12026-93-6Relevant articles and documents
Monodispersed microporous polyoxotungstate with regular shape
Ito, Takeru,Inumaru, Kei,Misono, Makoto
, p. 830 - 831 (2000)
Monodispersed fine particles of (NH4)3PW12O40 having regular shape were successfully prepared as precipitates by the titration of NH4HCO3 solution to H3PW12O40/s
Origin of microporosity of ammonium dodecatungstophosphate unveiled by single crystal structure analysis
Ito, Takeru,Hashimoto, Masato,Uchida, Sayaka,Mizuno, Noritaka
, p. 1272 - 1273 (2001)
The single crystals of ammonium dodecatungstophosphate were successfully synthesized and the structure was analyzed. The intrinsic crystal structure (cubic, Pn3m) had no cavity. It follows that the microporosity observed for the powdery sample originated
Comparison of the surface properties of the metal-oxygen cluster compounds, 12-tungstophosphoric acid and ammonium 12-tungstophosphate from the sorption of benzene, nitrogen and pyridine
Nayak, Vikram S.,Moffat, John B.
, p. 75 - 94 (1993)
The surface properties of ammonium 12-tungstophosphate and its parent acid, 12-tungstophosphoric acid have been evaluated from measurements of the adsorption of benzene, nitrogen and pyridine. Ammonium 12-tungstophosphate prepared from a number of different ammonium salts is found to have different surface areas, benzene sorption capacities and diffusivities and numbers of Bronsted acid sites, the latter as estimated from the sorption of pyridine. The surface areas, sorption capacities and acidity distributions of both the parent acid and ammonium 12-tungstophosphate show significant differences and are strongly influenced by duration calcination of its temperature and environment.
Novel catalytic acetylation of alcohols with Preyssler's anion, [NaP 5Wa30O110]14-1
Alizadeh,Razavi,Farrash Bamoharram,Hassanzadeh,Khoshnavazi,Mohammadi Zonoz
, p. 524 - 528 (2008/10/08)
Sodium 30-tungstopentaphosphate, the so-called Preyssler's anion with a formula of [NaP5W30O110]14- (I) catalyzes the acetylation of alcohols (CnH2n + 1OH, n = 2, 3, 4, 5) with acetic acid. High yield is obtained with I as pure acid or supported on silica. Both homogeneous and heterogeneous catalysts are discussed and compared. H14[NaP5W30O110], abbreviated as H14-P5, under homogeneous conditions, as well as supported on silica (heterogeneous conditions) is found to be an excellent catalyst. Our data indicate that, when the ammonium salt of I is employed as the catalyst, the yield increases as the alcohol carbon-chain is increased. This behavior is found to be quite general. The catalysts can be easily recovered and recycled with retention of their initial structure and activity.