Benzyl alcohol

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Contents

Benzyl alcohol
Alkohol benzylowy.svg
Benzyl-alcohol-3D-vdW.png
Names
Preferred IUPAC name
Phenylmethanol
(Hydroxymethyl)benzene
Other names
Benzyl alcohol
α-Cresol
α-Toluenol
α-Hydroxytoluene
alpha-Hydroxyphenylmethane
Phenylcarbinol
Benzenemethanol
Benzyl hydroxide
Benzylic acid
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.002.600 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 202-859-9
E number E1519 (additional chemicals)
KEGG
PubChem CID
RTECS number
  • DN3150000
UNII
  • InChI=1S/C7H8O/c8-6-7-4-2-1-3-5-7/h1-5,8H,6H2 Yes check.svgY
    Key: WVDDGKGOMKODPV-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C7H8O/c8-6-7-4-2-1-3-5-7/h1-5,8H,6H2
    Key: WVDDGKGOMKODPV-UHFFFAOYAH
  • c1ccc(cc1)CO
  • c1ccc(cc1)CO
Properties [1]
C7H8O
Molar mass 108.140 g·mol−1
AppearanceColorless liquid
Odor Slightly aromatic
Density 1.044 g/cm3
Melting point −15.2 °C (4.6 °F; 257.9 K)
Boiling point 205.3 °C (401.5 °F; 478.4 K)
3.50 g/100 mL (20 °C)
4.29 g/100 mL (25 °C)
Solubility in other solventsSoluble[ vague ] in benzene, methanol, chloroform, ethanol, ether, acetone
log P 1.10
Vapor pressure 0.18 kPa (60 °C)
Acidity (pKa)15.40
−71.83·10−6 cm3/mol
1.5396
Viscosity 5.474 cP
1.67 D
Thermochemistry
Std molar
entropy (S⦵298)
217.8 J/(K·mol)
−352 kJ/mol
Hazards
NFPA 704 (fire diamond)
NFPA 704.svgHealth 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
Flash point 93 °C (199 °F; 366 K)
436 °C (817 °F; 709 K)
Explosive limits 1.3–13%
Lethal dose or concentration (LD, LC):
1250 mg/kg (rat, oral)
Safety data sheet (SDS) External MSDS
Pharmacology
P03AX06 ( WHO )
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Benzyl alcohol (also known as α-cresol ) is an aromatic alcohol with the formula C6H5CH2OH. The benzyl 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 as a solvent for its polarity, low toxicity, and low vapor pressure. Benzyl alcohol has moderate solubility in water (4 g/100 mL) and is miscible in alcohols and diethyl ether. The anion produced by deprotonation 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. [2] It is also found in castoreum from the castor sacs of beavers. [3] Benzyl esters also occur naturally. [4]

Preparation

Benzyl alcohol is produced industrially from toluene 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. [5]

For laboratory use, Grignard reaction of phenylmagnesium bromide (C6H5MgBr) with formaldehyde and the Cannizzaro reaction of benzaldehyde also give benzyl alcohol. The latter also gives benzoic acid, an example of an organic disproportionation reaction.

Reactions

Like most alcohols, it reacts with carboxylic acids to form esters. In organic synthesis, benzyl esters are popular protecting groups because they can be removed by mild hydrogenolysis. [6]

Benzyl alcohol reacts with acrylonitrile to give N-benzylacrylamide. This is an example of a Ritter reaction: [7]

C6H5CH2OH + NCCHCH2 → C6H5CH2N(H)C(O)CHCH2

Applications

Benzyl alcohol is used as a general solvent for inks, waxes, shellacs, paints, lacquers, and epoxy resin coatings. Thus it can be used in paint strippers, especially when combined with compatible viscosity enhancers to encourage the mixture to cling to painted surfaces. [8]

It is a precursor to a variety of esters and ethers, used in the soap, perfume, and flavor industries. E.g. benzyl benzoate, benzyl salicylate, benzyl cinnamate, dibenzyl ether, benzyl butyl phthalate.

It can be used as a local anesthetic, especially with epinephrine. [9]

As a dye solvent, it enhances the process of dying wool, nylon, and leather. [10]

Use in health care

Benzyl alcohol is used as a bacteriostatic preservative at low concentration in intravenous medications, cosmetics, and topical drugs. [11] 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. [11] [12]

Benzyl alcohol, sold under the brand name Ulesfia, was approved by the U.S. Food and Drug Administration (FDA) in 2009, as a 5% solution for the treatment of head lice in people 6 months of age and older. [13] It affects the louse's spiracles, preventing them from closing. [13] These then become clogged with water or mineral oil or other matter and cause the insect to die from asphyxiation. [13]

Benzyl alcohol is used effectively for treating lice infestations as the active ingredient in lotion shampoo with 5% benzyl alcohol. [13]

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.

