METHOD FOR DEODORIZING MERCAPTO ACID BY EXTRACTING MALODOROUS COMPOUNDS AND PRODUCT DEODORIZED BY THE METHOD

摘要

PURPOSE: To deodorize mercapto acid by extracting malodorous compounds contained in the acid by bringing the acid into contact with carbon dioxide in gas, liquid or solid form. The effect of deodorization is long-lasting. ;CONSTITUTION: The deodorization is carried out by extracting decomposition products contained in a crude mercapto acid of the formula I [A is a divalent radical expressed by the formula II ((n) is 1-4), the formula III (R is 1-3C alkyl) or the formula IV] (particularly, preferably mercaptoacetic acid or mercaptopropionic acid) by bringing the crude mercapto acid into contact with carbon dioxide in gas, liquid or solid form. The extraction temp. and pressure are chosen so as to maintain the carbon dioxide outside the supercritical region. The extraction may be carried out by direct contact of the acid with carbon dioxide or by contact with carbon dioxide in an acid solution of a polar solvent or by contact with carbon dioxide contained in an inert gas. The carbon dioxide used can be regenarated and reused. This method is preferably applied to the permanent liquid.;COPYRIGHT: (C)1994,JPO