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采用共沉淀法制备了A l2O3-T iO2复合载体(简称复合载体),研究了该复合载体负载Pd后制备的Pd/A l2O3-T iO2催化剂在乙炔选择加氢反应中的催化性能。考察了复合载体合成条件(复合载体中T iO2的含量、中和反应温度、沉淀终点pH、A lC l3的质量浓度、沉淀物老化时间)对Pd/A l2O3-T iO2催化剂活性和选择性的影响。实验结果表明,复合载体的最佳合成条件为:T iO2质量分数30%,中和反应温度40℃,沉淀终点pH=9,A lC l3的质量浓度0.20g/mL,沉淀物不老化。采用最佳条件下合成的复合载体所制备的Pd/A l2O3-T iO2催化剂(Cat-02)的选择性大于85%,乙炔转化率达到90%以上,优于Pd/A l2O3催化剂。与工业催化剂G-58C相比,Cat-02在活性上还有一定差距,但具有更好的选择性。
A l2O3-T iO2 composite support (referred to as composite support) was prepared by co-precipitation method. The catalytic performance of Pd / Al 2 O 3 -TiO 2 catalyst supported on Pd on the selective hydrogenation of acetylene was studied. The catalytic activity and selectivity of Pd / Al 2 O 3 -TiO 2 catalysts for the synthesis of Pd / Al 2 O 3 -TiO 2 catalysts were investigated under the following conditions: the content of T iO 2, the neutralization reaction temperature, the pH of the precipitate, the mass concentration of AlCl 3 and the aging time of the precipitate influences. The experimental results showed that the optimal conditions for the synthesis of the composite support were as follows: the mass fraction of T iO2 was 30%, the neutralization temperature was 40 ℃, the final pH value was 9, and the mass concentration of AlCl3 was 0.20 g / mL. The selectivity of Pd / Al203-Ti02catalyst (Cat-02) prepared by using the composite carrier synthesized under the best conditions is more than85% and the conversion of acetylene is over90%, which is better than that of Pd / Al203catalyst. Compared with the industrial catalyst G-58C, Cat-02 has a certain difference in activity, but has better selectivity.