Photodegradation of lignin: The role of singlet oxygen

The photochemical irradiation of some phenoxyacetophenone derivatives in the presence of oxygen by using visible light did not produce any decomposition product. In the presence of singlet oxygen, sensitized by using Bengal Rose, decomposition products were obtained. The products obtained were similar to those obtained by direct beta-C-O cleavage on the substrate. In this case, the observed behavior can be explained assuming an attack of singlet oxygen on a phenoxy part of the molecule.

The photochemical irradiation of some phenoxyacetophenone derivatives in the presence of oxygen by using visible light did not produce any decomposition product. In the presence of singlet oxygen, sensitized by using Bengal Rose, decomposition products were obtained. The products obtained were similar to those obtained by direct/3-C--O cleavage on the substrate. In this case, the observed behavior can be explained assuming an attack of singlet oxygen on a phenoxy part of the molecule.