Aliphatic carbonyl compounds are prepared by an aldol condensation of carbonyl compounds R.sup.1 --CH.sub.2 --CO--R.sup.2 (I; R.sup.1 and R.sup.2 =H or C.sub.1 -C.sub.8 -alkyl) in the presence of hydrogen and of a catalyst which has both condensing and hydrogenating properties, by using a catalyst system wherein the active components are from 1 to 90 percent by weight of a noble metal of group VIII of the periodic table and from 10 to 99 percent by weight of an oxide or salt of a rare earth metal, or of a mixture of different oxides and/or salts of rare earth metals.
脂肪族羰基化合物是通过使用催化剂体系来进行羰基化合物R.sup.1-CH.sub.2-CO-R.sup.2(I; R.sup.1和R.sup.2= H或C.sub.1-C.sub.8-烷基)的Aldol缩合反应,在
氢气的存在下,催化剂既具有缩合性能又具有加氢性能。所使用的催化剂体系包含以下活性成分:来自周期表第VIII族的贵
金属1-90重量%和来自稀土
金属的氧化物或盐,或不同稀土金属氧化物和/或盐的混合物,重量百分比为10-99%。