Transalkylation and Disproportionation between Methylbenzene and 1,3,5-Trimethylbenzene Over the Hβ Zeolite Supported Phosphotungstic Acid Catalyst

The effect of phosphotungstic acid (PW) supported by Hβ on the transalkylation and disproportionation of methylbenzene and 1,3,5-trimethylbenzene to produce dimethylbenzene was studied. The results indicate that the transalkylation of methylbenzene and the disproportionation of 1,3,5-trimethylbenzene are the main reactions. With increasing the PW content loaded on the Hβ catalyst, the conversion of 1,3,5-trimethylbenzene, the selectivity and yield of dimethylbenzene increase at first and then decrease. When the mass fraction of Hβ-supported PW is 10%, the total activity reaches maximum, and the overall feed conversion, the yield and the selectivity of dimethylbenzene are 77.0%, 38.5% and 51.1%, respectively. XRD patterns of the catalysts indicate that the PWs are highly dispersed on the surface of Hβ-support and have no effect on the crystal structure of support.