超临界干燥法制备载Ru-Pd硅气凝胶及其催化加氢制备1,4-环己二胺

Synthesis of 1,4-cyclohexanediamine over Ru-Pd/SiO_2 catalyst prepared by supercritical drying

采用溶胶-凝胶法及超临界干燥法制备了载Ru-Pd硅气凝胶催化剂,利用XRD、TEM、N_2吸附-脱附等方法对制备的催化剂进行表征,通过单因素实验考察了催化剂用量、氢气压力、反应温度、反应时间对催化剂催化性能的影响,并研究了催化剂的稳定性。实验结果表明,所制备的载Ru-Pd硅气凝胶催化剂比表面积大、孔隙率高,Ru和Pd在载体表面分散均匀;在催化剂用量为1.0 g、反应压力为4.2 MPa、反应温度为140℃、反应时间为3 h条件下,催化剂的催化性能良好,对硝基苯胺转化率接近100%,1,4-环己二胺选择性为72%;5次实验后催化剂仍具有较好的催化活性,稳定性良好。

Ru-Pd/SiO2 catalyst was prepared by sol-gel and supercritical drying methods,and was characterized by means of XRD,TEM and N2 adsorption-desorption.The effects of catalyst dosage,H2 pressure,reaction temperature and reaction time on the properties of the catalyst were investigated by single factor experiments.The stability of the catalyst was also investigated.The results showed that the prepared Ru-Pd/SiO2 catalyst had a high specific surface area and a high porosity.Ru and Pd were well dispersed on the surface of the support.Under the conditions of catalyst dosage 1.0 g,H2 pressure 4.2 MPa,reaction temperature 140℃and reaction time 3 h,the catalyst had a good performance.The conversion of p-nitroaniline was close to 100%and the selectivity to 1,4-cyclohexanediamine was 72%.The catalyst had a good catalytic activity after being used for 5 times,which exhibited good stability.