In organic chemistry, 3-hydroxybutanal (acetaldol, aldol) is an organic compound with the formula CH3CH(OH)CH2CHO and the structure H3C−CH(OH)−CH2CH=O. It is classified as an aldol (R−CH(OH)−CHR'−C(=O)−R") and the word "aldol" can refer specifically to 3-hydroxybutanal. It is formally the product of the dimerization of acetaldehyde (CH3CHO). A thick colorless or pale-yellow liquid, it is a versatile and valuable intermediate with diverse impacts.[2] The compound is chiral although this aspect is not often exploited.

3-Hydroxybutanal
Skeletal formula of 3-hydroxybutanal
Names
Preferred IUPAC name
3-Hydroxybutanal[1]
Other names
  • Acetaldol
  • 3-Hydroxybutyraldehyde
  • beta-Hydroxybutyraldehyde
  • β-Hydroxybutyraldehyde
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.003.210 Edit this at Wikidata
EC Number
  • 203-530-2
MeSH 3-hydroxybutanal
UNII
  • InChI=1S/C4H8O2/c1-4(6)2-3-5/h3-4,6H,2H2,1H3 checkY
    Key: HSJKGGMUJITCBW-UHFFFAOYSA-N checkY
  • InChI=1/C4H8O2/c1-4(6)2-3-5/h3-4,6H,2H2,1H3
    Key: HSJKGGMUJITCBW-UHFFFAOYAI
  • CC(O)CC=O
Properties
C4H8O2
Molar mass 88.106 g·mol−1
Appearance colorless liquid
Density 0.98 g/mL
Boiling point 162 °C (324 °F; 435 K)
Related compounds
Related aldehydes
Glycolaldehyde

Lactaldehyde

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Production

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Acetaldehyde dimerizes upon treatment with aqueous sodium hydroxide:[2]

2 CH3CHO → CH3CH(OH)CH2CHO + H2O

This is the prototypical aldol reaction.

Reactions and uses

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Dehydration of 3-hydroxybutanal gives crotonaldehyde. Distillation of 3-hydroxybutanal is sufficiently forcing to effect this conversion:[2]

CH3CH(OH)CH2CHO → CH3CH=CHCHO + H2O

Hydrogenation of 3-hydroxybutanal gives 1,3-butanediol:

CH3CH(OH)CH2CHO + H2 → CH3CH(OH)CH2CH2OH

This diol is a precursor to 1,3-butadiene, precursor to diverse polymers.

Polymerization of 3-hydroxybutanal is also spontaneous, but can be stopped with the addition of water.

Aldol has been used in making perfumes and in ore flotation.[3]

Former or niche uses

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It was formerly used in medicine as a hypnotic and sedative.[4]

See also

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References

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  1. ^ "3-hydroxybutanal – Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification and Related Records. Retrieved 13 October 2011.
  2. ^ a b c Kohlpaintner, Christian; Schulte, Markus; Falbe, Jürgen; Lappe, Peter; Weber, Jürgen (2008). "Aldehydes, Aliphatic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a01_321.pub2. ISBN 978-3527306732.
  3. ^ American Heritage Dictionary, 1973.
  4. ^ Hans Brandenberger, Robert A. A. Maes. (1997). Analytical Toxicology: For Clinical, Forensic, and Pharmaceutical Chemists. New York: de Gruyter.