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| {{chembox
| | Jayson Berryhill is how I'm known as and my wife doesn't like it at all. My day job is an invoicing officer but I've currently applied for another one. Ohio is exactly where his home is and his family members enjoys it. Doing ballet is some thing she would by no means give up.<br><br>Have a look at my blog: psychic chat online ([http://carssocial.com/profile-28063/info/ http://carssocial.com/profile-28063/info/]) |
| | Watchedfields = changed
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| | verifiedrevid = 477238480
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| | ImageFileR1 = Acetaldehyde-tall-2D-skeletal.png
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| | ImageSizeR1 = 75px
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| | ImageNameR1 = Skeletal structure of acetaldehyde
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| | ImageFileL2 = Acetaldehyde-3D-balls.png
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| | ImageSizeL2 = 125px
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| | ImageNameL2 = Ball-and-stick model
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| | ImageFileL1 = Acetaldehyde-2D-flat.svg
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| | ImageNameL1 = Lewis structure of acetaldehyde
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| | ImageSizeL1 = 132px
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| | ImageFileR2 = Acetaldehyde-3D-vdW.png
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| | ImageNameR2 = Space-filling model
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| | IUPACName = ethanal
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| | SystemicName = ethanal
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| | OtherNames=Acetic Aldehyde<br>Ethyl Aldehyde<ref>SciFinderScholar (accessed 4 Nov 2009). Acetaldehyde (75-07-0) Substance Detail.</ref>
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| | Section1 = {{Chembox Identifiers
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| | ChEBI_Ref = {{ebicite|correct|EBI}}
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| | ChEBI = 15343
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| | SMILES = O=CC
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| | PubChem = 177
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| | UNII_Ref = {{fdacite|correct|FDA}}
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| | UNII = GO1N1ZPR3B
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| | KEGG_Ref = {{keggcite|correct|kegg}}
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| | KEGG = C00084
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| | InChI = 1/C2H4O/c1-2-3/h2H,1H3
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| | InChIKey = IKHGUXGNUITLKF-UHFFFAOYAB
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| | SMILES1 = CC=O
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| | StdInChI_Ref = {{stdinchicite|correct|chemspider}}
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| | StdInChI = 1S/C2H4O/c1-2-3/h2H,1H3
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| | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
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| | StdInChIKey = IKHGUXGNUITLKF-UHFFFAOYSA-N
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| | ChEMBL_Ref = {{ebicite|correct|EBI}}
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| | ChEMBL = 170365
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| | CASNo = 75-07-0
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| | CASNo_Ref = {{cascite|correct|CAS}}
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| | EINECS = 200-836-8
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| | RTECS = AB1925000
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| | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
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| | ChemSpiderID=172
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| }}
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| | Section2 = {{Chembox Properties
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| | C=2|H=4|O=1
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| | Appearance = Colourless liquid<br />Etherial odor
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| | Density = 0.784 g·cm<sup>−3</sup> (20 °C) <ref name=Celanese>[http://www.chemvip.com/eurprodbull-acetaldehyde-de.pdf ''Stoffdaten Acetaldehyd bei Celanese Chemicals.''] as of December 1999.</ref>
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| 0.7904–0.7928 g·cm<sup>−3</sup> (10 °C)<ref name=Celanese/>
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| | Solubility = soluble
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| | SolubleOther = miscible with [[ethanol]], [[ether]], [[benzene]], [[toluene]], [[xylene]], [[turpentine]], [[acetone]] <br> slightly soluble in [[chloroform]]
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| | MeltingPtC = −123.37
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| | BoilingPtC = 20.2
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| | Viscosity = ~0.215 at 20 °C
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| | pKa = 13.57
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| | LogP = -0.34
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| | RefractIndex = 1.3316
