Preparation Of Ordered Mesoporous Carbon-Based Solid Acid And Study On Catalytic Synthesis Of Bisphenol A

In recent years, as the energy shortage and environment pollution become moreand more serious, it’s important to develop the green chemical process. As a kind ofnovel solid acid catalyst, carbon-based solid acid attracts much attention because ofthe high acid density, excellent catalytic activity and good stability. However, theapplication in the reaction of macromolecules involved is limited since the lowspecific surface area and lack of appropriate pore structure. Therefore, meosporouscarbon-based solid acid catalyst becomes the ideal choice for the macromolecularinvolved reaction catalyzed by Br nsted acid, which has ordered mesoporousstructure, high specific area and tunable pore size. In this work, the orderedmesoporous carbon was synthesized by soft template method, using F127as templateand a soluble low-molecular weight resol as precursor. Then the ordered carbon-basedsolid acid catalyst was prepared through template removal and sulfonation ofincompletely carbonized mesoporous carbon, which was used in the synthesis ofbisphenol A from condensation of phenol with acetone.Firstly, the suitable temperature of template removal was set at350℃via thestudy of template removal process, and the template was removed basically at thetemperature. The effects of carbonization and sulfonation conditions on orderedmesoporous structure, skeleton composition and surface acidity were investigated byN2adsorption-desorption, XRD, TEM, FT-IR and acid-base titration. Theexperimental results showed the mesoporous carbon-based solid acid carbonized atlower temperature contained a higher acid density while the mesoporous structure wasdestroyed seriously. As the rise of the carbonization temperature from400℃to700℃,the specific surface area of mesoporous carbon increased and the mesoporous carbonskeleton transformed to graphite structure gradually. The obtained mesoporouscarbon-based solid acid possessed ordered mesopores while the acid density wasdecreased. The effect of sulfonation temperature between140℃and200℃onmesoporous carbon-based solid acid was investaged. The results indicated thatsulfonation at higher temperature was beneficial to increasing acid density while thesample skeleton was destroyed seriously. The optimal preparation conditions of ordered mesoporous carbon-based solidacid was found as follows: template removal at350℃, carbonization at500℃andsulfonation at180℃. The obtained catalyst had ordered mesoporous structure togetherwith uniform mesopores, and also contained an amount of-SO3H groups density ashigh as1.71mmol/g.The resulting catalyst was applied to the synthesis of bisphenol A fromcondensation of acetone with phenol and showed significantly higher activity thanamorphous carbon-based solid acid and strong acid cation exchange resin. The resultsindicated the remarkable catalytic performance of the ordered mesoporouscarbon-based solid acid was attributed to ordered meosoporous structure and highdensity of-SO3H groups. Moreover, the effect of cocatalyst mercaptoacetic acid onthe catalytic performance was discussed. The catalytic activity was improvedobviously when cocatalyst was added in reaction system, which showed a broadapplication prospects in the reaction catalyzed by Br nsted acid.