Patent ID: 6833476
Filing Date: 2004-12-21
Classification: C07B,C07C

Abstract:
A process for the treatment of a mixture comprising a derivative of the formula: wherein:Z represents a single bond or a chalcogen atom, wherein X1, X2 and X3 identical or different represent halogens, with the condition that at least two halogens are other than fluorine and are exchageable by the action of liquid hydrofluoric acid; R1 and R2 are halogens, alkyls, aryls or nitriles and X3 is an electron-withdrawing group which does not interfere with the reaction; and a carbamoyl fluoride, wherein said derivative and said carbamoyl fluoride are subjected to a reaction temperature at least equal to 70Â° C. in the presence of hydrofluoric acid, and, wherein, at said temperature, the ratio of, on the one hand, the sum of the hydrofluoric acid (HF) and of the carbamoyl fluoride to, on the other hand, the sum of the exchangeable halogens, of the isocyanate functional groups and of the carbamoyl fluoride [(HF+carbamoyl fluoride)/(exchangeable halogen+isocyanate+carbamoyl fluoride)] is maintained at a value at most equal to 1.2.