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| }}
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| | Section3 = {{Chembox Structure
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| | MolShape = trigonal planar (sp²) at C<sub>1</sub><br />tetrahedral (sp³) at C<sub>2</sub>
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| | Dipole = 2.7 [[Debye|D]]
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| }}
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| | Section4 = {{Chembox Thermochemistry
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| | DeltaHf = −166 kJ·mol<sup>−1</sup>
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| | Entropy = 250 J·mol<sup>−1</sup>·K<sup>−1</sup>
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| }}
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| | Section7 = {{Chembox Hazards
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| | ExternalMSDS = [http://www.hmdb.ca/system/metabolites/msds/000/000/889/original/HMDB00990.pdf?1358893258 HMDB]
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| | GHSPictograms = {{GHSp|GHS02}}{{GHSp|GHS07}}{{GHSp|GHS08}}<ref name="sigma">{{Sigma-Aldrich|Fluka|id=00070|name=Acetaldehyde|accessdate=2013-07-20}}</ref>
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| | HPhrases = {{H-phrases|224|319|335|351}}<ref name="sigma" />
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| | PPhrases = {{P-phrases|210|261|281|305+351+338}}<ref name="sigma" />
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| | EUClass = Very flammable ('''F+''')<br />Harmful ('''Xn''')<br />[[Carcinogen|Carc. Cat. 3]]
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| | NFPA-H = 2
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| | NFPA-F = 4
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| | NFPA-R = 2
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| | RPhrases = {{R12}} {{R36/37}} {{R40}}
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| | SPhrases = {{S2}} {{S16}} {{S33}} {{S36/37}}
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| | FlashPtK = 234.15
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| | AutoignitionK = 458.15
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| | ExploLimits = 4.0-60%
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| | LD50 = 1930 mg/kg (rat, oral)
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| }}
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| | Section8 = {{Chembox Related
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| | Function = [[aldehyde]]s
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| | OtherFunctn = [[Formaldehyde]]<br /> [[Propionaldehyde]]
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| | OtherCpds = [[Ethylene oxide]]
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| }}
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| }}
| |
| '''Acetaldehyde''' (systematic name '''ethanal''') is an [[organic compound|organic chemical compound]] with the [[chemical formula|formula]] [[Methyl|CH<sub>3</sub>]][[formyl|CHO]], sometimes abbreviated by chemists as MeCHO (Me = [[methyl]]). It is one of the most important [[aldehyde]]s, occurring widely in nature and being produced on a large scale in industry. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants. It is also produced by the partial oxidation of [[ethanol]] and may be a contributing factor to [[hangover]]s from alcohol consumption, produced in the liver by the enzyme [[alcohol dehydrogenase]]. Pathways of exposure include air, water, land, or groundwater, as well as drink and smoke.<ref>[http://www.epa.gov/chemfact/f_acetal.txt CHEMICALS IN THE ENVIRONMENT: ACETALDEHYDE (CAS NO. 75-07-0)]</ref> Consumption of [[disulfiram]] inhibits [[acetaldehyde dehydrogenase]], the enzyme responsible for the metabolism of acetaldehyde, thereby causing it to build up in the body.
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| ==History==
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| Acetaldehyde was first observed by the Swedish pharmacist/chemist [[Carl Wilhelm Scheele]] (1774);<ref>C. W. Scheele (1774) "Om Brunsten eller Magnesia nigra och dess egenskaper" (On brown-stone or black magnesia [i.e., manganese ore] and its properties), ''Kungliga Svenska vetenskapsakademiens handlingar'' (Proceedings of the Royal Swedish Academy of Sciences), '''35''' : 89-116 ; 177-194. On [http://books.google.com/books?id=5ME4AAAAMAAJ&pg=PA109#v=onepage&q&f=false pages 109-110], Scheele mentions that refluxing ("digesting") ethanol (Alkohol vini) with manganese dioxide (Brunsten) and either hydrochloric acid (Spirtus salis) or sulfuric acid (Spiritus Vitrioli) produces a smell like "Aether nitri" (ethanol treated with nitric acid). Later investigators realized that Scheele had produced acetaldehyde.</ref> it was then investigated by the French chemists [[Antoine François, comte de Fourcroy]] and [[Louis Nicolas Vauquelin]] (1800), and the German chemists [[Johann Wolfgang Döbereiner]] (1821, 1822, 1832)<ref>See:
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| * (Döbereiner) (1821) [http://babel.hathitrust.org/cgi/pt?q1=D%C3%B6bereiner;id=nyp.33433069069122;view=1up;seq=288;start=1;size=10;page=search;num=270#view=1up;seq=287 "Neue Aether"] (A new ether), ''Journal für Chemie und Physik'', '''32''' : 269-270. Döbereiner names the new "ether" "Sauerstoffäther" (oxygen-ether).
