Date of Award

Spring 1999

Document Type

Thesis

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 Eafwd vs. ΔHrxn,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: ΔHf°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)

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