Trichome

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Not to be confused with Benzoin (resin).
For other uses, see Benzoin (disambiguation).
Benzoin
Names
Preferred IUPAC name
2-Hydroxy-1,2-diphenylethan-1-one
Other names
2-Hydroxy-2-phenylacetophenone
2-Hydroxy-1,2-diphenylethanone
Desyl alcohol
Bitter almond oil camphor
Identifiers
3D model (JSmol)
3DMet
391839
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.938 Edit this at Wikidata
KEGG
RTECS number
  • DI1590000
UNII
  • 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 checkY
    Key: ISAOCJYIOMOJEB-UHFFFAOYSA-N checkY
  • 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
  • O=C(c1ccccc1)C(O)c2ccccc2
  • c1ccc(cc1)C(C(=O)c2ccccc2)O
Properties
C14H12O2
Molar mass 212.248 g·mol−1
Appearance Off-white crystals
Density 1.310 g/cm3 (20 °C)[1]
Melting point 135 to 139[1] °C (275 to 282 °F; 408 to 412 K)
Boiling point 330 to 356[1] °C (626 to 673 °F; 603 to 629 K)
Slightly soluble
Solubility in ethanol Very good[1]
Solubility in ether Slightly soluble
Solubility in chlorine Soluble
Solubility in chloroform Very good[1]
Hazards
GHS labelling:
H412
P273, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
1
0
Lethal dose or concentration (LD, LC):
10.000 mg/kg
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Benzoin (/ˈbɛnzoʊ.ɪn/ 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[edit]

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.[2] The catalytic synthesis by the benzoin condensation was improved by Nikolay Zinin during his time with Liebig.[3][4]

Uses[edit]

The main use of benzoin is as a precursor to benzil, which is used as a photoinitiator.[5][6] The conversion proceeds by organic oxidation using copper(II),[7] nitric acid, or oxone. In one study, this reaction is carried out with atmospheric oxygen and basic alumina in dichloromethane.[8]

Benzoin also sees wide spread use in powder coating formulations, where it acts as a degassing agent during the curing stage. This action prevents surface defects such as 'pinholing'.[9][10]

Benzoin can be used in the preparation of several pharmaceutical drugs including oxaprozin, ditazole, and phenytoin.[11]

Preparation[edit]

Benzoin is prepared from benzaldehyde via the benzoin condensation.[12]

References[edit]

  1. ^ a b c d e William M. Haynes (2016). CRC Handbook of Chemistry and Physics (97th ed.). Boca Raton: CRC Press. p. 3-40. ISBN 978-1-4987-5429-3.
  2. ^ Wöhler, Liebig; Liebig (1832). "Untersuchungen über das Radikal der Benzoesäure". Annalen der Pharmacie. 3 (3): 249–282. doi:10.1002/jlac.18320030302. hdl:2027/hvd.hxdg3f.
  3. ^ N. Zinin (1839). "Beiträge zur Kenntniss einiger Verbindungen aus der Benzoylreihe". Annalen der Pharmacie. 31 (3): 329–332. doi:10.1002/jlac.18390310312. Archived from the original on 2022-07-09. Retrieved 2020-09-10.
  4. ^ N. Zinin (1840). "Ueber einige Zersetzungsprodukte des Bittermandelöls". Annalen der Pharmacie. 34 (2): 186–192. doi:10.1002/jlac.18400340205. Archived from the original on 2022-07-09. Retrieved 2019-06-30.
  5. ^ 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
  6. ^ Nakamura, Kenichiro (2015). Photopolymers : photoresist materials, processes, and applications. Boca Raton, FL. ISBN 978-1-4665-1731-8. OCLC 884012539.{{cite book}}: CS1 maint: location missing publisher (link)
  7. ^ Clarke, H. T.; Dreger.E. E. (1941). "Benzil". Organic Syntheses; Collected Volumes, vol. 1, p. 87.
  8. ^ 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.[permanent dead link]
  9. ^ Maxwell, B.E; Wilson, R.C; Taylor, H.A; Williams, D.E; Farnham, W; Tria, J (November 2001). "Understanding benzoin's mode of action in powder coatings". Progress in Organic Coatings. 43 (1–3): 158–166. doi:10.1016/S0300-9440(01)00181-3.
  10. ^ Jahromi, Shahab; Mostert, Ben; Derks, Andreas; Koldijk, Fokelien (December 2003). "Mechanism of action of benzoin as a degassing agent in powder coatings". Progress in Organic Coatings. 48 (2–4): 183–193. doi:10.1016/S0300-9440(03)00096-1.
  11. ^ U.S. patent 2,242,775
  12. ^ Roger Adams; C. S. Marvel (1921). "Benzoin". Organic Syntheses. 1: 33; Collected Volumes, vol. 1, 1941, p. 94.

External links[edit]

  • Benzoin synthesis, Organic Syntheses, Coll. Vol. 1, p. 94 (1941); Vol. 1, p. 33 (1921)
source: https://en.wikipedia.org/wiki/Benzoin_(organic_compound)

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