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| * (Döbereiner) (1822) [http://babel.hathitrust.org/cgi/pt?num=124&u=1&seq=344&view=1up&size=100&id=nyp.33433069069148&q1=D%C3%B6bereiner#view=1up;seq=140 "Döbereiner's Apparat zur Darstellung des Sauerstoffaethers"] (Döbereiner's apparatus for the preparation of oxygen-ether), ''Journal für Chemie und Physik'', '''34''' : 124-125.
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| * J. W. Döbereiner (1832) [http://books.google.com/books?id=mAYAAAAAMAAJ&pg=PA466#v=onepage&q&f=false "Bildung des Sauerstoff-Aethers durch atmosphärische Oxidation des Alkohols"] (Formation of oxy-ether by atmospheric oxidation of alcohol), ''Journal für Chemie und Physik'', '''64''' : 466-468. In this paper, Döbereiner made acetaldehyde by exposing ethanol vapor to air in the presence of platinum black.</ref> and [[Justus von Liebig]] (1835).<ref>William H. Brock, ''Justus von Liebig: The Chemical Gatekeeper'' (Cambridge, England: Cambridge University Press, 1997), [http://books.google.com/books?id=VugoemP2th0C&pg=PA83#v=onepage&q&f=false pages 83-84].</ref> In 1835, Liebig named it "aldehyde";<ref>J. Liebig (1835) [http://books.google.com/books?id=85c5AAAAcAAJ&pg=PA289#v=onepage&q&f=false "Sur les produits de l'oxidation de l'alcool"] (On the products of the oxidation of alcohol), ''Annales de Chimie et de Physique'', '''59''' : 289-327. From page 290: "Je le décrirai dans ce mémoire sous le nom ''d'aldehyde'' ; ce nom est formé de ''alcool dehydrogenatus''." (I will describe it in this memoir by the name of ''aldehyde'' ; this name is formed from ''alcohol dehydrogenatus''.)</ref> the name was later altered to "acetaldehyde".<ref>The name change occurred at least as early as 1868. See, for example: Eugen F. von Gorup-Besanez, ed., ''Lehrbuch der organischen Chemie für den Unterricht auf Universitäten'' … [Textbook of Organic Chemistry for Instruction at Universities … ], 3rd ed. (Braunschweig, Germany: Friedrich Vieweg und Sohn, 1868), vol. 2, [http://books.google.ca/books?id=UJyCAAAAIAAJ&pg=PA88#v=onepage&q&f=false page 88].</ref>
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| ==Production==
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| In 2003, global production was about 1 million tonnes. Before 1962, ethanol and acetylene were the major sources of acetaldehyde. Since then, ethylene is the dominant feedstock.<ref name=Ull/>
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| The main production method is the oxidation of [[ethylene]] via the [[Wacker process]]. The process involves oxidation of ethylene using a [[homogeneous catalysis|homogeneous]] palladium/copper system:
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| :2 CH<sub>2</sub>=CH<sub>2</sub> + O<sub>2</sub> → 2 CH<sub>3</sub>CHO
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| In the 1970s, the world capacity of this process, the Wacker-Hoechst direct oxidation, increased to over 2×10^6 t/a.
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| Also, when smaller capacities are required, it can also be prepared by the partial [[oxidation]] of ethanol, in an exothermic reaction. This process typically is conducted over a silver catalyst at about 500-650 °C.<ref name=Ull/>
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| : CH<sub>3</sub>CH<sub>2</sub>OH + 1/2O<sub>2</sub> → CH<sub>3</sub>CHO + H<sub>2</sub>O
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| This method is one of the oldest routes for the industrial of preparation of acetaldehyde.
