Pd/HZSM-5催化剂催化加氢丙酮合成甲基异丁基酮

以HZSM-5为载体，采用浸渍法制备系列Pd/HZSM-5催化剂，在高压连续流动固定床反应器中考察Pd/HZSM-5催化剂催化加氢丙酮一步法合成甲基异丁基酮性能，并对工艺条件进行优化。结果表明，当HZSM-5载体上Pd负载质量分数为0.5%时，在反应温度140 ℃、氢压1 MPa、空速0.48 h^-1和氢酮物质的量比为1条件下，Pd/HZSM-5催化剂催化活性较高，丙酮转化率为45.91%，甲基异丁基酮选择性为94.33%。采用XRD、H₂-TPD、SEM、EDS和TGA等对催化剂进行表征，结果表明，负载质量分数0.5%的Pd在HZSM-5分子筛表面分散均匀，且0.5%Pd/HZSM-5催化剂具有较高氢吸附能力，失活的主要原因为催化剂表面积炭，采用流化床反应器取代传统的固定床反应器可以很好的解决催化剂积炭问题。

Catalytic hydrogenation of acetone to methyl isobutyl ketone over Pd/HZSM-5 catalysts

Using HZSM-5 molecular sieve as the support, Pd/HZSM-5 catalysts were prepared by impreg- nation method. The catalytic performance of Pd/HZSM-5 catalysts for catalytic hydrogenation of acetone to methyl isobutyl ketone were investigated in a fixed-bed reactor and the process conditions were optimized. The results indicated that Pd/HZSM-5 catalyst with 0.5wt% Pd loading exhibited the best catalytic activity, and acetone conversion of 45.91% and the selectivity to methyl isobutyl ketone of 94.33 % were attained under the condition of reaction temperature 140 ℃ ,hydrogen pressure 1 MPa,space velocity 0.48 h^ -1 and hydrogen/acetone molar ratio 1. The catalysts were characterized by the techniques of XRD, H2-TPD, SEM,EDS and TGA. The characterization results indicated that palladium of 0.5% Pd/HZSM-5 catalyst was dispersed uniformly on the surface of HZSM-5 molecular sieve and 0.5% Pd/HZSM-5 catalyst possessed better hydrogen adsorption capacity. The carbon deposition played a major role in the deactivation of Pd/HZSM-5 catalysts. The problem of catalyst coking could be solved by using the fluidized bed reactor to replace the conventional fixed bed reactor.