Photoreduction of 2,6-dichloroquinone in aqueous solution: Use of a diode array spectrophotometer concurrently to drive and detect a photochemical reaction

The aqueous photoreaction of 2,6-dichloro-1,4-benzoquinone produces 2,6-dichlorohydroquinone, 2,6-dichloro-3-hydroxy-1,4-benzoquinone and dioxygen. This reaction was used to demonstrate that a commercial diode-array spectrophotometer is a useful tool for the study of photochemical reactions. The white light going through the sample cell concurrently drives and detects photoreactions. It is shown how quantum yields can be determined. A method for interpreting the full time course of the photoreaction is also presented.