Henkel Reaction (Raecke Process) (Henkel Process)

B. Raecke, DE 936036 (1952) and DE 958920 (1952) to Henkel & Co.

Industrial scale thermal rearrangement or disproportionation of alkaline salts of aromatic acids to symmetrical diacids in the presence of cadmium or other metallic salts:

Review: B. Raecke, Angew. Chem. 70, 1 (1958); Y. Ogata et al., J. Org. Chem. 25, 2082 (1960); E. McNelis, ibid. 30, 1209 (1965); J. Szammer, L. Otvos, Radiochem. Radioanal. Lett. 45, 359 (1980).