The invention relates to a process for purifying 4,4′-dichlorodiphenyl sulfone comprising: (a) providing a suspension comprising particulate 4,4′-dichlorodiphenyl sulfone in carboxylic acid, (b) carrying out a solid-liquid separation of the suspension to obtain residual moisture containing 4,4′-dichlorodiphenyl sulfone and a carboxylic acid comprising filtrate, (c) washing the residual moisture containing 4,4′-dichlorodiphenyl sulfone with an aqueous base and then with water, (d) mixing the aqueous base after being used for washing with a strong acid, or mixing the aqueous base after being used for washing, the carboxylic acid comprising filtrate and a strong acid, (e) carrying out a phase separation in which an aqueous phase and an organic phase comprising the carboxylic acid are obtained.

The invention relates to a process for purifying 4,4′-dichlorodiphenyl sulfone comprising: (a) providing a suspension comprising particulate 4,4′-dichlorodiphenyl sulfone in carboxylic acid, (b) carrying out a solid-liquid separation of the suspension to obtain residual moisture containing 4,4′-dichlorodiphenyl sulfone and a carboxylic acid comprising filtrate, (c) washing the residual moisture containing 4,4′-dichlorodiphenyl sulfone with an aqueous base and then with water, (d) mixing the aqueous base after being used for washing with a strong acid, or mixing the aqueous base after being used for washing, the carboxylic acid comprising filtrate and a strong acid, (e) carrying out a phase separation in which an aqueous phase and an organic phase comprising the carboxylic acid are obtained.

A continuous-flow preparation method of diol sulfone using a two-stage micro-reaction system. The system includes a first micro-mixer, a first micro-channel reactor, a second micro-mixer, and a second micro-channel reactor communicated in sequence. The method includes: feeding hydrogen peroxide, a catalyst and a diol thioether solution simultaneously to the first micro-mixer followed by mixing; feeding the reaction mixture to the first micro-channel reactor for continuous oxidation; and feeding the reaction mixture and water simultaneously to the second micro-mixer and the second micro-channel reactor for continuous quenching and crystallization to obtain diol sulfone.

A continuous-flow preparation method of diol sulfone using a two-stage micro-reaction system. The system includes a first micro-mixer, a first micro-channel reactor, a second micro-mixer, and a second micro-channel reactor communicated in sequence. The method includes: feeding hydrogen peroxide, a catalyst and a diol thioether solution simultaneously to the first micro-mixer followed by mixing; feeding the reaction mixture to the first micro-channel reactor for continuous oxidation; and feeding the reaction mixture and water simultaneously to the second micro-mixer and the second micro-channel reactor for continuous quenching and crystallization to obtain diol sulfone.

Chemoenzymatic process for coproducing a disulfide and a sulfoxide or a sulfone The present invention relates to a chemoenzymatic process for coproducing disulfide and sulfoxide or sulfone from a composition M comprising: 1) a sulfide, 2) optionally an oxidizing agent, 3) an organic compound bearing at least one thiol group, 4) an enzyme E catalyzing the oxidation of said sulfide to sulfoxide or to sulfone, 5) an enzyme D catalyzing the formation of a disulfide bridge between two equivalents of said organic compound bearing at least one thiol group to form a dimer, and 6) a cofactor common to the two enzymes E and D; and also to a composition enabling especially the implementation of this process. The present invention also relates to the use of a mercaptan for reducing a disulfide bridge formed between two equivalents of an organic compound bearing at least one thiol group, and more particularly to the use thereof as regeneration substrate of the process described above.

Chemoenzymatic process for coproducing a disulfide and a sulfoxide or a sulfone The present invention relates to a chemoenzymatic process for coproducing disulfide and sulfoxide or sulfone from a composition M comprising: 1) a sulfide, 2) optionally an oxidizing agent, 3) an organic compound bearing at least one thiol group, 4) an enzyme E catalyzing the oxidation of said sulfide to sulfoxide or to sulfone, 5) an enzyme D catalyzing the formation of a disulfide bridge between two equivalents of said organic compound bearing at least one thiol group to form a dimer, and 6) a cofactor common to the two enzymes E and D; and also to a composition enabling especially the implementation of this process. The present invention also relates to the use of a mercaptan for reducing a disulfide bridge formed between two equivalents of an organic compound bearing at least one thiol group, and more particularly to the use thereof as regeneration substrate of the process described above.

