Preparation method of 2,3,5-trimethylhydroquinone dialkyl acid ester

The invention provides a preparation method of 2,3,5-trimethylhydroquinone dialkyl acid ester. The preparation method comprises the following steps: under catalysis of polymer ionic liquid, carrying out rearrangement and acylation reaction on 2,6,6-trimethyl cyclohexyl-2-ene-1, 4-diketone and an acylating agent to prepare the 2,3,5-trimethylhydroquinone dialkyl acid ester. Compared with the traditional acid catalysis, the process has the advantages of easiness in recovering of the catalyst, environmental friendliness, slight corrosion to equipment, high activity, high selectivity and the like.