PROCESS FOR THE PREPARATION OF POLYSULPHURIZED OLEFIN COMPOSITIONS WITH A HIGH SULPHUR AND VERY LOW CHLORINE CONTENT

摘要

A description is given of polysulphurised olefin compositions with a high sulphur content and a very low chlorine content, which are obtained by a process in which: (1) sulphur mono- and/or dichloride is reacted with at least one C2-C12 aliphatic monoolefin to form an addition product or adduct; (2) hydrogen sulphide is reacted with an alkali metal hydroxide or ammonium hydroxide in solution in at least one substantially anhydrous C1-C4 aliphatic monoalcohol with optional addition of elemental sulphur; (3) the said adduct and, conjointly, at least one monohalogenated hydrocarbon compound are placed in contact with the alcoholic solution obtained at the end of stage (2); (4) the mixture resulting from stage (3) is heated, the monoalcohol is removed while water is being added; and (5) after separation and removal of the aqueous phase the organic phase, consisting at least predominantly of the required polysulphurised olefin composition, is recovered. These compositions, which have a sulphur content which may go up to approximately 65 mass% and a chlorine content which is generally lower than approximately 0.1 mass%, are employed especially as additives for improving the extreme-pressure properties of lubricants.