Process for deodorizing a mercapto acid by extracting malodorous compound therefrom with a supercritical fluid

A process for deodorizing a mercapto acid by extraction of a greater part of malodorous decomposition products contained therein, said process comprising (a) treating said mercapto acid in the presence of at least one polar solvent for said mercapto acid with a supercritical extraction fluid having a critical temperature ranging from 0.degree. to 135.degree. C. and a critical pressure ranging from 10.sup.6 to 10.sup.7 Pascals, said mercapto acid having the formula

• HS--A--COOH (I)
• wherein
• A represents
• (i) --(CH.sub.2).sub.n -- wherein n is an integer ranging from 1 to 4,
• (ii) ##STR4## wherein R represents linear or branched C.sub.1 -C.sub.3 alkyl, or (iii) ##STR5## and (b) lowering the extraction pressure whereby said malodorous decomposition products are removed with said extraction fluid.