镁铝复合氧化物表面酸碱性对丙酮缩合反应的影响  

Influence of surface acid-base properties of magnesium-aluminum composite oxides on acetone condensation reaction

作　　者：杨坤[1] 王芳珠[1] 阎永凤[1] 赵瑞玉[1] 

机构地区：[1]中国石油大学化学化工学院,山东青岛266555

出　　处：《工业催化》2011年第5期34-39,共6页Industrial Catalysis

摘　　要：采用共沉淀法制备不同镁铝比的系列水滑石样品HLDs,水滑石焙烧得到系列镁铝复合氧化物LDOs。分别以吡啶和乙酸为探针分子,采用FT-IR法对系列LDOs样品的表面酸碱性进行测定,考察镁铝复合氧化物表面酸碱性对其催化丙酮缩合反应性能的影响。研究结果表明,镁铝物质的量比为3的复合氧化物催化性能较好,丙酮转化率最高可达36.09%,异佛尔酮选择性最高达67.34%,该催化剂表面具有较弱的酸性位及较小的酸性位密度,其表面碱性位密度与酸性位密度比值高,表明镁铝氧化物催化剂的表面酸碱比是影响丙酮缩合制备异佛尔酮反应的关键因素,进一步证实丙酮缩合反应为酸碱协同作用的催化反应。Magnesiumaluminum composite oxides catalysts（LDOs） were prepared by calcining hydrotalcite samples（HLDs） with different Mg/Al ratios,which were prepared by coprecipitation.The surface acid/base density and strength properties of LDOs catalyst were characterized using acetic acid and pyridine as the probe molecules by FTIR.The influence of the surface acid/base properties of LDOs on acetone condensation reaction was investigated.The results showed that the catalyst LDO3 exhibited the best catalytic activity,with acetone conversion of 36.09% and the selectivity to isophorone of 67.34%.The catalyst possessed weaker surface acidic sites,smaller density of surface acidic sites,and higher ratio of alkali density to acidic density.The results also indicated that the ratio of acid to alkali on the surface of magnesiumaluminum composite oxides catalyst was the key factor of the preparation of isophorone from acetone.It was concluded that acetone oligomerization was catalytic reaction of the cooperation of acidic and basic active sites.

关 键 词：催化化学 镁铝复合氧化物 表面酸碱性 FT-IR法 丙酮 缩聚 

分 类 号：TQ426.6[化学工程] TQ224.223