Selective Oligomerization Process Of Isobutene In Mixed C₄

The state proposed an energy development plan,which will promote ethanol gasoline for vehicles nationwide in stages.As one of the original gasoline additives,the consumption of methyl tert-butyl ether(MTBE)will gradually decrease until the gasoline additive component is completely withdrawn,and its raw material isobutylene should also find new application ways.In this paper,supported Fe₂O₃-N/?molecular sieve and Fe₂O₃-Cl/?molecular sieve catalysts were prepared by equal volume impregnation method,and the selective oligomerization of isobutylene in mixed C₄ was evaluated.Under the optimum preparation conditions of catalysts,the effects of inhibitors on the selective oligomerization of isobutylene in mixed C₄ were studied.The effects of Fe impregnation amount,calcination temperature,reaction space velocity,reaction temperature and inhibitor addition on the conversion rate of isobutene selective oligomerization and the selectivity of polymerized products in mixed C₄ were mainly discussed.Specific research contents are as follows:(1)Supported Fe₂O₃-N/?molecular sieve catalyst:The effect of different Fe impregnation amount(0,3%,6%,9%,12%),different calcination temperatures(350?,400?,450?,500?,550?,600?)and different reaction condition(reaction space velocity,reaction temperature)on that selective oligomerization of isobutylene in mixed C₄were investigated.The results show that when the Fe impregnation amount is 6%,the calcination temperature is 550?,the reaction temperature is 60?,the reaction space velocity is 1.5 h^-1,and the reaction pressure is 1 MPa,the selective oligomerization effect of isobutylene is the best.(2)Supported Fe₂O₃-Cl/?molecular sieve catalyst:The effect of different Fe impregnation amount(0,3%,6%,9%,12%),different calcination temperatures(350?,400?,450?,500?,550?,600?)and different reaction condition(reaction space velocity,reaction temperature)on that selective oligomerization of isobutylene in mixed C₄were investigated.The results show that when the Fe impregnation amount is 3%,the calcination temperature is 550?,the reaction temperature is 70?,the reaction space velocity is 2 h^-1,and the reaction pressure is 1 MPa,the selective oligomerization effect of isobutylene is the best.(3)Effect of inhibitor on isobutene selective oligomerization:The best catalysts obtained from the first two parts were used to explore the amount of inhibitor ethanol(mass ratio of alcohol to olefin:3%,5%,10%,20%,30%)and the best reaction conditions.The results show that the optimum reaction conditions of supported Fe₂O₃-N/?molecular sieve catalyst are as follows:the mass ratio of alcohol to olefin is 1:5,the reaction temperature is65?,the reaction space velocity is 1.5 h^-1,and there are fewer kinds of C₈ products,and the selectivity can reach more than 15%.The optimum reaction conditions of supported Fe₂O₃-Cl/?molecular sieve catalyst are as follows:the mass ratio of alcohol to olefin is 1:5,the reaction temperature is 65?,the reaction space velocity is 2 h^-1,the selectivity of C₈can reach 25%,and the product is single.