Zn-doped nano-Cr2O3 catalyst for fluorination of chlorinated light olefins

Abstract

A series of Zn-doped nano-Cr2O3 catalysts were prepared by the microwave-assisted combustion method, and the catalysts were successfully applied to the fluorination of 1, 1, 2, 3-tetrachloropropene to synthesize 2-chloro-3, 3, 3-trifluoropropene, and the fluorination of vinylidene chloride to vinylidene fluoride using anhydrous hydrogen fluoride, which is much more efficient than catalyst reported in literatures. By XRD, XPS, and NH3-TPD, it was confirmed that the doping of a small amount of Zn did not have a great influence on the crystal structure of the catalyst but had a great influence on the acidity of the catalyst surface, which increased the number of weak acids and medium acids on the catalyst surface. In addition, the addition of a small amount of Zn could increase the content of high-valent chromium and produce more CrOxFy active centers. As the number of acid sites increases, it provides adsorption centers for chlorine-containing molecules, and the increase of CrOxFy active centers promotes the reaction. They work together to improve the catalytic performance of the catalyst.