Preparation Of Supported Oxides Solid Super-acid Catalyst By Sol-Gel Method

This paper is divided into four parts.In the first part of this paper, a summary of the evolution of the solid acid catalysts was made and cast a light on the problems and limitations of such catalysts used in the Organic reaction. Taking the Organic reaction's character into account, we put forward to a possible measurement.The solid acid catalysts were prepared in the second part of this paper. Major contents of preparation was that conditions been selected or be confirmed. Firstly, the molar ratio of W, Zr and content of WO₃-ZrO₂ was studied, which suggested that enough amounts of acid centers can't be formed if the content is too low, neither is activity. The higher WO₃-ZrO₂ loading, the higher activity. But the overloading of WO₃-ZrO₂ would make pores blocked and specific surface areas decrease, which made dispersity of WO₃-ZrO₂ loading on support decrease, and then led to lower catalytic activity. Therefore, the appropriate loading was an important factor for the catalytic activity. Finally activation of catalysts had been studied, and it was suggested that there was a best calcinations temperature. Because the temperature wa too lower to grow acidic center, this will influence the catalytic activity. However, if temperature was much too high, the acidic centers were lose, catalytic activity become lower. The conclusion was obtained by single factor condition. Subsequently, the condition of the preparation of the catalysts were optimized.Under the optimum synthesis conditions, the structure and acidity of the catalyst was characterized by means of Py-IR, XRD, BET, TEM, DSC-TG and Hammett indicator in the third part of this paper. The results showed that the WO₃/ZrO₂-SiO₂ catalyst assumes regular porous net structure. The catalyst had a reasonably large surface area 649.1 m².g^-1 and aperture volume 1.09 cm³/g.The components of catalyst existed mainly at amorphous state. The thermostability was good and the catalyst surface only had the L sourcenter but the non-B sourcenter.The fourth part used WO₃/ZrO₂-SiO₂ catalyst which was prepared by sol-gel method to catalyze the esterification of acetic acid and ethanol.The results had proven that its catalytic properties was higher than the strong sulfuric acid catalyst. However, non-catalytic activity in the one-stage process synthesis MMF experiment.The results showed that the catalyst exerted a positive role on the design and practical application of solid acid catalysts for esterification's reaction and overcomethe traditional liquid acid catalyst insufficiency. It was one kind of new environment friendly solid strong acid catalyst.