Name = Benzaldehyde
IUPACName = Benzaldehyde
SystematicName = Benzenecarbaldehyde
ImageFileL1 = Benzaldehyde.png
ImageSizeL1 = 100px
ImageNameL1 = Benzaldehyde
ImageFileR1 = Benzaldehyde-3D-vdW.png
ImageSizeR1 = 120px
ImageNameR1 = Benzaldehyde
OtherNames = Phenylmethanal
Section1 = Chembox Identifiers
SMILES = c1ccccc1C=O
CASNo = 100-52-7
ChemSpiderID = 235
Section2 = Chembox Properties
Appearance = colorless liquid
Density = 1.0415 g/ml, liquid
Solubility = Slightly soluble
(0.6 wt at 20 °C)
MeltingPt = −26 °C
BoilingPt = 178.1 °C
Viscosity = 1.4 cP at 25 °C
Section4 = Chembox Thermochemistry
DeltaHf = −86.8 kJ/mol
DeltaHc = −3525.1 kJ/mol
Section7 = Chembox Hazards
EUClass = Harmful (Xn)
RPhrases = R22
SPhrases = S2, S24
FlashPt = 63 C (Closed Cup)
NFPA-H = 2
NFPA-F = 2
ExternalMSDS = [http://www.jtbaker.com/msds/englishhtml/b0696.htm J. T. Baker]
Section8 = Chembox Related
Benzyl alcohol Benzoic acid
Benzaldehyde (C6H5CHO) is a chemical compound consisting of a
benzenering with an aldehydesubstituent. It is the simplest representative of the aromaticaldehydes and one of the most industrially used members of this family of compounds. At room temperature it is a colorless liquid with a characteristic and pleasant almond-like odor: benzaldehyde is an important component of the scent of almonds, hence its typical odor. It is the primary component of bitter almond oil extract, and can be extracted from a number of other natural sources in which it occurs, such as apricot, cherry, and laurel leaves, peach seeds and, in a glycosidecombined form ( amygdalin), in certain nuts and kernels. Currently benzaldehyde is primarily made from tolueneby a number of different processes.
Benzaldehyde can be obtained by many processes. Currently liquid phase chlorination or oxidation of
tolueneare among the most used processes. There are also a number of discontinued applications such as partial oxidation of benzyl alcohol, alkalitreating of benzal chlorideand reaction between benzene and carbon monoxide.
On oxidation, benzaldehyde is converted into the odorless
benzoic acid. Benzyl alcoholcan be formed from benzaldehyde by means of hydrogenationor by treating the compound with alcoholic potassium hydroxidethus undergoing a simultaneous oxidation and reduction which result in the production of potassium benzoateand benzyl alcohol. Reaction of benzaldehyde with anhydrous sodium acetateand acetic anhydrideyields cinnamic acid, while alcoholic potassium cyanidecan be used to catalyze the condensation of benzaldehyde to benzoin.
Benzaldehyde can also undergo
disproportionationin concentrated alkali (Cannizzaro's reaction): one molecule of the aldehyde is reduced to the corresponding alcohol and another molecule is simultaneously oxidized to the salt of a carboxylic acid. The speed of this reaction depends on the substituents present in the aromatic ring.
While it is commonly employed as a commercial food
flavorant ( almondflavor) or industrial solvent, benzaldehyde is used chiefly in the synthesis of other organic compounds, ranging from pharmaceuticals to plastic additives. It is also an important intermediate for the processing of perfume and flavoring compounds and in the preparation of certain aniline dyes.
The synthesis of
mandelic acidstarts from benzaldehyde:
hydrocyanic acidis added to benzaldehyde and the resulting mandelic acid nitrileis subsequently hydrolysed to a racemic mixtureof mandelic acid. (The scheme above depicts only one of the two formed enantiomers).
Glaciologists LaChapelle and Stillman reported in 1966 that benzaldeyde and
N-heptaldehydeinhibit the recrystallization of snow and therefore the formation of depth hoar. This treatment may prevent avalanches caused by unstable depth hoar layers. However, the chemicals are not in widespread use because they damage vegetation and contaminate water supplies.Fact|date=February 2007
Almonds, apricots, apples and cherry kernels, contain significant amounts of amygdalin. This glycosidebreaks up under enzyme catalysis into benzaldehyde, hydrocyanic acidand two molecules of glucose.
* [http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc01/icsc0102.htm International Chemical Safety Card 0102]
* [http://ecb.jrc.it/ European Chemicals Bureau]
* [http://www.chemicalland21.com/arokorhi/specialtychem/perchem/BENZALDEHYDE.htm Benzaldehyde description at ChemicalLand21.com]
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