Phenethyl alcohol,or2-phenylethanol,is anorganic compoundwith thechemical formulaC6H5CH2CH2OH.It is a colourless liquid with a pleasant floral odor. It occurs widely in nature, being found in a variety ofessential oils.It is slightly soluble in water (2mlper 100 ml ofH2O), but miscible with mostorganic solvents.The molecule of phenethyl alcohol consists of a phenethyl group (C6H5CH2CH2−) attached to ahydroxyl group(−OH).
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| Names | |
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| IUPAC name
2-Phenylethanol
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| Other names
2-Phenylethanol
Phenethyl alcohol Benzyl carbinol β-Hydroxyethylbenzene Benzeneethanol | |
| Identifiers | |
3D model (JSmol)
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| DrugBank | |
| ECHA InfoCard | 100.000.415 |
| KEGG | |
PubChemCID
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| UNII | |
CompTox Dashboard(EPA)
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| Properties | |
| C8H10O | |
| Molar mass | 122.167g·mol−1 |
| Odor | Soft, like roses |
| Density | 1.017 g/cm3 |
| Melting point | −27 °C (−17 °F; 246 K) |
| Boiling point | 219 to 221 °C (426 to 430 °F; 492 to 494 K) |
| logP | 1.36[2] |
| Hazards | |
| NFPA 704(fire diamond) | |
| Safety data sheet(SDS) | JT Baker MSDS |
Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa).
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Synthesis
editPhenethyl alcohol is prepared commercially via two routes. Most common is theFriedel-Craftsreaction betweenbenzeneandethylene oxidein the presence ofaluminium trichloride.
- C6H6+ CH2CH2O + AlCl3→ C6H5CH2CH2OAlCl2+ HCl
The reaction affords the aluminium alkoxide that is subsequently hydrolyzed to the desired product. The main side product is diphenylethane, which can be avoided by use of excess benzene.Hydrogenationofstyrene oxidealso affords phenethyl alcohol.[3]
Laboratory methods
editPhenethyl alcohol can also be prepared by the reaction betweenphenylmagnesium bromideandethylene oxide:
- C6H5MgBr + (CH2CH2)O → C6H5CH2CH2OMgBr
- C6H5CH2CH2OMgBr +H+→ C6H5CH2CH2OH + MgBr+
Phenethyl alcohol can also be produced bybiotransformationfromL-phenylalanineusing immobilizedyeastSaccharomyces cerevisiae.[4]It is also possible to produce phenethyl alcohol by thereductionofphenylacetic acidusingsodium borohydrideandiodineinTHF.[5]
Occurrence and uses
editPhenethyl alcohol is found in extract ofrose,carnation,hyacinth,Aleppo pine,orange blossom,ylang-ylang,geranium,neroli,andchampaca.It is also anautoantibioticproduced by the fungusCandida albicans.[6]
Fusel alcoholslike phenethyl alcohol are grain fermentation byproducts, and therefore trace amounts of phenethyl alcohol are present inmany alcoholic beverages.
It is therefore a common ingredient in flavors and perfumery, particularly when the odor of rose is desired.[3]It is used as anadditive in cigarettes.It is also used as apreservativeinsoapsdue to its stability inbasic conditions.It is of interest due to itsantimicrobialproperties.
See also
editReferences
edit- ^Merck Index(11th ed.). p. 7185.
- ^"Phenylethyl alcohol_msds".
- ^abFahlbusch, Karl-Georg; Hammerschmidt, Franz-Josef; Panten, Johannes; Pickenhagen, Wilhelm; Schatkowski, Dietmar; Bauer, Kurt; Garbe, Dorothea; Surburg, Horst (2003). "Flavors and Fragrances".Ullmann's Encyclopedia of Industrial Chemistry.doi:10.1002/14356007.a11_141.ISBN978-3-527-30673-2.
- ^Eshkol N, Sendovski M, Bahalul M, Katz-Ezov T, Kashi Y, Fishman A (2009)."Production of 2-phenylethanol from L-phenylalanine by a stress tolerant Saccharomyces cerevisiae strain".Journal of Applied Microbiology.106(2): 534–542.doi:10.1111/j.1365-2672.2008.04023.x.PMID19200319.
- ^Kanth JV, Periasamy M (1991). "Selective Reduction of Carboxylic Acids into Alcohols Using NaBH and I2".Journal of Organic Chemistry.56:5964–5965.doi:10.1021/jo00020a052.
- ^Lingappa, BT; Prasad, M; Lingappa, Y; Hunt, DF; Biemann, K (1969). "Phenethyl alcohol and tryptophol: Autoantibiotics produced by the fungus Candida albicans".Science.163(3863): 192–4.Bibcode:1969Sci...163..192L.doi:10.1126/science.163.3863.192.PMID5762768.S2CID12430791.