concentration of the catalyst, the recycling of the catalyst, the reuse of the solventon the reaction were particularly studied. The study found that, the optimum reactiontemperature was120°C; reaction time was6h (3h adding2,3,5-trimethylphenolsolution drop by drop+3h holding time); Oxidation liquid was washed until the washliquid color is yellow-green; When the catalyst was processed the catalyst can beunlimited use. The target product of2,3,5-trimethylbenzoquinone may be prepared bythe2,3,5-trimethylhydroquinone using insurance powder, the molar yield is95.76%.