METHOD FOR PURIFYING ORGANIC SULFONATE WITH SOLVENT

PURPOSE:To obtain the titled compound useful as a surfactant, etc., without causing a phenomenon of increasing the viscosity in emulsion phase inversion, by purifying an organic sulfonate from a mixture thereof with the unreacted material with a specific extracting solvent. CONSTITUTION:An organic sulfonate is extracted and purified from a mixture thereof with the unreacted material obtained in producing the organic sulfonate, particularly petroleum sulfonate. In the process, an aqueous solution of a 1-4C saturated monocarboxylic acid having hydrophilicity and a higher boiling point than water, e.g. formic acid, acetic acid, propionic acid or butyric acid, is used as an extracting solvent. The concentration of the above-mentioned aqueous solution is preferably 10-90vol.%, particularly preferably 20-80vol.%. The extraction temperature is preferably 20-95 deg.C, particularly preferably 50-80 deg.C.