Process Optimization Of Selective Hydrogenation Of Benzene To Cyclohexene

Cyclohexene is a very important organic chemical raw material.Selective hydrogenation of.benzene is a major method to produce cyclohexene in industry.The lower conversion ratio and selectivity are two major problems in the process of selective hydrogenation of benzene;to this end,we performed the study on optimization of the process of selective hydrogenation of benzene to cycloh.exene.The hydrogenation catalyst was prepared with precipitation method,in which Ru-Zn is major catalyst,Zirconia is carrier,Zinc sulfate and Zinc hydroxide are assistant catalyst.The deactivation,regeneration and pretreatment of catalysts were investigated.The influences of active ingredient,carrier,additives and auxiliary components on catalytic activity were investigated.The optimum composition is as follows,Ru is moderate;the amount of.water in reaction is equal or slightly larger than that of benzene;the concentration of zinc ion in the solution is about 4.0%;the ratio of catalyst/dispersant is 1/5;the solution pH is 5.6-5.8;the content of Zinc in the catalyst is about 1%.The optimum reaction condition was determined as follows,reaction temperature of 150?,reaction pressure of 5.0MPa,stirring speed of 115rpm,ratio of circulating slurry to benzene of 3.0,benzene load of 36t/h.Under this optimum condition,the conversion of benzene and the selectivity of cyclohexene are 40.6%and 80.7%,respectively,which is at an advanced level in China.