GB789314A - Manufacture of methane chlorination products - Google Patents

Abstract

The invention comprises a method for preparing methane chlorination products in which a mixture of chlorine and methane, methyl chloride, methylene chloride, or chloroform or a mixture thereof, with or without an inert gas is kept at an elevated temperature below the decomposition temperature of the products, and mixed with already reacted gas circulating in the reaction chamber in a proportion by volume of less than 1 : 3, e.g. between about 1 : 4 and 1 : 5, and reaction takes place without substantial supply or withdrawal of heat to or from the vessel, the fresh gas having such a temperature that on admixture, the resulting temperature is between the lowest starting temperature of the reaction and the said decomposition temperature. The fresh gas preferably enters the reaction chamber at a temperature between about -20 DEG and +320 DEG C. Part of the reacted product may be passed to a second reaction zone preferably containing a heat-retaining filler. The products are withdrawn at the same rate as fresh material is introduced. Thus the reaction is adiabatic, requiring an insulated reaction chamber. The method may be carried out by preheating the mixture of methane and its chlorinated derivatives, mixing chlorine and circulating in the reaction chamber into which reacted gas is mixed with the fresh mixture which has been heated to above the starting temperature of about 320 DEG C., the heat of reaction raising the temperature further. After passing through a packed auxiliary reaction chamber, the product contains little residual chlorine. A drawing of suitable apparatus with dimensions described in the Specification is given. In examples, the percentage compositions of various starting materials and preheating temperatures are given, with the circulation ratios to give products containing varying proportions of methyl chloride, methylene chloride, chloroform and carbon tetrachloride from mainly the first two, or mainly methylene chloride and chloroform, to almost wholly carbon tetrachloride.