GB622642A - Dehydrochlorination of chlorinated hydrocarbons and distillation of resulting compounds - Google Patents

Abstract

<PICT:0622642/III/1> In the dehydrochlorination of chlorinated hydrocarbons by reaction with a hydroxide and distillation of the resulting products, the start of the reaction is effected in an apparatus resistant to corrosion and then the liquid and vapour products are introduced into a distillation column non-resistant to corrosion where the reaction is continued and the products rectified. The process is exemplified by the conversion of chlorethanes to chlorethylenes as given by the reactions <FORM:0622642/III/1> A distillation column A having cast iron plates is connected by conduits 4, 5 for vapours and liquids respectively to a preliminary reaction column B made of stone ware or enamelled metal into which the chlorethanes, milk of lime and water are injected continuously through lines 1, 2, 3. Chlorethylene and undecomposed chlorethanes pass through line 9 to a column C from which chlorethylenes are recovered through line 10, while chlorethanes are recovered through line 11 and passed to a secondary corrosion resistant reactor D to which further supplies of lime and water are admitted at 12, 13. In the Specification as open to inspection under Sect. 91, the described procedure is stated to be applicable to any chemical reaction in which the reactants used produce corrosion of the reactor and fractionating columns, e.g. the direct chlorination of benzene, the treatment of chlorides of benzene and organometallic compounds with caustic soda &c. This subject-matter does not appear in the Specification as accepted.ALSO:<PICT:0622642/IV (b)/1> In the dehydrochlorination of chlorinated hydrocarbons by reaction with a hydroxide and distillation of the resulting products, the start of the reaction is effected in an apparatus resistant to corrosion and then the liquid and vapour products are introduced into a distillation column non-resistant to corrosion where the reaction is continued and the products rectified. The process is exemplified by the conversion of chlorethanes to chlorethylenes as given by the reactions. <FORM:0622642/IV (b)/1> A distillation column A having cast-iron plates is connected by conduits 4, 5 for vapours and liquids respectively to a preliminary reaction column B made of stone-ware or enamelled metal into which the chlorethanes, milk of lime and water are injected continuously through lines 1, 2, 3. Chlorethylene and undecomposed chlorethanes pass through line 9 to a column C from which chlorethylenes are recovered through line 11 and passed to a secondary corrosion-resistant reactor D to which further supplies of lime and water are admitted at 12, 13. In the Specification as open to inspection under Sect. 91, the described procedure, using the apparatus specified, is stated to be applicable to any chemical reaction in which the reactant used produces corrosion of the reactor and fractionating columns, e.g. the direct chlorination of benzene and treatment of the product with caustic soda. This subject-matter does not appear in the Specification as accepted.