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在低碱度下采用共沉淀法成功制备了非负载型Ru-Zn催化剂,用于苯选择加氢制环己烯反应.固定氢氧化钠沉淀剂的量,考察了不同氯化锌加入量对催化剂结构和催化性能的影响,采用N2吸附、X射线衍射和程序升温还原等手段对催化剂进行了表征.同时考察了选用具有最佳锌含量的Ru-Zn催化剂时搅拌速度和硫酸锌添加剂等对催化反应性能的影响,最后考察了催化剂多次使用时的反应性能.研究表明,Zn含量16.7%(质量分数)的Ru-Zn催化剂具有最佳的催化性能;在Zn SO4水溶液(0.45 mol/L)中,优化反应条件(哈氏合金釜,1200 r/min,150 oC,H2压5 MPa)下反应45 min,苯转化率57%时环己烯选择性可达80%(收率超过45%).钌催化剂中Zn O晶体对于环己烯选择性达到80%非常重要.催化剂回收循环反应5次时反应性能基本不变,表明低碱度下制备的催化剂具有良好的稳定性,显示了工业化应用前景.
The unsupported Ru-Zn catalyst was successfully prepared by co-precipitation at low alkalinity for the selective hydrogenation of benzene to cyclohexene. The amount of sodium hydroxide precipitating agent was fixed and the amount of different zinc chloride added Catalyst structure and catalytic performance of the catalyst were characterized by N2 adsorption, X-ray diffraction and temperature-programmed reduction catalysts were also investigated.When selected Ru-Zn catalyst with the best zinc content of the stirring speed and zinc sulfate additives The results show that the Ru-Zn catalyst with Zn content of 16.7% (mass fraction) has the best catalytic performance. When Zn SO4 aqueous solution (0.45 mol / L) ) For 45 min under optimized conditions (Hastelloy, 1200 r / min, 150 oC and H2 pressure 5 MPa). The selectivity to cyclohexene was up to 80% at benzene conversion of 57% (the yield exceeded 45 %) .In the ruthenium catalyst, it is very important for the selectivity of cyclohexene to 80% for the ZnO crystal.The reaction performance is basically unchanged after the catalyst is recycled for 5 cycles, indicating that the catalyst prepared at low basicity has good stability, Industrial application prospects.