Photolysis of the Resin Acid Dehydroabietic Acid in Water

Abstract

The effects of UV254-radiation and artificial solar radiation on the degradation of dehydroabietic acid (DHAA) in humic water and in humus-free control water were examined. The reaction rates were determined, the degradation products were tentatively identified, and the toxicity changes of the solutions were monitored. Our results demonstrate that the presence of dissolved organic matter (DOM) in water affects the light-induced degradation rate of DHAA. In the UV-experiments, the degradation was substantially slower in humic water than in humus-free control water, whereas the degradation rate was accelerated by the presence of DOM in the simulated sunlight-experiments. These differences are obviously due to different reaction pathways in the experiments. Irradiation of the aqueous DHAA solutions gave rise to a great number of degradation products of which e.g. 7-oxodehydroabietic acid and 7-oxodehydroabietin were formed in high amounts. During photolysis of DHAA in humic water, decarboxylation of DHAA to ...