Process for aromatic isocyanate manufacture

Claim 1

IN A PROCESS FOR THE PREPARATION OF AN AROMATIC ISOCYANATE, THE STEPS COMPRISING FEEDING A PRIMARY MONOAMINE SELECTED FROM THE GROUP CONSISTING OF ANILINE ALKYL SUBSTITUTED ANILINES AND HALOGEN SUBSTITUTED ANILINES INTO A REACTION ZONE CONTAINING A LIQUID RECTING MASS COMPRISING AN INERT ORGANIC LIQUID DILUENT AND PHOSGENE IN EXCESS OF THE AMOUNT REQUIRED TO REACT WITH SAID MONOAMINE TO FORM THE CORRESPONDING ISOCYANATE; MAINTAINING THROUGHTOUT THE PEROID OF FEEDING SAID MONOAMINE A PHOSGENE REFLUX AND A TEMPERATURE OF THE LIQUID REACTING MASS BELOW THE DECOMPOSITION TEMPERATURE OF THE AROMATIC CARBAMYL CHLORIDE CORRESPONDING TO THE MONOAMINE; AND SUBSEQUENTLY HEATING THE REACTING MASS AT A TEMPERATURE ABOVE THE DEOCMPOSITION TEMPERATURE OF SAID CARBAMYL CHLORIDE AND NOT IN EXCESS OF ABOUT 150* C. WHILE MAINTAINING A REFLUX OF PHOSGENE WHEREBY SAID AROMATIC ISOCYANATE FORMS.