Patent ID: 8148524

Claim:
A process for producing a sulfonyl chloride compound comprising: (A) a step comprising reacting a pyridazine compound represented by the formula (1): wherein R 1 represents a hydrogen atom, a halogen atom, an alkyl group which may be substituted with a halogen atom or atoms, an alkenyl group which may be substituted with a halogen atom or atoms, an alkynyl group which may be substituted with a halogen atom or atoms, an alkoxy group which may be substituted with a halogen atom or atoms, an alkylthio group, an alkylsulfonyl group, an alkoxycarbonyl group, a cyano group, a nitro group, a carbamoyl group, an amino group, an alkylamino group or a dialkylamino group, R 2 and R 3 are the same or different and each represents a hydrogen atom, a halogen atom or an alkyl group which may be substituted with a halogen atom or atoms, R 4 represent a hydrogen atom, a halogen atom, an alkyl group which may be substituted with a halogen atom or atoms, an alkenyl group which may be substituted with a halogen atom or atoms, an alkoxy group which may be substituted with a halogen atom or atoms, an alkylthio group, an alkylsulfonyl group, an alkoxycarbonyl group, a cyano group, a nitro group, a carbamoyl group, an amino group, an alkylamino group or a dialkylamino group, with a sulfonating agent selected from the group consisting of chlorosulfonic acid, fuming sulfuric acid and anhydrous sulfuric acid; (B) a step comprising contacting the reaction mixture obtained in the step (A) with a chlorinating agent selected from the group consisting of thionyl chloride, sulfuryl chloride, phosgene, oxalyl chloride, phosphorus oxychloride, phosphorus pentachloride and phosphorus trichloride; and (C) a step comprising mixing the reaction mixture obtained in the step (B) with an aqueous inorganic base solution to separate an aqueous layer and an organic layer containing a sulfonyl chloride compound represented by the formula (2), wherein the inorganic base is an alkali metal hydroxide, an alkali metal carbonate, an alkaline earth metal carbonate or an alkali metal hydrogen carbonate: wherein R 1 to R 4 are the same meanings as defined above.