The invention relates to a method for high selectively synthesizing dimethylbenzene through
benzene and
methanol alkylation reaction. The method takes the
benzene as a
raw material a, a
toluene is taken as a
raw material b, the
methanol is taken as a
raw material c, according to the
molar ratio, a / c equals to 0.50-3.00 / 1.00, b / c equals to 0.60-3.00 / 1.00, under the conditions that the
reaction temperature is between 380 and 480 DEG C, the reaction pressure is between 0.50 and 6.0
mega pascals, the reaction
space velocity is between 0.5 and 5.0 h<-1> and the carrier gas is H2, N2 or CO2, the dimethylbenzene is produced in a
fixed bed reactor under the
catalysis of
molecular sieve based catalysts, the catalysts are one or a plurality of molecular sieves of
zeolite socony mobile-5 (ZSM-5), USY, mobile composite of matter (MCM)-22 or EU-1, a load metallic
oxide is Mo, Ni or La metallic
oxide, and the load of the metallic
oxide is 0.50-10.00%. The method utilizes the
benzene with relative surplus capacity and the inexpensive
methanol to produce the dimethylbenzene with high industrial added value. The appropriate
molecular sieve based catalyst is adopted, the utilization ratio of the methanol
alkylation reaction for high selectively synthesizing the dimethylbenzene cannot be less than 90%, and the catalyst stability can satisfy industrial application requirements. Moreover, the
toluene is added into the reaction raw materials, so that
toluene byproducts can be inhibited from being produced; and in addition, an H2, N2 or CO2 carrier gas
atmosphere is adopted, so that the reaction stability of the catalyst is enhanced.