| 摘要 |
A process for preparing aromatic isocyanates comprises reacting one or more aromatic primary mono-, di- or polyamines with excess phosgene in presence of an inert organic solvent in a reaction zone with incomplete conversion to isocyanate, then contacting the reaction mass in a different zone with a mixture of phosgene and hydrogen chloride wherein the concentration of hydrogen chloride is greater than that which would be theoretically produced by complete phosgenation of the amine(s) and the amount of phosgene is at least sufficient to complete the conversion. Examples describe the production of 2, 4-tolylene diisocyanate, phenyl isocyanate, 3, 4-dichlorophenyl isocyanate and 1, 3-phenylene diisocyanate, but many other possible products of the process are listed in the Specification. U.S.A. Specification 2,680,127 is referred to. |
