Abstract: For the presulphurization of catalysts based on metal oxides, intended especially for the hydrotreating of hydrocarbon feedstocks, at least one tertiary mercaptan (for example tert-dodecyl mercaptan) is employed as sulphurizing agent. This tertiary mercaptan can be employed alone or combined with another sulphur-donor compound. The presulphurization according to the invention may be carried out in situ or ex situ.

Abstract: The process includes the reaction of a chloro-formamidinium chloride with a polystyrene-divinylbenzene resin functionalized with primary amine groups. The resins which can be obtained according to this process may in particular have a spacer arm of general formula (IV): ##STR1## with X representing oxygen or sulphur and m being equal to 1 or 2. This spacer arm bears at its end, on the right, a primary amine group or a guanidine group.

Abstract: This process for the synthesis of 3-mercaptopropionic acid esters by addition reaction of H.sub.2 S to the corresponding acrylic acid ester is carried out in the presence of a solid-support functionalized with basic guanidine functional groups, on condition that these groups are free of hydrogen that is directly attached to a nitrogen atom.

Abstract: This process for the synthesis of 3-mercaptopropionic acid by an addition reaction of H.sub.2 S with acrylic acid is carried out in the presence of a solid support having basic guanidine functional groups, provided that the latter do not contain hydrogen bonded directly to a nitrogen atom.

Abstract: The process includes the reaction of a chloroformamidinium chloride with a polystyrene-divinylbenzene resin functionalized with primary amine groups. The resins which can be obtained according to this process may in particular have a spacer arm of general formula (IV):--CH.sub.2 --(--X--CH.sub.2 --CH.sub.2 --).sub.m -- (IV)with X representing oxygen or sulphur and m being equal to 1 or 2. This spacer arm bears at its end, on the right, a primary amine group or a guanidine group.

Abstract: The preparation of organic disulphides and polysulphides by reaction of sulphur with a mercaptan or with a polysulphide of lower sulphur order in order to convert it into polysulphide of higher order, or alternatively by reaction of a mercaptan with an organic polysulphide of high sulphur order in order to convert it into polysulphide of lower sulphur order, in the presence of a catalyst in the form of a resin with a basic function, characterized in that the resin is based on polystyrene-divinylbenzene (PS-DVB) functionalized with primary amino groups and having the general formula (I): ##STR1## being the PS-DVB resin support, L being a linear organic radical which is as long as or longer than the methylene radical (--CH.sub.2 --).

Abstract: In a process for the preparation of organic disulphides and polysulphides by reaction of sulphur with a mercaptan or with a polysulphide of lower sulphur order in order to convert it into polysulphide of higher order, or alternatively by reaction of a mercaptan with an organic polysulphide of a high sulphur order in order to convert it into a polysulphide of lower sulphur order, in the presence of a catalyst in the form of a resin with a basic function, the resin is based on a polystyrene-divinyl benzene support functionalized with guanidine or amidine groups, and the reaction is preferably conducted in the presence of methanol.

Abstract: The process includes the reaction of a chloroformamidinium chloride with a polystyrene-divinylbenzene resin functionalized with primary amine groups. The resins which can be obtained according to this process may in particular have a spacer arm of general formula (IV):--CH.sub.2 (--X--CH.sub.2 --CH.sub.2 --(.sub.m -- (IV)with X representing oxygen or sulphur and m being equal to 1 or 2. This spacer arm bears at its end, on the right, a primary amine group or a guanidine group.

Abstract: The invention relates to the manufacture of methyl mercaptan by catalytic hydrogenation of dimethyl disulphide on a catalyst based on sulphide(s) of at least one transition metal.The selectivity with respect to methyl mercaptan is considerably improved by working in the presence of water and/or hydrogen sulphide.

Abstract: The invention relates to the manufacture of dimethyl disulphide from methyl mercaptan and sulphur. The process according to the invention is characterized in that it comprises:(a) a first reaction zone in which the methyl mercaptan and sulphur are introduced and reacted in the presence of a catalyst,(b) a degassing zone in which the products originating from the first reaction zone are treated to remove at least partially the dissolved hydrogen sulphide, and(c) a second reaction zone in which the products originating from the degassing zone are brought into contact with a catalyst.

Abstract: The invention relates to the preparation of organic disulphides and polysulphides by the action of sulphur on a mercaptan or on a polysulphide which is lower in sulphur, in the presence of a basic catalyst.In the process according to the invention, an anion exchange resin is used as catalyst.

Abstract: This invention relates to improvement to a process for the preparation of mercaptoalcohols containing, more particularly, up to 24 carbon atoms and, preferably, more than 3 carbon atoms, by reaction of the corresponding vicinal epoxides with hydrogen sulphide.The process comprises incorporating into the reaction mixture a catalyst comprising a guanidine and/or of organic derivatives of a guanidine, and/or of guanidine salts, in particular of guanidine salts. The catalyst can be either in liquid and/or solid form, depending on the nature of the catalyst and its solubility in the reaction mixture, or fixed and/or impregnated into various solid materials. The materials can be organic in nature such as neutral and/or basic polymer resins, polymers or copolymers, or can be inorganic in nature such as alumninas, silicas, aluminosilicates, zeolites, active charcoals, oxides and/or metal salts.

Abstract: The invention relates to the synthesis of dithiols and more particularly that of .alpha.,.omega.-dithiols having 5 to 20 carbon atoms.The process according to the invention comprises reacting a di-(tertiary-alkylthio)alkane with hydrogen sulphide in the presence of a solid acid catalyst. The alkane dithiol is obtained selectively and a tertiary-alkyl mercaptan is obtained as by-product. It is possible to reuse the latter in a cyclical process to produce the original di-(tertiary-alkylthio)alkane.

Abstract: The invention relates to the synthesis of tertiary mercaptans from isobutylene homopolymers and from hydrogen sulphide by means of heterogeneous catalysis.In the processs according to the invention, the reaction is carried out at a temperature below 45.degree. C., preferably between 0.degree. and 35.degree. C., in the presence of a catalyst consisting of a dry cation exchange resin.Excellent yields of tertiary mercaptan are thus obtained, while the formation of undesirable byproducts is virtually avoided.

Abstract: Process for the synthesis of a mercaptan from an olefin, by the action of hydrogen sulphide thereon, in the presence of a catalyst comprising a cation exchange resin, characterized in that this resin is dry and that the reaction is effected at a temperature ranging between 45.degree. and 75.degree. C.

Abstract: Improved process for the production of 2-mercapto ethanol-1 through the action of gaseous hydrogen sulphide on liquid ethylene oxide, under a pressure comprised between 5 and 15 bars and a temperature maintained at between 30.degree. and 70.degree. C., in the presence of a catalyst and/or diluent.The obtention of mercapto ethanol with excellent yields.

Abstract: Improvement in the photoinitiated synthesis of mercaptans, in which an ethylenic compound is treated with hydrogen sulphide, preferably under pressure, in the presence of ultraviolet radiation and a photoinitiator involves the use of a xanthenic compound, possibly substituted, as the initiator. Preferably, the xanthenic compounds is employed in conjunction with an organic compound of an element of Group V A of the Periodic Classification of the Elements.