Partial oxidation of phenol in supercritical water with NaOH and H2O2: Hydrogen production and polymer formation.

The catalytic supercritical water partial oxidation of phenol using H2O2 as oxidant in the presence of NaOH was explored to enhance hydrogen production and inhibit phenol polymerization. The results indicated that H2 production was enhanced in the presence of NaOH when phenol supercritical water oxidation was controlled at a lower O/C ratio. Compared with the individual catalytic partial oxidation of phenol, the reaction with NaOH and H2O2 simultaneously enhanced H2 production and inhibited polycyclic polymer generation at O/C ratios below 0.5. A peak hydrogen gasification efficiency value of 62.35% was observed at an O/C ratio of 0.3 with 1.0 wt% NaOH, and a phenol removal efficiency of nearly 75% was reported. Phenol polymerization was effectively inhibited for reaction times limited to 50 s. Moreover, other phenol reaction pathways reported in the literature were compared with the partial oxidation of phenol in supercritical water with NaOH and H2O2.