benzoin

1. A balsamic resin obtained from certain tropical Asian trees of the genus Styrax and used in perfumery and medicine. Also called benjamin, gum benjamin, Also called gum benzoin.
2. A white or yellowish crystalline compound, C₁₄H₁₂O₂, derived from benzaldehyde.

[Earlier benjoin, from French benjoin and Italian benzoino, both from Arabic lubān jāwī, frankincense of Java.]

A colourless crystalline compound, C₆H₅CHOHCOC₆H₅; m.p. 137°C. It is a condensation product of benzenecarbaldehyde (benzaldehyde), made by the action of sodium cyanide on benzenecarbaldehyde in alcoholic solution. It also occurs naturally as the resin of a tropical tree. It is both a secondary alcohol and a ketone, and gives reactions characteristic of both types of compound.

A balsamic resin from Styrax benzoin and other Styrax species, used chiefly as a topical protectant and antiseptic. Benzoin acts as an expectorant and thus is sometimes used in steam inhalations in treating respiratory disorders.

Benzoin is a tree with a sweet, warm and soothing fragrance. Its penetrating qualities are useful in massage for easing tired muscles. It is used in treating arthritis, bronchitis, chapped skin, coughing, laryngitis, and stress.

Safety Precautions: May cause skin sensitivity and contact dermatitis.

Benzoin
IUPAC name	2-hydroxy-1,2-di(phenyl)ethanone
Identifiers
CAS number	119-53-9
PubChem	8400
SMILES	O=C(c2ccccc2)C(O)c1ccccc1
Properties
Molecular formula	C14H12O2
Molar mass	212.24 g mol−1
Density	1.31 g/cm3
Melting point	137 °C
Boiling point	344 °C
Solubility in water	Slightly Soluble
Solubility in Chlorine	Soluble
Hazards
NFPA 704	1 2 0
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

"Benzoin" is also used to describe benzoin resin, which does not contain the benzoin described on this page.

Benzoin is an organic compound consisting of an ethylene bridge flanked by phenyl groups and with hydroxyl and ketone functional groups. It appears as off-white crystals, with a light camphor odor. Benzoin is synthesized from benzaldehyde in the benzoin condensation.

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.

Contents 1 History 2 Alternative names 3 Uses 4 References

History

Benzoin was first synthesized 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 the research of Nikolay Zinin during his time with Liebig. ^[2][3]

Alternative names

Benzoin is also known by several alternative names:

• 2-Hydroxy-2-phenylacetophenone
• 2-Hydroxy-1,2-Diphenylethanone
• desyl alcohol
• bitter almond oil camphor

Uses

The main uses of benzoin are:

• As a photocatalyst in photopolymerization and as a photoinitiator
• As the raw material for synthesis of benzil by organic oxidation with nitric acid or oxone. In one study, this reaction is carried out with atmospheric oxygen and basic alumina in dichloromethane.^[4]

References

1. ^ Wöhler, Liebig (1832). "Untersuchungen über das Radikal der Benzoesäure". Annalen der Pharmacie 3 (3): 249–282. doi:10.1002/jlac.18320030302. 
2. ^ N. Zinin (1839). "Beiträge zur Kenntniss einiger Verbindungen aus der Benzoylreihe". Annalen der Pharmacie 31 (3): 329–332. doi:10.1002/jlac.18390310312. 
3. ^ N. Zinin (1840). "Ueber einige Zersetzungsprodukte des Bittermandelöls". Annalen der Pharmacie 34 (2): 186–192. doi:10.1002/jlac.18400340205. 
4. ^ 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. 

• Synthesis

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