Safety

Sensitization to benzyl alcohol occurs very rarely, mainly in patients with stasis dermatitis. [14]

Benzyl alcohol is not considered to be a carcinogen, and no data are available regarding teratogenic or reproductive effects. [5]

Benzyl alcohol has low acute toxicity with an LD50 of 1.2 g/kg in rats. [5] It oxidizes rapidly in healthy individuals to benzoic acid, 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. [15] [16]

Related Research Articles

<span class="mw-page-title-main">Benzoic acid</span> Organic compound (C6H5COOH)

Benzoic acid is a white solid organic compound with the formula C6H5COOH, whose structure consists of a benzene ring with a carboxyl substituent. The benzoyl group is often abbreviated "Bz", thus benzoic acid is also denoted as BzOH, since the benzoyl group has the formula –C6H5CO. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, which was for a long time its only source.

<span class="mw-page-title-main">Carboxylic acid</span> Organic compound containing a –C(=O)OH group

In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group attached to an R-group. The general formula of a carboxylic acid is often written as R−COOH or R−CO2H, sometimes as R−C(O)OH with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion.

<span class="mw-page-title-main">Ester</span> Compound derived from an acid

In chemistry, an ester is a compound derived from an acid in which the hydrogen atom (H) of at least one acidic hydroxyl group of that acid is replaced by an organyl group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well, but not according to the IUPAC.

<span class="mw-page-title-main">Toluene</span> Chemical compound

Toluene, also known as toluol, is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the odor associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) attached to a phenyl group. As such, its systematic IUPAC name is methylbenzene. Toluene is predominantly used as an industrial feedstock and a solvent.

<span class="mw-page-title-main">Solvent</span> Substance dissolving a solute resulting in a solution

A solvent 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 polar molecules, and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within the cell.

<span class="mw-page-title-main">Benzalkonium chloride</span> Surfactant and antiseptic agent

Benzalkonium chloride, also known as alkyldimethylbenzylammonium chloride (ADBAC) and by the trade name Zephiran, is a type of cationic surfactant. It is an organic salt classified as a quaternary ammonium compound. ADBACs have three main categories of use: as a biocide, a cationic surfactant, and a phase transfer agent. ADBACs are a mixture of alkylbenzyldimethylammonium chlorides, in which the alkyl group has various even-numbered alkyl chain lengths.

<span class="mw-page-title-main">Protecting group</span> Group of atoms introduced into a compound to prevent subsequent reactions

A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction. It plays an important role in multistep organic synthesis.

<span class="mw-page-title-main">Benzocaine</span> Local anaesthetic drug

Benzocaine, sold under the brand name Orajel amongst others, is a local anesthetic, belonging to the amino ester drug class, commonly used as a topical painkiller or in cough drops. It is the active ingredient in many over-the-counter anesthetic ointments such as products for oral ulcers. It is combined with antipyrine to form A/B ear drops. In the US, products containing benzocaine for oral application are contraindicated in children younger than two years old. In the European Union, the contraindication applies to children under 12 years of age.

<span class="mw-page-title-main">Lithium diisopropylamide</span> Chemical compound

Lithium diisopropylamide is a chemical compound with the molecular formula LiN(CH 2)2. It is used as a strong base and has been widely utilized due to its good solubility in non-polar organic solvents and non-nucleophilic nature. It is a colorless solid, but is usually generated and observed only in solution. It was first prepared by Hamell and Levine in 1950 along with several other hindered lithium diorganylamides to effect the deprotonation of esters at the α position without attack of the carbonyl group.

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.

<span class="mw-page-title-main">Diethyl azodicarboxylate</span> Chemical compound

Diethyl azodicarboxylate, conventionally abbreviated as DEAD and sometimes as DEADCAT, is an organic compound with the structural formula CH3CH2−O−C(=O)−N=N−C(=O)−O−CH2CH3. Its molecular structure consists of a central azo functional group, RN=NR, flanked by two ethyl ester groups. This orange-red liquid is a valuable reagent but also quite dangerous and explodes upon heating. Therefore, commercial shipment of pure diethyl azodicarboxylate is prohibited in the United States and is carried out either in solution or on polystyrene particles.

<span class="mw-page-title-main">Hippuric acid</span> Chemical compound

Hippuric acid is a carboxylic acid and organic compound. It is found in urine and is formed from the combination of benzoic acid and glycine. Levels of hippuric acid rise with the consumption of phenolic compounds. The phenols are first converted to benzoic acid, and then to hippuric acid and excreted in urine.

<span class="mw-page-title-main">Benzyl benzoate</span> Chemical compound

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 lotion. Typically two to three applications are needed. It is also present in Balsam of Peru, Tolu balsam, and in a number of flowers.

Benzyl chloride, or α-chlorotoluene, is an organic compound with the formula C6H5CH2Cl. This colorless liquid is a reactive organochlorine compound that is a widely used chemical building block.

Toluene toxicity refers to the harmful effects caused by toluene on the body.

The Marcusson apparatus, Dean-Stark apparatus, Dean–Stark receiver, distilling trap, or Dean–Stark Head is a piece of laboratory glassware used in synthetic chemistry to collect water from a reactor. It is used in combination with a reflux condenser and a distillation flask for the separation of water from liquids. This may be a continuous removal of the water that is produced during a chemical reaction performed at reflux temperature, such as in esterification reactions. The original setup by Julius Marcusson was refined by the American chemists Ernest Woodward Dean (1888–1959) and David Dewey Stark (1893–1979) in 1920 for determination of the water content in petroleum.

