Process for the preparation of monocarbonyl or biscarbonyl compounds

Process for preparing monocarbonyl or biscarbonyl compounds of the formula ##STR14## wherein Q represents hydrogen or the radicals ##STR15## in which R.sub.1 is C.sub.1 to C.sub.6 alkyl;

• X represents linear or branched alkylene having 1 to 20 C atoms, linear or branched alkylene having 2 to 20 C atoms in which one --CH.sub.2 -group of the alkylene chain is replaced by oxygen or the --SO.sub.2 -group, substituted linear or branched alkylene having 1 to 20 C atoms, this alkylene being substituted by one or more groups which are inert under the reaction conditions;
• aralkylene or alkylenearylene having 7-12 C atoms each;
• substituted aralkylene or alkylenearylene having 7-12 C atoms each, the substituent being a group which is inert under the reaction conditions;
• o-, m-, or p-phenylene, substituted o-, m- or p-phenylene, the substituent being a group which is inert under the reaction conditions;
• a divalent five-membered or six-membered heterocyclic radical, containing one or two heteroatoms in the heterocyclic ring;
• or a single bond between two adjacent C-atoms;
• and
• R represents hydrogen, C.sub.1 to C.sub.4 alkyl or the group ##STR16## wherein R.sub.1 is defined as above;
• glyoxal, alkylglyoxals and dialkylacetals thereof being disclaimed from the formula I, said process consisting of
• (a) reacting an unsaturated compound of the formula ##STR17## wherein n is 0 or 1, Q.sub.1 represents hydrogen or the radicals ##STR18## in which R.sub.1 is C.sub.1 to C.sub.6 alkyl;
• R.sub.2 and R.sub.3 independently of one another represent hydrogen C.sub.1 to C.sub.4 alkyl or, if n is 1 and Q.sub.1 represents the radical ##STR19## R.sub.2 and R.sub.3 together can be a further single bond between two adjacent C atoms or alkylene having 2 to 4 carbon atoms;
• Y has the same meaning as X in formula I if n is 1, or, if n is o, Y together with R.sub.3 represents linear or branched alkylene having 2 to 20 C atoms, linear or branched alkylene having 2 to 20 C atoms in which one --CH.sub.2 -group of the alkylene chain is replaced by oxygen or the --SO.sub.2 -group, substituted linear or branched alkylene having 2 to 20 C atoms, this alkylene being substituted by one or more groups which are inert under the reaction conditions, aralkylene or alkylenearylene having 7-12 C atoms, substituted aralkylene or alkylenearylene having 7-12 C atoms, the substituent being a group which is inert under the reaction conditions;
• and
• R is defined as in formula I, is reacted in a lower aliphatic alcohol, at temperatures from -80.degree. C. to +20.degree. C. with the equivalent amount of ozone to yield a peroxide-containing solution of the ozonisation products of the compound of formula II
• (b) hydrogenating the peroxide-containing solution of the ozonisation products thus obtained at pH 2 to 7 and at temperatures from 15.degree. to 45.degree. C., said solution being fed continuously, while hydrogen is passed in under a pressure of 1 to 20 bar, into a suspension of a noble metal catalyst in the lower aliphatic alcohol used in stage (a), at such a rate that, over the entire course of hydrogenation, a peroxide content of not more than 0.1 mole/l is set up and maintained in the suspension, whereby the ozonisation products are cleaved reductively into the corresponding carbonyl compound, and then separating the carbonyl compound so formed.