Methanediol, also known as formaldehyde monohydrate or methylene glycol, is an organic compound with chemical formula . It is the simplest geminal diol. In aqueous solutions it coexists with (short polymers). The compound is closely related and convertible to the industrially significant derivatives paraformaldehyde (), formaldehyde (), and 1,3,5-trioxane ().[
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Methanediol is a product of the hydration of formaldehyde. The equilibrium constant for hydration is estimated to be 103,[
Eric V. Anslyn, Dennis A. Dougherty (2006), Modern physical organic chemistry. University Science Books. . 1095 pages] predominates in dilute (<0.1%) solution. In more concentrated solutions, it oligomerizes to .
Occurrence
The dianion, methanediolate, is believed to be an intermediate in the crossed Cannizzaro reaction.
Gaseous methanediols can be generated by electron irradiation and sublimation of a mixture of methanol and oxygen ices.
Methanediol is believed to occur as an intermediate in the decomposition of carbonyl compounds in the atmosphere, and as a product of ozonolysis on these compounds.
Safety
Methanediol, rather than formaldehyde, is listed as one of the main ingredients of "Brazilian blowout", a hair-straightening formula marketed in the United States. The equilibrium with formaldehyde has caused concern since formaldehyde in hair straighteners is a health hazard.
See also
