摘要
以甲醇转化及甲苯-甲醇烷基化反应为探针,考察了 ZSM-5型甲苯-甲醇烷基化催化剂的活性稳定性。用 TPD、(?)R 等方法测试了催化剂表面酸性质,表明沸石表面酸性质及载体本身的性质均是影响催化剂活性稳定性的重要因素。催化剂表面上的 L 酸中心与较强的 B 酸中心共同存在时可加速甲醇自身转化反应,从而引起催化剂积炭失活,稳定性下降。
Activity and stability of modified H-ZSM-5 zeolite catalysts are examined inconnection with toluene disproportionation,methanol conversion.and alkylation oftoluene with methanol.Temperature programmed desorption of ammonia(NH_3-TPD)and IR are used to explain changes in the nature,strength and number ofacid sites in ZSM-5 zeolites and carrier.Zeolite surface acidity and characteris-tics of the carrier are found to be important contributing factors to stability ofcatalyst activity.Coexistence of Lewis acid sites and Br(?)nsted acid sites mayaccelerate conversion of methanol causing coking and leading to catalyst deacti-vation and decrease in stability.
出处
《石油化工》
CAS
CSCD
北大核心
1990年第8期555-560,共6页
Petrochemical Technology
