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用La2O3负载量不同的La2O3/γ-Al2O3催化柠檬醛和丙酮反应,采用GS/MS、LC/MS、13C NMR等方法鉴定反应产物,并研究了La2O3负载量对反应产物分布、La2O3/γ-Al2O3催化剂的结构性质和酸碱性质的影响.得出以下结论:La2O3是以无定形态负载在γ-Al2O3上;随着La2O3负载量的增加,催化剂比表面积减少,孔径分布趋于均一.La2O3/γ-Al2O3表面增加的弱酸位点密度有利于柠檬醛转化率的提高,增加的中强碱位点密度有利于PSI产率提高;而强碱位点的形成和密度增加对柠檬醛自身缩合生成PCS有促进作用.催化剂循环使用性较好.
The reactions of citral and acetone were catalyzed by La2O3 / γ-Al2O3 with different La2O3 loadings. The reaction products were characterized by means of GS / MS, LC / MS and 13C NMR. The effect of La2O3 loading on the reaction product distribution, Al 2 O 3 catalyst. The conclusions are drawn as follows: La 2 O 3 is supported on γ-Al 2 O 3 in amorphous state; with the increase of La 2 O 3 loading, the specific surface area decreases and the pore size distribution tends to be uniform. / γ-Al2O3 increased the conversion of citral, and the increased density of mid-strong base was in favor of increasing the yield of PSI. However, the formation of strong base and the increase of density on the self-condensation of citral Generate PCS has a catalytic role. Recycling catalyst is better.