Photosensitization by Vat Dyes

IT is well known that cellulose fabrics dyed with certain vat dyes disintegrate on exposure to light1. The experimental evidence suggests that a photosensitized oxidation of the cellulose is responsible. It is known that dyes do, in fact, photosensitize a number of reactions2; but no systematic survey of the field has been attempted, and the factors which determine the relative efficiencies of different dyes are not known. In a preliminary study of photosensitization, we have found that such dyes can initiate the autoxidation of tetralin, and the polymerization of styrene.