Abstract: Methods and apparatus for purifying DMSO are disclosed including a method of purifying DMSO involving providing a first DMSO composition having impurities; freezing a portion of the first DMSO composition on a first surface to form a second DMSO composition having higher DMSO purity than the first DMSO composition such that a third DMSO composition remains from the unfrozen portion of the first DMSO composition; separating the second DMSO composition from the third DMSO composition; and melting a portion of the second DMSO composition. The freezing of the portion of the first DMSO composition, the separating of the second DMSO composition from the third DMSO composition, and the melting of the portion of the second DMSO composition may happen simultaneously. DMSO purification apparatus employing such methods and other methods are also taught.

Abstract: Methods and apparatus for purifying DMSO are disclosed including a method of purifying DMSO involving providing a first DMSO composition having impurities; freezing a portion of the first DMSO composition on a first surface to form a second DMSO composition having higher DMSO purity than the first DMSO composition such that a third DMSO composition remains from the unfrozen portion of the first DMSO composition; separating the second DMSO composition from the third DMSO composition; and melting a portion of the second DMSO composition. The freezing of the portion of the first DMSO composition, the separating of the second DMSO composition from the third DMSO composition, and the melting of the portion of the second DMSO composition may happen simultaneously. DMSO purification apparatus employing such methods and other methods are also taught.

Abstract: One aspect of this invention relates to processes for solidifying dimethylsufoxide including the steps of partially solidifying a liquid phase including dimethylsulfoxide and one or more impurities, to form a mixture comprising solid dimethylsulfoxide and a liquid residue, and substantially separating the solid dimethylsulfoxide from the liquid residue, wherein the liquid residue comprises liquid dimethylsulfoxide and at least a portion of the impurities, and wherein the liquid residue is not subsequently treated by any step of partial solidification. In certain embodiments of the processes of the invention, ultra-high purity DMSO that exceeds the purity specifications for U.S.P. grade DMSO can be produced by employing solidification, fractional solidification and/or melt crystallization processes.