Thermodynamic Properties of Trifluoromethanethiol from 12°K to Its Boiling Point. Entropy from Molecular and Spectroscopic Data

Journal Article · Fri Jan 01 04:00:00 EST 1960 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.1730801· OSTI ID:4174856

Dininny, R. E.; Pace, E. L.

The heat capacity of trifluoromethanethiol was measured at 12 to 227 K. The heat of fusion at the triple point temperature, 116.04 deg K, was 1157 cal mole^-1. The heat of vaporization at the normal boiling poirt, 235.16 deg K, was 4798 cal mole^-1. The vapor pressure was measured, and the data represented by the equation log₁₀p_mm = (--1352.568/ T) -- 2.b86918 log₁₀T + 15.00409. The entropy of trifluoromethanethiol as calculated from the calorimetric data was 69.45 plus or minus 0.17 eu at 235.16 deg K. The result calculated from spectroscopic data and structural parameters for the molecule was 70.19 eu. The discrepancy of 0.74 plus or minus 0.17 eu was attributed to a potential barrier of 1540 plus or minus 260 cal mole^-1 which restricted the internal rotation of the trifluoromethyl group.

• Research Organization: Western Reserve Univ., Cleveland
• Sponsoring Organization: USDOE
• NSA Number: NSA-14-012967
• OSTI ID: 4174856
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 3 Vol. 32; ISSN JCPSA6; ISSN 0021-9606
• Publisher: American Institute of Physics (AIP)
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALCOHOLS
CALORIMETERS
ENTROPY
EQUATIONS
FLUORINATED HYDROCARBONS
LOW TEMPERATURE
MEASURED VALUES
MELTING
METHANE
MOLECULES
ORGANIC SULFUR COMPOUNDS
PRESSURE
ROTATION
SPECIFIC HEAT
SPECTROSCOPY
TEMPERATURE
THERMODYNAMICS
VAPORS