Preparation Of The Supported Resin Catalysts And The Application In The Hydroxylation Of Phenol Using H₂O₂ As An Oxidation Agent

Pyrocatechol and hydroquinone, as the important raw material intermediates in fine chemical industries, are used in many fields. The catalytic hydrogenation of phenol by hydrogen peroxide is the optimal green way to produce pyrocatechtechol and hydroquinone. So the catalysts had become the emphases studied. The supported resin catalysts were prepared by the ion-exchange method. The results show that, the supported resin catalysts have exhibited good catalytic behaviors on the phenol hydroxylation reaction. Macroporous acidic iron-exchange resin cation D061 and D001-SS are better carriers as phenol hydroxylation reaction catalysts. The procedures for preparing the supported resin catalysts have been optimized. The factors, which affect the catalytic activity of catalysts, include the catalysts carrier, the active components, marinated time, and desiccation temperature. And the most suitable conditions have been found. These catalysts which can be prepared easily have low preparation costs, reclaimed easily, moderate reaction condition and low dosage.BET, XRD, SEM, TEM and XPS were used for characterization of phenol hydroxylation catalysts. The results showed that, the active components of the supported resin catalysts were ferric oxide and ferric hydroxide, having properties of a crystal or crystalloid, dried temperature was the important factor which affects the structure of the active components, the higher desiccation temperature, the more crystal grain, but the heat-durability of the resin limits the desiccation temperature. The reaction process of phenol hydroxylated by H2O2 has been also studied systematically. The factors, which affect the reaction process, include the catalysts amount, reaction time, reaction temperature, phenol/H2O2 (molar ratio). And the repetition of the test have also been checked up, the catalysts were recycled, and recovery percentage of catalysts was 75%～80%.At last, the ingredients percent in solution have been calculated by internal standardization. The factors, which affect the ingredients percent in solution, include initial phenol concentration, water amount, PH and reaction time were studied. The best reaction conditions have been acquired when the initial phenol concentration was equal to 3.06～4.06 mol ? L?1; catalysts weight was to 0.5g; phenol/H2O2(molar ratio) was equal to 3:1; water amount was equal to 30ml; reaction temperature was 70℃; reaction time was 1h; PH=2～4. As a result, the conversion of phenol has been as high as 11.85%, the selectivity of dihydroxybenzene has been as high as 99%, the weight percent of diphenol has been as high as 5.5%, and the weight percent of tar was 0.0022%.