Phenethyl alcohol, or 2-phenylethanol, is the

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

that consists of a phenethyl group (C₆H₅CH₂CH₂) attached to OH. It is a colourless liquid that is slightly soluble in water (2 ml/100 ml H₂O), but miscible with most organic solvents. It occurs widely in nature, being found in a variety of

essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the o ...

s. It has a pleasant floral odor.

Synthesis

Phenethyl alcohol is prepared commercially via two routes. Most common is the Friedel-Crafts reaction between

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms ...

and

ethylene oxide Ethylene oxide is an organic compound with the formula . It is a cyclic ether and the simplest epoxide: a three-membered ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless and flammable gas with a faintly sw ...

in the presence of

aluminium trichloride Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula . It forms hexahydrate with the formula , containing six water molecules of hydration. Both are colourless crystals, but samples are often contam ...

. :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.

Hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic ...

styrene oxide Styrene oxide is an epoxide derived from styrene. It can be prepared by epoxidation of styrene with peroxybenzoic acid, in the Prilezhaev reaction: Styrene oxide is slightly soluble in water. A trace amount of acid in water causes hydrolysis ...

also affords phenethyl alcohol.

Laboratory methods

Phenethyl alcohol can also be prepared by the reaction between

phenylmagnesium bromide Phenylmagnesium bromide, with the simplified formula , is a magnesium-containing organometallic compound. It is commercially available as a solution in diethyl ether or tetrahydrofuran (THF). Phenylmagnesium bromide is a Grignard reagent. It is ...

and

: :C₆H₅MgBr + CH₂CH₂O → C₆H₅CH₂CH₂OMgBr :C₆H₅CH₂CH₂OMgBr + H⁺ → C₆H₅CH₂CH₂OH Phenethyl alcohol can also be produced by biotransformation from L-

phenylalanine Phenylalanine (symbol Phe or F) is an essential α-amino acid with the formula . It can be viewed as a benzyl group substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of alanine. This essential amin ...

using immobilized yeast ''

Saccharomyces cerevisiae ''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungus microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have b ...

''. It is also possible to produce phenethyl alcohol by the reduction of

phenylacetic acid Phenylacetic acid (PAA; conjugate base phenylacetate), also known by various synonyms, is an organic compound containing a phenyl functional group and a carboxylic acid functional group. It is a white solid with a strong honey-like odor. Endogen ...

using

sodium borohydride Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula Na BH4. This white solid, usually encountered as an aqueous basic solution, is a reducing agent that finds applica ...

and

iodine Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...

in THF.

Occurrence and uses

Phenethyl alcohol is found in extract of

rose A rose is either a woody perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred species and tens of thousands of cultivars. They form a group of plants that can be ...

carnation ''Dianthus caryophyllus'' (), commonly known as the carnation or clove pink, is a species of ''Dianthus''. It is likely native to the Mediterranean region but its exact range is unknown due to extensive cultivation for the last 2,000 years.Med ...

, hyacinth,

Aleppo pine ''Pinus halepensis'', commonly known as the Aleppo pine, also known as the Jerusalem pine, is a pine native to the Mediterranean region. Description ''Pinus halepensis'' is a small to medium-sized tree, tall, with a trunk diameter up to , ex ...

orange blossom Orange Blossom is a French band that plays a mix of electronic and world music. The band was formed in Nantes in 1993 with Pierre-Jean Chabot (known as ''PJ Chabot'') on violin and Jean-Christophe Waechter (known as ''Jay C.'') on percussions ...

ylang-ylang ''Cananga odorata'', known as ylang-ylang ( ) or cananga tree, is a tropical tree that is native to the Philippines, Malaysia, Indonesia, New Guinea, the Solomon Islands, and Queensland, Australia. It is also native to parts of Thailand and Viet ...

geranium ''Geranium'' is a genus of 422 species of annual, biennial, and perennial plants that are commonly known as geraniums or cranesbills. They are found throughout the temperate regions of the world and the mountains of the tropics, but mostly i ...

neroli Neroli oil is an essential oil produced from the blossom of the bitter orange tree (''Citrus aurantium subsp. amara'' or ''Bigaradia''). Its scent is sweet, honeyed and somewhat metallic with green and spicy facets. Orange blossom is also extract ...

, and

champaca ''Magnolia champaca'', known in English as champak (), is a large evergreen tree in the family Magnoliaceae.

. It is also an

autoantibiotic Autotoxicity, meaning self-toxicity, is a biological phenomenon whereby a species inhibits growth or reproduction of other members of its same species through the production of chemicals released into the environment. Like allelopathy, it is a type ...

produced by the fungus ''

Candida albicans ''Candida albicans'' is an opportunistic pathogenic yeast that is a common member of the human gut flora. It can also survive outside the human body. It is detected in the gastrointestinal tract and mouth in 40–60% of healthy adults. It is usu ...

''. It is therefore a common ingredient in flavors and perfumery, particularly when the odor of rose is desired. It is used as an additive in cigarettes. It is also used as a

preservative A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or b ...

soap Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are us ...

s due to its stability in basic conditions. It is of interest due to its

antimicrobial An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals ar ...

properties.

References

{{Alcohols Flavors Perfume ingredients Primary alcohols Phenyl compounds

Synthesis

Laboratory methods

Occurrence and uses

See also

References