A process for reducing cracking of linear and cyclic acetals, in particular formals

The reductive cleavage of linear and cyclic acetals, in particular formals, in an aqueous, formate-containing medium can be achieved by hydrogenation with hydrogen in the presence of a heterogeneous hydrogenation catalyst at a pH below 7 at a temperature of at least 160 DEG C. The catalyst-poisoning effect of the formate is overcome at 160 to 300 ° C, in particular 180 to 280 DEG C, so that the weight ratio metal hydrogenating activity to acetal 0.1, can be much lower than in the prior art, namely, to be smaller at a suspension process.