GB569291A - Improvements in or relating to the manufacture of vinyl chloride - Google Patents

Abstract

Vinyl chloride is manufactured by treating ethylene dichloride with an alkali in the presence of water and a compound of the general formula CH2(OH)CH2OR, where R is an alkyl group containing not more than four carbon atoms or an alkoxyethyl group in which the alkoxy radical contains not more than four carbon atoms. It is preferable that the water and diluent should be miscible and that the reaction mixture be agitated by mechanical stirring, pumping through a coil or heating to a temperature near the boiling point of ethylene dichloride. The amount of alkali should preferably be in at least a slight excess of the theoretical amount required for complete dehydrochlorination. In the examples: (1) a solution of sodium hydroxide in a mixture of water and diethylene glycol monoethyl ether is passed down a column and heated while ethylene dichloride is passed in at the bottom. Vinyl chloride is taken off at the top of the column, any unconverted ethylene dichloride also removed is recycled. The spent solution passing out of the bottom of the column is distilled to recover ethylene dichloride and diethylene glycol monoethyl ether; (2) a solution of sodium hydroxide in a mixture of water and diethylene glycol monoethyl ether is circulated through a heated coil reactor and ethylene dichloride and aqueous caustic soda added slowly. The vapours evolved are passed through a condenser and the condensate layer containing diethylene glycol monoethyl ether returned to the system as solvent for fresh caustic soda. The circulating liquid is filtered through a bed of granite chips after removing the vapours and returned to the coil.