Calorimetric and spectroscopic measurements on the SO 2 oxidation catalyst model system M 2S 2O 7–M 2SO 4–V 2O 5/SO 2(g) or Ar(g) (M=K or Cs) at 430–470°C

• Published in: Thermochimica acta Vol. 379; no. 1; pp. 187 - 193
• Main Authors: Hatem, G., Eriksen, K.M., Fehrmann, R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2001
• Subjects: Calorimetric measurements; Redox reactions; SO 2 oxidation catalysts; Vanadium Oxo sulfato complexes; Redox reactions; SO 2 oxidation catalysts; Calorimetric measurements; Vanadium Oxo sulfato complexes
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/S0040-6031(01)00616-5

Calorimetric measurements have been performed on the melt–gas systems M 2S 2O 7–V 2O 5 and M 2S 2O 7–M 2SO 4(sat)–V 2O 5 (M=K and Cs) in SO 2(g) and Ar(g) at 430–480°C and for mole fractions X V 2O 5 =0–0.1. Enthalpies have been obtained for complex formation reactions as (VO) 2O(SO 4) 4 4−+SO 4 2−⇄2VO 2(SO 4) 2 3−+S 2O 7 2− for V(V) and 2VO(SO 4) 2 2−+3SO 4 2−+SO 3⇄2VO(SO 4) 3 4−+S 2O 7 2− for V(IV). Similarly enthalpies of the V(V)–V(IV) redox reactions (VO) 2O(SO 4) 4 4−+SO 2⇄2VO(SO 4) 2 2−+SO 3 and 2VO 2(SO 4) 2 3−+SO 4 2−+SO 2⇄2VO(SO 4) 3 4− could be calculated. These enthalpies of reduction compare well with those obtained by spectrophotometric measurements in the same temperature range.