Abstract
Sulfonated sites in quinoline Yellow WS, which is distributed under the name of "D & C Yellow No.203"have not been clarified as yet. Treatment of 2-(2'-quinolyl)-1, 3-indandione with fuming sulfuric acid, gave several sulfonated products and two of product dye were identified as 2-(2'-quinolyl)-1, 3-indandione-6'-sulfonic acid and 2-(2'-quinoly)-1, 3-indandione-5, 6'-disulfonic acid by nuclear magnetic resonance, infrared and mass spectra. Commercial samples of quinoline Yellow WS consist of the disodium 2-(2'-quinolyl)-1, 3-indandione-5, 6'-disulfonate and contain other sulfonated derivatives.
