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Abstract

Process for the preparation of symmetrical diacylhydrazines having general formula (I): R.sub.1 --CO--NH--NH--CO--R.sub.1 wherein R.sub.1 represents a linear or branched C.sub.1 -C.sub.18 alkyl group; a linear or branched C.sub.2 -C.sub.8 alkoxyalkyl group; a C.sub.2 -C.sub.8 cyanoalkyl group; a C.sub.5 -C.sub.8 cycloalkyl group, said cycloalkyl group optionally containing a heteroatom selected from oxygen, nitrogen and sulfur; a C.sub.6 -C.sub.18 aryl group; a C.sub.7 C.sub.20 arylalkyl group or alkylaryl group, said arylalkyl or alkylaryl groups optionally substituted with one or more hydroxyl groups, or with one or more linear or branched C.sub.1-C.sub.8 alkoxyl groups; comprising: (a) reacting an ester of a carboxylic acid having general formula (II): R.sub.1 --CO--OR.sub.2 wherein R.sub.1 has the same meanings defined above and R.sub.2 represents a linear or branched C.sub.1 -C.sub.18 alkyl group, with hydrazine, in its pure or hydrated state, obtaining a monoacylhydrazine having general formula (III): R.sub.1 --CO--NH--NH.sub.2 ; (b) reacting the monoacylhydrazine having general formula (III) obtained in step (a), with a .beta.-ketoester having general formula (IV): R.sub.3 --CO--CH.sub.2 --COOR.sub.4 wherein R.sub.3 represents a linear or branched C.sub.1 -C.sub.18 alkyl group, or a C.sub.6 -C.sub.18 aryl group and R.sub.4 represents a linear or branched C.sub.1 -C.sub.18 alkyl group, obtaining the desired symmetrical diacylhydrazine having general formula (I).

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