Radiolysis of 2-, 3- and 4-chlorobenzonitrile in aqueous solution and product analysis

Steady-state radiolysis of 2-, 3-, and 4-chlorobenzonitriles under various experimental conditions and HPLC-analysis of the resulting major products were performed. The initial G-values (G i ) of the products have been determined. Hydrated electrons (e aq - ) react with the substrates forming the corresponding radical anions which decay by dehalogenation yielding cyanophenyl radicals. In the presence of a H-donor (e.g. t-butanol) they form benzonitrile, the only product identified. At higher concentrations the cyanophenyl radicals may also undergo oligomerization. H-atoms are also found to react with the three chlorobenzonitriles, but no product could be identified. Attack of OH-radicals was found to occur preferably on the position with the highest electron density. Several final products are identified in this case. Also the reactions with the primary products of the water radiolysis in the presence of air have been studied. Based on the experimental data some probable reaction mechanisms were postulated.