Process for the chlornation of hydrocarbons

A process for the chlorination of aliphatic hydrocarbons containing 1 to 4 carbon atoms to produce a chlorinated hydrocarbon using hydrogen chloride as the source of chlorine and a fluorocarbon as a chlorine carrier, said process consisting essentially of steps operated in tandem:

• first, subjecting an unsaturated aliphatic fluorocarbon, selected from the group consisting of perchlorofluorocarbons and perfluorocarbons, to oxychlorination with hydrogen chloride and oxygen in the presence of a catalyst to give reaction products consisting essentially of water and the corresponding saturated perchlorofluorocarbon with reactivity lower than hexachloroethane;
• second, isolating said saturated perchlorofluorocarbon from the reaction products of the first step and reacting it with an aliphatic hydrocarbon containing 1 to 4 carbon atoms in the vapor phase to produce the chlorinated hydrocarbon, hydrogen chloride and the unsaturated aliphatic fluorocarbon;
• third, separating hydrogen chloride and unsaturated aliphatic fluorocarbon from the reaction products of the second step to produce a crude chlorinated hydrocarbon product, and recycling the hydrogen chloride and the unsaturated aliphatic fluorocarbon to the first step;
• and
• fourth, subjecting the crude chlorinated hydrocarbon product to addition chlorination in order to convert traces of unsaturated aliphatic fluorocarbon to the corresponding saturated perchlorofluorocarbon, separating the saturated perchlorofluorocarbon from the chlorinated hydrocarbon, and recycling the saturated perchlorofluorocarbon to the second step, thereby providing a continuous process without the production or consumption of fluorocarbon, whereby the process conforms to the provisions of the Montreal Protocol.