Method for purifying heminellitene from mixed C9 aromatic hydrocarbon solvent oil

The process of purifying hemimellitene from mixed C9 arene solvent oil includes the following steps: heating mixed C9 arene solvent oil in a reaction kettle to 40-140 deg.c and adding catalyst anhydrous aluminum trichloride through stirring; introducing alkylating agent C2-C5 olefins for alkylating reaction at 40-140 deg.c to alkylate hemimellitene in the material into alkyl hemimellitene and further stirring after finishing introducing alkylating agent; water washing the alkylated liquid at 40-140 deg.c, stilling, taking the upper layer liquid, refluxing the upper layer liquid, decompression rectifying and cutting alkyl hemimellitene fraction; dealkylating alkyl hemimellitene at 300-650 deg.c under the action of catalyst M-H molecular sieve; and decompression rectifying or normal pressure rectifying to obtain hemimellitene in purity ovre 92 %. The present invention has the advantages of high hemimellitene product purity and continuous production.