Thermodynamic properties ({Delta}H{sub f}(298), S(298), and C{sub p}(T) (300 {le} T {le} 1500)) of fluorinated propanes
- New Jersey Inst. of Tech., Newark, NJ (United States)
- ML-MLBT, Wright Patterson AFB, OH (United States)
Chlorofluorocarbons (CFCs) are being replaced by hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) because of their noneffects or less adverse effects on the stratospheric ozone layer. Thermodynamic properties ({Delta}H{sub f}{degree}{sub 298}, S{degree}{sub 298}, and C{sub p}(T) (300 {le} T/K {le} 1500)), frequencies, geometries, and internal rotational barriers for 1-fluoropropane, 1,1-difluoropropane, 1,1,1-trifluoropropane, 1,2-difluoropropane, 1,1,2-trifluoropropane, 1,1,2,2-tetrafluoropropane, 1,1,1,2-tetrafluoropropane, and 1,1,1,2,2-pentafluoropropane are calculated using ab initio methods. Enthalpies of formation ({Delta}H{sub f}{degree}{sub 298} in kcal/mol) for the above eight compounds are estimated using the G2MP2 composite calculation method and isodesmic reactions. Entropies (S{degree}{sub 298} in cal/mol K) and heat capacities (C{sub p}(T) in cal/mol K) are estimated using HF/6--31 G(d) determined frequencies and MP2(full)/6--31G(d) determined geometries. {Delta}H{sub f}{degree}{sub 298} for the above compounds are {minus}67.37, {minus}123.66, {minus}183.09, -109.75, {minus}164.68, {minus}216.38, {minus}221.57, and {minus}271.14 kcal/mol, respectively. Rotational barriers are determined, and hindered internal rotational contributions for S{degree}{sub 298} and C{sub p}(T) are calculated using the rigid rotor harmonic oscillator approximation with direct integration over energy levels of the intramolecular rotation potential energy curve.
- OSTI ID:
- 682161
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Vol. 103, Issue 28; Other Information: PBD: 15 Jul 1999
- Country of Publication:
- United States
- Language:
- English
Similar Records
Kinetic analysis of HO{sub 2} addition to ethylene, propene, and isobutene, and thermochemical parameters of alkyl hydroperoxides and hydroperoxide alkyl radicals
Reaction of OH radical with C{sub 2}H{sub 3}Cl: Rate constant and reaction pathway analysis