Grunwald-Winstein equation

Winstein-Grunwald equation An equation which accounts for the effect of solvent... 

The value of m from the Winstein-Grunwald equation (for 2-endo-tosylate 0.69, i.e. between 2-adamantyl tosylate, 0.91, and isopropyl tosylate, m = 0.44)also points to some participation of the solvent. Finally, as shown by Nordlander et al. kjikj, = 30 for the solvolysis of 2-endo-norbornyl tosylate. If this ester was solvolyzed with considerable steric hindrance to ionization the solvent participation would be unusually great while the ratio observed coincides with that for trans-2-methylcyclopentyl tosylate (kjikj = 30). 

In interpreting many aspects of displacement reactions, particularly solvolysis, it is important to be able to characterize the nucleophilicity of the solvent. Assessment of solvent nucleophilicity can be done by comparing rates of a standard substitution process in various solvents. One such procedure is based on the Winstein-Grunwald equation ... 

Univariate LSERs may possess the conventional LEER form, as exemplified by Eq. (8-67), the Grunwald-Winstein equation, or they may simply be plots of log k against a solvent parameter such as Z, (30), or ir. Brownstein developed an LEER form for the latter type of correlation, writing... 

The Hammett equation is not the only LFER." ° Some, like the Hammett equation, correlate structural changes in reactants, but the Grunwald-Winstein relationship (see p. 452) correlates changes in solvent and the Brpnsted relation (see p. 337) relates acidity to catalysis. The Taft equation is a structure-reactivity equation that correlates only field effects. ... 

The extended (two-term) Grunwald-Winstein equation has been applied to the solvolyses of ethyl chloroformate (117) and ethyl chlorothioformate (118). For each substrate, there is evidence for two competing reaction channels. " Solvolysis... 

The specific rates of solvolysis of benzyl p-toluenesulfonate and nine benzylic-ring-substituted derivatives (324) have been satisfactorily correlated using Aij and Tots scales within the extended Grunwald-Winstein equation. The reactions of Z-phenylethyl X-benzenesulfonates (325) with Y-pyridines (326) in acetonitrile at 60 °C have been studied at high pressures. The results indicated that the mechanism of the reaction moves from a dissociative 5)vr2 to an early-type concerted 5)vr2 with increasing pressure. 

Correlation of structure and reactivity in the oxidation of substituted aromatic anils by pyridinium fluorochromate (PFC) has been attempted using Grunwald-Winstein and Hammett equations. The stoichiometry between the substrate and oxidant is 1 2 in the oxidation of cyclic ketones by PFC to 1,2-diketones. PFC oxidation of secondary alcohols has been investigated. ... 

Studies of medium effects on hexacyanoferrate(II) reductions have included those of dioxygen,iodate, peroxodisulfate, - [Co(NH3)5(DMSO)] +, and [Co(en)2Br2]+. Rate constants for reaction with dioxygen depended strongly on the electron-donor properties of the organic cosolvent. Rate constants for reduction of peroxodisulfate in several binary aqueous media were analyzed into their ion association and subsequent electron transfer components. Rate constants for reduction of [Co(en)2Br2] in methanol water and dioxan water mixtures were analyzed by a variety of correlatory equations (dielectric constant Grunwald-Winstein Swain Kamlet-Taft). 

Other examples of linear free energy relationships include the Brpnsted relation, the Grunwald-Winstein relationship, and the Taft equation. See Rho Value... 

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