CERIC SULFATE OXIDATION OF P-METHOXYTOLUENE - KINETICS AND REACTION RESULTS

The chemical oxidation in the indirect electrochemical process for oxidizing 4-methylanisole (MA) by a sulfuric aqueous solution of ceric sulfate was studied. The dissolution of MA into the aqueous phase precedes the pure homogeneous oxidation consecutive steps: 4-methylanisole --> anise alcohol --> anisaldehyde --> anisic acid. The kinetic parameters for each of the steps were deduced from the measurement of the rate of reaction by absorption spectroscopy. The MA oxidation in the two-phase medium shows that the aldehyde yield reaches 80% at 50-degrees-C when the initial concentration of cerium(IV) is less then 40 mol m-3. Anise alcohol may be obtained with a selectivity as high as 50%. The alcohol yield decreases to 15% for a conversion of MA of 8.5%. It is shown that it is possible to achieve a MA conversion, in a liquid-liquid CSTR fed with a 300 mol m-3 Ce(IV) solution, of more than 50% with an aldehyde selectivity of 75%.