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

• Published in: Applied catalysis. A, General Vol. 332; no. 1; pp. 159 - 165
• Main Authors: Kirillova, Marina V., da Silva, José A.L., Fraústo da Silva, João J.R., Pombeiro, Armando J.L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2007; Elsevier
• Subjects: Alkanes; Carboxylation; Carboxylic acids; Catalysis; Chemistry; C–H activation; Exact sciences and technology; General and physical chemistry; Heteropolyacids; Homogeneous catalysis; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Vanadium; Heteropolyacids; C–H activation; Homogeneous catalysis; Vanadium; Carboxylation; Alkanes; Carboxylic acids; Catalytic reaction; Hydrocarbon; Transition metal; Activation; Heteropolyacid; C-H activation; Carboxylic acid; Alkane
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2007.08.018

The vanadium containing heteropolyacids H 4[PMo 11VO 40] × 34H 2O ( HPA-1), H 5[PMo 10V 2O 40] × 32H 2O ( HPA-2) and H 6[PMo 9V 3O 40] × 34H 2O ( HPA-3) act as highly active catalysts for the direct transformation of light C 1–C 3 alkanes into the corresponding carboxylic acids in the presence of CO and in the K 2S 2O 8/CF 3COOH system. ▪ The vanadium containing heteropolyacids H 4[PMo 11VO 40] × 34H 2O ( HPA-1), H 5[PMo 10V 2O 40] × 32H 2O ( HPA-2) and H 6[PMo 9V 3O 40] × 34H 2O ( HPA-3) act as highly active catalysts for the direct transformation of light C 1–C 3 alkanes into the corresponding carboxylic acids in the presence of CO and in the K 2S 2O 8/CF 3COOH 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 × 10 3 (for the ethane and propane conversions) or up to 3 × 10 3 (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.