Steady-state radiolysis and product analysis of aqueous diphenyloxide in the presence of air and N2O

The radiation-induced decomposition and product analysis of diphenyloxide (DPO; diphenylether), selected as a representative of the toxic polyaromatic, volatile, hydrocarbons produced by combustion of coal, was investigated in aqueous solution. In the presence of air an initial degradation yield, Gi(-DPO)0=4.6 was obtained. Phenol (Gi=1.3) appeared to be the major decomposition product in addition to a number of hydroxy-compounds as well as a mixture of aldehydes and carboxylic acids. DPO as well as the resulting products can be decomposed at an absorbed radiation dose of about 5 kGy. By performing analogous studies in solution saturated with N2O an initial yield of Gi(-DPO)=5.0 and similar radiolytic products were found. Again phenol (Gi=1.5) is observed as the main product. In this case a much lower radiation dose (∼2.5 kGy) is found to be sufficient for the decomposition of DPO and its radiolytic products. Most likely reaction mechanisms are presented for explanation of the observed products