Abstract:

The reason for the deactivation of catalysts in the process of preparing high value-added hydrogenated nitrile rubber by heterogeneous catalytic hydrogenation of nitrile rubber was investigated. It was found that the cause of the decrease in catalyst activity was not the loss, agglomeration or poisoning of noble metal nanoparticles. The reactants could not contact with the active sites, which was the real reason for the reduced activity. Therefore, the effective removal of the polymers from the active sites was the key to catalyst regeneration and reuse. Secondly, based on the similarity-intermiscibility theory, the recycled catalyst was treated with a single or a mixed solvent to elute the polymers and recover its activity. The results showed that the catalyst activity could be restored to 90% of the fresh catalyst activity by washing with ethyl acetate, butanone, N,N-dimethylfirmamide or N-methylpyrrolidone. When treated with a mixed solvent, its catalyst activity could be increased to 95% of the fresh catalyst activity, and could remain steady after recycling 4 times. SEM and TG characterization results showed that after the organic solvent regeneration, Pd active sites on the surface of the catalyst were exposed, thus its hydrogenation activity was remarkably improved.

Key words: polymers, multiphase reaction, hydrogenation, deactivation, regeneration, solvents, nitrile butadiene rubber

摘要：

对丁腈橡胶非均相催化加氢制备高附加值氢化丁腈橡胶过程中催化剂失活的原因进行了探究，发现造成催化剂活性下降的原因并不是贵金属纳米颗粒的流失、团聚或中毒，而是催化剂表面的活性位被聚合物覆盖而无法与反应物接触，因此将覆盖在活性位上的聚合物进行脱除才是催化剂再生和重复利用的关键。根据相似相容原理选择单溶剂或者混合溶剂对反应后催化剂进行处理，结果表明经过乙酸乙酯、丁酮、N,N-二甲基甲酰胺以及N-甲基吡咯烷酮这四种有机溶剂处理后，其催化加氢活性可以恢复至新鲜催化剂活性的90%；当用混合溶剂处理后，其催化活性可以提高至新鲜催化剂活性的95%，且循环利用4次其催化活性仍能保持不变。

关键词: 聚合物, 多相反应, 加氢, 失活, 再生, 溶剂, 丁腈橡胶