One-step production of phenol by selective oxidation of benzene in a biphasic system

Abstract

Phenol production through the direct hydroxylation of benzene with hydrogen peroxide using a catalytic membrane reactor has been studied. The reaction was carried out in a biphasic system separated by a membrane. This new system showed a high selectivity to phenol, minimizing its over-oxidation in over-oxygenated by-products. The effect of various reaction parameters such as the addition of hydrogen peroxide mode, amount of hydrogen peroxide, type of membrane, type of catalyst and organic acid was investigated. The results showed that iron(II) sulphate as the catalyst, 18 mmol of hydrogen peroxide pumped for 4 h in the aqueous phase as oxidant feeding, acetic acid and polypropylene hydrophobic porous support gave the best system performance in terms of produced phenol (17.42 mmol), selectivity to phenol (99.94%), benzene conversion to phenol (1.20%), and hydrogen peroxide conversion to phenol (96.78%).