Temperature-dependent A factor in thermal unimolecular reactions

Journal Article · Thu Jan 11 04:00:00 EST 1979 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100464a017· OSTI ID:6486734

Frost, W

The Laplace transform technique for reconstructing the pressure falloff of the thermal unimolecular rate constant k/sub uni/ is generalized to include the critical energy E/sub 0/ and the temperature-dependent A factor in the form A/sub infinity/'(kT)/sup n/. It is shown that positive n decreases the curvature of the falloff plot and negative n increases it, relative to n = 0. If n is not known in advance, the altered curvature complicates the extrapolation of k/sub uni/ to the limiting high-pressure rate constant k/sub infinity/, especially at high temperatures (e.g., the shock tube). Examples of the decomposition of butane and 2,3-dimethylbutane, for which n is known, illustrate how ignorance of n (which is negative in these cases) could easily lead to an overestimate of k/sub infinity/. 10 figures, 2 tables.

• Research Organization: Laval Univ., Quebec
• OSTI ID: 6486734
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 83:1; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ACTIVATION ENERGY
ALKANES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CYANIDES
DECOMPOSITION
ENERGY
ETHANE
HIGH TEMPERATURE
HYDROCARBONS
INTEGRAL TRANSFORMATIONS
ISOMERIZATION
KINETICS
LAPLACE TRANSFORMATION
LOW PRESSURE
ORGANIC COMPOUNDS
PRESSURE DEPENDENCE
REACTION KINETICS
SHOCK TUBES
TEMPERATURE DEPENDENCE
TRANSFORMATIONS
VERY HIGH TEMPERATURE