GB948271A - Improvements in or relating to the purification of cyanuric chloride - Google Patents

Abstract

<PICT:0948271/C1/1> Cyanuric chloride is purified by a process involving melting, distillation, and recovery of the product in solid form, wherein the melt is subjected to fractional distillation in a column, the fractionated product is removed by means of a carrier gas introduced into the column, whereby part of the cyanuric chloride vapour is condensed and returned into the top of the column and the carrier gas and cyanuric chloride vapour are conducted into a separator device, in which the carrier gas and cyanuric chloride vapour, with production of a mixed vortex, and very intimately mixed with an inert coolant, with cooling and deposition of the solid cyanuric chloride. The inert coolant may be a gas or an atomized volatile liquid, e.g. methane, ethane, propane, butane, difluorodichloromethane, methyl chloride, dimethyl ether, nitrogen, hydrogen, oxygen and noble gases, liquid CO2 being preferred. The carrier gas may be nitrogen, carbon dioxide or a noble gas. In an example cyanuric chloride 1 is heated to boiling in flask 2 and the resulting vapours are fractionated in column 3. A reflux is produced by condenser 4 which is cooled by a coolant, e.g. pressurized water flowing in at 5 and out at 6. This coolant preferably operates so that the gases leaving the condenser are at a temperature 10-50 DEG C. below the boiling point of cyanuric chloride. Carrier gas (nitrogen) is introduced just below the condenser at 7. This gas becomes saturated with cyanuric chloride, and the mixture 8 of the two passes through pipe 9 to a wide chamber 10 in which it is cooled by cold nitrogen introduced at 11. The cyanuric chloride precipitates on the bottom of the chamber and may be removed at 12, while the carrier gas leaves the chamber at 13 via a dust filter 14.