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| Acetaldehyde is produced by the [[hydration]] of [[acetylene]], catalyzed by [[mercury (element)|mercury]] salts. The reaction produces ethenol, which [[tautomer]]izes to acetaldehyde. This industrial route was dominant prior to the [[Wacker process]].<ref name="Dmitry2007">{{Cite journal| title = Hydration of Acetylene: A 125th Anniversary | author = Dmitry A. Ponomarev and Sergey M. Shevchenko | journal = [[J. Chem. Ed.]] | volume = 84 | issue = 10 | year = 2007 | pages = 1725 | url = http://jchemed.chem.wisc.edu/HS/Journal/Issues/2007/OctACS/ACSSub/p1725.pdf | doi = 10.1021/ed084p1725}}</ref> One drawback of this process is the formation of [[polymerization]] and [[condensation]] products of acetaldehyde. Furthermore, the production of acetylene is costly and environmentally problematic. The [[wet oxidation]] process was used before the Wacker process was commercially established. [[Iron(III) sulfate]] is added to reoxidize the mercury metal to the mercury(II) salt to maintain required concentration of catalyst and, thus, avoiding direct handling of mercury. Acetylene reacts at 90-95<sup>o</sup>C and the acetaldehyde formed is separated from water and mercury and cooled to 25-30<sup>o</sup>C. [[Iron(II) sulfate]] is formed in the reaction and is oxidized in a separate reactor with 30% [[nitric acid]] at 95<sup>o</sup>C. Pure acetaldehyde is obtained by [[fractional distillation]] of the aqueous solution at about 200 kPa.
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| ===Other methods===
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| Traditionally but no longer viable economically, acetaldehyde was produced by the partial [[dehydrogenation]] of ethanol:
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| : CH<sub>3</sub>CH<sub>2</sub>OH → CH<sub>3</sub>CHO + H<sub>2</sub>
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| In this endothermic process, ethanol vapor is passed at 260–290°C over a copper-based catalyst. The process was once attractive because of the value of the hydrogen coproduct.<ref name=Ull>Marc Eckert, Gerald Fleischmann, Reinhard Jira, Hermann M. Bolt, Klaus Golka, 'Acetaldehyde' in Ullmann's Encyclopedia Of Industrial Chemistry 2007, Wiley-VCH, Weinheim. {{DOI|10.1002/14356007.a01_031.pub2}}</ref>
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| The [[hydroformylation]] of [[methanol]] catalysts like cobalt, nickel, or iron salts produces acetaldehyde. This process is of no industrial importance. Similarly noncompetitive, acetaldehyde arises from [[synthesis gas]] with modest selectivity.<ref name=Ull/>
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| ==Reactions==
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| Like many other [[carbonyl compound]]s, acetaldehyde [[tautomer]]izes to give the [[enol]]. The enol of acetaldehyde is [[vinyl alcohol]] (IUPAC name: ethenol):
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| :CH<sub>3</sub>CH=O <math>\overrightarrow{\leftarrow}</math> CH<sub>2</sub>=CHOH
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| The [[equilibrium constant]] is only 6 x 10<sup>−7</sup> at room temperature, so that the amount of the enol in a sample of acetaldehyde is very small.<ref>'' Keto-Enol Equilibrium Constants of Simple Monofunctional Aldehydes and Ketones in Aqueous Solution'' Keeffe, J. R., Kresge, A. J., Schepp, N. P., [[Journal of the American Chemical Society]], '''1990''', Volume 112, Pages 4862-4868. [http://pubs.acs.org/doi/abs/10.1021/ja00168a035]</ref>
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| [[File:Ethanal Ethenol Tautomerie.svg|thumb|left|upright=1.3|Ethanal-ethenol tautomerism]]{{clear left}}
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| ===Condensation reactions===
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| Because of its small size and its availability as the anhydrous monomer (unlike formaldehyde), it is a common electrophile in [[organic synthesis]].<ref>Sowin, T. J.; Melcher, L. M. ”Acetaldehyde” in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. {{DOI|10.1002/047084289X}}</ref> With respect to its condensation reactions, acetaldehyde is [[prochiral]]. It is mainly used as a source of the "CH<sub>3</sub>C<sup>+</sup>H(OH)" [[synthon]] in [[aldol condensation|aldol]] and related condensation reactions.<ref name="Behrens2004">{{OrgSynth | author = Behrens, C.; Paquette, L. A. | title = N-Benzyl-2,3-Azetidinedione | collvol = 10 | collvolpages = 41 | year = 2004 | prep = V75P0106}}.</ref> Grignard reagents and organolithium compounds react with MeCHO to give hydroxyethyl derivatives.<ref name="Walter1955">{{OrgSynth | author = Walter, L. A. | title = 1-(α-Pyridyl)-2-Propanol | collvol = 3 | collvolpages = 757 | year = 1955 | prep = cv3p0757}}.</ref> In one of the more spectacular condensation reactions, three equivalents of [[formaldehyde]] add to MeCHO to give [[pentaerythritol]], C(CH<sub>2</sub>OH)<sub>4</sub>.<ref name="Schurink1941">{{OrgSynth | author = Schurink, H. B. J. | title = Pentaerythritol | collvol = 1 | collvolpages = 425 | year = 1941 | prep = CV1P0425}}.</ref>
