Study Of Multicomponent Metal Oxide Catalyst On Propane Oxidation To Acrylic Acid

In the catalytic system of selective oxidation of propane to acrylic acid, multi-component metal oxide is currently the best catalyst. Multi-component metal oxide catalysts generally experienced high-temperature calcination, so the catalysts'crystal structure is relatively stable, which means it can maintain a good and stable catalytic performance while have a higher activity and selectivity to the target products under the reaction conditions. At present, the most effective catalyst reported on the selective oxidation of propane to acrylic acid is Mo-V-Te-Nb-O composite metal oxide catayst.The performance of mixed metal-oxide Mo-V-Te-Nb-O catalysts was appraised in a fixed bed microreactor, several factors'impact on the catalyst's performance, including time and temperature of the hydration reaction,drying method,calcination mode and temperature of the catalyst's precursor, was studied. Space velocity, reaction temperature as well as activation time were investigated to obtain the optimal parameters of the reaction. The performance of Mo-V-Te-Nb mixed oxide catalyst prepared by using TeO2 as Te source instead of telluric acid was also investigated. The impact of precalcination of the catalyst was studied. The experimental results show that a 120-minute Mo-V-Te hydration reaction span and a 150-minute Mo-V-Te-Nb hydration reaction period under 70℃and 80℃respectively are preferable in the process of catalyst's preparation; using rotary evaporation drying process is better, after which a 12 hours vacuum drying was induced that could enhance catalyst's performance. The results of the analysis of the catalyst show that the best space velocity is 600h-1, the optimal temperature is 400℃, after 300 minutes activation the performance of the catalyst would maintain stable. The performance of the catalyst prepared using TeO2 as Te source was not as good as the catalyst prepared using tellurium, but using precalcination would improve its catalytic performance. A 300℃precalcination process could improve the performance of the catalyst, under which the conversion of propane as well as the selectivity of acrylic acid of the catalyst have much improvement.