Temperature dependence of sulfur solubility in dimethyl sulfoxide and changes in concentration of supersaturated sulfur solutions at 25 °C

Abstract

This is the first systematic study on the isothermal dependence of the solubility of rhombic sulfur in dimethyl sulfoxide at a temperature range of 298–448 K (25–175 °C) using a gravity method. It was found that sulfur solubility is affected not only by the temperature of the solvent, but also by the phase transition of sulfur to monoclinic modification occurring during the dissolution process, as well as by the melting of the rhombic phase of sulfur. It was shown that the concentration of a supersaturated sulfur solution in dimethyl sulfoxide under standard states, obtained by cooling isothermally heated solutions to 298 K (25 °C), increases significantly as the temperature of the isotherm rises, which contrasts with the findings available in the existing literature. Key aspects of sulfur solubility in DMSO are considered.