Ni/活性炭催化剂制备因素对气相甲醇羰基化的影响

Effects of preparation factors on the performance of Ni/AC catalysts for vapor phase carbonylation of methanol

利用催化反应、TEM和TPR表征考察了制备因素包括Ni含量和催化剂前体对Ni/活性炭(Ac)催化剂甲醇羰基化性能的影响.催化剂制备采用垂湿浸渍法.结果表明,Ni含量为2.5%(mass)时.羰基化活性最高.用Ni(NO_3)_2、Ni(OAc)_2和NiCl_2制备的催化剂,催化性能基本相同,活性都较低.用Ni(NH_3)_6^(2+)和Ni(en)_n^(2+)(n=0.8和3)络合物制备的催化剂活性都较高,前者尤高.这与高羰基化活性与浸渍过程活性炭与络合阳离子间发生静电相互作用使Ni分散度显著提高有关.

Activity tests, TEM and TPR measurements have been used to investigate the effects of preparation factors including Ni loadings and catalyst precursors on the nickel/active carbon catalysts for vapor phase carbonylation of methanol. The catalysts were prepared by incipient wetness impregnation method. The results indicate that with increasing Ni loadings from 1 to 12 mass %, the carbonylation activity of the catalysts reaches a maximum at 2. 5% of Ni. The catalysts prepared using Ni complexes such as Ni(NH3)62+ (from basic carbonate) and Ni(en)n2+ (from nitrate, n = 0. 8 and 3) instead of Ni( I ) salts such as Ni(NO3)2, Ni(OAc)2 and NiCl2 as precursors give rise to higher activities due to higher dispersion of the Ni caused by stronger interaction electrostatically between active carbon support and complex cations during impregnation.