Note 14 — VOLUME VI slice I Châtelet to Chicago (continued 5)

Victor Meyer and G. Heyl (Ber., 1895, 28, p. 2776) attempted a solution from the following data. It is well known that di-ortho-substituted benzoic acids are esterified with difficulty. Two acids corresponding to the formula of Kekulé and Claus are triphenyl acrylic acid, (C6H5)2C:C(COOH)·C6H5, and triphenyl acetic acid, (C6H5)3C·COOH. Experiments showed that the second acid was much more difficult to esterify than the first, pointing to the conclusion that Claus’ formula for benzene was more probable than Kekulé’s.