The invention relates to a process for producing 4,4′-dichlorodiphenyl sulfone, comprising: (I) reacting thionyl chloride, chlorobenzene and aluminum chloride forming an intermediate reaction product and hydrogen chloride; (II) mixing aqueous hydrochloric acid and the intermediate reaction product to obtain an organic phase comprising 4,4′-dichlorodiphenyl sulfoxide and an aqueous phase; (III) cooling the organic phase to a temperature below the saturation point of 4,4′-dichlorodiphenyl sulfoxide to obtain a suspension; (IV) solid-liquid-separation of the suspension to obtain crystallized 4,4′-dichlorodiphenyl sulfoxide, and mother liquor; (V) washing the crystallized 4,4′-dichlorodiphenyl sulfoxide with a carboxylic acid to obtain carboxylic acid-wet 4,4′-dichlorodiphenyl sulfoxide; (VI) reacting the washed 4,4′-dichlorodiphenyl sulfoxide and an oxidizing agent in a carboxylic acid as solvent to obtain a reaction mixture comprising 4,4′-dichlorodiphenyl sulfone and carboxylic acid; (VII) separating the reaction mixture comprising 4,4′-dichlorodiphenyl sulfone and carboxylic acid into a residual moisture comprising 4,4′-dichlorodiphenyl sulfone as crude product and a liquid phase comprising carboxylic acid.

The invention relates to a process for producing 4,4′-dichlorodiphenyl sulfone, comprising: (I) reacting thionyl chloride, chlorobenzene and aluminum chloride forming an intermediate reaction product and hydrogen chloride; (II) mixing aqueous hydrochloric acid and the intermediate reaction product to obtain an organic phase comprising 4,4′-dichlorodiphenyl sulfoxide and an aqueous phase; (III) cooling the organic phase to a temperature below the saturation point of 4,4′-dichlorodiphenyl sulfoxide to obtain a suspension; (IV) solid-liquid-separation of the suspension to obtain crystallized 4,4′-dichlorodiphenyl sulfoxide, and mother liquor; (V) washing the crystallized 4,4′-dichlorodiphenyl sulfoxide with a carboxylic acid to obtain carboxylic acid-wet 4,4′-dichlorodiphenyl sulfoxide; (VI) reacting the washed 4,4′-dichlorodiphenyl sulfoxide and an oxidizing agent in a carboxylic acid as solvent to obtain a reaction mixture comprising 4,4′-dichlorodiphenyl sulfone and carboxylic acid; (VII) separating the reaction mixture comprising 4,4′-dichlorodiphenyl sulfone and carboxylic acid into a residual moisture comprising 4,4′-dichlorodiphenyl sulfone as crude product and a liquid phase comprising carboxylic acid.

The present invention relates to processes for preparing for preparing 3-(methylsulfonyl)propionitrile. The processes comprise the steps of first reacting 2-chloroethyl methyl sulfide with sodium cyanide or potassium cyanide in a solvent or a solvent mixture to form 3-(methylthio)propionitrile, and then reacting the isolated 3-(methylthio)propionitrile with acetic anhydride, acetic acid, and hydrogen peroxide to form 3-(methylsulfonyl)propionitrile.

The present invention relates to processes for preparing for preparing 3-(methylsulfonyl)propionitrile. The processes comprise the steps of first reacting 2-chloroethyl methyl sulfide with sodium cyanide or potassium cyanide in a solvent or a solvent mixture to form 3-(methylthio)propionitrile, and then reacting the isolated 3-(methylthio)propionitrile with acetic anhydride, acetic acid, and hydrogen peroxide to form 3-(methylsulfonyl)propionitrile.