The electro-oxidn. of 1,4-benzoquinone in water soln. was investigated. The benzoquinone concn., intermediate products, dissolved org. C (DOC), COD, and toxicity of the oxidized soln. was monitored during oxidn. with Ti/IrO2 and Ti/SnO2 anodes (in the following text: IrO2 and SnO2 anodes). It was found that the most important parameter is the nature of the anode. With the IrO2 anode, primary oxidn. was attained, i.e. benzene ring rupture occurred, resulting in an accumulation of carboxylic acids formation as final non-toxic products. With the SnO2 anode, carboxylic acids are formed in a much faster reaction and then oxidized, giving only CO2 as the final product. Detoxification of benzoquinone soln. using both electrodes was detd. in the course of the reaction by the Microtox test, activated sludge respirometric test, and were also predicted using a developed formula. Calcd. av. toxicity, knowing the chem. compn. of the oxidized soln., DOC, and individual EC50 of the components were in agreement with obsd. values. The biodegradability of compds. in the soln. at the end of electrolysis with the IrO2 anode was demonstrated. [on SciFinder (R)]