NMR-STUDY OF EPSILON-CAPROLACTAM IN VARIOUS SOLVENTS - GRAPHICAL DETERMINATION OF MONOMER SHIFT, DIMER SHIFT AND DIMERIZATION CONSTANT FROM THE DILUTION SHIFT DATA

Abstract

A graphical method for the simultaneous determination of the monomer shift, dimer shift and dimerization constant of a self-association system from the dilution NMR shift data is proposed. This method avoids the conventional extrapolation to infinite dilution to obtain the monomer shift. Three self-association systems: epsilon-caprolactam in [H-2(1)]chloroform, [H-2(3)]acetone and [H-2(3)]acetonitrile were studied at various temperatures. The enthalpy and entropy of dimerization were also determined from van't Hoff plots.