β Scribed by L. Kimtys
No coin nor oath required. For personal study only.
The carboxyl proton chemical shifts of neat trimethylacetic acid and its solutions in cyclohexane have been measured as a function of temperature. Formation, at the melting point, of a carboxyl group satellite line on the low field side has been found. The intensity of this satellite line rises with decreasing temperature, whereas the intensity of the main line decreases. The chemical shifts of the monomer (Ξ΄~m~ = 4Β·9 Β± 0Β·6 ppm) and dimers, the equilibrium constants, enthalpy (Ξ__H__ = β(11Β·3 Β± 0Β·6) kcal/mol) and entropy (Ξ__S__ = β(13Β·5 Β± 0Β·7) cal/mol. degree) changes have been calculated using the concentration dependence of the chemical shifts of trimethylacetic acid in cyclohexane solutions at various temperatures. The chemical shift of the satellite line has been shown to correspond to the chemical shift of the cyclic dimers of the acid.
π SIMILAR VOLUMES
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