镁-镧复合氧化物固体碱催化甲醛、丁醛缩合制备2,2-二羟甲基丁醛

Magnesium-lanthanum mixed metal oxide:a solid base for synthesis of 2,2-dimethylol-1-butanal from formaldehyde and n-butyraldehyde

以镁-镧复合氧化物为固体碱催化剂,首次用于甲醛、丁醛间的羟醛缩合反应.GC、GC-MS分析发现:2,2-二羟甲基丁醛为主产物,2-乙基丙烯醛为最主要的副产物.筛选Mg-Al复合氧化物、MgO和Mg-La复合氧化物3种固体碱,发现Mg-La复合氧化物具有最佳催化活性.当甲醛和丁醛摩尔比为2.5∶1时,在50℃反应4 h,丁醛转化率为75%、DMB选择性为37%、DMB得率为28%.催化剂可以循环使用4次,没有明显失活,有利于降低反应成本,减少环境污染.

A magnesium-lanthanum mixed metal oxide was used as solid base for synthesis of 2,2-dimethylol-l-butanal from the reactions between formaldehyde and n-butyraldehyde for the first time. GC and GC-MS results showed that the main product was 2,2-dimethylol-l-butanal while 2-ethylacrylaldehyde was the pfincipae by-product. Among the solid bases such as Mg-A1 oxide, MgO and Mg-La oxide, the latter was found to be the optimal catalyst. Under proper conditions,i, e. , formaldehyde ：butyraldehyde （ molar ratio） = 2.5：1.0, after reaction for 4 h under 50 ℃, the conversion of butyraldehyde was 75 % while the selectivity and the yield of 2,2-dimethylol-l-butanal were 37% and 28% ,respectively. Furthermore, the catalyst could be easily separated from the reaction mixture and used repetitively for 4 times without significant loss of activity.