PROCESS AND REACTOR FOR PRODUCING PHOSGENE

The invention relates to a process for producing phosgene by gas phase reaction of carbon monoxide and chlorine in the presence of a catalyst in a reactor that comprises a plurality of contact tubes arranged parallel to one another, which contact tubes are filled with the catalyst and around which at least one fluid heat transfer medium flows, a feed stream of a mixture of a chlorine input stream and a carbon monoxide input stream being conducted into the contact tubes and reacted to form a phosgene-containing product gas mixture, characterised in that the product gas mixture is discharged from the contact tubes at an outlet end of the contact tubes. The method according to the invention is characterised in that the gas phase reaction is carried out in the reactor such that the position of the highest temperature in a contact tube (hot spot) moves along the longitudinal axis of the contact tube at a predetermined rate of migration, the hot spot having a rate of migration in the longitudinal direction of the contact tubes which is in the range of 1 to 50 mm per day. The invention also relates to a reactor for carrying out the process.