Relationship between infrared spectra and stoichiometry of pyridine-H₃PW₁₂O₄₀ salts using a new TGA-infrared coupling

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• 作者：Alexandre Vimont ; Arnaud Travert ; Claude Binet ; Cé ; line Pichon ; Pierre Mialane ; Francis Sé ; cheresse and Jean-Claude Lavalley
• 关键词：Infrared ; TGA ; Pyridinium ; Pyridine ; Acidity ; 12-Tungstophosphoric acid ; Heteropolyacid
• 刊名：Journal of Catalysis
• 出版年：2006
• 出版时间：1 July 2006
• 年：2006
• 卷：241
• 期：1
• 页码：221-224
• 全文大小：182 K

文摘

A new thermogravimetric–infrared coupled apparatus was used to determine the stoichiometry of the pyridinium salts resulting from absorption of pyridine on H₃PW₁₂O₄₀ (HPW). Gravimetric measurements showed that two pyridinium salts with definite stoichiometry—(Py₂H⁺)₃PW₁₂O₄₀ (bis-pyridinium salt) and (PyH⁺)₃PW₁₂O₄₀ (mono-pyridinium salt)—are formed. Their infrared spectra closely correspond to those reported for pyridinium salts in strong acid solutions. The splitting of the ν8b and ν19b bands of absorbed pyridine (1610–1603 cm⁻¹ and 1540–1532 cm⁻¹, respectively) is characteristic of mono-pyridinium formation in the HPW structure.