The thermodynamic functions of ethyl tert-butyl and ethyl tert-amyl ethers in the gas phase

The thermodynamic functions Sdegrees(7), C(p)degrees (T), Hdegrees(T) - Hdegrees(0), -[Gdegrees(T) - Hdegrees(0)], Delta(f)Hdegrees(T), and Delta(f)Gdegrees(T) of ethyl tert-butyl and ethyl tert-amyl ethers in the ideal gas state were calculated by statistical thermodynamics methods. The structure parameters, vibrational frequencies, and internal rotation potential functions were calculated at the B3LYP/6-31G(d,p) level of density functional theory. Corrections for the interaction of rotating groups were determined from the entropy values obtained in calorimetric studies. The method of isodesmic reactions was used to calculate the enthalpies of formation; the electronic energies of the molecules participating in these reactions were calculated using the B3LYP/6-311+G(3df, 2p) functional.