Benzaldehyde 1047095 224654785 2008-07-09T20:52:24Z Rror 6252166 Reverted edits by [[Special:Contributions/65.194.139.10|65.194.139.10]] (using [[WP:HG|Huggle]]) {{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<br />Benzenecarboxaldehyde<br />Benzoic aldehyde | Section1 = {{Chembox Identifiers | SMILES = c1ccccc1C=O | CASNo = 100-52-7 }} | Section2 = {{Chembox Properties | Formula = C<sub>7</sub>H<sub>6</sub>O | MolarMass = 106.13 g/mol | Appearance = colorless liquid | Density = 1.0415 g/ml, liquid | Solubility = Slightly soluble<br /> (0.6 wt at 20 °C) | MeltingPt = &minus;26 °C | BoilingPt = 178.1 °C | Viscosity = 1.4 [[Poise|cP]] at 25 °C }} | Section4 = {{Chembox Thermochemistry | DeltaHf = &minus;86.8 kJ/mol | DeltaHc = &minus;3525.1 kJ/mol | Entropy = }} | Section7 = {{Chembox Hazards | EUClass = Harmful ('''Xn''') | RPhrases = {{R22}} | SPhrases = {{S2}}, {{S24}} | FlashPt = 63 C ([[Pensky-Martens closed cup|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 = [[aldehyde]]s | OtherFunctn = [[anisaldehyde]]<br />[[vanillin]] | OtherCpds = [[Benzyl alcohol]]<br />[[Benzoic acid]] }} }} '''Benzaldehyde''' (C<sub>6</sub>H<sub>5</sub>CHO) 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 [[Bay laurel|laurel]] [[leaf|leaves]], [[peach]] [[seed]]s and, in a [[glycoside]] combined form ([[amygdalin]]), in certain [[Nut (fruit)|nut]]s and [[seed|kernel]]s. Currently benzaldehyde is primarily made from [[toluene]] by a number of different processes. == Production == Benzaldehyde can be obtained by many processes. Currently liquid phase [[Halogenation|chlorination]] or [[redox|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 [[redox|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 [[catalysis|catalyze]] the condensation of benzaldehyde to [[benzoin]]. [[Image:Benzaldehyd-chemical-annizzaro.png|390px|Cannizzaro reaction]] Benzaldehyde can also undergo [[disproportionation]] in concentrated alkali ([[Cannizzaro reaction|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 [[flavour]]ant ([[almond]] flavour) 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 flavouring compounds and in the preparation of certain [[aniline]] [[dye]]s. The synthesis of [[mandelic acid]] starts from benzaldehyde: [[Image:Benzaldehyde-chemical-mandelicacid.png|390px|mandelic acid synthesis]] First [[hydrocyanic acid]] is added to benzaldehyde and the resulting mandelic acid [[nitrile]] is subsequently [[hydrolysis|hydrolysed]] to a [[racemic mixture]] of [[mandelic acid]]. (The scheme above depicts only one of the two formed [[enantiomer]]s). 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 == [[Image:Benzaldehyde-chemical-amygdalin.png|450px|amygdalin]] [[Almond]]s, [[apricot]]s, [[apple]]s 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 == {{unreferenced|date=September 2007}} <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] [[Category:flavors]] [[Category:Aldehydes]] [[Category:Aromatic compounds]] [[Category:Solvents]] [[Category:DEA List I chemicals]] [[cs:Benzaldehyd]] [[de:Benzaldehyd]] [[es:Benzaldehído]] [[fa:بنزآلدهید]] [[fr:Benzaldéhyde]] [[it:Benzaldeide]] [[lv:Benzaldehīds]] [[hu:Benzaldehid]] [[nl:Benzaldehyde]] [[ja:ベンズアルデヒド]] [[pl:Aldehyd benzoesowy]] [[pt:Benzaldeído]] [[ru:Бензойный альдегид]] [[fi:Bentsaldehydi]] [[sv:Bensaldehyd]] [[tr:Benzaldehit]] [[zh:苯甲醛]]