供氢剂对正庚基苯催化裂化反应的影响

以Y型分子筛为催化剂,在脉冲微反装置上进行正庚基苯催化裂化实验,考察了4种供氢剂对正庚基苯催化裂化反应的影响。实验结果表明,供氢剂可提高正庚基苯裂化反应的转化率,改变正庚基苯裂化反应产物的组成;供氢剂降低了反应产物中苯的含量,提高了烷基苯的含量;供氢剂降低了反应产物中的烯烃总含量,但对丙烯含量影响不大;供氢剂抑制了正庚基苯的二次裂化反应,降低了反应产物中小分子烷烃的含量,提高了大分子烷烃的支链化程度。供氢剂可以促进按Rideal机理进行的氢转移反应,不同类型供氢剂对氢转移反应影响程度有所不同;供氢剂有利于正庚基苯发生双分子裂化反应,并抑制了正庚基苯的单分子裂化。

Effects of Hydrogen Donors on Catalytic Cracking of 1-Phenylheptane

The cracking of 1-phenylheptane with or without hydrogen donors was carried out on a pulse micro-reactor and the effects of four hydrogen donors on the cracking were investigated.It was showed that the hydrogen donors could obviously increase the conversions of 1-phenylheptane and alter the composition of the cracking products.It was demonstrated that the addition of hydrogen donors reduced the amount of benzene and increased the amount of alkylbenzene.The addition of the hydrogen donors led to decreasing the content of alkenes in the cracking products,while the content of propene maintained unchanged.It was also found that the hydrogen donors depressed the secondary cracking of 1-phenylheptane and the branching degree of the large alkane molecules was slightly enhanced.It was concluded that the addition of the hydrogen donors in the cracking system could evidently promote hydrogen transfer reactions which was conducted according to Rideal mechanism,but the effects of different hydrogen donors were much different.In addition,the fact that the cracking of 1-phenylheptane via bimolecular mechanism is favored by the hydrogen donors is useful for the product quality control in fluid catalytic cracking.