Study On The Deactivated Titanosilicate Zeolite As A Catalyst For Cracking Of Pentene

The development of catalytic cracking of pentene to ethene and propene has very important research significance and industrial application value.Its core is high-effciency catalysts.In this study,the catalytic cracking process of pentene using deactivated titanium silicalite-1（De-TS-1）was developed as catalyst for catalytic cracking of pentene.The active centers of catalytic cracking were identified and regulated,so as to construct a new and efficient catalyst of catalytic cracking of pentene.The development of De-TS-1 as catalyst for efficient pentene cracking process provides a new idea for the recycling of waste catalyst and a new scheme for the development of new solid acid catalyst.The research content is mainly divided into the following four aspects:1.The structure and acid properties of deactivated titanium silicalite-1（De-TS-1）were analyzed.The results show that De-TS-1 has the basic requirements of high efficiency catalyst for pentene cracking:MFI topology,weak Br（?）nsted acid center.The catalytic pentene cracking process with De-TS-1 as catalyst was developed,which exhibited good catalytic performance.2.By means of pickling and K⁺exchange,combined with UV-Vis spectroscopy,vacuum infrared spectroscopy and pyridine infrared spectroscopy,it was proved that the active center of De-TS-1 catalytic pentene cracking is the silanol group adjacent to the titanium hydroxyl group（Si-OH（Ti））.3.The active center in De-TS-1 was regulated by pickling and phosphorus（P）modification.It was found that the P-modified De-TS-1 showed excellent catalytic performance,with the total selectivity of ethylene and propylene is 77.1%and the life of one-way is 213h,respectively.Its comprehensive catalytic performance is better than that of the classical ZSM-5 catalyst.Further studies showed that the P modification could further reduce the acid density and acid strength of Br（?）nsted acid in De-TS-1,thus promoting the main reaction of ethylene and propylene,and inhibiting the side reactions such as hydrogen transfer and aromatics isomerization during pentene cracking.4.The process conditions of De-TS-1 catalytic cracking of pentene were investigated.The process conditions:the temperature of reaction is 550℃,the space velocity of reaction is 3.84h^-1and the partial pressure of pentene in the reaction is0.02Mpa.