Preparation of Hydrocracking Catalysts Promoted by Organometallics ( Co, Ni, Mo )

为了提高硫化钼催化剂的加氢活性，在MoO_3/Al_2O_3催化剂上掺杂了Ni、Co、Fe有机金属络合物。在对新制备的催化剂进行预硫化后，进行了模型试验反应，以确定催化剂的催化性能，如HY或加氢裂化(HC)活性。与用Ni或Co硝酸盐制备的Ni-Mo或Co-Mo催化剂相比，新制备的催化剂具有更高的HY活性。金属酞菁(Me(PC))是一种比其他有机金属更好的助剂。Me(Pc)-MoS_2/Al_2O_3催化剂的HY活性随焙烧温度的升高而降低。经高温焙烧后，催化剂表面的Me(Pc)结构被破坏，表明Me(Pc)结构对HY活性中心的形成是有效的。当催化剂在氮气气氛中焙烧时，Me(Pc)结构受到的破坏较小。在各种Me(Pc)‘S催化剂中，酞菁镍的HY活性最高，而Me(Pc)-MoS_2/Al_2O_3催化剂的HY活性远低于Me(Pc)-MoS_2/Al_2O_3催化剂，说明MoS_2中的Mo原子与Me(Pc)’S中的Ni或Co原子之间的协同作用是硫化钼催化剂HY活性中心形成的关键。另一方面，Me(Pc)-MoS_2/Al_2O_3催化剂的HC活性远低于Ni-Mo和Co-Mo催化剂，表明该催化剂对HY反应具有较好的催化选择性。MoO_3/Al_2O_3负载的Me(Pc)/Al_2O_3催化剂S在400ﾟC下于N_2中焙烧和在5vol%H_2S/H_2中预硫化后没有观察到铝酸盐或氧化物的生成。Ni或Co的高度分散状态以及金属状态有利于提高硫化钼催化剂的HY活性。

Organometallic complexes of Ni, Co and Fe were doped on a MoO_3/Al_2O_3 catalyst in order to enhance hydrogenation (HY) activity of Molybdenum sulfide catalysts. After presulfiding newly prepared catalysts, model test reactions were carried out to clarify catalytic functions of the catalysts such as HY or hydrocracking (HC) activity. Higher HY activities were obtained over the newly prepared catalysts as compared to Ni-Mo or Co-Mo catalysts prepared using Ni or Co nitrate.Metal phthalocyanines (Me(pc)) were found to be better promoters than other organometallics. The HY activities of the catalysts (Me(Pc)-MoS_2/Al_2O_3) decreased with the increase in calcination temperature. XRD and FT-IR measurements revealed that Me(Pc) structure on the catalysts was damaged after high temperature calcination in air indicating that Me(Pc) structure is effective for the formation of HY active sites. When the catalysts were calcined in N_2 atmosphere, the Me(Pc) structure was less damaged. Nickel phthalocyanine gave the highest HY activity among various Me(Pc)'s. Much lower HY activity was observed over Me(Pc)/Al_2O_3 catalysts as compared to Me(Pc)-MoS_2/Al_2O_3 catalysts, indicating that the synergy between Mo atom in MoS_2 and Ni or Co atom in Me(Pc)'s is essential for the formation of HY active sites of the molybdenum sulfide catalysts. On the other hand, HC activities of the Me(Pc)-MoS_2/Al_2O_3 catalysts were much less than those of Ni-Mo and Co-Mo catalysts showing that this newly prepared catalysts have superior catalytic selectivity for HY reaction.A formation of aluminate or oxide was not observed after calcination of Me(Pc)/Al_2O_3 Me(Pc)'s supported on MoO_3/Al_2O_3 were stable during calcination in N_2 and presulfurization in 5vol% H_2S/H_2 at 400ﾟC. These new findings mentioned above seem to show that highly dispersed state of Ni or Co as well as metallic state are suitable for promoting HY activity of the molybdenum sulfide catalysts.