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.