Process of hydroxylation of phenol to dihydroxyl phenol

The hydroxylation of phenol on composite catalyst and the process control in a novel tubular flow reactor were studied. The effects such as the quota of hydrogen peroxide feeding to every stage of the tubular flow reactor, temperature, molar ratio of phenol to hydrogen peroxide, etc. on the reaction results and the hydroxylation process in the axial direction of the tubular reactor were investigated. The results showed the convertion of phenol was about 44% and selectivity to catechol and hydroxyquinone was about 80% when the initial phenol concentration was 12%, molar ratio of phenol to hydrogen peroxide was 2.0 and the feeding rates of hydrogen peroxide in stages were 6, 5, 6, 4, 4 mL/min, respectively.