β沸石催化剂上甲苯歧化及与1,2,4-三甲苯烷基转移反应研究

Disproportionation of toluene and transalkylation between toluene and 1,2,4-trimethylbenzene over β zeolite catalyst

对在液固相连续反应装置上以β沸石为催化剂进行甲苯歧化及甲苯与1,2,4 三甲苯烷基转移生成二甲苯及苯的反应进行了研究,并对影响反应的因素如温度、压力、氢气用量、反应物空速等进行了探讨。结果表明,该催化剂对上述反应有较好的催化作用。对于甲苯歧化反应,在温度280℃,压力3 5MPa,甲苯重量空速4h-1,n氢/n甲苯4∶1时,甲苯转化率为47 26%,苯与二甲苯总选择性为93 50%。对于甲苯与三甲苯的烷基转移反应,当进料比n甲苯/n三甲苯=2,温度280℃,压力3 5MPa,总重量空速4h-1,n氢/n烃=2∶1时,总转化率为47 17%,二甲苯选择性为83 25%,二甲苯收率达39 26%。

Disproportionation of toluene and transalkylation between toluene and 1,2,4trimethylbenzene over β zeolite catalyst were studied in liquidsolid reactor. The appropriate operating conditions were as follows: 280 ℃, 35 MPa, toluene WHSV 4 h-1 and nH2/nT=4 for disproportionation of toluene, and 280 ℃, 35 MPa, WHSV 4 h-1,nH2/(nT+nTMB)=2 and nT/nTMB=2 for transalkylation. Under the experimental condition, toluene conversion of 4726% and total selectivity to benzene and xylene of 9350% were obtained for disproportionation of toluene; total toluene and trimethylbenzene conversion of 4717%, selectivity to xylene of 8325% and xylene yield of 3926% were obtained for transalkylation.