Oxidation of acetaminophen by ultrasound waves and H2O2 combined technology

This study analyses the colour acquired by oxidizing paracetamol aqueous samples through the combined US/H2O2 technology. When operating with only the action of the waves [US]=1.0 kWh/mmol C8H9NO2, the water acquires progressively hue according to a ratio of 0.0004 AU/min, with a degradation output of 14%. Working under these conditions, the presence of hydroquinone, muconic acid and formic acid was evaluated. Colour formation presents a maximum intensity when water containing paracetamol is degraded using molar ratios of 1.5 mol H2O2/mol C8H9NO2. This dosage leads to the formation of benzoquinone, as well as muconic and formic acids, reaching an efficiency of 30%. Oxidazing with 6.0 mol H2O2/mol C8H9NO2, colour formation occurs slowly during the first hour of reaction, leading to the formation of benzoquinone, hydroquinone, acetamide, phoroglucinol and formic and muconic acids. This last one presents a molecular structure that is prone to reacting with other species that are present in the system forming complexes.