Kevill, Dennis N.
M.S. (Master of Science)
Department of Chemistry and Biochemistry
Organochlorine compounds--Mathematical models; Organophophorus compounds--Mathematical models; Solvolysis--Mathematical models
The extended Grunwald-Winstein equation is applied to the solvolysis of dimethyl chlorothiophosphate [(CH[sub 3]O)[sub 2]PSCl] and dimethyl chlorophosphate [(CH[sub 3]O)[sub 2] POCl]. The kinetics of the solvolysis o f both compounds were determined in a variety of pure and binary solvent mixtures. In the Grunwald-Winstein equation k is the specific rate constant in a given solvent mixture and k[sub 0] is the rate constant in 80 % ethanol. Using established values for the solvent nucleophilicities (N[sub r]) and the solvent ionizing power with a chloride-ion leaving group (Y[sub Cl]), the multiple regression analysis of log(k/ko) versus 1N[sub r] + mY[sub Cl] + c gives values for m, the sensitivity to changes in the solvent ionizing power; for l, the sensitivity to changes in the solvent nucleophilicity; and for c. the constant (residual) term. There is reasonable linear relationship between the log(k/ko) and (lN[sub r] + mY[sub Cl]) for both compounds. A comparison with solvolyses of related compounds with phenyl or m-chlorophenyl groups within (RO)[sub 2]POCl is also made. The dimethyl chlorophosphate (1 = 1.27, m 0.47) appears to follow the same mechanism as was discussed in previous related studies by Miller and Abduljaber. The dimethyl chlorothiophosphate varies only a very little from that trend (1 = 1.17, m = 0.55) and unlike for the solvolyses of chloroformate esters, introduction of sulfur does not give any observable movement towards an ionization pathway.
Carver, Jeffrey S., "Application of the extended Grunwald-Winstein equation to the solvolysis of dimethyl chlorophosphate and dimethyl chlorothiophosphate" (1998). Graduate Research Theses & Dissertations. 1502.
viii, 55 pages
Northern Illinois University
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