Four Toluene Isomerization Reactions In The Zeolite

C10 aromatic hydrocarbons contains a lot of mixed tetramethylbenzene.So it is feasible to synthesis of durene by mixed tetramethylbenzene isomerization.Hβzeolite has moderate acidity, good thermal stability and shape selectivity because of unique structure. HP is showed hard coking, high catalytic actibity in the catalytic reaction which is used petrochemical industry.This paper presented a new process for production of durene from mixed tetramethylbenzene. The catalyzed isomerization with the presence of hydrogen occured over Hβzeolite in the fixed-bed microreactor experimental device, which used mixed tetramethylbenzene as raw materials. The effects of reaction temperature, reaction pressure and volume space velocity on the catalytic were investigated.The experimental results show that at the reaction conditions of 250℃～260℃,2.0MPa～2.5MPa, 1.4h-1～2.0h-1.In this paper, ion exchange and the chemical liquid deposition method were used to modify Hβzeolite. Analytical technique including XRD, Py-IR, N2 physisorption and NH3-TPD were used to characterize the structure and acidity of HP zeolite before and after modification. Catalytic performance of zeolite were evaluated by the isomerization of mixed tetramethylbenzene for synthesis of durene in the fixed-bed microreactor experimental device. The rule of different modified methods to the influence of structure, acidity and catalytic performance for Hβzeolite were studied.Cu2+,Mo6+ and Mg2+ were used to modify Hβzeolite by ion-exchange method. The results show that pore structure, acid and acid strength of HP zeolite can be modulated and catalytic performance improved by modification of Cu2+,Mo6+ and Mg2+. Largely, modified Hβzeolite echanced conversion of 1,2,3,5-TEMB and 1,2,3,4-TEMEB,selectivity to durene and the yield of durene. Aqueous solution of NiO,P2O5 and mixed both were used to modify HP zeolite by the chemical liquid deposition method. The results show that the framework structure of loaded oxide to HP zeolite was not destroyed. Modified Hβzeolite covered the acid sites of zeolite and optimized distribution to B and L acid. Hβzeollites modified by proper nickel oxide,phosphorus pentoxide and mixed both exhibited excellent catalytic performance.It was improved the conversion of 1,2,3,5-TEMB and 1,2,3,4-TEMB,the selectivity to durene and the yield of durene.