The effects of temperature and concentration on self-association of octan-3-ol both in pure liquid and CCl 4 solution have been studied by two-dimensional (2D) Fourier transform near-infrared (FT-NIR) correlation spectroscopy, conventional FT-IR spectroscopy, and dielectric measurements. The interpretation of 2D correlation spectra was supported by simulation studies. A particular attention has been paid for comparison of the present results with that previously published for octan-1-ol. The obtained results indicate that population of the free OH groups changes faster than that of the associated species with increasing temperature. This results from the fact that in the open-chain multimers the terminal hydrogen bonds break easier than the interior ones. The open-chain dimers are less favorable than the higher associates due to the lack of the cooperativity effect. Hence, these species appear as a result of temperature-induced dissociation of higher multimers in concentrated solutions and in neat alcohols. At low concentration of alcohol in CCl 4 the nonpolar (cyclic) species dominates. An increase in the concentration of the sample increases the number and length of the linear associates, and this effect is more pronounced for primary alcohols. In octan-1-ol, formation of the linear associates is favored, whereas in octan-3-ol the cyclic species dominates. The present results reveal the presence of at least two kinds of associated species and argue against frequently assumed equilibrium between the monomers and one kind of associates at all concentrations.

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We study the shift in the critical temperature T(c) in binary mixtures in strong electric fields. In experiments we measure the nonlinear dielectric effect (NDE) in a mixture of nitrobenze and n-octane and calculate Piekara's factor. We find that the critical anomaly of Piekara's factor is a function of an electric field strength. We propose to explain this observation as a result of a downward shift of T(c), and this allows us to calculate (∂T(c)/∂E(2)) = (-22 ± 10) × 10(-16) (K m(2))/V(2). In the theoretical part we amend Landau and Lifshitz's formula and show that the downward shift of Tc can be estimated from a simple mean-field theory taking into account the linear and quadratic terms in an expansion of the constitutive relation ε(x) between the electric constant ε and mixture composition x.

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