针对苯与乙醇烷基化制备乙苯的反应,选用纳米片型ZSM-5分子筛为母体催化剂,采用固定床反应器考察了其在苯-乙醇烷基化反应中的催化性能并评价其稳定性。探究了Mg、Zn、B元素等体积浸渍改性对催化剂的烷基化反应性能的影响,精确调控负载量,并在苛刻条件下评价改性催化剂及母体催化剂的稳定性。结果表明,使用母体催化剂时,苯-乙醇烷基化反应连续运行150 h,苯转化率保持在45%以上,乙基(乙苯+二乙苯)选择性稳定在96.9%左右,表明母体催化剂具有优良的稳定性。经Mg、Zn、B负载改性后,改性催化剂的乙基选择性均有所提升,其中经1% B负载后改性效果最佳,苯转化率提升至46.7%,乙基选择性达98.6%,产品中二甲苯含量降至1 050 ppm。在空速15 h^-1的苛刻条件下,改性催化剂可稳定运行130 h而不失活。

Regarding the reaction for preparing ethylbenzene through benzene-ethanol alkylation,nanoplate-type ZSM-5 molecular sieve is selected as the parent catalyst.The catalytic performance and stability of the catalyst in benzene-ethanol alkylation reaction are evaluated in a fixed bed reactor.The influences of volume impregnation modification with elements such as Mg,Zn,and B on the alkylation reaction performance of the catalyst are explored,the loading amount are precisely regulated,and the stability of the modified and parent catalysts is evaluated under harsh conditions.It is indicated that under the optimized conditions including atmospheric pressure,350℃,a space velocity of 6 h^-1,and a carrier gas flow rate of 30 mL/min,the benzene-ethanol alkylation have undergone for 150 h continuously over the parent ZSM-5 molecular sieve,which presents a benzene conversion rate above 45% and an ethyl (ethylbenzene+diethylbenzene) selectivity of 96.9%,demonstrating an excellent stability.The ethyl selectivity is all enhanced as the modified catalysts that are obtained by modifying the parent catalyst through loading with Mg,Zn,and B,respectively,are served.Among them,the catalyst through loading with 1% B shows the best effect,increasing the benzene conversion rate to 46.7%,enhancing the ethyl selectivity to 98.6%,and reducing the content of xylene in the product to 1 050 ppm.Under the harsh condition with a space velocity of 15 h^-1,the modified catalyst can operate stably for 130 h without deactivation.