Elucidation of liquid-force fields in methyl fluoride by means of vapor-pressure isotope effects. [/sup 12/CH/sub 3/F, /sup 13/CH/sub 3/F and /sup 12/CD/sub 3/F]

Technical Report · Fri Jan 01 00:00:00 EST 1982

OSTI ID:5318328

Shulman, J; Ishida, T

The vapor pressure isotope effects (VPIE) of the three isotopic methyl fluorides: /sup 12/CH/sub 3/F, /sup 13/CH/sub 3/F, and /sup 12/CD/sub 3/F, were studied using differential manometry and a precision cryostat. Absolute pressures were measured using a spiral quartz gauge, and differential pressures were obtained by use of capacitance gauges. The gases were purified to better than 99.995% by preparative gas chromatography and a gas-solid adsorption system. Vapor pressures were measured between 132.52/sup 0/K and 213.12/sup 0/K which correspond to the pressures of 3.712 and 1887.1 torr. Analysis of the vapor pressure data revealed an inverse isotope effect (ln(f/sub c//f/sub g/) < 0) for the /sup 12/CH/sub 3/F//sup 13/CH/sub 3/F isotopic pairs and a normal effect (ln(f/sub c//f/sub g/) > 0) for the /sup 12/CH/sub 3/F//sup 12/CD/sub 3/F isotopic pairs. A series of calculations using Wilson's FG-matrix method and a modified Schachtschneider-Snyder program resulted in a temperature-dependent internal-external interaction in the condensed phase: A strongly temperature-dependent internal-external interaction between the C-F stretching motion and a translation motion in the direction of its figure axis is necessary to explain the observed isotopic vapor pressures.

• Research Organization: City Univ. of New York, NY (USA); State Univ. of New York, Stony Brook (USA)
• DOE Contract Number: AC02-80ER10612
• OSTI ID: 5318328
• Report Number(s): DOE/ER/10612-7; ON: DE82014663
• Resource Relation: Other Information: Thesis. Portions of document are illegible
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON 13
ISOTOPE EFFECTS
DEUTERIUM
METHYL FLUORIDE
PURIFICATION
VAPOR PRESSURE
CRYOSTATS
DESIGN
EQUIPMENT
GAS CHROMATOGRAPHY
LIQUIDS
LOW TEMPERATURE
PRESSURE GAGES
TEMPERATURE DEPENDENCE
CARBON ISOTOPES
CHROMATOGRAPHY
CONTROL EQUIPMENT
EVEN-ODD NUCLEI
FLUIDS
FLUORINATED ALIPHATIC HYDROCARBONS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MEASURING INSTRUMENTS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHYSICAL PROPERTIES
SEPARATION PROCESSES
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
THERMOSTATS
400302* - Organic Chemistry- Isotope Effects- (-1987)
400301 - Organic Chemistry- Chemical &amp; Physicochemical Properties- (-1987)