Benzil rearrangement kinetics and pathways in high-temperature water

We have elucidated the kinetics for both the rearrangement of benzil (1,2-diphenylethanedione) to benzilic acid and for the subsequent reactions of benzilic acid in pure high-temperature liquid water (HTW). The rearrangement is rapid, and the benzilic acid formed can react via two parallel pathways. One is decarboxylation to form benzhydrol and the other is a self-reaction to form diphenylketene plus benzophenone. Diphenylketene is hydrated in HTW to form diphenylacetic acid, which can decarboxylate to form diphenylmethane. Benzhydrol reacts slowly in HTW, but it forms diphenylmethane and benzophenone in equal amounts. This set of reaction pathways is shown to be consistent with the experimental data obtained from the reactions of benzil, diphenylacetic acid, and benzhydrol, individually, in HTW.