Process and apparatus for the preparation of chlorinated chloroformates

The invention relates to a process for the preparation of monochloromethyl chloroformate and trichloromethyl chloroformate by photochlorination of methyl chloroformate. According to the process, in a first step at 60-70@C chlorination is carried out until the ester is reacted to at most 50%, then the reaction mixture is separated by rectification and the unreacted methyl chloroformate is fed back into the reactor. The molar ratio in the reactor between ester and chlorine gas is between 3:1 and 2:1. The monochloromethyl chloroformate obtained during the rectification as a bottom product is either drawn off as a final product or completely or partially led into a further photochlorination reactor in which the molar ratio between monochloromethyl chloroformate and chlorine gas is 1:2-1:3 and the temperature 90-110@C. The reaction product is separated by rectification and the head product is fed back into the second reactor, while the trichloromethyl chloroformate formed as the bottom product is led off as a final product. The invention further relates to a suitable apparatus for carrying out the process continuously.