Antioxidant efficiency of polyhydric phenols in photooxidation of benzaldehyde

An experimental system is described for the observation of the kinetics of photochemically initiated oxidation reactions; this system is based on the measurement of oxygen consumption with a polarographic oxygen electrode. The photooxidation of benzaldehyde in dilute aqueous solution was examined and appears to conform to a free radical chain mechanism. The antioxidant efficiency of some polyhydric phenols was determined kinetically and found to be catechol greather than pyrogallol greater than hydroquinone greather than resorcinol greater than n-propyl gallate for the benzaldehyde photooxidation.