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| In a [[Strecker amino acid synthesis|Strecker reaction]], acetaldehyde condenses with [[cyanide]] and [[ammonia]] to give, after [[hydrolysis]], the [[amino acid]] alanine.<ref name="Kendall1941">{{OrgSynth | author = Kendall, E. C. McKenzie, B. F. | title = ''dl''-Alanine | collvol = 1 | collvolpages = 21 | year = 1941 | prep = CV1P0021}}.</ref> Acetaldehyde can condense with amines to yield imines, such as the condensation with cyclohexylamine to give N-ethylidenecyclohexylamine. These imines can be used to direct subsequent reactions like an aldol condensation.<ref>{{OrgSynth | author = [[Georg Wittig|Wittig, G.]]; Hesse, A. | title = Directed Aldol Condensations: β-Phenylcinnamaldehyde | collvol = 6 | collvolpages = 901 | year = 1988 | prep = cv6p0901}}.</ref>
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| It is also an important building block for the synthesis of [[heterocyclic compounds]]. A remarkable example is its conversion upon treatment with [[ammonia]] to 5-ethyl-2-methylpyridine ("aldehyde-collidine”).<ref name="Frank1963">{{OrgSynth | author = Frank, R. L.; Pilgrim, F. J.; Riener, E. F. | title = 5-Ethyl-2-Methylpyridine | collvol = 4 | collvolpages = 451 | year = 1963 | prep = CV4P0451}}</ref>
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| ===Acetal derivatives===
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| Three molecules of acetaldehyde condense to form “[[paraldehyde]],” a cyclic trimer containing C-O single bonds. The condensation of four molecules of acetaldehyde give the cyclic molecule called [[metaldehyde]].
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| Acetaldehyde forms a stable [[acetal]] upon reaction with [[ethanol]] under conditions that favor dehydration. The product, CH<sub>3</sub>CH(OCH<sub>2</sub>CH<sub>3</sub>)<sub>2</sub>, is in fact called "acetal".<ref name="Adkins1941">{{OrgSynth | author = Adkins, H.; Nissen, B. H. | title = Acetal | collvol = 1 | collvolpages = 1 | year = 1941 | prep = CV1P0001}}</ref> although [[acetal]] is used more widely to describe other compounds with the formula RCH(OR')<sub>2</sub>
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| ==Biochemistry==
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| In the [[liver]], the [[enzyme]] [[alcohol dehydrogenase]] oxidizes [[ethanol]] into acetaldehyde, which is then further oxidized into harmless [[acetic acid]] by [[acetaldehyde dehydrogenase]]. These two oxidation reactions are coupled with the reduction of NAD<sup>+</sup> to [[NADH]].<ref name="Hipolito, L. 2007">{{cite journal | author1 = Hipolito, L. | author2 = Sanchez, M. J. | author3 = Polache, A. | author4 = Granero, L. | title = Brain metabolism of ethanol and alcoholism: An update | journal = Curr. Drug Metab. | year = 2007 | volume = 8 | pages = 716–727 | doi = 10.2174/138920007782109797 | pmid = 17979660 | issue = 7}}</ref> In the brain, [[alcohol dehydrogenase]] has a minor role in the oxidation of [[ethanol]] to acetaldehyde. Instead, primarily the enzyme [[catalase]] oxidizes ethanol to acetaldehyde.<ref name="Hipolito, L. 2007"/> The last steps of alcoholic [[fermentation (food)|fermentation]] in bacteria, plants, and [[yeast]] involve the conversion of [[pyruvate]] into acetaldehyde and [[carbon dioxide]] by the enzyme [[pyruvate decarboxylase]], followed by the conversion of acetaldehyde into ethanol. The latter reaction is again catalyzed by an alcohol dehydrogenase, now operating in the opposite direction.
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| ==Uses==
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| Traditionally, acetaldehyde was mainly used as a precursor to acetic acid. This application has declined because acetic acid is made more efficiently from methanol by the [[Monsanto process|Monsanto]] and [[Cativa process]]es. In terms of condensation reactions, acetaldehyde is an important precursor to [[pyridine]] derivatives, [[pentaerythritol]], and [[crotonaldehyde]]. Urea and acetaldehyde combine to give a useful [[resin]]. [[Acetic anhydride]] reacts with acetaldehyde to give ethylidene diacetate, a precursor to [[vinyl acetate]], which is used to produce [[polyvinyl acetate]].
