Process for the preparation of aldehydes

Process for the preparation of aldehydes, by the reduction of carboxylic acids or esters, anhydrides or salts thereof, which comprises hydrogenating as feed at least one compound of the general formula R'COOR, wherein R represents a hydrogen atom, an alkyl or an acyl group, or a metal and R' represents an optionally substituted hydrocarbyl group having at most two alpha-hydrogen atoms, provided it has at most one beta-hydrogen atom, in case it has two alpha-hydrogen atoms, in a reaction zone at a temperature of 250.degree. to 550.degree. C. a weight hourly space velocity of 0.1 to 4.0 kg/kg/h and a molar ratio of hydrogen gas to feed compound of more than 0.1 in the presence of a catalyst comprising at least one rare earth metal and iron on a gamma-alumina carrier, wherein the total amount of iron and rare earth metals lies between 0.01 and 0.2 gat/100 g of carrier and the atomic ratio of iron to rare earth metal lies between 0.4 and 4.0;

• and separating an aldehyde-containing product from said reaction zone.