Process for producing aminoalkylthiosulfuric acid compound

A process for producing an aminoalkylthiosulfuric acid compound represented by formula (1):

• wherein R1 and R2 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, or R1 and R2 are bonded to represent a polymethylene group having 2 to 9 carbon atoms, and n represents an integer of 2 to 9,
• the process comprising the following steps (A2), (B2), (C2) and (D2):
• (A2) a step of obtaining a mixture of a solid containing an alkali metal chloride and a liquid containing an aminoalkylthiosulfuric acid compound represented by formula (1) by reacting a hydrochloride of chloroalkylamine compound represented by formula (2):
• wherein R1, R2 and n are as defined above,
• with an alkali metal salt of thiosulfuric acid in the presence of not less than 1 part by weight and less than 2 parts by weight of water with respect to 1 part by weight of the hydrochloride of the chloroalkylamine compound represented by formula (2) at between 50° C. and 100° C.,
• (B2) a step of separating the solid containing the alkali metal chloride and the liquid containing the aminoalkylthiosulfuric acid compound represented by formula (1) from the mixture obtained in step (A2),
• (C2) a step of obtaining a mixture of a solid containing the aminoalkylthiosulfuric acid compound represented by formula (1) and a liquid containing water by adjusting the temperature of the liquid containing the aminoalkylthiosulfuric acid compound represented by formula (1) and obtained in step (B2) to not lower than −15° C. and lower than 50° C.,
• (D2) a step of obtaining the aminoalkylthiosulfuric acid compound as solid by separating the solid containing the aminoalkylthiosulfuric acid compound represented by formula (1) and the liquid containing water from the mixture obtained in step (C2).