Method for breakdown of formates

A process for decomposing formates in formate-containing compositions of matter, which comprises reacting formate-containing compositions of matter in the presence of at least one heterogeneous catalyst comprising lanthanum and at a temperature of from 80 to 180° C. and a pressure of from 0.1 to 60 bar,

• wherein the formate-containing compositions of matter have a pH of from 6.5 to 10,
• the catalyst is a lanthanum oxide/copper/copper oxide/aluminum oxide catalyst, comprising 4 to 15 wt % of lanthanum reckoned as La2O3 and based on the total weight of the catalyst,
• the formate-containing composition of matter comprises carbonyl compounds formed by an aldol reaction of alkanals with formaldehyde and/or their corresponding hydrogenation products, and
• at least 50 wt % of formate is decomposed.