Abstract: The invention relates to a process for the preparation of 1,1,1-trifluoro-2,2-dichloroethane by chlorinating 1,1,1-trifluoro-2-chloroethane, in which the chlorination is carried out under an elevated pressure. The pressure is preferably 10 to 400 bar, particularly 50 to 250 bar. If the reaction is initiated by heat, it is preferably carried out at 200.degree. to 300.degree. C. If it is initiated by a free-radical starter, the reaction is preferably carried out at 150.degree. to 250.degree. C.

Abstract: A process is disclosed for the separation of halogenated hydrocarbons from concentrated hydrochloric acid, which contains 10 to 37% by weight of hydrogen chloride. The hydrochloric acid is freed from the halogenated hydrocarbons in an extraction with paraffins having more than 7 carbon atoms, or with paraffin waxes having dropping points from 70.degree. to 160.degree. C. or with paraffin/paraffin wax mixtures, preferably in a continuous counterflow extraction or cross-flow extraction.

Abstract: A process is described for the removal of dimethyl ether in methyl chloride by catalytic cleavage by means of hydrogen chloride. Dimethyl ether is present as an impurity in crude methyl chloride produced by the catalytic esterification of methanol. The crude methyl chloride is cooled so that water and hydrogen chloride separate out. Gaseous hydrogen chloride is then added to the methyl chloride in an amount corresponding to at least twice the molar amount of dimethyl ether, and the gaseous mixture is passed over a methanol esterification contact catalyst at an elevated temperature.

Abstract: Methyl chloride is manufactured from methanol and hydrogen chloride in the gaseous phase in the presence of an aluminum oxide catalyst. The reaction is carried out in the presence of from 1 to 80 liters of oxygen per kg of methanol.

Abstract: Crude monochloromethane is freed from dimethylether by a washing with aqueous hydrochloric acid.