The rapid determination of benzil, benzoin and hydrobenzoin in mixtures by quantitative infrared spectrophotometry

Abstract

From the infrared spectra of mixtures of benzil, benzoin and hydrobenzoin in solution in chloroform, benzoin and hydrobenzoin are determined by means of their absorption bands at 3460 and 3590 cm^–1, respectively. Benzil is determined from the carbonyl absorption at 1680 cm^–1 after subtracting the contribution of benzoin to the absorbance at this frequency. The most suitable concentrations are 0·1 to 1·0 per cent. for benzil and benzoin and 0·1 to 2·0 per cent. for hydrobenzoin.