Chemistry:Methanediol

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Short description: Organic compound (CH2(OH)2); simplest geminal diol
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
3D model (JSmol)
Abbreviations MADOL
1730798
ChEBI
ChemSpider
EC Number
  • 207-339-5
UNII
Properties
CH4O2
Molar mass 48.041 g·mol−1
Appearance Colourless liquid
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).
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Infobox references
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Methanediol, also known as formaldehyde monohydrate or methylene glycol, is an organic compound with chemical formula CH
2
(OH)
2
. It is the simplest geminal diol. In aqueous solutions it coexists with oligomers (short polymers). The compound is closely related and convertible to the industrially significant derivatives paraformaldehyde ((CH
2
O)
n
), formaldehyde (H
2
C=O
), and 1,3,5-trioxane ((CH
2
O)
3
).[3]

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

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.[5]

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.[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] Research funded by the Professional Keratin Smoothing Council (PKSC), an industry association that represents selected manufacturers of professional-use only keratin smoothing products, has disputed the risk.[8]

See also

References

  1. "Methanediol - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification and Related Records. https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=79015. 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. 3.0 3.1 Reuss, Günther; Disteldorf, Walter; Gamer, Armin Otto; Hilt, Albrecht (2000). "Ullmann's Encyclopedia of Industrial Chemistry". 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. 5.0 5.1 Zhu, Cheng; Kleimeier, N. Fabian; Turner, Andrew M.; Singh, Santosh K.; Fortenberry, Ryan C.; Kaiser, Ralf I. (4 January 2022). "Synthesis of methanediol [CH 2 (OH) 2 : The simplest geminal diol"]. Proceedings of the National Academy of Sciences 119 (1): e2111938119. doi:10.1073/pnas.2111938119. PMID 34969838. Bibcode2022PNAS..11911938Z. 
  6. "Hair Smoothing Products That Could Release Formaldehyde". Occupational Safety and Health Administration. https://www.osha.gov/SLTC/formaldehyde/hazard_alert.html. 
  7. SpecialChem. "Industry News". http://www.specialchem4cosmetics.com/markets/hair-care/news.aspx?id=5947&lr=chal2d161210&li=100091733. 
  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.