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NMR Studies on the Effect of Solvents on the Dimerization of Benzoic Acid
Author(s) -
Tsay ShyrJin,
Lin WeiChuwan
Publication year - 1966
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.196600016
Subject(s) - chemistry , dimer , benzoic acid , solvent , chemical shift , monomer , proton , dielectric , solvent effects , proton nmr , population , computational chemistry , organic chemistry , polymer , physics , demography , optoelectronics , quantum mechanics , sociology
The chemical shifts of carboxyl proton in benzoic acid have been measured in a variety of solvents. The characteristic monomer and dimer chemical shifts have been evaluated at 23°. A detailed discussion is given to illustrate the solvent shifts of carboxyl proton, from which the dielectric constant of solvent is considered as the main factor. The plot of carboxyl proton shift against (∈—1)/(∈+1) reveals a roughly linear dependence, indicating that a high field shift will be brought about by an increasing dielectric constant of solvent. Another linear relationship between log (δ—δ D ) and log ∈ suggests that an increase of ∈ will destroy the cyclic dimer, leading to an increase of the monomeric population and therefore to a higher field of the carboxyl proton signal.