Method for the production of N,N-carbonyldiazoles

A process for preparing a N,N′-carbonyldiazole of formula (I)

• where either
• X1, X2 and X3 independently of one another are each CR1 or nitrogen, R1 being hydrogen or straight-chain or branched C1-C6 alkyl, and
• R2 is hydrogen,
• or
• X1 and X3 are CR1, the radical R1 in X1 being hydrogen or straight-chain or branched C1-C6 alkyl and the radical R1 in X3 forming, together with R2, a —CH═CH—CH═CH— bridge, and
• X2 is CR1 or nitrogen, R1 being hydrogen or straight-chain or branched C1-C6 alkyl,
• by reacting azoles of the general formula (II),
• wherein X1, X2, X3, and R2 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.