Determination of equilibrium constant between nitrogen dioxide and dinitrogen tetraoxide by means of infrared absorption spectroscopy
1966 Volume 15 Issue 12 Pages 1332-1338
Details
1966 Volume 15 Issue 12 Pages 1332-1338
The infrared absorption spectra of equilibrium mixtures of nitrogen dioxide and dinitrogen tetraoxide were observed under various pressures and temperatures. In order to secure a temperature homogeneity in the cell, it was placed wholly in an air bath which was provided with heaters, a fan and a regulator.
The band at 1617 cm-1 of nitrogen dioxide and the bands at 1735 cm-1 and 1255 cm-1 of dinitrogen tetraoxide were used as key bands. From the integrated intensities of these key bands, the partial pressures of both species, Pm(of NO2) and Pd(of N2O4), were obtained, and the equilibrium constants K's in various temperatures were calculated as P2m/Pd. Although the calculation of K's seemed not to be sufficiently accurate the plotting of log K versus 1/T made a fairly good straight line, and from its gradient has been obtained the dissociation heat of dinitrogen tetraoxide as 17.5 kcal/mol.
