Direct and efficient transformation of gaseous alkanes into carboxylic acids catalyzed by vanadium containing heteropolyacids

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• 作者：Marina V. Kirillova ; José ; A.L. da Silva ; Joã ; o J.R. Fraú ; sto da Silva ; Arm ; o J.L. Pombeiro
• 关键词：Alkanes ; C– ; H activation ; Heteropolyacids ; Vanadium ; Carboxylation ; Carboxylic acids ; Homogeneous catalysis
• 刊名：Applied Catalysis A ; General
• 出版年：2007
• 期刊代码：4_0926860x
• 类别：ch
• 出版时间：1 November 2007
• 卷：332
• 期：1
• 页码：159-165
• 文件大小：285 K

摘要

The vanadium containing heteropolyacids H₄[PMo₁₁VO₄₀] × 34H₂O (HPA-1), H₅[PMo₁₀V₂O₄₀] × 32H₂O (HPA-2) and H₆[PMo₉V₃O₄₀] × 34H₂O (HPA-3) act as highly active catalysts for the direct transformation of light C₁–C₃ alkanes into the corresponding carboxylic acids in the presence of CO and in the K₂S₂O₈/CF₃COOH system. Propionic acid (ca. 70%yield), iso- and n-butyric acids (ca. 65%overall yield), and acetic acid (ca. 20%) are the major products obtained from the carboxylation of ethane, propane and methane, respectively, with vanadium playing a main catalytic role. The effects of the catalyst amount have been studied and overall turnover numbers (TONs) up to ca. 12 × 10³ (for the ethane and propane conversions) or up to 3 × 10³ (for the methane carboxylation to acetic acid) have been achieved for very high alkane-to-catalyst molar ratios which also promote the selectivity towards acetic acid.