PURPOSE: To safely produce an aqueous slurry having high quality and improved color tone on an industrial scale at a low cost because of the non-use of large amounts of solvent, bleaching agent and a high bleaching temperature.
CONSTITUTION: This aqueous slurry containing an α-sulfofatty acid alkyl ester salt contains 20-75wt.% of an α-sulfofatty acid alkyl ester salt of formula (R is an 8-22C alkyl or alkenyl; R' is a 1-6C alkyl; M is an alkali metal such as Na or K) and ≤0.05wt.% (based on the α-sulfofatty acid alkyl ester salt) of a reducing inorganic compound such as sulfurous acid, its salt, thiosulfuric acid or its salt. The aqueous slurry can be produced by sulfonating a fatty acid alkyl ester with sulfuric anhydride, etc., esterifying the sulfonated product with a small amount of a 1-6C alcohol and neutralizing the esterified product with an alkaline aqueous solution. The aqueous slurry is preferably maintained to pH4-8 and at 40-60°C.
TAKAMI AZUSA
TANO TETSUO
NAGAAI KAZUO
