Benzyl alcohol

Chembox new
Name = Benzyl alcohol
ImageFile = Benzyl-alcohol-2D-skeletal.png ImageSize = 150px
ImageName = Benzyl alcohol
ImageFile1 = Benzyl-alcohol-3D-vdW.png ImageSize1 = 100px
ImageName1 = Benzyl alcohol
IUPACName = Benzyl alcohol
OtherNames = Phenylmethanol
Phenylcarbinol
Section1 = Chembox Identifiers
CASNo = 100-51-6
SMILES = OCc1ccccc1
Section2 = Chembox Properties
C=7|H=8|O=1
Density = 1.044 g/cm³
MeltingPt = -15 °C
BoilingPt = 205 °C
Section7 = Chembox Hazards
ExternalMSDS = [http://www.sciencelab.com/msds.php?msdsId=9927099 ScienceLab.com]

Benzyl alcohol is an organic compound with the formula C₆H₅CH₂OH. The benzyl group is often abbreviated "Bn", 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. Benzyl alcohol is partially soluble in water (4 g/100 mL) and completely miscible in alcohols and ether. It is prepared by the hydrolysis of benzyl chloride using sodium hydroxide::C₆H₅CH₂Cl + NaOH → C₆H₅CH₂OH + NaClIt can also be prepared via a Grignard reaction by reacting phenylmagnesium bromide (C₆H₅MgBr) with formaldehyde, followed by acidification. Like most alcohols, it reacts with carboxylic acids to form esters. 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 y _yl. flavor industries. It is often added to intravenous medication solutions as a preservative due to its bacteriostatic and antipruritic properties. It is also used as a photographic developer.

Illustrative organic synthetic uses

In organic synthesis, benzyl esters are popular protecting groups because they can be removed by mild hydrogenolysis. [OrgSynth | author = Furuta, K.; Gao, Q.-Z.; Yamamoto, H. | title = Chiral (Acyloxy)borane Complex-Catalyzed Asymmetric Diels-Alder Reaction: (1R)-1,3,4-Trimethyl-3-Cyclohexene-1-Carboxaldehyde | collvol = 9 | collvolpages = 722 | year = 1998 | prep = cv9p0722]

BnOH reacts with acrylonitrile to give N-benzylacrylamide. This is an example of a Ritter reaction: [OrgSynth | author = Parris, C. L. | title = N-benzylacrylamide | collvol = 5 | collvolpages = 73 | year = 1973 | prep = cv5p0073] :C₆H₅CH₂OH + NCCHCH₂ → C₆H₅CH₂N(H)C(O)CHCH₂

Nanotechnological uses

Benzyl alcohol has been used as a dielectric solvent for the dielectrophoretic reconfiguration of nanowires. [cite journal | title = Nanowires get reconfigured | author = Alexander Wissner-Gross | date = 19 Oct 2006 | url = http://nanotechweb.org/articles/journal/5/10/2/1 | publisher = Nanotechweb.org]

Use in Health Care

Benzyl alcohol is used as a bacteriostatic preservative at low concentration in intravenous medications. It is oxidized rapidly in healthy individuals to benzoic acid, conjugated with glycine in the liver, and excreted as hippuric acid. High concentrations can result in toxic effects including respiratory failure, vasodilation, hypotension, convulsions, and paralysis. Newborns, especially if critically ill, may not metabolize benzyl alcohol as readily as adults. Reports in the early 1980's of sixteen neonatal deaths associated with the use of saline flush solutions containing benzyl alcohol preservative led to recommendations to avoid its use in neonates. [cite journal | url = http://www.cdc.gov/MMWR/preview/mmwrhtml/00001109.htm | title = Neonatal Deaths Associated With Use Of Benzyl Alcohol — United States | journal = Morbidity and Mortality Weekly Report | date = 11 Jun 1982 | volume = 31 | issue = 22 | pages = 290–1]

Other uses

Benzyl alcohol has nearly the same refraction index of quartz and wool fibre. If a clear quartz object is immersed in benzyl alcohol therefore it becomes almost invisible. This has been used as a method to non-destructively recognize if an object is made of true quartz or not (see Crystal skulls). Similarly, white wool immersed in benzyl alcohol also becomes almost invisible clearly revealing contaminants such as dark & medullated fibres and vegetable matter.

References