Direct Hydroxylation of Benzene to Phenol by Dielectric Barrier Discharge Plasma

Direct synthesis of phenol from benzene was realized using atmospheric dielectric barrier discharge (DBD) plasma. In the process, various experimental parameters such as irradiation time, electrode height, and discharge power were found to play crucial roles in determining the yield and selectivity of phenol. Also, serious carbonization phenomenon was observed at the surface of used electrode due to the extensive interaction between benzene and electrode, which greatly inhibited the hydroxylation of benzene to phenol. To resolve this issue, silica coated electrode was employed, and significant improvement of conversion efficiency was obtained. The yield of phenol as high as 19.5% could be obtained in the optimal condition, and its selectivity was 83.3% based on the analysis of gas chromatography-mass spectrometry.