Influence of small amounts of tungsten on the physico-chemical and catalytic properties of PMo11–xWxVO4–40 heteropolyanions
Influence of small amounts of tungsten on the physico-chemical and catalytic properties of PMo11–xWxVO4–40 heteropolyanions
复制标题
少量钨对 PMo11–xWxVO4–40 杂多阴离子物理化学和催化性能的影响
DOI：
10.1039/ft9938903301
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
G. Hervé
中科院分区：
文献类型：
--
作者：
C. Marchal;A. Davidson;R. Thouvenot;G. Hervé
The preparation, characterization and catalytic properties of acids with the general formula H4PMo11–xWxVO40, x= 0–6, and their pyridinium salts are described. The 31P NMR spectra reveal that the solids synthesized are mixtures of species with different x values. Three distinct stoichiometric ratios of W : Mo (1 : 10, 2 : 9, 3 : 8) have been used to vary the proportion of each species in these solids (labelled y= 1, 2 and 3). Their thermal stabilities and redox properties in solution are close to those of pure H4PMo11 VO40. Their Bronsted acidity increases in the order y= 1 < y= 2 < y= 3. Their catalytic properties for the oxydehydrogenation of isoubtyric acid methacrylic acid are modified drastically. An important decrease in oxidative activity and an increase in acid activity are observed even with small amounts of tungsten. Tungsten may modify either the electronic transfer between the Keggin units or the oxygen lability.
