Dimethyl sulfoxide

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Dimethyl sulfoxide (or DMSO) is an organosulfur compound with the formula (CH3)2SO. This colorless liquid is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is miscible in a wide range of organic solvents as well as water.

Properties

Chemical

DMSO will oxidize a primary halide to form an aldehyde, process known as Kornblum oxidation.

Gentle oxidation of DMSO gives dimethyl sulfone.

DMSO will form trimethylsulfoxonium iodide with methyl iodide:

(CH3)2SO + CH3I → [(CH3)3SO]I

Physical

DMSO is a clear, colorless, odorless liquid at standard conditions. It is miscible with a variety of liquids, such as water, alcohol, diethyl ether. As a polar aprotic solvent, DMSO can dissolve a surprising variety of organic and inorganic compounds [1]

Availability

DMSO is available at chemical suppliers. It is also commonly available at pet stores for cleaning dogs ears. In some countries, such as the Russian Federation, DMSO is sold in drugstores (it is useful for making poultices).

Preparation

DMSO can be prepared by oxidizing dimethyl sulfide with oxygen or nitrogen dioxide.

Projects

  • Organic extractions
  • Chemoluminescence of the Luminol-NaOH-DMSO System

Handling

Safety

DMSO penetrates the skin very readily and has the unusual property that many individuals perceive a garlic-like taste in the mouth after contact of DMSO with the skin. DMSO isn't very toxic, but it can act as a pathway to allow any toxic substances dissolved in it straight into the blood stream.

Because DMSO easily penetrates the skin, substances dissolved in DMSO may be quickly absorbed. Glove selection is important when working with DMSO. Butyl rubber, fluoroelastomer, neoprene, or thick (15 mil) latex gloves are recommended. Nitrile gloves, which are very commonly used in chemical laboratories, may protect from brief contact but have been found to degrade rapidly with exposure to DMSO.

Storage

DMSO should be stored in closed bottles, to prevent outside contamination. As it has a high boiling point, very little solvent evaporates over time. However, due to it's high melting point (19°C), DMSO will freeze if kept in a cold place. DMSO will slowly absorb water from air, so if you want to keep it dry, it's best to keep it in sealed containers/bottles, with fresh molecular sieves.

Disposal

DMSO wastes should be mixed with another organic solvent and burned in an incinerator equipped with an afterburner and a scrubber.

References

  1. http://www.gaylordchemical.com/uploads/images/pdfs/literature/102B_english.pdf

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