Research on H3+xPVxMoyW12-x-yO40 for Partial Oxidation of Methane
|School||East China University of Science and Technology|
|Keywords||methane sol-gel multicomponent heteropoly acid partial oxidation|
Partial oxidation of methane is one of the most challenges all over the world. It is widely acknowledged that the key is to find a suitable catalytic system, which can increase the conversion of methane as well as the selectivity of the target product. In the past several decades, researches mainly focus on gas-solid phase or gas-liquid phase reaction catalytic system. However, in gas-solid phase reactions, it couldn’t increase the conversion of methane as well as the selectivity of the target product at the same time while in gas-liquid phase reaction, reaction kettle is corroded badly because of necessary fuming sulfuric acid or trifluoroacetic acid, which make it difficult for industrial applications. This paper raises a supported multicomponent heteropoly acid catalyst for partial oxidation of methane in dilute sulfuric acid. Since it has a strong acid and good redox properties.Based on the former research, PW12-PMo12-NaVO3was taken as the active component to choose a suitable carrier and loading method at first. Sol-gel method is taken and loading processes were discussed and optimized. Then H4PVMo4W7O40was compared with PW12-PMo12-NaVO3, and it has a better performance. Different x of H3+xPVxMoyW12-x-yO40was investigated and H5PV2Mo4W6O40performed best in partial oxidation of methane.Keggin structure of H5PV2Mo4W6O40was confirmed by results of its characterization, then it was loaded by sol-gel method and used in partial oxidation of methane. Different hydrolysis time, hydrolysis temperature, H2O/TEOS ratio, aging temperature, catalyst loading, calcination temperature and calcination time were investigated. Experimental results show that per-pass conversion of methane can amount to1.49%on the following conditions: H5PV2Mo4W6O40is loaded20%, mole ratio of TEOS:ethanol:water is1:4:10, hydrolyzing in80℃for2h, aging in60℃for24h, calcining in350℃for4h.