Production of isocyanates from substituted ureas

A method for the production of isocyanates from di- and tri-substituted ureas having the formula R(NHCONR'R'").sub.x wherein R is a substituted or unsubstituted mono-, di- or trivalent organic radical selected from the group consisting of a saturated or mono-olefinic unsaturated straight or branched chain aliphatic or cycloaliphatic radical containing not more than 32 carbon atoms, an alkoxyalkyl radical having not more than 32 carbon atoms, an aryl radical, and an alkaryl radical containing 1 to 5 rings;

• R' and R" are the same or different and are the same radicals enumerated for R;
• R' and R" but not both may be hydrogen;
• and x is an integer of from 1 to 3, which comprises thermally decomposing said urea at a temperature in the range of from 230.degree.C. to 350.degree.C. while said urea is dissolved in an inert reaction medium solvent to produce the isocyanate and corresponding amine, said reaction medium solvent being higher boiling than the isocyanate product and selected from the group consisting of high molecular weight aliphatic, cycloaliphatic, and aromatic hydrocarbons or substituted hydrocarbons and in the presence of an inert carrier agent consisting of an inert carrier gas or inert carrier solvent or mixtures thereof, said inert carrier gas being selected from the group consisting of nitrogen, helium, argon, methane, ethane and propane, said inert carrier solvent being lower boiling than the isocyanate product and selected from the group consisting of lower boiling aliphatic, cycloaliphatic or aromatic hydrocarbons, substituted hydrocarbons, oxygenated compounds selected from ethers oxygenated compounds selected from ethers or ketones and the sulfur analogues of said oxygenated compounds and separately recovering the isocyanate and amine.