Hydrogenation of carbazole and N-ethylcarbazole over Raney-Ni catalyst were realized in the temperature range of 393-503 K. 4[H] adduct dominated the hydrogenation products and the formation of 2[H] adduct was the rat...Hydrogenation of carbazole and N-ethylcarbazole over Raney-Ni catalyst were realized in the temperature range of 393-503 K. 4[H] adduct dominated the hydrogenation products and the formation of 2[H] adduct was the rate-limiting step during the period, in which the conversion of carbazole was less than 40%. The hydrogenation process followed pseudo-first-order kinetics and the hydrogenation activation energies of carbazole and N-ethylcarbazole were 90 kJ/mol and 115 kJ/mol, respectively. The reaction starting position as well as the pathway of the hydrogenation of （N-ethyl）carbazole were investigated by comparing the kinetic characteristics of hydrogen uptake of carbazole and N- ethylcarbazole. The results showed that the reaction was a stepwise hydrogenation process and the first H_2 was added to the C1 = C10 double bond in the hydrogenation.展开更多
文摘在Ni-Al合金粉上浸渍硝酸铜溶液,经不同温度焙烧得到Cu改性Ni-Al合金粉,采用质量分数10%NaOH溶液浸渍上述改性合金粉得Cu/Raney-Ni催化剂。采用EDX、XRD、N 2吸附-脱附、TEM和NH 3-TPD等手段表征了Ni-Al合金粉及相应Raney-Ni催化剂的元素含量、晶体结构、孔结构特征、表面形貌和表面酸碱性,并以1,4-丁烯二醇加氢制1,4-丁二醇为探针反应,考察了焙烧温度对Raney-Ni催化剂加氢性能的影响。表征分析表明,焙烧温度500℃所制备的CRT500催化剂比表面积较大,为64.96 m 2/g;弱酸中心比例较高,达81.2%。结果表明,焙烧温度升高,BED可实现完全转化,BDO选择性和收率均先升高后降低。其中,CRT500加氢性能较好,BED转化率为100.00%,BDO选择性为61.88%。进一步升高焙烧温度,催化剂RCT550和RCT600的BDO选择性和收率反而降低,这是由于高温下催化剂易发生团聚或烧结。结合催化剂表征可知,CRT500具有较好的加氢性能,这与该催化剂具有合适的Ni/Al物质的量比(3.84)、弱酸中心所占比例较大和活性组分Ni分散性好等因素有较大关联。
基金supported by the National Natural Science Foundation of China(U1162127,U1462201,21076189,21476202 and 21276231)
文摘Hydrogenation of carbazole and N-ethylcarbazole over Raney-Ni catalyst were realized in the temperature range of 393-503 K. 4[H] adduct dominated the hydrogenation products and the formation of 2[H] adduct was the rate-limiting step during the period, in which the conversion of carbazole was less than 40%. The hydrogenation process followed pseudo-first-order kinetics and the hydrogenation activation energies of carbazole and N-ethylcarbazole were 90 kJ/mol and 115 kJ/mol, respectively. The reaction starting position as well as the pathway of the hydrogenation of （N-ethyl）carbazole were investigated by comparing the kinetic characteristics of hydrogen uptake of carbazole and N- ethylcarbazole. The results showed that the reaction was a stepwise hydrogenation process and the first H_2 was added to the C1 = C10 double bond in the hydrogenation.
