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. The ...
that consists of a phenethyl group (C
6H
5CH
2CH
2) attached to OH. It is a colourless liquid that is slightly soluble in water (2 ml/100 ml H
2O), 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 chemical formula, formula . It is a cyclic ether and the simplest epoxide: a three-membered Ring (chemistry), ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless a ...
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 ...
.
:C
6H
6 + CH
2CH
2O + AlCl
3 → C
6H
5CH
2CH
2OAlCl
2 + 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 Catalysis, catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or S ...
of
styrene oxide 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 o ...
and ethylene oxide
Ethylene oxide is an organic compound with the chemical formula, formula . It is a cyclic ether and the simplest epoxide: a three-membered Ring (chemistry), ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless a ...
:
: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 amino a ...
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 been o ...
''. 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 appli ...
and iodine
Iodine is a chemical element with the 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 , and boils to a vi ...
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
Hyacinth or Hyacinthus may refer to:
Nature Plants
* Hyacinth (plant), genus ''Hyacinthus''
** ''Hyacinthus orientalis'', common hyacinth
* Grape hyacinth, ''Muscari'', a genus of perennial bulbous plants native to Eurasia
* Hyacinth bean, ''Labl ...
, 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 , exce ...
, 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 in ...
, 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 us ...
''.
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 by ...
in 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 use ...
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.
See also
* 1-Phenylethanol
* Congener
* Wine chemistry
Wine is a complex mixture of chemical compounds in a hydro-alcoholic solution with a pH around 4.
The chemistry of wine and its resultant quality depend on achieving a balance between three aspects of the berries used to make the wine: their sugar ...
* Phenethylamine
Phenethylamine (PEA) is an organic compound, natural monoamine alkaloid, and trace amine, which acts as a central nervous system stimulant in humans. In the brain, phenethylamine regulates monoamine neurotransmission by binding to trace amin ...
References
{{Alcohols
Flavors
Perfume ingredients
Primary alcohols
Phenyl compounds