助剂对Ni/AC催化剂甲醇羰化的影响

Effect of Promoters on Ni/AC Catalysts Used for Methanol Carbonylation

分别以Ni(NO3)2.6H2O、ZnAc2.6H2O、Cu(NO3)2.6H2O、(NH4)6Mo7O24及La(NO3)3.4H2O为前体,采用同时浸渍法制备了主活性组分为镍的双金属活性炭负载型催化剂,考察了Zn、Cu、Mo及La等第二金属元素对甲醇羰化合成醋酸Ni/AC催化剂的助催化作用。活性评价表明:以Mo和La为助剂时,可有效地提高甲醇转化率和羰化产物收率,Mo的添加有利于醋酸甲酯的生成,La则使醋酸的选择性提高;Zn、Cu的加入反而使甲醇转化率及羰化产物收率下降。催化剂的羰基化活性顺序为:Ni-Mo/AC>Ni-La/AC>Ni/AC>Ni-Zn/AC>Ni-Cu/AC。关于稀土元素的影响,结果是La优于Ce。

The active carbon supported bimetallic catalysts using nickel as the main active component were prepared by the co-impregnation method. The precursors were Ni （NO3）2· 6H2O. Zn （AcO）2·6H2O, Cu （NO3）2·6H2O.（NH4）6Mo7O24 and La（NO3）3·4H2O respectively. The promoters effect of the second metallic element, such as zinc, copper, molybdenum and lanthanum, in the carbonylation of methanol to acetic acid was studied. Molybdenum and lanthanum could effectively improve the conversion of methanol and the yield of carbonyl compounds. Molybdenum was favourable for producing methyl acetate and lanthanum could raise the selectivity to acetic acid. Zinc and copper were harmful to the catalyst. The catalytic activity decreased in the order of Ni-Mo/AC〉Ni-La/AC〉Ni/AC〉Ni-Zn/AC〉Ni-Cu/AC. A mong the rare-earth metals lanthanum was superior to cerium in catalytic activity.