(VO)_2P_2O_7催化剂上正丁烷选择氧化反应路径的原位瞬态DRIFTS研究

In-Situ Transient DRIFTS Studies of the Reaction Pathway of n-Butane Selective Oxidation over (VO)_2P_2O_7 Catalysts

在钒磷复合氧化物(VO)2P2O7催化剂上,运用脉冲反应和反应物组成序贯切换的瞬态反应技术,对正丁烷和C4烯烃(1丁烯、1,3丁二烯)选择氧化制顺酐过程进行了瞬态原位DRIFTS研究,考察了正丁烷选择氧化反应体系的反应网络和基元过程序列结构。获得了含羰基的非环状饱和与不饱和物种都可能是正丁烷选择氧化制顺酐过程的中间物的证据,在1丁烯和1,3丁二烯的原位瞬态DRIFTS研究中检测到了呋喃。推断中间物呋喃在生成顺酐前可能经历了开环形成含羰基的非环状不饱和物种的过程。基于实验结果及与文献的比较,提出了正丁烷在VPO催化剂上选择氧化可能的反应路径。

The reaction pathway of n-butane selective oxidation to maleic anhydride (MA) over vanadium phosphorous oxide (VO)(2)P2O7 catalysts was systematically probed using in situ transient Diffuse Reflectance Infrared Fourier-Transform Spectroscopy (DRIFTS) in high temperature/high pressure chamber. The unsaturated and saturated noncyclic carbonyl species were determined to be intermediates in n-butane selective oxidation to MA. Furan was detected on the surface of the (VO)(2)P2O7 catalysts in 1-butene, 1, 3-butadiene selective oxidation. It was deduced that furan ring was cleaved to form unsaturated noncyclic carbonyl species before its conversion to MA. Based on these results and in comparison with the literature, a simplified scheme of the reaction network structure can be proposed for n-butane selective oxidation to maleic anhydride.