| 摘要 |
PURPOSE: Provided is an integrated method of preparing phenol from benzene, which comprises recycling of byproducts such as biphenol compounds to increase the final selectivity to phenol, to save the cost, and to improve the productivity. CONSTITUTION: The method comprises the steps of: (1) forming phenol continuously by direct oxidation of benzene with hydrogen peroxide, the oxidation being performed in a three-phase reaction system comprising a first liquid phase including benzene and an organic solvent, a second liquid phase including water and a solid phase including active catalyst based on titanium silicate TS-1, under the ratio of H2O2/benzene of 10-70; (2) separating phenol and unreacted benzene from the reaction mixture of the oxidation zone by distillation; (3) separating the solvent and byproducts from the mixture discharged from step (2) by extraction; (4) converting the byproducts of step(3) into phenol by hydrodeoxygenation carried out continuously in aqueous solution, at 250-500 deg.C, under 1-100 bar, and in the presence of a catalyst based on an element of Group VIB or a mixture thereof, or Group VIII or a mixture thereof; and (5) recycling the phenol obtained from step (4) to the distillation step (2). |
