摘要
美国联合碳化物公司首次合成出的AlPO_4-5分子筛属六方晶系,由PO_4及AlO_4四面体单元交替组成的中性骨架构成,具有直孔道结构,孔径为0.8nm,热稳定好,但无离子交换能力,表面不具B酸,L酸也较少,不宜直接作酸性催化剂.但是它负载了金属及金属氧化物后,在裂解、加氢裂解、重整、异构化、加氢异构化及歧化等反应中都有一定的活性及选择性.专利也曾报导,AlPO_4-5经改性后渗合到沸石中用于裂解反应,可提高油品性能.
Supported catalysts of metal oxide/AlPO4-5 molecular sieve have been studied. It was found that the supported catalyst reduced easier showed higher activity. The cracking activity of Co/AlPO4-5 catalyst for n-alkane was studied in detail. After reduction, there were two active centers, the metal particle and the B acid,on the catalyst. The selectivity for cracking reaction of these' two active centers was different, metal particle led to the formation of CH4 through free radical mechanism, while B acid brought about the formation of C3, C4 hydrocarbons through carbonium ion mechanism.
基金
中国石科院基础部基金
