论文部分内容阅读
采用2种方法制备了原位负载稀土三元催化剂,即先将均相的Y(CCl3OO)3-Glycerin体系负载在载体上,后逐滴加入ZnEt2(标记为Y(CCl3OO)3-Glycerin/γ-Al2O3/ZnEt2);或先将ZnEt2与载体反应,再与均相的Y(CCl3OO)3-Glycerin体系反应(标记为ZnEt2/γ-Al2O3/Y(CCl3OO)3-Glycerin).研究发现原位负载催化剂催化环氧丙烷和二氧化碳共聚合反应的活性比未负载前低24%～36%,通过分析催化剂制备过程中所生成的乙烷量的变化,证明原位负载时催化剂组分如Y(CCl3OO)3、Glycerin或ZnEt2发生了向载体孔隙内的扩散渗透,使得催化剂各组分配比与未负载催化剂相比发生了偏差,从而降低了催化活性;另一方面,表面羟基与ZnEt2反应形成了低效率的活性种,也是原位负载催化剂活性不高的原因之一.提出了影响原位负载稀土三元催化剂活性的2个主要因素,即活性种的反应活性和活性种的数量.通过调节催化剂组分配比、负载化阶段的振荡研磨时间、原位负载时的活性种状态、载体的表面状态等,可使负载催化剂的活性比未负载的稀土三元催化剂提高3.5%.
In this paper, two kinds of methods were used to prepare rare earth ternary catalysts. The homogeneous Y (CCl3OO) 3-Glycerin system was first loaded on the support, and ZnEt2 (labeled as Y (CCl3OO) 3-Glycerin / γ -Al2O3 / ZnEt2) or ZnEt2 was first reacted with the support and then reacted with a homogeneous Y (CCl3OO) 3-Glycerin system (labeled as ZnEt2 / γ-Al2O3 / Y (CCl3OO) 3-Glycerin) The activity of propylene oxide and carbon dioxide copolymerization catalyzed by supported catalyst was 24% -36% lower than that of unburned catalyst. The change of ethane amount generated during the preparation of catalyst was proved that the catalyst components such as Y ( CCl3OO) 3, Glycerin or ZnEt2 into the pores of the carrier diffusion into the carrier, so that the proportion of each component of the catalyst compared with the unsupported catalyst deviated, thereby reducing the catalytic activity; the other hand, the surface hydroxyl and ZnEt2 formed Low efficiency active species is also one of the reasons that the activity of in-situ supported catalyst is not high. Two main factors that affect the activity of in situ supported rare earth three-component catalyst are proposed, that is, the reactivity of active species and the number of active species. Catalyst group ratio, load Oscillation of the polishing period, the state of the active species in situ during loading, the support surface state and the like, can increase the activity of supported catalyst 3.5% the rare earth unsupported three-way catalyst.