介孔Cu-Mn复合氧化物催化氧化苯甲醇合成苯甲醛的研究

A Research of Mesoporous Copper-Manganese Mixed Oxides for Selective Oxidation of Benzyl Alcohol to Benzaldehyde

采用无模板共沉淀法合成介孔Cu-Mn复合氧化物,该氧化物具有很高的比表面积且可大量合成.该复合氧化物(Cu-Mn-x,x=1,2,4)作为催化剂应用在以O_2为氧化剂,甲苯为溶剂的苯甲醇选择性氧化合成苯甲醛的研究中,发现该催化剂显示出很高的活性.当n(Cu)∶n(Mn)的设计比例为1∶2时活性最高,在102℃的温度下,苯甲醇转化率达到90%时仅需20 min,选择性达到98%.催化剂的物理化学特性采用了XRD、SEM、TEM、BET、H2-TPR和EDS技术进行表征.结果表明,Cu和Mn具有协同促进作用,能够互相提高催化活性,但必须控制在一定的比例范围内;另外催化剂的活性与用量关系很大,量越大活性越高.

A novel template-free co-precipitation method was applied to synthesize mesoporous coppermanganese mixed oxides with high surface area, which can be obtained in large quantities. Catalytic activity of copper-manganese mixed oxides (Cu-Mn-x, x=1, 2, 4) has been studied in selective oxidation of benzyl alcohol using molecular oxygen as oxidizing agent and toluene as solvent. The catalysts exhibited highest activity, in which 90% conversion of the benzyl alcohol was achieved with 98% selectivity to benzaldehyde within a short reaction period only in 20 min at 102 ℃, when the design mole ratio of Cu/Mn was 1∶2. The physicochemical properties of the catalysts were characterized by XRD, SEM, TEM, BET, H2-TPR and EDS techniques. It shows that Cu and Mn can improve the catalytic performance each other effectively but there must be an appropriate mole ratio of Cu/Mn. In addition, there is a great relationship between the activity and the amount of catalysts, which shows that the higher activity the more catalysts.