Hydroxylation of phenol with H2O2 over binary Cu–Pd–alginate catalyst in the fixed-bed flow reactor

A series of Cu–alginate and Cu–Pd–alginate catalysts were prepared by the ion exchange of Na–alginate, and their structures were well characterized by FT-IR, XPS and ICP-AES measurements. Their catalytic activities for phenol hydroxylation in the fixed-bed flow reactor were investigated. The effects of different reaction conditions, such as molar ratio of phenol/H2O2, reaction temperature, weight hourly space velocity, solution and weight ratio of water/phenol were evaluated. Under the optimum reaction conditions, 17.1 % phenol conversion was obtained with selectivities to catechol and hydroquinone being 67.7 and 31.4 %, respectively. The 16.0–18.0 % phenol conversion and selectivities to HQ 30.0–32.0 %, CAT 66.0–68.0 % and BQ 0.7–2.0 % of the long-run catalytic test confirmed the excellent stable catalytic activity of the catalyst.