Density, refractive index, viscosity and 1H nuclear magnetic resonance measurements of dimethyl sulphoxide at 2 °C intervals in the range 20–60 °C. Structural implications

Abstract

The density, refractive index, kinematic viscosity and 400 MHz ¹H n.m.r. spectra of pure DMSO have been measured very accurately at two degree intervals in the range 20–60 °C. The measurements were analysed statistically to detect marked changes in these physical properties that might indicate a liquid structural transition temperature previously suggested to occur between 40 and 60 °C. Over the temperature range studied it was found that the measurements of density and refractive index varied linearly with temperature, whereas smooth, curved plots were obtained for measurements of kinematic viscosity and ¹H n.m.r. chemical shifts with temperature. There is no evidence from these results that the intermolecular-association structure of DMSO breaks down over the temperature range studied.