Sodium-23 nuclear magnetic resonance of resins and mixed solvent systems

Abstract

The sodium-23 spin-lattice relaxation time (T\) was determined at JO MHz on Dowex 50W-X2 ion exchanger resin as a function of the dielectric constant of the solvent. The relaxation time varied from 24.8 msec in distilled water (D = 78.5) to values too short to determine in water--ethanol mixtures below a dielectric constant of 35. Similar studies were conducted on 250 m m sodium bisulfite (NaHS0 3 ) in a series of aqueous-nonaqueous mixtures. The results indicate that T\ may be expressed as a function of the macroscopic dielectric constant for any binary solvent system. For systems with a dielectric constant greater than 65 the relationship is given by T\ = a exp(bD), where a andb are constants for a particular solvent system.