Thermodynamic properties of 1-methylcyclopentanol and 1-chloro-1-methylcyclopentane in the ideal gas state

Abstract

The enthalpies of evaporation, the saturated vapor pressures of 1-methylcyclopentanol (I) and 1-chloro-1-methylcyclopentane (II) and the energy of combustion of crystal I were measured. IR and Raman spectra of both compounds were recorded and vibrational analyses were made. Thermodynamic functions of I and II in the ideal gas state were calculated by the statistical thermodynamics methods. In order that the experimental and calculated entropies of gaseous 1,1-ClMeCP agree, it is necessary to determine the contribution of pseudorotation as the contribution of motion with potential function V( ø) = 5800 − 3060 cos( ø) − 2740 cos(2 ø) J mol −1 and pseudorotational moment of inertia 15.24 × 10 −40 g cm 2. The molecular rotation in the plastic crystal state of II is discussed.