Kinetic Studies of Bimolecular Nucleophilic Substitution. IV. Rates of the SN2 and E2 Reactions of β-Substituted Ethyl Chlorides with Sodium Acetate in Aqueous Solutions

Rates in the SN2 and E2 reactions of a series of β-substituted ethyl chloride (RCH2CH2Cl, R=Et, MeO, PhO, Gl, and H) in aqueous solutions have been measured at temperatures ranging from 90 to 150°C, using sodium acetate as a nucleophile. The mild rate-retarding effect of β-subtituents in the SN2 reactions, observed in the rate order, H>Et>MeO>Cl>PhO, may be attributed to the steric effects. In a similar fashion, the retardation of E2 reaction rates by the β-substituents, which is in the rate sequence H>MeO>Et>PhO>Cl, may be ascribed to the steric effects, which outweigh the electronic effects. The β-substituent effects of several other substituents, which are known in the literature, have also been discussed.

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