Vapor phase association in acetic and trifluoroacetic acids. Thermal conductivity measurements and molecular orbital calculations

Journal Article · Wed Apr 09 04:00:00 EST 1980 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00528a015· OSTI ID:5030397

Frurip, D J; Curtiss, L A; Blander, M

Thermal conductivity measurements are reported for the vapors of acetic acid and trifluoroacetic acid in the temperature range 350 to 415 K over the pressure range 100 to 2000 Torr. Very large enhancements of the thermal conductivity were found and analysis of the data is consistent with a monomer-dimer equilibrium for both vapors. The standard thermodynamic parameters for the dimerization reactions are -..delta..H/sub 2/ = 14.64 kcal mol/sup -1/ and -..delta..S/sub 2/ = 35.50 cal mol-/sup 1/ K/sup -1/ for acetic acid, and -..delta..H/sub 2/ = 13.66 kcal mol-/sup 1/ and -..delta..S/sub 2/ = 36.15 cal mol-/sup 1/ K/sup -1/ for trifluoroacetic acid. No evidence was found for the presence of significant amounts of associated species larger than the dimer. Ab initio molecular orbital calculations were performed on the monomers and dimers of both acids to determine the lowest energy structures.

• Research Organization: Argonne National Lab., IL
• OSTI ID: 5030397
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 102:8; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ACETIC ACID
ATOMIC MODELS
CARBOXYLIC ACIDS
DATA
DIMERS
EXPERIMENTAL DATA
INFORMATION
MATHEMATICAL MODELS
MOLECULAR STRUCTURE
MOLECULES
MONOCARBOXYLIC ACIDS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHYSICAL PROPERTIES
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES