Studies On Catalysts Of Organic Sulfonic Acids

The commonly used organic acid catalysts such as strong acid cation exchange resin and supported para-toluenesulfonic acid, etc. have several disadvantages. The active components of them are easy to loss and the thermal stability and solvent stability are poor. In this paper, several sulfonic acid solid catalysts were prepared to obtain better thermal stability and solvent stability than the cation exchange resin, which had similar activities with it.In this thesis, the catalysts were prepared by the following way. The polymerization of styrene was bonded or supported on the cheap silica gel, activated carbon and diatomite, and then the solid acid catalysts with the organic sulfonic acids as active centers were synthetized by sulfonation of benzene rings with the concentrated sulfuric acid. The types of carriers, extraction conditions, preparation methods and preparation conditions were investigated, which could influence the catalysts. FT-IR, BET, XRF, elemental analysis, SEM, GC, etc. were employed for the catalyst characterization. As measured by chemical titration method, the acid amounts of the organic sulfonic acids catalyst bonded on silica were 2.70mmol·g^-1, the acid amounts of the organic sulfonic acids catalysts supporteded on activated carbon and diatomite made by adsorption were 1.88mmol·g^-1 and 1.43mmol·g^-1, the acid amounts of the organic sulfonic acids catalyst supporteded on activated carbon prepared by impregnation were 1.34mmol·g^-1. The acid amounts of these catalysts were similar with the common strong acid cation exchange resin.Then, the novel four kinds of organic acid solid catalysts as well as strong acid cation exchange resin and activated carbon supported para-toluenesulfonic acid were applied to the synthesis of n-butyl phthalate, in order to investigate the activity and reusability of them. The results showed that the organic sulfonic acids catalyst bonded on silica and the organic sulfonic acids catalyst supporteded on activated carbon made by adsorption had good activity and stability to meet people'needs to catalysts and environmental protection requirements. The highest yield could be up to 99.1%. Comparetion of acid amounts of the catalysts before and after the reaction and TG showed that the deactivation of the catalysts was due to the loss of sulfonic acids, which were far less than the loss extent of strong acid cation resin and activated carbon supported para-toluenesulfonic acid.