Preparation Of Vinyl Fluoride And Difluoroethane Catalyst By Acetylene Hydrogen Fluoride

Acetylene can react with anhydrous hydrogen fluoride under the effect of catalyst by hydrogen fluoride reaction, and its product are vinyl fluoride and difluoroethane, which can be used for producing PVF and containing fluorine fine chemicals, and they are also good ODS substitutes. They have important applications in the field of refrigeration and composite material. Suitable gas phase catalyst has far-reaching research value in the fixed bed reactor.In this thesis,the catalyst was prepared by coprecipitation method using chromic nitrate and ammomium hydroxide, and investigated the influence of metal content on the catalyst performance by adding Zn and Mg; in order to improve the activity and life of the catalyst, and volumetric immersion method, we prepared the catalyst by using respectively χ-alumina, α-alumina, γ-alumina as the carrier, and adding the load metals of Cr, Ni and Co to examine the effect of different carrier and metal load on the properties of acetylene hydrogen fluoride. Using X-ray diffraction(XRD), scanning electron microscope(SEM), the measurement of specific surface test(BET), and particle size analysis to characterize the physical and chemical properties of the synthetic catalyst.The evaluation apparatus of catalyst was established based on the requirements of evaluation systems and the technology characteristics of acetylene hydrogen fluoride.Firstly, the evaluation condition of catalyst was determined at the reaction temperature of250 o C, aiespeed of 600 h-1, the molar ratio of acetylene to hydrogen fluoride of 3:1-6:1.The selectivity of VF and R152 a and conversion rate of acetylene were 58% and 80%,respectively, at 1% zinc content by using coprecipitation. The selectivity of VF and R152 a and conversion rate of acetylene were 86% and 99%, respectively, usingα-alumina load 5% chromium catalyst by impregnation. The selectivity of fluorine ethylene anf the total selectivity of product were 60% and 83%, respectively, using the bimetallic catalyst(γ-alumina as the carrier, loading 5% chromium and 1% nickel).The annual output of 10000 tons of acetylene hydrogen fluorine chemical industry plant was simulated and designed by Aspen according to the experimental data.Simulation results showed that the total investment using Cr(5%)· Ni(1%)/γ-Al2O3 as a catalyst was higher than that of Cr(5%)/α-Al2O3 as catalyst with the same production capacity. However, the latter is superior to the former in the total revenue. This showed that catalytic performance and the proportion of products were effected the application of this process.