Calorimetric study of ammonia sorption on H4SiW12O40
- 1 January 2003
- journal article
- Published by Royal Society of Chemistry (RSC) in Physical Chemistry Chemical Physics
- Vol. 5 (17) , 3606-3609
Abstract
Using a Microscal flow microcalorimeter, integral sorption and desorption enthalpies of ammonia on silicotungstic acid H4SiW12O40 dehydrated at 433 K and 483 K were determined. The quantitative coverage determination enabled us to estimate the amounts of the irreversibly as well as (much smaller) reversibly bonded ammonia at its equilibrium state in the gas phase (p NH3 =1.01 kPa). It has been shown that irreversible sorption at 373 K results in the formation of NH4 + ions while at 298 K two NH3 molecules are adsorbed per one proton in heteropolyacids. This suggests the formation of an NH4 +·NH3 adduct which is also present in N2H7I, the only known solid salt of a diammonium ion.Keywords
This publication has 18 references indexed in Scilit:
- Study of the acidity of carbon supported and unsupported heteropolyacid catalysts by ammonia sorption microcalorimetryApplied Catalysis A: General, 1999
- Acidity of Keggin-Type Heteropolycompounds Evaluated by Catalytic Probe Reactions, Sorption Microcalorimetry, and Density Functional Quantum Chemical CalculationsThe Journal of Physical Chemistry B, 1998
- Flow adsorption microcalorimetryThermochimica Acta, 1998
- Study of the acidity of H3PW12O40 supported on activated carbon by microcalorimetry and methanol dehydration reactionReaction Kinetics, Mechanisms and Catalysis, 1995
- Vibrational spectroscopy of the ammoniated ammonium ions NH4+(NH3)n (n = 1-10)The Journal of Physical Chemistry, 1991
- On the Structure of the Cation N2H with an N-H ċ N Hydrogen Bond in the Monoammonia Adduct of Ammonium IodideAngewandte Chemie International Edition, 1988
- Characterization of 12-tungstophosphoric acid and related salts using photoacoustic spectroscopy in the infrared region I. Thermal stability and interactions with ammoniaJournal of Catalysis, 1984
- Gas-phase solvation of the ammonium ion in ammoniaThe Journal of Chemical Physics, 1975
- High-pressure mass spectrometry. V. Thermodynamics of solvation reactions. NH4+-NH3The Journal of Physical Chemistry, 1974
- Das System NH4J/NH3. I. Phasen aus NH4J und NH3 im Temperaturbereich −35° bis +25°C und im NH3‐Dampfdruckbereich 0 bis etwa 760 TorrZeitschrift für anorganische und allgemeine Chemie, 1962