Benzoin

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Not to be confused with Benzoin resin.

Benzoin


IUPAC name 2-hydroxy-1,2-di(phenyl)ethanone
Other names 2-hydroxy-2-phenylacetophenone, 2-hydroxy-1,2-diphenylethanone, desyl alcohol, bitter almond oil camphor
Identifiers
CAS number	579-44-2^Y
PubChem	8400
ChemSpider	8093^Y
UNII	L7J6A1NE81^Y
KEGG	C01408^Y
ChEBI	CHEBI:17682^Y
ChEMBL	CHEMBL190677^Y
Jmol-3D images	Image 1 Image 2
SMILES O=C(c1ccccc1)C(O)c2ccccc2 c1ccc(cc1)C(C(=O)c2ccccc2)O
InChI InChI=1S/C14H12O2/c15-13(11-7-3-1-4-8-11)14(16)12-9-5-2-6-10-12/h1-10,13,15H^Y Key: ISAOCJYIOMOJEB-UHFFFAOYSA-N^Y InChI=1/C14H12O2/c15-13(11-7-3-1-4-8-11)14(16)12-9-5-2-6-10-12/h1-10,13,15H Key: ISAOCJYIOMOJEB-UHFFFAOYAO
Properties
Molecular formula	C₁₄H₁₂O₂
Molar mass	212.24 g mol⁻¹
Appearance	off-white crystals
Density	1.31 g/cm³
Melting point	132–137 °C
Boiling point	344 °C
Solubility in water	Slightly Soluble
Solubility in Chlorine	Soluble
Hazards
NFPA 704	1 2 0
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Benzoin (/ˈbɛnzoʊ.ɨn/ or /-ɔɪn/) is an organic compound with the formula PhCH(OH)C(O)Ph. It is a hydroxy ketone attached to two phenyl groups. It appears as off-white crystals, with a light camphor-like odor. Benzoin is synthesized from benzaldehyde in the benzoin condensation. It is chiral and it exists as a pair of enantiomers: (R)-benzoin and (S)-benzoin.

Benzoin is not a constituent of benzoin resin obtained from the benzoin tree (Styrax) or tincture of benzoin. The main component in these natural products is benzoic acid.

History

Benzoin was first reported in 1832 by Justus von Liebig and Friedrich Woehler during their research on oil of bitter almond, which is benzaldehyde with traces of hydrocyanic acid.^[1] The catalytic synthesis by the benzoin condensation was improved by Nikolay Zinin during his time with Liebig.^[2]^[3]

Uses

The main uses of benzoin are as a precursor to benzil, which is a photoinitiator.^[4] The conversion proceeds by organic oxidation using copper(II),^[5] nitric acid, or oxone. In one study, this reaction is carried out with atmospheric oxygen and basic alumina in dichloromethane.^[6]

References

↑ Wöhler, Liebig; Liebig (1832). "Untersuchungen über das Radikal der Benzoesäure". Annalen der Pharmacie 3 (3): 249–282. doi:10.1002/jlac.18320030302.
↑ N. Zinin (1839). "Beiträge zur Kenntniss einiger Verbindungen aus der Benzoylreihe". Annalen der Pharmacie 31 (3): 329–332. doi:10.1002/jlac.18390310312.
↑ N. Zinin (1840). "Ueber einige Zersetzungsprodukte des Bittermandelöls". Annalen der Pharmacie 34 (2): 186–192. doi:10.1002/jlac.18400340205.
↑ Hardo Siegel, Manfred Eggersdorfer "Ketones" in Ullmann's Encyclopedia of Industrial Chemistry Wiley-VCH, 2002 by Wiley-VCH, Wienheim. doi:10.1002/14356007.a15_077
↑ Clarke, H. T.; Dreger.E. E. (1941), "Benzil", Org. Synth. ; Coll. Vol. 1: 87
↑ Konstantinos Skobridis, Vassiliki Theodorou, Edwin Weber (2006). "A very simple and chemoselective air oxidation of benzoins to benzils using alumina". Arkivoc. 06-1798JP: 102–106.

External links

Benzoin synthesis, Organic Syntheses, Coll. Vol. 1, p. 94 (1941); Vol. 1, p. 33 (1921)

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