焦化苯中的噻吩与乙醇在HZSM5沸石上的反应

REMOVAL OF THIOPHENE FROM COKING BENZENE OVER HZSM 5 ZEOLITE

焦化苯中加入少量的乙醇，在一定的温度下用ＨＺＳＭ５催化剂能将其中的噻吩分解生成硫化氢及微量的重组分硫化物．研究结果表明，反应体系中乙基正碳离子的存在是加速噻吩分解的主要原因，且当反应温度高于４００℃时，ＨＺＳＭ５催化剂脱噻吩活性的稳定性较好；在ｎ（Ｂ）／ｎ（ＥｔＯＨ）＝６５６（Ｂ为焦化苯），温度４００℃，常压，ＷＨＳＶ３５～３９ｈ－１的条件下，焦化苯中噻吩的脱除率可达９８％．

The removal of thiophene from coking benzene by catalytic reaction with EtOH on HZSM 5 zeolite has been studied. Thiophene reacting with H + and CH 3CH + 2 is converted into H 2S and a few amount of alkylthiophene and dialkylthiophene. At low temperature, an acid catalyzed opening of thiophene ring and polymerization between thiophene and alkylthiophene take place on HZSM 5 to give some surface species, including olefinic thiol like intermediate and polymer like aggregate, which deposit on the HZSM 5 surface and poison the surface active centers, and the catalytic activity descends quickly. At reaction temperature higher than 400℃, these surface species undergo almost complete decomposition and acid catalysis to form H 2S. It is showed that the HZSM 5 has excellent and stable activity.The ideal condition for removing thiophene from coking benzene with thiophene content of 2 92 mmol/L is n (B)/ n (EtOH)=6 56, 400℃, WHSV 3 5～3 9 h -1 , the removal rate of thiophene is more than 98%.