Solvent theory

A) In addition to the more modem Bronsted and Lewis theories, it is important not to forget the classic Arrhenius theory in its modern form, the so-called solvents theory, where it can be applied, i.e., with solvents that undergo self-dissociation in this form it was originally formulated in 1949 by Jander3 in Germany and is illustrated by the following reaction equations ... 

B) From the foregoing, it is clear that the Arrhenius or solvents theory cannot work for aprotic solvents most adequate here is the Bransted-Lowry or proton theory, in which an acid is defined as a proton donor and a base as a proton acceptor, and under conditions such that the acid by donating its proton is converted into its conjugate base, and the base by accepting a proton is converted into its conjugate acid. This mutual relationship is illustrated by the following equilibrium reaction ... 

The above solvents theory (A) and proton theory (B) have shown that in theory the neutrality point (of the pure solvent) lies for the amphiprotic solvents at pH = pKs and for the aprotic protophilic solvents at a pH somewhere between the highest acidity (of the protonated solvent) and an infinitely high pH. However, the true pH of the neutrality point of the solvent can only be obtained from a reliable pH measurement and the problem is whether and how this can be achieved. For water as a solvent, the true pH = - logaH+ = colog aH+ is fixed by the internationally adopted convention E°m ( H2(latm) = 0... 

Spontaneous decarboxylations of carboxylate ions and hydrolyses of aryl phosphate dianions and aryl sulfate monoanions are much faster in organic solvents than in water (Thomson, 1970 Kemp and Paul, 1970 Bunton et al., 1967 Kirby and Varvoglis, 1967). This solvent effect is consistent with the Hughes-Ingold qualitative solvent theory because these reactions involve dispersion of charge in forming the transition state. 

Laity JL, Burstain IG, Appel BR. 1973. Photochemical smog and the atmospheric reactions of solvents. In Tess RW, ed. Solvents theory and practice. Advances in Chemistry Series 124, Washington, DC American Chemical Society, 95-112. 

Levy A. 1973. The photochemical smog reactivity of organic solvents. Solvent theory and practices. American Chemical Society, Washington, DC Adv Chem Ser 124 70-94. 

Nagarajan, R. and K. Ganesh. 1989. Block copolymer self-assembly in selective solvents theory of solubilization in spherical micellefc/lacromolecule 2 4312-4325. 

Excellent discussions of solvent effects on reactions of this type have been given by Popovici and Pop (1957), by Palit (1947) and by Caldin and Peacock (1955). The qualitative Hughes-Ingold solvent theory (Ingold, 1953) predicts that reaction (29), in which uncharged reactants pass to... 

The rate of reaction (31) increases with decreasing solvent polarity. This observation agrees with the Hughes-Ingold solvent theory for reactions of this charge type. 

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