Cu_(3/2)PMo_(12)O_(40)改性骨架镍催化剂上羰基和碳碳双键的加氢反应

Hydrogenation of Carbonyl Compounds and Carbon-Carbon Double Bond Compounds on Raney Nickel Modified by Cu_(3/2)PMo_(12)O_(40)

研究了Cu3 / 2 PMo12 O40 表面改性的骨架镍催化剂上含羰基化合物 (正丁醛、异丁醛、丙酮、丁酮和环己酮 )及含碳 碳双键化合物 (苯、糠醇和 1 辛烯 )的加氢反应 .结果表明 ,随着骨架镍催化剂上Cu3 / 2 PMo12 O40 附着量的增加 ,含羰基化合物的加氢反应速率上升 ,而含碳 碳双键化合物的加氢反应速率下降 .与未改性的骨架镍催化剂相比 ,当骨架镍催化剂上Cu3 / 2 PMo12O40 附着量为 6 3%时 ,羰基的加氢活性提高 2倍以上 ,碳 碳双键的加氢活性下降 30 %以上 .计算了各种化合物在催化剂上的表观活化能 .结果表明 ,Cu3 / 2 PMo12 O40 表面改性的骨架镍催化剂上 ,羰基加氢反应的表观活化能降低 ,而碳 碳双键加氢反应的表现活化能升高 .从动力学角度讨论了Cu3 / 2 PMo12 O40 对骨架镍催化剂的影响 .用XPS对骨架镍表面的Cu3 / 2 PMo12 O40 进行了研究 ,发现杂多酸盐的Keggin型结构已被破坏 ,Cu3 / 2 PMo12 O40 分子中的Cu2 + 被还原为Cu0 ,而Mo6+ 被部分还原为Mo5+和Mo4+ ;Cu2 + 和Mo6+ 价态的变化是由骨架镍表面吸附的活泼氢所引起的 .羰基加氢选择性的提高是Cu0

The influence of Cu-3/2 PMo12 O-40-modified Raney nickel (MRNi) catalyst for hydrogenation of carbonyl compounds and C-C double bond compounds was studied using butyl aldehyde, isobutyl aldehyde, acetone, butanone, cyclohexanone, benzene, furfuryl alcohol and 1-octene as model compounds. The hydrogenation activity for carbonyl compounds increases dramatically with the increase of Cu3/2PMo12O40 loading on the catalyst. When the loading reaches 6.3%, the activity is one time more than that of RNi. On the other hand, the hydrogenation activity for C = C bond compounds decreases gradually with the increase of Cu3/2PMo12O10 loading. The activity is about 30% of that of RNi when the loading reaches 6.3%. The effect of reaction temperature on the hydrogenation was studied and the activation energy was calculated for RNi and MRNi catalysts. The activation energy of hydrogenation of carbonyl compounds decreases, but that of C = C bond compounds increases over MRNi catalyst. The states of Cu and Mo in Cu3/2PMo12O40, a modifier for RNi, were studied by XPS technique. The valence states of Cu2+ and Mo6+ on the catalyst surface were greatly changed, i.e. Cu2+ was reduced to Cu while Mo Was partially reduced to Mo and MO. owing to the presence of active hydrogen adsorbed on the catalyst surface. The presence of Cu was beneficial to hydrogenation of carbonyl compounds, and the existence of Mo improved adsorption and activation of carbonyl groups.