Partial wet oxidation of p-coumaric acid: Oxidation intermediates, reaction pathways and implications for wastewater treatment

p-Coumaric acid is representative of the polyphenolic fraction typically found in olive oil processing and wine-distillery wastewaters. The batch oxidation of p-coumaric acid has been investigated using a high-pressure reactor at temperatures varying from 403 to 523 K and pressures from 3 to 7 MPa. Concentrations of reaction intermediates were determined as a function of oxidation time using High Performance Liquid Chromatography (HPLC) as the main analytical technique, and an oxidation mechanism for p-coumaric acid is suggested. The results are discussed with respect to developing an integrated chemical-biological treatment process for organic wastewater.