沉淀法制备苯选择加氢制环己烯双助剂Ru系催化剂研究

Study on Ru-M_1-M_2 Catalyst Prepared by Precipitation Method for Selective Hydrogenation of Benzene to Cyclohexene

用沉淀法制备了苯选择加氢制环己烯双助剂Ru系催化剂,其中Ru为活性组分,Zn和La为助剂,ZrO2为分散剂.研究了Ru/ZrO2比、Zn和La及其含量、ZnSO4及碱金属离子等对催化剂性能的影响.结果表明,Ru/ZrO2=10%、(Zn+La)/Ru=8%、La/Zn=1∶3,加入ZnSO4且保留碱金属离子,Ru-La-Zn/ZrO2催化剂不但具有较高的活性选择性,而且具有很好的沉降分离性能.运用TPR、XRD、BET比表面测定等技术对催化剂进行了表征,并对双助剂Ru-La-Zn/ZrO2的催化作用给予了解释.

A new biassistant Ru-M_1-M_2/ZrO_2 catalyst for high selective partial hydrogenation of benzene to cyclohexene was prepared by precipitation method which involves ruthenium (Ⅲ) chloride and zinc sulphate and lanthanum (Ⅲ) chloride co-precipitation with sodium hydroxide and zirconium dioxide as supports. The influence of Ru/ZrO_2 ratio, assistants and loading, alkali metal ions, incorporation of zinc sulphate on the catalytic activity and selectivity of the Ru-based catalysts have been investigated. The best results obtained were that Ru/ZrO_2 = 10%, (Zn+La)/Ru = 8%, La/Zn = 1∶3. Increased cyclohexene yields and selectivities have also been observed in the presence of alkali metal ions. And the incorporation of zinc sulphate enhanced the sedimentation performance and favored the selectivity of Ru-M_1-M_2/ZrO_2 catalysts. Temperature programmed reduction, X-ray diffraction analyses and surface area measurements were used as tools for characterizing the catalysts. And the catalyst of Ru-La-Zn/ZrO_2 was explained on the molecular level.