Bleaching methyl ester sulfonate

Fatty JicidFster Sulfonates. Fatty acid ester sulfonates (FAES) are generally produced from methyl esters, ie, methyl ester sulfonate (MES) and prepared via sulfonation, followed by bleaching and neutralization, in a relatively difficult and complex process ... 

After bleaching, the a-sulfonated ester has to be neutralized with sodium hydroxide or some other aqueous base to obtain the salt. Hydrolysis of the ester groups is avoided if the temperature does not exceed 45 °C and the pH is between 7.5 and 9. Neutralization is thus performed in a continuous process to ensure pH control and effective heat removal [33]. The concentration of the NaOH solution has to be calculated so that a slurry is obtained that has a low viscosity so as to facilitate further processing. For example, neutralization can produce a 40% aqueous slurry of sodium palm kernel methyl ester a-sulfonate or a 25% aqueous slurry of sodium tallow methyl ester a-sulfonate [33],... 

S. are made by SO3 ->sulfonation of the methyl esters of preferably Cis-ig fatty acids. Reaction takes place in two steps, a rather rapid formation of a mixed anhydride, followed by a slower rearrangement. The sulfonation mixture is rather dark and must be bleached with H2O2 at 60-80 °C, and it is finally neutralized. By-product is the disodium salt of the a-sulfo fatty acid. 

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