A process for the preparation of a polyunsaturated thiol comprising: (1) reacting a polyunsaturated alcohol in the presence of a compound of formula R.sub.2—SO.sub.2Hal wherein R.sub.2 is a C.sub.1-20 hydrocarbyl group, such an C.sub.1-10 alkyl group, to form a polyunsaturated sulphonyl ester; (2) converting the polyunsaturated sulphonyl ester to a polyunsaturated thioester by reacting with an anion of formula .sup.−SC(═O)R.sub.4 wherein R.sub.4 is a C.sub.1-20 hydrocarbyl group; (3) converting the polyunsaturated thioester to form a polyunsaturated thiol optionally in the presence of an antioxidant, e.g. using a metal carbonate. (4) reacting said polyunsaturated thiol with a compound (LG)R.sup.3COX wherein X is an electron withdrawing group and R.sup.3 is an alkylene group carrying a leaving group (LG), such as LG-CH.sub.2— forming

##STR00001## where X is an electron withdrawing group and LG is a leaving group; optionally in the presence of an antioxidant, so as to form a polyunsaturated ketone compound.

A process for the preparation of a polyunsaturated thiol comprising: (1) reacting a polyunsaturated alcohol in the presence of a compound of formula R.sub.2—SO.sub.2Hal wherein R.sub.2 is a C.sub.1-20 hydrocarbyl group, such an C.sub.1-10 alkyl group, to form a polyunsaturated sulphonyl ester; (2) converting the polyunsaturated sulphonyl ester to a polyunsaturated thioester by reacting with an anion of formula .sup.−SC(═O)R.sub.4 wherein R.sub.4 is a C.sub.1-20 hydrocarbyl group; (3) converting the polyunsaturated thioester to form a polyunsaturated thiol optionally in the presence of an antioxidant, e.g. using a metal carbonate. (4) reacting said polyunsaturated thiol with a compound (LG)R.sup.3COX wherein X is an electron withdrawing group and R.sup.3 is an alkylene group carrying a leaving group (LG), such as LG-CH.sub.2— forming

##STR00001## where X is an electron withdrawing group and LG is a leaving group; optionally in the presence of an antioxidant, so as to form a polyunsaturated ketone compound.

A process for the preparation of a polyunsaturated thiol comprising: (1) reacting a polyunsaturated alcohol in the presence of a compound of formula R.sub.2—SO.sub.2Hal wherein R.sub.2 is a C.sub.1-20 hydrocarbyl group, such an C.sub.1-10 alkyl group, to form a polyunsaturated sulphonyl ester; (2) converting the polyunsaturated sulphonyl ester to a polyunsaturated thioester by reacting with an anion of formula .sup.−SC(═O)R.sub.4 wherein R.sub.4 is a C.sub.1-20 hydrocarbyl group; (3) converting the polyunsaturated thioester to form a polyunsaturated thiol optionally in the presence of an antioxidant, e.g. using a metal carbonate. (4) reacting said polyunsaturated thiol with a compound (LG)R.sup.3COX wherein X is an electron withdrawing group and R.sup.3 is an alkylene group carrying a leaving group (LG), such as LG-CH.sub.2— forming

##STR00001## where X is an electron withdrawing group and LG is a leaving group; optionally in the presence of an antioxidant, so as to form a polyunsaturated ketone compound.

The invention relates to a process for the co-production of methyl mercaptan and of dimethyl disulfide, comprising the following successive steps: a) reaction of at least one carbon oxide in the presence of hydrogen sulfide (H.sub.2S) and hydrogen to form a stream (M) comprising methyl mercaptan, water, and possibly unreacted hydrogen sulfide, b) purification of the stream (M) to obtain a stream (N) enriched in methyl mercaptan and a stream containing the uncondensable compounds (M.sub.uncond), c) optional recycling of the stream of uncondensable compounds (M.sub.uncond) obtained from step b) into step a), d) recovery of a first portion of the stream (N) including methyl mercaptan purified in step b), e) oxidation with sulfur of the second portion of the stream (N) of methyl mercaptan, to form a stream (O) comprising dimethyl disulfide, hydrogen sulfide, and possibly unreacted methyl mercaptan, f) purification of the stream (O) to separate, on the one hand, the enriched dimethyl disulfide and, on the other hand, the hydrogen sulfide and possibly the methyl mercaptan that has not reacted in step e), g) recycling of the hydrogen sulfide and possibly of the methyl mercaptan isolated in step f) into the stream (M) obtained from step a), h) recovery of the dimethyl disulfide isolated in step f).

The invention relates to a process for the co-production of methyl mercaptan and of dimethyl disulfide, comprising the following successive steps: a) reaction of at least one carbon oxide in the presence of hydrogen sulfide (H.sub.2S) and hydrogen to form a stream (M) comprising methyl mercaptan, water, and possibly unreacted hydrogen sulfide, b) purification of the stream (M) to obtain a stream (N) enriched in methyl mercaptan and a stream containing the uncondensable compounds (M.sub.uncond), c) optional recycling of the stream of uncondensable compounds (M.sub.uncond) obtained from step b) into step a), d) recovery of a first portion of the stream (N) including methyl mercaptan purified in step b), e) oxidation with sulfur of the second portion of the stream (N) of methyl mercaptan, to form a stream (O) comprising dimethyl disulfide, hydrogen sulfide, and possibly unreacted methyl mercaptan, f) purification of the stream (O) to separate, on the one hand, the enriched dimethyl disulfide and, on the other hand, the hydrogen sulfide and possibly the methyl mercaptan that has not reacted in step e), g) recycling of the hydrogen sulfide and possibly of the methyl mercaptan isolated in step f) into the stream (M) obtained from step a), h) recovery of the dimethyl disulfide isolated in step f).

The invention relates to a process for preparing methyl mercaptan from a mixture of carbon oxide, hydrogen sulfide and hydrogen, in the presence of a catalyst based on molybdenum and potassium supported on zirconia, said catalyst not comprising any promoter.

The invention relates to a process for preparing methyl mercaptan from a mixture of carbon oxide, hydrogen sulfide and hydrogen, in the presence of a catalyst based on molybdenum and potassium supported on zirconia, said catalyst not comprising any promoter.

The invention relates to a process for preparing methyl mercaptan from a mixture of carbon oxide, hydrogen sulfide and hydrogen, in the presence of a catalyst based on molybdenum and potassium supported on zirconia, said catalyst not comprising any promoter.

The present invention relates to a new, enhanced process for the manufacture of Cysteamine Bitartrate (I) and of its key intermediate thiazolidine (II).

Furthermore, it relates to a new processes for the manufacture of crystalline anhydrous Cysteamine Bitartrate (polymorph L2) and monohydrate Cysteamine Bitartrate (polymorph L1). The crystalline anhydrous Cysteamine Bitartrate (polymorph L2) so obtained is characterized by particularly fine particle size and good appearance.

The present invention discloses high pressure flow reactor vessels and associated systems. Also disclosed are processes for producing thiol compounds and sulfide compounds utilizing these flow reactor vessels.