Benzoin

Not to be confused with Benzoin resin.

Benzoin

Names
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	119-53-9 Y
ChEBI	CHEBI:17682 Y
ChEMBL	ChEMBL190677 Y
ChemSpider	8093 Y
Jmol 3D model	Interactive image Interactive image
KEGG	C01408 Y
PubChem	8400
UNII	L7J6A1NE81 Y
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
SMILES O=C(c1ccccc1)C(O)c2ccccc2 c1ccc(cc1)C(C(=O)c2ccccc2)O
Properties
Chemical formula	C14H12O2
Molar mass	212.25 g·mol−1
Appearance	off-white crystals
Density	1.31 g/cm3
Melting point	132 to 137 °C (270 to 279 °F; 405 to 410 K)
Boiling point	344 °C (651 °F; 617 K)
Solubility in water	Slightly Soluble
Solubility in ethanol	Slightly Soluble
Solubility in alcohol	Soluble
Solubility in ether	Slightly Soluble
Solubility in chlorine	Soluble
Vapor pressure	{{{value}}}
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

Benzoin (/ˈbɛnzoʊ.ᵻn/ 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. The catalytic synthesis by the benzoin condensation was improved by Nikolay Zinin during his time with Liebig.

Uses

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

Preparation

Benzoin is prepared from benzaldehyde via the benzoin condensation.

External links

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