Benzoin

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	119-53-9
PubChem	8400
ChemSpider	8093
UNII	L7J6A1NE81
KEGG	C01408
ChEBI	CHEBI:17682
ChEMBL	CHEMBL190677
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 ; Key: ISAOCJYIOMOJEB-UHFFFAOYSA-N 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
	(verify) (what is: /?); Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
	Infobox references

From Wikipedia, the free encyclopedia

Jump to: navigation, search

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.

[edit] 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]

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]

^ 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., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1p0087 ; 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. http://www.arkat-usa.org/ark/journal/2006/I10_General/1798/06-1798JP%20as%20published%20mainmanuscript.asp.

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