Purification of photographic image-forming sulfonamido compounds employing immiscible solvents

Abstract

A process for purifying a photographic image-forming sulfonamido compound comprises the steps of: a. preparing a first solution by dissolving an unpurified image-forming sulfonamido compound in an aprotic solvent; b. removing impurities from said first solution by, at least once: i. mixing said first solution with an immiscible nonpolar, low-boiling organic solvent to form a mixture of said first solution and a second solution comprising said immiscible nonpolar, low-boiling organic solvent and at least a portion of said impurities; and ii. separating said first solution from said second solution; and c. recovering purified image-forming sulfonamido compound from said first solution. The process is useful in the purification of a nondiffusible sulfonamido compound which is alkali-cleavable upon oxidation to release a diffusible sulfonamido color-providing moiety.

Dependencies are inferred from the claim text.