Benzyl alcohol is an

aromatic In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to satur ...

alcohol with the formula C₆H₅CH₂OH. The

benzyl In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure . Benzyl features a benzene ring () attached to a methylene group () group. Nomenclature In IUPAC nomenclature, the prefix benzyl refers to a substi ...

group is often abbreviated "Bn" (not to be confused with "Bz" which is used for benzoyl), thus benzyl alcohol is denoted as BnOH. Benzyl alcohol is a colorless liquid with a mild pleasant aromatic odor. It is a useful solvent due to its polarity, low toxicity, and low

vapor pressure Vapor pressure (or vapour pressure in English-speaking countries other than the US; see spelling differences) or equilibrium vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phas ...

. Benzyl alcohol has moderate

solubility In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solub ...

in water (4 g/100 mL) and is miscible in alcohols and

diethyl ether Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable li ...

. The

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

produced by

deprotonation Deprotonation (or dehydronation) is the removal (transfer) of a proton (or hydron, or hydrogen cation), (H+) from a Brønsted–Lowry acid in an acid–base reaction.Henry Jakubowski, Biochemistry Online Chapter 2A3, https://employees.csbsju. ...

of the alcohol group is known as benzylate or benzyloxide.

Natural occurrences

Benzyl alcohol is produced naturally by many plants and is commonly found in fruits and teas. It is also found in a variety of essential oils including jasmine, hyacinth and

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 ...

. It is also found in

castoreum Castoreum is a yellowish exudate from the castor sacs of mature beavers. Beavers use castoreum in combination with urine to scent mark their territory. Both beaver sexes have a pair of castor sacs and a pair of anal glands, located in two cavitie ...

from the castor sacs of beavers. Benzyl esters also occur naturally.

Preparation

Benzyl alcohol is produced industrially from

toluene Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) a ...

via benzyl chloride, which is hydrolyzed: : C₆H₅CH₂Cl + H₂O → C₆H₅CH₂OH + HCl Another route entails hydrogenation of benzaldehyde, a by-product of the oxidation of toluene to

benzoic acid Benzoic acid is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, ...

. For laboratory use,

Grignard reaction The Grignard reaction () is an organometallic chemical reaction in which alkyl, allyl, vinyl, or aryl-magnesium halides (Grignard reagent) is added to a carbonyl group in an aldehyde or ketone. This reaction is important for the formation of ...

of phenylmagnesium bromide (C₆H₅MgBr) with

formaldehyde Formaldehyde ( , ) (systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section ...

and the

Cannizzaro reaction The Cannizzaro reaction, named after its discoverer Stanislao Cannizzaro, is a chemical reaction which involves the base-induced disproportionation of two molecules of a non-enolizable aldehyde to give a primary alcohol and a carboxylic acid. ...

of benzaldehyde also give benzyl alcohol. The latter also gives benzoic acid, an example of an organic

disproportionation In chemistry, disproportionation, sometimes called dismutation, is a redox reaction in which one compound of intermediate oxidation state converts to two compounds, one of higher and one of lower oxidation states. More generally, the term can ...

reaction.

Reactions

Like most alcohols, it reacts with carboxylic acids to form

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides a ...

s. In organic synthesis, benzyl esters are popular protecting groups because they can be removed by mild hydrogenolysis. Benzyl alcohol reacts with

acrylonitrile Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid although commercial samples can be yellow due to impurities. It has a pungent odor of garlic or onions. In terms of its molecula ...

to give ''N''-benzylacrylamide. This is an example of a Ritter reaction: :C₆H₅CH₂OH + NCCHCH₂ → C₆H₅CH₂N(H)C(O)CHCH₂

Applications

Benzyl alcohol is used as a general

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

for inks, waxes, shellacs, paints, lacquers, and epoxy resin coatings. Thus it can be used in paint strippers, especially when combined with compatible

viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...

enhancers to encourage the mixture to cling to painted surfaces. It is a precursor to a variety of

s and

ethers In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be ...

, used in the soap, perfume, and flavor industries. E.g.

benzyl benzoate Benzyl benzoate is an organic compound which is used as a medication and insect repellent. As a medication it is used to treat scabies and lice. For scabies either permethrin or malathion is typically preferred. It is applied to the skin as a ...

benzyl salicylate Benzyl salicylate is a salicylic acid benzyl ester, a chemical compound most frequently used in cosmetics as a fragrance additive or UV light absorber. It appears as an almost colorless liquid with a mild odor described as "very faint, sweet-flor ...

, benzyl cinnamate, dibenzyl ether,

benzyl butyl phthalate Benzyl butyl phthalate (BBP) is an organic compound historically used a plasticizer, but which has now been largely phased out due to health concerns. It is a phthalate ester of containing benzyl alcohol, and ''n''-butanol tail groups. Like mos ...

. It can be used as a local anesthetic, especially with epinephrine. As a dye solvent, it enhances the process of dying wool, nylon, and leather.

Use in health care

Benzyl alcohol is used as a

bacteriostat A bacteriostatic agent or bacteriostat, abbreviated Bstatic, is a biological or chemical agent that stops bacteria from reproducing, while not necessarily killing them otherwise. Depending on their application, bacteriostatic antibiotics, disinfect ...

ic preservative at low concentration in intravenous medications, cosmetics, and topical drugs. Some caution is necessary if a high percent of Benzyl alcohol is used as benzaldehyde arises from benzyl alcohol when used as preservative in an injectable formulation solution. Benzyl alcohol, sold under the brand name Ulesfia, was approved by the U.S.

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...

(FDA) in 2009, as a 5% solution for the treatment of

head lice The head louse (''Pediculus humanus capitis'') is an obligate ectoparasite of humans. Head lice are wingless insects that spend their entire lives on the human scalp and feeding exclusively on human blood. Humans are the only known hosts of thi ...

in people 6 months of age and older. It affects the louse's spiracles, preventing them from closing. These then become clogged with water or mineral oil or other matter and cause the insect to die from

asphyxiation Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects primarily the tissues and organs. There are many circumstances that ca ...

. Benzyl alcohol is used effectively for treating lice infestations as the active ingredient in lotion shampoo with 5% benzyl alcohol.

Contact dermatitis

300px, Illustration of allergic contact dermatitis Benzyl alcohol is an ingredient used in the manufacture of soaps, topical creams, skin lotions, shampoos, and facial cleansers and is popular due to its anti-bacterial and anti-fungal properties. It is a common ingredient in a variety of household products and can cause severe

allergic contact dermatitis Allergic contact dermatitis (ACD) is a form of contact dermatitis that is the manifestation of an allergic response caused by contact with a substance; the other type being irritant contact dermatitis (ICD). Although less common than ICD, ACD is ...

in a significant percentage of the population.

Safety

Benzyl alcohol has low acute toxicity with an of 1.2 g/kg in rats. It oxidizes rapidly in healthy individuals to

, conjugated with glycine in the liver, and excreted as hippuric acid. Very high concentrations can result in toxic effects including respiratory failure, vasodilation, hypotension, convulsions, and paralysis. Benzyl alcohol is toxic to neonates and is associated with the gasping syndrome... Benzyl alcohol is severely toxic and highly irritating to the eye. Pure benzyl alcohol produces

cornea The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical ...

l necrosis.. Benzyl alcohol is not considered to be a carcinogen, and no data are available regarding teratogenic or reproductive effects.

References

External links

* * {{DEFAULTSORT:Benzyl Alcohol Flavors Primary alcohols Alcohol solvents Perfume ingredients Aromatic solvents Benzyl compounds E-number additives Antimicrobials