Patent ID: 6414194
Filing Date: 2002-07-02
Classification: C07C

Abstract:
A process for solidifying dimethylsulfoxide, comprising the steps of:a. providing a liquid phase comprising dimethylsulfoxide and one or more impurities, b. partially solidifying the liquid phase to form a mixture comprising solid dimethylsulfoxide and a liquid residue, wherein the liquid residue comprises liquid dimethylsulfoxide and at least a portion of the impurities, and c. substantially separating the solid dimethylsulfoxide from the liquid residue, wherein the process does not include the step of recycling the liquid residue such that the recycle results in subsequent treatment of the liquid residue by a solidification step b, and the dimethylsulfoxide separated in step c is not subsequently subjected to step b, and the ultraviolet absorbance of the separated dimethylsulfoxide at 275 nanometers is less than 0.20, and the ratio of the ultraviolet absorbance at 295 nanometers to the absorbance at 275 nanometers is less than 0.45, wherein the ultraviolet absorbance spectrum of the separated dimethylsulfoxide is measured as a liquid between 270 and 350 nanometers in a 1 centimeter cell at a temperature of less 20Â° C. using water as a blank.