for the purposes of this invention and the following examples selectivity is defined by the following equation the reactor is charged with 540 ml of isobutyric acid after heating to 40 u00b0 c under 55 psig ihbu is fed into the reactor at 1 5 ml min air is fed into the reactor at 1 slpm liquid overflow and gas effluent is collected weighed and analyzed by gc hourly after 7 hours the feeds are ceased gas is vented and the reactor is cooled emptied and its contents weighed and analyzed the overflow was found to contain 91 0 isobutyric acid 3 96 ipf 2 48 acetone 1 48 ihbu 0 97 co 2 and 0 11 isopropanol the reactor is charged with 540 ml of 95 isobutyric acid and 5 acetone after heating to 40 u00b0 c under 55 psig a mixture of 95 ihbu and 5 acetone is fed into the reactor at 1 5 ml min air is fed into the reactor at 1 slpm liquid overflow and gas effluent is collected weighed and analyzed by gc hourly after 7 hours the feeds are ceased gas is vented and the reactor is cooled emptied and its contents weighed and analyzed the overflow was found to contain 86 0 isobutyric acid 2 25 ipf 8 72 acetone 2 45 ihbu 0 55 co 2 and.