Abstract: By conducting a sulfonation step for bringing a fatty acid alkyl ester into contact with a sulfonating gas in the presence of a coloring inhibitor to sulfonate the fatty acid alkyl ester, an esterification step for esterifying the product of the sulfonation step with a lower alcohol, a neutralization step for neutralizing the esterified product of the esterification step to obtain a neutralized product, a bleaching step for bleaching the neutralized product to obtain a bleached product, and preferably an optional deodorization step for deodorizing the bleached product, the production process can be simplified and &agr;-sulfofatty acid alkyl ester salts which have a pale color close to white and preferably have less odor can be obtained.

Abstract: A high concentration aqueous solution of the salt of an alpha-sulfo fatty acid ester is produced by (a) neutralizing the sulfonated product of a fatty acid ester with an aqueous caustic alkali solution having a concentration of 15 through 50% by weight, in the presence of an alcohol having 1 to 4 carbon atoms in an amount of 5 through 20% by weight based on the weight of the sulfonated product, to form an acidic neutralized product having a pH of 2.5 through 4 and; then, (b) adding an aqueous caustic alkali solution having a concentration of 1 through 5% by weight to the acidic neutralized product to adjust the pH of the acidic neutralized product to 6 through 7. The aqueous solution of the salt of the alpha-sulfo fatty acid ester thus obtained includes only small amounts of the undesired alpha-sulfo fatty acid salt.

Abstract: Process for the production of light-colored internal olefin sulfonates substantially free from unreacted olefins comprises sulfonating an internal olefin with gaseous SO.sub.3 to produce a sulfonation reaction mixture, neutralizing said sulfonation reaction mixture with caustic alkali without hydrolysis of sulton contained in the mixture, adding to the neutralized sulfonation reaction mixture an extracting reagent selected from halogenated hydrocarbons to form an extract phase containing unreacted olefin and a raffinate phase containing internal olefin sulfonates and sultons, and hydrolyzing the resulting raffinate phase in the presence of caustic alkali.

Abstract: A method of bleaching olefin sulfonates, which comprises adding more than 0.1% by weight of hydrogen peroxide, with more than 0.1% by weight of phosphate alone or silicate alone or a mixture of the two, to an olefin sulfonate having 12 to 22 carbon atoms, and treating at a temperature in the range of from 30.degree. to 130.degree. C.

Abstract: A cylindrical apparatus for continuous sulfonation of an organic liquid is provided with an annular feeding device for permitting the organic liquid to flow in the form of a film down a reaction wall. The annular feeding device is provided with a number of slots in a horizontal and equidistant manner in a row.