金属氧化物对H_3PW_(12)O_(40)/γ-Al_2O_3在甘油制丙烯醛过程中性能的影响

Study on catalytic properties of H_3PW_(12)O_(40)/γ-Al_2O_3 catalysts modified with metal oxides for preparation of acrolein from glycerol

采用分步等体积浸渍法制备了CeO2、La2O3、MgO、ZnO改性的PW/γ-Al2O3催化剂,用FTIR、XRD、BET、TG-DTA和活性评价等表征手段,考察了不同金属氧化物对PW/γ-Al2O3催化剂催化甘油脱水制丙烯醛反应性能的影响。结果表明:氧化物的引入,修饰了催化剂的表面性质,降低了催化剂的表面酸量。CeO2的添加,提高了催化剂的活性,尤其La2O3的添加,明显改善了催化剂的反应稳定性。而不同氧化物抑制积炭能力的强弱为:MgO>ZnO>La2O3>CeO2。

The CeO2, La2O3, MgO or ZnO modified H3PW12O40/γ-Al2O3 catalysts were prepared by stepwise incipient wet impregnation method, and the effects of those metal oxide promoters on the catalytic behaviors of the catalysts in the reaction of glycerol dehydration to acrolein were investigated by FTIR, BET, XRD, TG-DTA and reaction activity evaluation. The results indicated that addition of promoters improved the surface properties of the catalysts and decreased the amount of surface acid. CeO, promotor increased the activity of catalyst, and especially La2O3 promoter improved the stability of the catalyst significantly. The ability of resistance to carbon deposition of the promoters is in the following order：. MgO 〉ZnO〉La2O3〉CeO2.