Dimethyl Sulfoxide

Abstract

[67-68-5] C2H6OS (78.13) InChI = 1/C2H6OS/c1-4(2)3/h1-2H3 InChIKey = IAZDPXIOMUYVGZ-UHFFFAOYAR (polar aprotic solvent: acidity scale;2 displacement reactions;3-11 dealkoxycarbonylations;12-21 oxidations;22-31 addition reaction; SnAr; functional group conversion; oxidation of alcohols; Swern; disulfides preparation; selective deprotection) Alternate Name: DMSO. Physical Data: mp 18.4 °C; bp 189 °C; d 0.917 g cm−3. Solubility: miscible with water and numerous organic solvents in all proportions. Form Supplied in: colorless, odorless liquid; widely available. Handling, Storage, and Precautions: is readily absorbed through the skin and should always be handled with gloves in a fume hood; its reactions form foul-smelling byproducts and should be carried out with good ventilation, and the waste byproducts and liquids used for washing should be treated with Potassium Permanganate solution to oxidize volatile sulfur compounds; DMSO undergoes appreciable disproportionation to dimethyl sulfide (stench!) and dimethyl sulfone above 90 °C. DMSO decomposes exothermally while being kept at 150 °C prior to recovery by vacuum distillation. Traces of alkyl bromides lead to a delayed, vigorous, and strongly exothermic reaction at 180 °C. Addition of zinc oxide as a stabilizer extends the induction period and markedly reduces the exothermicity. The proposed retardants, sodium carbonate and zinc oxide, do not affect the decomposition temperature. At temperatures above 200 °C, DMSO shows decomposition to be both faster and more energetic when chloroform or sodium hydroxide is present. Drying: anhydrous material available by vacuum distillation from calcium hydride.