The present invention relates to a process for drying methyl mercaptan, notably by azeotropic distillation, comprising the following steps: 1) a stream (A) comprising methyl mercaptan and water is introduced into a distillation column (1); 2) said stream (A) is distilled in said column (1); 3) the distillate (B) is recovered in gaseous form, preferably at the top of the column; 4) the distillate (B) is condensed, preferably in a condenser (2), so as to obtain a condensate (C) in liquid form; 5) said condensate (C) is separated, preferably using a decanter (3), so as to obtain two separate liquid phases: an aqueous phase (D); and an organic phase (E) comprising methyl mercaptan; 6) all or part of the organic phase (E) is optionally introduced into the distillation column (1) as reflux; and 7) a stream (F) comprising the dried methyl mercaptan is recovered, preferably at the bottom of column (1).

The present invention also relates to processes for producing methyl mercaptan comprising said drying process.

The present invention discloses processes for producing methyl ethyl sulfide by contacting dimethyl sulfide and diethyl sulfide in the presence of a suitable catalyst. Methyl ethyl sulfide can be used as an odorant in natural gas. Integrated mercaptan and sulfide manufacturing systems and integrated methods for making mercaptans and sulfides also are disclosed.

The present invention discloses processes for producing methyl ethyl sulfide by contacting dimethyl sulfide and diethyl sulfide in the presence of a suitable catalyst. Methyl ethyl sulfide can be used as an odorant in natural gas. Integrated mercaptan and sulfide manufacturing systems and integrated methods for making mercaptans and sulfides also are disclosed.

The present invention relates to a process for preparing at least one mercaptan, comprising the following steps: A) H.sub.2S and at least one alcohol are introduced into a first reactor; B) the H.sub.2S and said at least one alcohol are reacted to obtain an outlet stream comprising at least one mercaptan, at least one dialkyl sulfide and at least one dialkyl disulfide (DADS) and possibly unreacted H.sub.2S; C) said outlet stream obtained from step B) is separated into: a stream F1 comprising the mercaptan(s), a stream F2 comprising the dialkyl sulfide(s) and the DADS(s), and optionally a stream F3 comprising H.sub.2S; D) a purification step is performed on stream F2 in order to separate: a stream F2 comprising the dialkyl sulfide(s); and the DADS(s); E) stream F2 is introduced with H.sub.2S into a second reactor; F) a sulfhydrolysis reaction of the dialkyl sulfide(s) with H.sub.2S is performed to obtain an outlet stream F4 comprising said mercaptan(s), and possibly unreacted H.sub.2S; G) optionally, stream F4 obtained from step F) is recycled into step A).

The present invention relates to a process for preparing at least one mercaptan, comprising the following steps: A) H.sub.2S and at least one alcohol are introduced into a first reactor; B) the H.sub.2S and said at least one alcohol are reacted to obtain an outlet stream comprising at least one mercaptan, at least one dialkyl sulfide and at least one dialkyl disulfide (DADS) and possibly unreacted H.sub.2S; C) said outlet stream obtained from step B) is separated into: a stream F1 comprising the mercaptan(s), a stream F2 comprising the dialkyl sulfide(s) and the DADS(s), and optionally a stream F3 comprising H.sub.2S; D) a purification step is performed on stream F2 in order to separate: a stream F2 comprising the dialkyl sulfide(s); and the DADS(s); E) stream F2 is introduced with H.sub.2S into a second reactor; F) a sulfhydrolysis reaction of the dialkyl sulfide(s) with H.sub.2S is performed to obtain an outlet stream F4 comprising said mercaptan(s), and possibly unreacted H.sub.2S; G) optionally, stream F4 obtained from step F) is recycled into step A).

Disclosed is to prevent generation of byproducts or a deterioration in the physical properties of a polythiol composition that may be caused by active oxygen during storage thereof by way of controlling the content of active oxygen in the polythiol composition after the synthesis of the polythiol. As a result, it is possible to enhance the long-term storage stability of a polythiol composition after it has been synthesized until it is used in the polymerization reaction.

A method for preparing a compound of formula RSH where R represents an alkyl group, by gas-phase catalytic reaction of hydrogen sulfide with a compound of formula ROH, in the presence of a solid catalyst, according to which method the reaction is performed in the presence of a catalyst which includes one or several pure or mixed rare-earth oxide(s), one or several pure or mixed rare-earth sulfide(s), or one or several pure or mixed rare-earth oxysulfide(s). When the rare earth is lanthanum, the catalyst is a mixed oxide of lanthanum and of at least one metal selected from rare earths or not and when the rare earth is cerium, the catalyst is supported on an alumina.

A method for preparing a compound of formula RSH where R represents an alkyl group, by gas-phase catalytic reaction of hydrogen sulfide with a compound of formula ROH, in the presence of a solid catalyst, according to which method the reaction is performed in the presence of a catalyst which includes one or several pure or mixed rare-earth oxide(s), one or several pure or mixed rare-earth sulfide(s), or one or several pure or mixed rare-earth oxysulfide(s). When the rare earth is lanthanum, the catalyst is a mixed oxide of lanthanum and of at least one metal selected from rare earths or not and when the rare earth is cerium, the catalyst is supported on an alumina.

A method for preparing a compound of formula RSH where R represents an alkyl group, by gas-phase catalytic reaction of hydrogen sulfide with a compound of formula ROH, in the presence of a solid catalyst, according to which method the reaction is performed in the presence of a catalyst which includes one or several pure or mixed rare-earth oxide(s), one or several pure or mixed rare-earth sulfide(s), or one or several pure or mixed rare-earth oxysulfide(s). When the rare earth is lanthanum, the catalyst is a mixed oxide of lanthanum and of at least one metal selected from rare earths or not and when the rare earth is cerium, the catalyst is supported on an alumina.

The present invention relates to a novel polyol or polythiol having three or more functional groups, a preparation method there for, and an optical body manufactured therefrom. Especially, the present invention relates to a poly(thio)urethane-based resin and an optical body, such as lenses, manufactured using the resin, wherein the poly(thio)urethane-based resin is prepared by obtaining a novel polyol and then combining a polythiol, which is prepared from the obtained polyol, with a polyiso(thio)cyanate.