Methanediol

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Methanediol
Skeletal formula of methanediol with some explicit hydrogens added
Spacefill model of methanediol
Ball and stick model of the methanediol
Names
Preferred IUPAC name
Methanediol[1]
Other names
  • Formaldehyde hydrate
  • Formaldehyde monohydrate
  • Methylene glycol
Identifiers
  • 463-57-0 checkY
3D model (JSmol)
Abbreviations MADOL
1730798
ChEBI
ChemSpider
ECHA InfoCard 100.006.673 Edit this at Wikidata
EC Number
  • 207-339-5
UNII
  • InChI=1S/CH4O2/c2-1-3/h2-3H,1H2 checkY
    Key: CKFGINPQOCXMAZ-UHFFFAOYSA-N checkY
  • OCO
Properties
CH4O2
Molar mass 48.041 g·mol−1
Appearance Colourless liquid
Density 1.199 g cm−3[citation needed]
Boiling point 194 °C (381 °F; 467 K) at 101 kPa[citation needed]
Vapor pressure 16.1 Pa[citation needed]
Acidity (pKa) 13.29[2]
1.401[citation needed]
Hazards
Flash point 99.753 °C (211.555 °F; 372.903 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY  (what is checkY☒N ?)
Infobox references

Methanediol, also known as formaldehyde monohydrate or methylene glycol, is an organic compound with chemical formula CH2(OH)2. It is the simplest geminal diol. It is not encountered in pure form, but as aqueous solutions, where it coexists with oligomers (short polymers). The compound is well characterized but of less technological significance than related paraformaldehyde ((CH2O)n), formaldehyde (H2C=O), and 1,3,5-trioxane ((CH2O)3).[3]

Methanediol is a product of the hydration of formaldehyde. The equilibrium constant for hydration is estimated to be 103,[4] CH2(OH)2 predominates in dilute (<0.1%) solution. In more concentrated solutions, it oligomerizes to HO(CH2O)nH.[3]

Occurrence[]

The dianion, methanediolate, is believed to be an intermediate in the crossed Cannizzaro reaction.

The compound is of some relevance to astrochemistry.[5]

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,[6][7] but the risk has been disputed.[8]

See also[]

References[]

  1. ^ "Methanediol - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification and Related Records. Retrieved 20 October 2011.
  2. ^ Bell, R. P.; McTigue, P. T. (1960). "603. Kinetics of the aldol condensation of acetaldehyde". Journal of the Chemical Society (Resumed): 2983. doi:10.1039/JR9600002983.
  3. ^ a b Reuss, Günther; Disteldorf, Walter; Gamer, Armin Otto; Hilt, Albrecht (2000). "Formaldehyde". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a11_619.
  4. ^ Eric V. Anslyn, Dennis A. Dougherty (2006), Modern physical organic chemistry. University Science Books. ISBN 1-891389-31-9. 1095 pages
  5. ^ Garrod, Robin T.; Weaver, Susanna L. Widicus; Herbst, Eric (2008). "Complex Chemistry in Star‐forming Regions: An Expanded Gas‐Grain Warm‐up Chemical Model". The Astrophysical Journal. 682 (1): 283–302. arXiv:0803.1214. Bibcode:2008ApJ...682..283G. doi:10.1086/588035.
  6. ^ "Hair Smoothing Products That Could Release Formaldehyde". www.osha.gov. Occupational Safety and Health Administration.
  7. ^ SpecialChem. "Industry News".
  8. ^ Golden, R.; Valentini, M. (July 2014). "Formaldehyde and methylene glycol equivalence: Critical assessment of chemical and toxicological aspects". Regulatory Toxicology and Pharmacology. 69 (2): 178–186. doi:10.1016/j.yrtph.2014.03.007. PMID 24709515.
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