Process for producing clear aqueous solution of magnesium salt of anionic surface active agent

Claim 1

A process for producing a clear aqueous solution of the magnesium salt of an anionic surface active agent consisting essentially of the steps of: (a) adding alkylbenzene sulfonic acid to an aqueous slurry containing a water-soluble anionic surface active agent selected from the group consisting of: (1) the sodium and magnesium salts of olefin sulfonic acids of 8 to 22 carbon atoms, (2) the sodium salts of alkylbenzene sulfonic acids of 10 to 15 carbon atoms, (3) the sodium and magnesium salts of alkyl sulfuric esters having alkyl radicals of 8 to 22 carbon atoms, and (4) the sodium and magnesium salts of alkyl ether sulfuric esters having alkyl radicals of 8 to 22 carbon atoms and having an average addition mole number of ethylene oxide of 1 to 10, and containing at least one alkaline compound selected from the group consisting of magnesium hydroxide and magnesium oxide, to thereby provide a clear aqueous solution having a pH of from approximately 2 to approximately 4, the amount of said alkylbenzene sulfonic acid being (i) sufficient to yield a pH within the range of from approximately 2 to approximately 4, and (ii) to provide a weight ratio of the water-soluble anionic surface active agent in the slurry to the alkylbenzene sulfonic acid within the range of from 20:80 to 95:5, and then: (b) adding at least one alkaline compound from the group consisting of alkali metal hydroxides, ammonia and triethanolamine to the aqueous solution in a sufficient amount to adjust the pH of the resultant solution within the range of from approximately 5.5 to approximately 8.