苯与丙烯烷基化反应中温度对Y沸石催化剂失活的影响

研究了丙烯与苯反应中反应温度对改性Y沸石催化剂失活的影响。通过TG、元素分析、FT-IR和裂解-色质等手段,分析了失活催化剂中的"焦炭"。结果表明,在较低反应温度下,催化剂失活的原因可能是由于沸石孔口直径为0 7～0 8nm,在超笼内生成较大分子的产物或中间化合物很难扩散出去,滞留在超笼中,导致孔口堵塞;在较高反应温度下,催化剂失活原因可能是催化剂活性中心缓慢地被积碳占据,直至积碳堵塞孔口后,活性便迅速下降。

Effect of Reaction Temperature on Deactivation of a HY Zeolite Catalyst for Alkylation of Benzene with Propylene

Effect of reaction temperature on coking deactivation of a modified HY zeolite catalyst for alkylation of benzene with propylene was investigated.Reaction temperature had substantial effect on the deactivation of the catalyst.At 178 ℃,activity of catalyst underwent a fast decay,while at 220 ℃,the initial activity could maintain for a certain period of time,and then decay occurred slowly till drastically in the end.Properties of coke deposited on catalyst were characterized by using TG,FT-IR,GC-MS and element analyzer.Deactivation of catalyst may be due mainly to (1) blocking of the pore aperture at lower temperatures by larger molecular compounds formed in the supercage of zeolite;(2) at higher reaction temperatures,covering of active sites by coke,followed by blocking of pore aperture by accumulated coke.