Patent ID: 7888515

Claim:
A process for preparing a N,N′-carbonyldiazole of 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 6 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 6 alkyl, by reacting azoles of the general formula (II), wherein X 1 , X 2 , X 3 , and R 2 are as defined for formula (I) with phosgene in a polar solvent, which is characterized in that (i) the polar solvent being selected from the group consisting of ethers, ketones and chlorinated aliphatic solvents, wherein the polar solvent possesses a maximum water content of 0.5% by weight, and (ii) the azole of the general formula (II) and the phosgene are metered into the solvent in such a way that in the time within which 1 mol of azole of the general formula (II) is metered in at the same time 0.17 to 0.34 mol of phosgene is metered in.