The chlorination of propiophenone; determination of pKa value and of the course of the reaction

Abstract

Chlorination of propiophenone in alkaline aqueous solution leads to formation of α-hydroxypropiophenone as the first detectable intermediate; this undergoes slower oxidation to aromatic acids without any accumulation of further intermediates. From the rates of the initial chlorination we have been able to determine the pKa value as 17.56 ± 0.51. Keywords: propiophenone, chlorination, hydrolysis, rearrangement, pKa.