Ferric oxide has been found to promote both the ketonization of acetic acid and its esterification with methyl alcohol, isopropyl alcohol, and benzyl alcohol. The competitive kinetic technique, where the esterification reaction is made to compete with the ketonization of acetic acid, has been used to elucidate the mechanistic model for the ketonization of acetic acid on iron oxide. The ketonization of acetic acid at 375°C is found to be a second‐order reaction which proceeds through a Langmuir‐Hinshelwood mechanism. Copyright © 1977 John Wiley & Sons, Inc.