Polysulphurized olefin compositions, their preparation and their use as additives for lubricants

摘要

Polysulphurized olefin compositions used as additives for gear oils, cutting oils, and as sulphurizing agents in organic media are obtained by a process comprising: a stage (1) in which at least one compound chosen from among sulphur dichloride and monochloride is reacted with at least one aliphatic monpolefin with 2 to 12 carbon atoms, thus forming an adduct; a stage (2) in which sulphurized hydrogen and at least one mercaptan is reacted with ammonium or alkali metal hydroxide dissolved in at least one aliphatic monoalcohol with 1 to 4 carbon atoms, which is substantially anhydrous, so as to give an alcoholic solution; a stage (3) in which contacting takes place between the adduct obtained in stage (1) and the alcoholic solution obtained in stage (2); a stage (4), in which the resulting mixture is heated and then the aliphatic monoalcohol is eliminated by distillation, while adding water in a quantity adequate for maintaining in solution the reagents and the mineral products formed during the reaction; and a stage (5) in which elimination takes place of the aqueous phase and recovery takes place of the organic phase mainly constituted by the polysulphurized olefin composition.