Societe Nationale Elf Aquitaine (production)

Henri Gongora

Yves Darche

Jacques Tournier-Lasserve

Jose-Luis Orozco

The invention relates to recovery of an aprotic polar solvent from a saline aqueous solution of this solvent, by a process which consists in desalting the said solution by electrodialysis then in distilling the desalted solution. To avoid precipitation of metal hydroxides during the electrodialysis, the brine is kept at an acidic pH.

Recovery of aprotic polar solvents from their saline aqueous solutions

The invention relates to the production of dialkyl disulphides of the R-SS-R type where R represents an alkyl radical having from 1 to 3 carbon atoms, by oxidation of the corresponding alkyl mercaptan R--SH by sulphur in the presence of a catalyst. A combination of an alkyl mercantap R'--SH with an alkylene oxide and an alkaline base is used as catalyst, R' representing an alkyl radical having from 6 to 18 carbon atoms. This catalyst enables a lower dialkyl disulphide of excellent quality to be obtained (absence of amine and coloration).

Process for the production of lower dialkyl disulphides

Process for the production of organic polysulphides of the type R--S.sub.n --R, where R is a hydrocarbon group and n a number from 2 to 8, by heating one or more mercaptans with sulphur, in the presence of a catalyst; the catalyst consists of the combination of a mercaptan with an alkene oxide and an alkaline base.

Process for the production of organic polysulphides and catalyst system

Continuous manufacture of an alkane sulphonyl chloride by the action of chlorine on the dialkyl disulphide corresponding to the alkane, in the presence of water or an aqueous hydrochloric acid solution. Firstly, a fine emulsion of the dialkyl disulphide is prepared with water or with an aqueous hydrochloric acid solution, after which the emulsion is treated with chlorine under constant agitation. Preferably, separation of the alkane sulphonyl chloride formed is effected in two different zones, the second of which operates under reduced pressure.

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Billere, France

Henri Gongora