Benzaldehyde


Benzaldehyde

Chembox new
Name = Benzaldehyde
IUPACName = Benzaldehyde
SystematicName = Benzenecarbaldehyde
ImageFileL1 = Benzaldehyde.png ImageSizeL1 = 100px
ImageNameL1 = Benzaldehyde
ImageFileR1 = Benzaldehyde-3D-vdW.png ImageSizeR1 = 120px
ImageNameR1 = Benzaldehyde
OtherNames = Phenylmethanal
Benzenecarboxaldehyde
Benzoic aldehyde
Section1 = Chembox Identifiers
SMILES = c1ccccc1C=O
CASNo = 100-52-7
ChemSpiderID = 235

Section2 = Chembox Properties
C=7|H=6|O=1
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
Entropy =

Section7 = Chembox Hazards
EUClass = Harmful (Xn)
RPhrases = R22
SPhrases = S2, S24
FlashPt = 63 C (Closed Cup)
NFPA-H = 2
NFPA-F = 2
NFPA-R =
ExternalMSDS = [http://www.jtbaker.com/msds/englishhtml/b0696.htm J. T. Baker]

Section8 = Chembox Related
Function = aldehydes
OtherFunctn = anisaldehyde
vanillin
OtherCpds = Benzyl alcohol
Benzoic acid

Benzaldehyde (C6H5CHO) is a chemical compound consisting of a benzene ring with an aldehyde substituent. It is the simplest representative of the aromatic aldehydes 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 glycoside combined form (amygdalin), in certain nuts and kernels. Currently benzaldehyde is primarily made from toluene by a number of different processes.

Production

Benzaldehyde can be obtained by many processes. Currently liquid phase chlorination or oxidation of toluene are among the most used processes. There are also a number of discontinued applications such as partial oxidation of benzyl alcohol, alkali treating of benzal chloride and reaction between benzene and carbon monoxide.

Reactions

On oxidation, benzaldehyde is converted into the odorless benzoic acid. Benzyl alcohol can be formed from benzaldehyde by means of hydrogenation or by treating the compound with alcoholic potassium hydroxide thus undergoing a simultaneous oxidation and reduction which result in the production of potassium benzoate and benzyl alcohol. Reaction of benzaldehyde with anhydrous sodium acetate and acetic anhydride yields cinnamic acid, while alcoholic potassium cyanide can be used to catalyze the condensation of benzaldehyde to benzoin.

Benzaldehyde can also undergo disproportionation in 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.

Uses

While it is commonly employed as a commercial food flavorant (almond flavor) 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 acid starts from benzaldehyde:

First hydrocyanic acid is added to benzaldehyde and the resulting mandelic acid nitrile is subsequently hydrolysed to a racemic mixture of mandelic acid. (The scheme above depicts only one of the two formed enantiomers).

Glaciologists LaChapelle and Stillman reported in 1966 that benzaldeyde and N-heptaldehyde inhibit 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

Biology

Almonds, apricots, apples and cherry kernels, contain significant amounts of amygdalin. This glycoside breaks up under enzyme catalysis into benzaldehyde, hydrocyanic acid and two molecules of glucose.

References

External links

* [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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Look at other dictionaries:

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  • Benzaldéhyde — Général Nom IUPAC Aldéhyde benzoïque Synonymes phenylmethanal Ben …   Wikipédia en Français

  • benzaldéhyde — ● benzaldéhyde nom masculin Aldéhyde benzoïque C6H5―CHO, principe odorant de l essence d amande amère. benzaldéhyde [bɛ̃zaldeid] n. m. ÉTYM. XXe, in Larousse 1928; de benz , et aldéhyde. ❖ ♦ Chim. Aldéhyde de formule C6H5–CHO, principe de l es …   Encyclopédie Universelle

  • benzaldehyde — [ben zal′də hīd΄] n. [ BENZ(O) + ALDEHYDE] a clear, volatile, pleasant smelling liquid, C6H5CHO, found in the oil of the bitter almond and used in making dyes, perfumes, chemicals, etc …   English World dictionary

  • benzaldehyde — /ben zal deuh huyd /, n. Chem. a colorless or yellowish, water soluble, volatile oil, C7H6O, having a bitter, almondlike odor, used chiefly in the organic synthesis of dyes, perfumes, and flavors, and as a solvent; artificial oil of bitter almond …   Universalium

  • benzaldehyde — noun a) A chemical compound (CHCHO) consisting of a benzene ring with an aldehyde substituent. benzaldehydes with polar substituents b) Any of various derivatives of benzaldehyde. See Also: benzal …   Wiktionary

  • benzaldehyde — benzaldehidas statusas T sritis chemija formulė C₆H₅CHO atitikmenys: angl. benzaldehyde rus. бензальдегид ryšiai: sinonimas – benzenkarbaldehidas …   Chemijos terminų aiškinamasis žodynas

  • benzaldehyde — A colorless oily liquid used as a flavoring agent and to make dyes, perfumes, and pharmaceuticals. Benzaldehyde is chemically related to benzene …   English dictionary of cancer terms

  • benzaldehyde — noun Etymology: International Scientific Vocabulary Date: circa 1860 a colorless nontoxic aromatic liquid C6H5CHO found in essential oils (as in peach kernels) and used in flavoring and perfumery, in pharmaceuticals, and in synthesis of dyes …   New Collegiate Dictionary

  • benzaldehyde — An aldehyde produced artificially or obtained from oil of bitter almond, containing not less than 80% of b.; a flavoring agent used in orally administered medicines. SYN: benzoic aldehyde. * * * benz·al·de·hyde ben zal də .hīd n a colorless… …   Medical dictionary


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