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| Names | |
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| Preferred IUPAC name Phenylmethanol (Hydroxymethyl)benzene | |
| Other names Benzyl alcohol α-Cresol α-Toluenol α-Hydroxytoluene alpha-Hydroxyphenylmethane Phenylcarbinol Benzenemethanol Benzyl hydroxide | |
| Identifiers | |
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3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.002.600 |
| EC Number |
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| E number | E1519(additional chemicals) |
| KEGG |
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| RTECS number |
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| UNII | |
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| Properties[1] | |
| C7H8O | |
| Molar mass | 108.140 g·mol−1 |
| Appearance | Colorless 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 solvents | Miscible withbenzene,methanol,chloroform,ethanol,ether,acetone |
| logP | 1.10 |
| Vapor pressure | 0.18 kPa (60 °C) |
| Acidity (pKa) | 15.40 |
| −71.83·10−6 cm3/mol | |
Refractive index (nD) | 1.5396 |
| Viscosity | 5.474 cP |
| 1.67 D | |
| Thermochemistry | |
Std molar entropy(S⦵298) | 217.8 J/(K·mol) |
Std enthalpy of formation(ΔfH⦵298) | −352 kJ/mol |
| Hazards | |
| NFPA 704 (fire diamond) | |
| 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): | |
LD50 (median dose) | 1250 mg/kg (rat, oral) |
| Safety data sheet (SDS) | External MSDS |
| Pharmacology | |
| P03AX06 (WHO) | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Benzyl alcohol (also known asα-cresol) is anaromaticalcohol with the formula C6H5CH2OH. Thebenzyl group is often abbreviated "Bn" (not to be confused with "Bz" which is used forbenzoyl), thus benzyl alcohol is denoted as BnOH. Benzyl alcohol is a colorless liquid with a mild pleasant aromatic odor. It is useful as a solvent for its polarity, low toxicity, and lowvapor pressure. Benzyl alcohol has moderatesolubility in water (4 g/100 mL) and ismiscible in alcohols anddiethyl ether. Theanion produced bydeprotonation of the alcohol group is known asbenzylate orbenzyloxide.
Benzyl alcohol is produced naturally by many plants and is commonly found in fruits and teas. It is also found in a variety ofessential oils includingjasmine,hyacinth andylang-ylang.[2] It is also found incastoreum from thecastor sacs of beavers.[3] Benzyl esters also occur naturally.[4]
Benzyl alcohol is produced industrially fromtoluene viabenzyl chloride, which is hydrolyzed:
Another route entails hydrogenation ofbenzaldehyde, a by-product of the oxidation of toluene tobenzoic acid.[5]
For laboratory use,Grignard reaction ofphenylmagnesium bromide (C6H5MgBr) withformaldehyde and theCannizzaro reaction of benzaldehyde also give benzyl alcohol. The latter also gives benzoic acid, an example of an organicdisproportionation reaction.
Like most alcohols, it reacts withcarboxylic acids to formesters. In organic synthesis, benzyl esters are popularprotecting groups because they can be removed by mildhydrogenolysis.[6][failed verification]
Benzyl alcohol reacts withacrylonitrile to giveN-benzylacrylamide. This is an example of aRitter reaction:[7]
Benzyl alcohol is used as a generalsolvent for inks, waxes, shellacs, paints,lacquers, andepoxy resin coatings. Thus it can be used in paint strippers, especially when combined with compatibleviscosity enhancers to encourage the mixture to cling to painted surfaces.[8]
It is a precursor to a variety ofesters andethers, used in the soap, perfume, andflavor 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]
Benzyl alcohol is used as abacteriostatic preservative at low concentration in intravenous medications, cosmetics, and topical drugs.[11]
Benzyl alcohol, sold under the brand nameUlesfia, was approved by the U.S.Food and Drug Administration (FDA) in 2009, as a 5% solution for the treatment ofhead lice in people 6 months of age and older.[12] It affects the louse'sspiracles, preventing them from closing.[12] These then become clogged with water or mineral oil or other matter and cause the insect to die fromasphyxiation.[12]
Benzyl alcohol is used effectively for treating lice infestations as the active ingredient in lotion shampoo with 5% benzyl alcohol.[12]
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.
Sensitization to benzyl alcohol occurs very rarely, mainly in patients withstasis dermatitis.[13]
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 anLD50 of 1.2 g/kg in rats.[5] It oxidizes rapidly in healthy individuals tobenzoic acid, conjugated withglycine in the liver, and excreted ashippuric acid. Very high concentrations can result in toxic effects including respiratory failure, vasodilation, hypotension, convulsions, and paralysis.
Benzyl alcohol is toxic toneonates and is associated with thegasping syndrome.[14][15][16]
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