Thermodynamic analysis of reaction equilibria in ionic and molecular liquid systems by high-temperature Raman spectroscopy

Angelos G Kalampounias; Soghomon Boghosian

doi:10.1366/000370209789379277

Thermodynamic analysis of reaction equilibria in ionic and molecular liquid systems by high-temperature Raman spectroscopy

Appl Spectrosc. 2009 Sep;63(9):1050-6. doi: 10.1366/000370209789379277.

Authors

Angelos G Kalampounias¹, Soghomon Boghosian

Affiliation

¹ Department of Chemical Engineering, University of Patras and Institute of Chemical Engineering and High Temperature Chemical Processes (FORTH/ICE-HT), GR-26504 Patras, Greece.

PMID: 19796488
DOI: 10.1366/000370209789379277

Abstract

A formalism for correlating relative Raman band intensities with the stoichiometric coefficients, the equilibrium constant, and the thermodynamics of reaction equilibria in solution is derived. The proposed method is used for studying: (1) the thermal dissociation of molten KHSO(4) in the temperature range 240-450 degrees C; (2) the dinuclear complex formation in molten TaCl(5)-AlCl(3) mixtures at temperatures between 125 and 235 degrees C. The experimental and calculational procedures for exploiting the temperature-dependent Raman band intensities in the molten phase as well as (if applicable) in the vapors thereof are described and used for determining the enthalpy of the equilibria: (1) 2HSO(4)(-)(l) <--> S(2)O(7)(2-)(l) + H(2)O(g), DeltaH(0)=64.9 +/- 2.9 kJ mol(-1); and (2) 1/2Ta(2)Cl(10)(l) + 1/2Al(2)Cl(6)(l) <--> TaAlCl(8)(l), DeltaH(0)=-12.1 +/- 1.5 kJ mol(-1).