EFFECT OF PRESSURE ON THE EQUILIBRIUM E- PLUS CO2 REVERSIBLE-ARROW CO2- IN 2-METHYLBUTANE AND 2,2-DIMETHYLBUTANE

The reaction e- + CO2 reversible CO2- was studied in two alkane solvents for temperatures from 22 to 100-degrees-C and for pressures up to 3000 bar. The equilibrium constants and thermodynamic quantities for this reaction are reported from which the energies and entropies of solution of the electron in 2-methylbutane and 2,2-dimethylbutane are obtained. The free energy of reaction decreases as the solvent density increases. The significance of the volume changes for this reaction, which are between -190 and -300 CM3/Mol, is discussed. The entropy of reaction decreases largely due to the entropy of polarization of the solvent by CO2-. Mobilities of excess electrons in 2-methylbutane are also reported for temperatures from 23 to 100-degrees-C and for applied pressures from 1 to 2500 bar. The decrease in mobility with increasing pressure is attributed to increased probability of electron trapping at high pressure.