Studies of carbon--isotope fractionation. Annual progress report, December 1, 1974--November 30, 1975

Technical Report · Mon Dec 01 04:00:00 EST 1975

DOI:https://doi.org/10.2172/7353313· OSTI ID:7353313

Ishida, T.

The vapor pressure isotope effect of /sup 13/C//sup 12/C-substitution in CClF/sub 3/ was measured at temperatures between 169/sup 0/ and 206/sup 0/K by means of cryogenic distillation. The /sup 13/C//sup 12/C-vapor pressure isotope effect in CHF/sub 3/ was also studied at temperatures between 161/sup 0/ and 205/sup 0/K by a similar method. The construction of a cryostat has progressed as scheduled. The investigation of carbon isotope exchange equilibria between carbon dioxide and various carbamates dissolved in various organic solvents has continued. The five-stage system of Taylor-Ghate design was improved to shorten the transient time. A single stage apparatus was designed, built, and tested. These systems are used to measure the equilibrium constants and various phase equilibria involved in the carbon dioxide--carbamate system. The investigation of the explicit method of total isotope effect has made progress. A satisfactory approximation was found for the classical partition function of a Morse oscillator. The method gives a reasonable result at rho identical with /sup 1///sub 2/..sqrt..(u/sub e//x/sub e/) greater than 1.5. The medium cluster approach was applied to isotopic methanes to investigate the effects of intermolecular distance and mutual orientations of molecules in the liquid upon vapor pressure isotope effect. It was found that all geometrical effects studied tend to vanish as the size of clusters is increased. Isotope effect in the zero-point energy shifts on condensation was calculated on the basis of London dispersion forces in liquid and a semi-empirical molecular orbital theory, and was favorably compared with experimental results. (auth)

• Research Organization: Brooklyn Coll., N.Y. (USA)
• OSTI ID: 7353313
• Report Number(s): COO-3127-14
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400202* -- Isotope Effects
Isotope Exchange
& Isotope Separation
400203 -- Isotope Exchange & Isotope Separation-- (-1987)
ALKANES
AMINES
CARBAMATES
CARBON 12
CARBON 13
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON ISOTOPES
CARBON OXIDES
CARBONIC ACID DERIVATIVES
CARBOXYLIC ACID SALTS
CHALCOGENIDES
CONTROL EQUIPMENT
CRYOSTATS
DESIGN
DEUTERIUM COMPOUNDS
DISTILLATION
ENERGY LEVELS
EQUATIONS
EQUIPMENT
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FLUIDS
HYDROCARBONS
HYDROGEN COMPOUNDS
ISOTOPE EFFECTS
ISOTOPES
ISOTOPIC EXCHANGE
LABELLED COMPOUNDS
LIGHT NUCLEI
LIQUIDS
LOW TEMPERATURE
MASS SPECTROSCOPY
MATHEMATICAL MODELS
MOLECULAR STRUCTURE
NUCLEI
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SOLVENTS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RESEARCH PROGRAMS
RESEARCH PROGRAMS DISTILLATION
SEPARATION PROCESSES
SOLVENTS
SPECTROSCOPY
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
THERMODYNAMICS
THERMOSTATS
VAPOR CONDENSATION
VAPOR PRESSURE