<span class="mw-page-title-main">Phenethyl alcohol</span> Chemical compound

Phenethyl alcohol, or 2-phenylethanol, is an organic compound with the chemical formula C6H5CH2CH2OH. It is a colourless liquid with a pleasant floral odor. It occurs widely in nature, being found in a variety of essential oils. It is slightly soluble in water, but miscible with most organic solvents. The molecule of phenethyl alcohol consists of a phenethyl group attached to a hydroxyl group.

<span class="mw-page-title-main">Mukaiyama Taxol total synthesis</span>

The Mukaiyama taxol total synthesis published by the group of Teruaki Mukaiyama of the Tokyo University of Science between 1997 and 1999 was the 6th successful taxol total synthesis. The total synthesis of Taxol is considered a hallmark in organic synthesis.

Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is the simplest aromatic aldehyde and one of the most industrially useful.

<span class="mw-page-title-main">Cumyl alcohol</span> Chemical compound

Cumyl alcohol, also called 4-isopropylbenzyl alcohol, is a liquid, hydroxy functional, aromatic organic chemical with formula C10H14O. It has the CAS Registry Number of 536-60-7 and the IUPAC name of (4-propan-2-ylphenyl)methanol. It is REACH registered with the EC number of 208-640-4.

References

  1. ↑ "Benzyl alcohol". Archived from the original on 26 July 2009.
  2. ↑ The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals (11th ed.), Merck, 1989, ISBN   091191028X ,1138
  3. ↑ Dietland Muller-Schwarze (2003). The Beaver: Its Life and Impact. p. 43. ISBN   978-0-8014-5010-5.
  4. ↑ d'Auria, John C.; Chen, Feng; Pichersky, Eran (2002). "Characterization of an Acyltransferase Capable of Synthesizing Benzylbenzoate and Other Volatile Esters in Flowers and Damaged Leaves of Clarkia breweri". Plant Physiology. 130 (1): 466–476. doi:10.1104/pp.006460. PMC   166578 . PMID   12226525.
  5. 1 2 3 Friedrich Brühne; Elaine Wright (2007). "Benzyl Alcohol". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a04_001.
  6. ↑ Furuta, Kyoji; Gao, Qing-Zhi; Yamamoto, Hisashi (1995). "Chiral (Acyloxy)borane Complex-Catalyzed Asymmetric Diels-Alder Reaction: (1R)-1,3,4-Trimethyl-3-Cyclohexene-1-Carboxaldehyde". Organic Syntheses . 72: 86.; Collective Volume, vol. 9, p. 722
  7. ↑ Parris, Chester L. (1962). "N-benzylacrylamide". Organic Syntheses . 42: 16.; Collective Volume, vol. 5, p. 73
  8. ↑ Benzyl alcohol, chemicalland21.com, archived from the original on 21 April 2009, retrieved 14 May 2006
  9. ↑ Wilson, L.; Martin, S. (May 1999). "Benzyl alcohol as an alternative local anesthetic". Annals of Emergency Medicine. 33 (5): 495–499. doi:10.1016/s0196-0644(99)70335-5. PMID   10216324.
  10. ↑ Michael Ash; Irene Ash (2004). Handbook of Preservatives. Synapse Info Resources. p. 292. ISBN   978-1-890595-66-1.
  11. 1 2 H. A. Mashayekhi; M. Rezaee; Sh. S. Garmaroudi; N. Montazeri; S. J. Ahmadi (2011). "Rapid and sensitive determination of benzaldehyde arising from benzyl alcohol used as preservative in an injectable formulation solution using dispersive liquid–liquid microextraction followed by gas chromatography". Anal. Sci. 27 (8): 865–868. doi: 10.2116/analsci.27.865 . PMID   21828928.
  12. ↑ N. N. Sudareva; E. V. Chubarova (2006). "Time-dependent conversion of benzyl alcohol to benzaldehyde and benzoic acid in aqueous solutions". J. Pharm. Biomed. Anal. 41 (4): 1380–1385. doi:10.1016/j.jpba.2006.02.028. PMID   16564153.
  13. 1 2 3 4 "Ulesfia- benzyl alcohol lotion". DailyMed. 8 April 2019. Retrieved 27 April 2020.
  14. ↑ "Registration Dossier - ECHA". echa.europa.eu. Retrieved 20 April 2023.
  15. ↑ Carl R. Baum (2008), "Examples of mass exposures involving the pediatric population", in Jerrold B. Leikin; Frank P. Paloucek (eds.), Poisoning and Toxicology Handbook (4th ed.), Informa, p. 726.
  16. ↑ Juan Gershanik; et al. (1982), "The gasping syndrome and benzyl alcohol poisoning", N Engl J Med , 307 (22): 1384–8, doi:10.1056/nejm198211253072206, PMID   7133084 .
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