Thermodynamic and kinetic analysis on Cl.+RCI -- Cl2+R.reactions, CH3CjO+O2= products and CjCHO+O2= products

Author

Jongwoo Lee, New Jersey Institute of Technology

Document Type

Thesis

Date of Award

Spring 5-31-1999

Degree Name

Master of Science in Chemical Engineering - (M.S.)

Department

Chemical Engineering, Chemistry and Environmental Science

First Advisor

Joseph W. Bozzelli

Second Advisor

Robert Pfeffer

Third Advisor

Robert Benedict Barat

Abstract

Thermodynamic Parameters, ΔH°_f(298), S°₍₂₉₈₎ and Cp(T) are evaluated for C₁ and C₂ chlorocarbon molecules and radicals. These thermodynamic properties are used in evaluation and comparison of R.+ Cl₂ => R-Cl + Cl. (defined forward direction) reaction rate constants from the kinetics literature. Data from some 20 reactions in the literature show linearity on a plot of Ea_fwd vs. ΔH_rxn,fwd, yielding a slope of (0.38 ± 0.04) and intercept of (10.10 ± 0.77) kcal/mole. Thermodynamic properties (ΔH°₍₂₉₈₎, S°₍₂₉₈₎ and Cp(T) from 300 to 1500 K) for reactants, adducts, transition states, and products in reactions of CH₃ and C₂H₅ with Cl₂ are calculated using CBSQ//MP2/6-311G(d,p). Evaluated thermodynamic property data are presented for all isomers of the stable molecules CH₃Cl, CH₂Cl₂, CHCl₃, CC1₄, C₂H₅Cl, C₂H₄Cl₂, C₂H₃Cl₃, C₂H₂CI₄, C₂HCl₅, C₂Cl₆, C₂H₃Cl, C₂H₂C2₂, C₂HCl₃, and C₂Cl₄. Evaluated thermodynamic property data are also presented for the alkyl radicals, (including isomers) C·H₂CL·, C·HCl₂, C·Cl₃, C₂H₄Cl·, C₂H₃Cl₂·, C₂H₂Cl₃·, C₂HCl₄·, and C₂Cl₅·, for the olefin radicals (including isomers) C₂H₂Cl·, C₂HCl₂·, and C₂Cl₃;.

Thermodynamic property and chemical kinetic analysis are performed on reactants, intermediates, transition states and products from reactions of the two radicals resulting via H atom abstraction from acetaldehyde: CH₃CjO and CjCHO with molecular oxygen. Density functional and ab initio calculations are utilized to estimate thermodynamic properties: ΔH_f°298, and Cp°(T) 300 - 1500K. Rate constants are estimated as a function of temperature and pressure using QRRK analysis for k(E) and modified strong collision analysis for fall-off for application to atmospheric and combustion kinetic modeling.

The important reaction paths are determined as:

CH₃CjO + O₂ ---> CH 2CO + HO₂ via HO₂ Elimination

CH₃CjO + O₂ ---> CyCOCO=O + OH via OH Elimination

CH₃CjO + O₂ ---> CCOQj (Stabilization)

CjCHO + O₂ ---> CO + C.H₂OOH via H shift (C.H₂OOH rapidly decays to CH₂O + OH)

CjCHO + O₂ ---> CQjCHO (Stabilization)

Recommended Citation

Lee, Jongwoo, "Thermodynamic and kinetic analysis on Cl.+RCI -- Cl2+R.reactions, CH3CjO+O2= products and CjCHO+O2= products" (1999). Theses. 860.
https://digitalcommons.njit.edu/theses/860