Molecular motion in aqueous mixtures with organic liquids by nmr relaxation measurements

Measurements of the nmr spin‐lattice relaxation time T 1 and of the self‐diffusion coefficient were performed for the organic component, and in some cases for the aqueous component, in binary mixtures of water with an organic liquid over the whole composition range at 25 °C. By isotopic substitution of one component and measurement of either the proton or deuteron resonance, the intramolecular and intermolecular contributions to the relaxation rates including that of water could be separated. From these data the reorientation time which is characteristic of the molecular motion is calculated and the behaviour of the intermolecular contribution is discussed. Comparison of the reorientation times for both components in the mixture leads to informations concerning intermolecular forces in the liquid.