Patent ID: 7482481

Claim:
A process for preparing isocyanates comprising reacting corresponding primary amines of formula (II): R 4 —NH 2 (II) wherein R 4 is at least one of an unbranched or a branched, acyclic or cyclic, un-substituted or substituted alkyl radical, which has from 1 to 30 aliphatic carbon atoms and in which one or more of CH 2 groups are replaceable by: at least one of heteroatom —O— or —S—; or, at least one heteroatom group —CO—, —NR—, or —SiR 2 —, and in which one or more of the hydrogen atoms are replaceable by at least one of an aryl group or a NH 2 group with phosgene in an inert solvent, wherein from 0.01 to 50 mol % of a phosphine oxide, based on the total amount of primary amine and isocyanate formed in a reaction solution, is used, and wherein the phosphine oxide is a tri-C 6 -C 8 -alkylphosphine oxide or a mixture thereof.