Patent ID: 7102012

Claim:
A process for preparing N,N′-carbonyldiazoles of the general formula (I) where either X 1 , X 2 and X 3 independently of one another are each CR 1 or nitrogen, R 1 being hydrogen or straight-chain or branched C 1 –C 8 alkyl, and R 2 is hydrogen, or X 1 and X 3 are CR 1 , the radical R 1 in X 1 being hydrogen or straight-chain or branched C 1 –C 6 alkyl and the radical R 1 in X 3 forming, together with R 2 , a —CH═CH—CH═CH— bridge, and X 2 is CR 1 or nitrogen, R 1 being hydrogen or straight-chain or branched C 1 –C 8 alkyl, by reacting azoles of the general formula (II), in which the radicals and symbols used have the definitions indicated for the general formula (I), with phosgene, this process being characterized in that (i) a halogenated aliphatic solvent from the group consisting of chlorinated aliphatic hydrocarbons, brominated aliphatic hydrocarbons and mixedly chlorine-/bromine-substituted aliphatic hydrocarbons is used and (ii) in that the entire amount of azole to be reacted is introduced as an initial charge and then phosgene is metered in.