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以不同硅铝比的HZSM-5为载体,采用化学还原法与沉淀法制备了负载型Ru/HZSM-5催化剂。通过XRD与TEM对催化剂进行了表征。系统考察了制备方法、硅铝摩尔比、温度、氢气压力、时间和Ru负载量对对苯二酚加氢的影响。由于化学还原法制备的催化剂中Ru粒径较小且分散均匀,得到了含有少量硼的非晶态钌硼合金,其催化性能明显优于沉淀法制备的Ru/HZSM-5催化剂。最佳优化反应条件为:硅铝摩尔比为740,反应时间为2.5 h,反应温度为140℃,氢气压力为2.5 MPa,Ru质量分数为1.0%,此时,对苯二酚转化率为100%,目标产物1,4-环己二醇选择性为90.13%。最后,对该催化体系下对苯二酚加氢的反应路径进行了分析。
The supported Ru / HZSM-5 catalyst was prepared by chemical reduction method and precipitation method with HZSM-5 with different Si / Al ratios. The catalysts were characterized by XRD and TEM. The effects of preparation method, molar ratio of silica to alumina, temperature, pressure of hydrogen, time and Ru loading on the hydrogenation of hydroquinone were systematically investigated. Due to the smaller particle size and uniform dispersion of Ru in the catalyst prepared by the chemical reduction method, an amorphous ruthenium-boron alloy containing a small amount of boron is obtained, and its catalytic performance is obviously better than that of the Ru / HZSM-5 catalyst prepared by the precipitation method. The optimal reaction conditions are as follows: the molar ratio of silicon to aluminum is 740, the reaction time is 2.5 h, the reaction temperature is 140 ℃, the pressure of hydrogen is 2.5 MPa and the mass fraction of Ru is 1.0%. At this time, the conversion of hydroquinone is 100 %, The target product 1,4-cyclohexanediol selectivity of 90.13%. Finally, the reaction pathway of hydrogenation of hydroquinone in the catalytic system was analyzed.