Catalytic decarboxylation of acetic acid with zirconia catalyst in supercritical water

Reactions of acetic acid were conducted with alkali (KOH) and zirconia (ZrO 2) catalysts in supercritical water (SCW) (673 K and 25 MPa-40 MPa). For co mparison, we also conducted the experiments without catalyst and/or water a t the same reaction conditions. Decarboxylation of acetic acid with zirconi a in supercritical water formed acetone, CO2, and water without forming any other compound. On the other hand, decomposition of acetic acid with alkal i produced methane (CH4) and CO2 with acetone. Without water and/or catalys t, the main products were also CO2 and CH4 (without catalyst) or acetone (w ith ZrO2); however, by-products, such as a water-insoluble compound were fo rmed. The structure of zirconia was changed during reaction in supercritica l water. The rate of decarboxylation of acetic acid exerted an effect on th e particle size of zirconia. (C) 2001 Elsevier Science B.V. All rights rese rved.