The stabilization and upgrading of pyrolysis oil requires the neutralization of the acidic components of the oil. The conversion of small organic acids, particularly acetic acid, to ketones is one approach to addressing the instability of the oils caused by low pH. In the ketonization reaction, acetic acid is converted to acetone, water, and CO2. Here, a 16 vol % acetic acid solution is converted to acetone in a flow reactor over the mixed oxide Fe0.2Ce0.2Al0.6Ox in the presence of several other components meant to represent pyrolysis oil. These components include hydroxyacetone, furfural, phenol, cresol, guaiacol, and eugenol. Hydroxyacetone also undergoes ketonization, forming acetone, 2-butanone, 3-pentanone, and 2- and 3-hexanone. A mechanism for the ketonization of hydroxyacetone through propanal is proposed and supported by incorporation of isotopically labeled water. Inhibition of the reaction occurs to a significant degree by the addition of furfural, guaiacol, and eugenol.