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| Global market for acetaldehyde is declining. Demand has been impacted by changes in the production of plasticizer alcohols, which has shifted from [[Butyraldehyde|n-butyraldehyde]] based on acetaldehyde to hydroformylation of [[propylene]]. Likewise, [[acetic acid]], once produced from acetaldehyde, is made predominantly by the lower-cost methanol carbonylation process.<ref>http://www.ihs.com/products/chemical/planning/ceh/acetaldehyde.aspx</ref> The impact on demand has led to increase in prices and thus slowdown in the market.<br />
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| [[File:Production of acetaldehyde.JPG|thumbnail|right|Production Of Acetaldehyde]]
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| Consumption of acetaldehyde (10<sup>3</sup> t) in 2003<ref name=Ull/><br />
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| (* Included in others -glyoxal/glyoxalic acid, crotonaldehyde, lactic acid, n-butanol, 2-ethylhexanol)
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| {| class="wikitable"
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| |-
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| ! Product !! USA !! Mexico !! W. Europe !! Japan !! Total
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| |-
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| | Acetic Acid/Acetic anhydride ||- || 11 || 89 || 47 || 147
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| |-
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| | Acetate esters || 35 || 8 || 54 || 224 || 321
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| |-
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| | Pentaerythritol || 26 || - || 43 || 11 || 80
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| |-
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| | Pyridine and pyridine bases || 73 || - || 10 || * || 83
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| |-
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| | Peracetic acid || 23 || - || - || * || 23
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| |-
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| | 1,3-Butylene glycol || 14 || - || - || * || 14
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| |-
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| | Others || 5 || 3 || 10 || 80 || 98
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| |-
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| | Total || 176 || 22 || 206 || 362 || 766
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| |}
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| [[China]] is the largest consumer of acetaldehyde in the world, accounting for almost half of global consumption in 2012. Major use has been the production of acetic acid. Other uses such as [[pyridine]]s and pentaerythritol are expected to grow faster than acetic acid, but the volumes are not large enough to offset the decline in acetic acid. As a consequence, overall acetaldehyde consumption in [[China]] may grow slightly at 1.6% per year through 2018. Western Europe is the second-largest consumer of acetaldehyde worldwide, accounting for 20% of world consumption in 2012. As with China, the Western European acetaldehyde market is expected to increase only very slightly at 1% per year during 2012–2018. However, [[Japan]] could emerge as a potential consumer for acetaldehyde in next five years due to newfound use in commercial production of [[butadiene]]. The supply of butadiene has been volatile in Japan and the rest of Asia. This should provide the much needed boost to the flat market, as of 2013.<ref>http://www.researchandmarkets.com/research/lc8hz5/acetaldehyde</ref>
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| ==Safety==
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| ===Exposure Limits===
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| The [[Threshold limit value]] is 25ppm (STEL/ceiling value) and the MAK (Maximum Workplace Concentration) is 50 ppm. At 50 ppm acetaldehyde, no irritation or local tissue damage in the nasal mucosa is observed. When taken up by the organism, acetaldehyde is metabolized rapidly in the liver to acetic acid. Only a small proportion is exhaled unchanged. After intravenous injection, the half-life in the blood is approximately 90 seconds.<ref name=Ull/>
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| ===Dangers===
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| ====Toxicity====
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| Acetaldehyde is toxic when applied externally for prolonged periods, an irritant, and a probable carcinogen.<ref name="Chemical Summary For Acetaldehyde"/> It is an [[air pollution|air pollutant]] resulting from combustion, such as automotive exhaust and [[tobacco smoking|tobacco smoke]]. It is also created by [[thermal degradation]] of polymers in the plastics processing industry.<ref>''[http://www.britannica.com/eb/article-242792 Smoking]''. (2006). [[Encyclopædia Britannica]]. Accessed 27 October 2006.</ref> Acetaldehyde naturally breaks down in the human body<ref>http://www.epa.gov/chemfact/f_acetal.txt</ref> but has been shown to excrete in urine of rats.<ref>[http://alcalc.oxfordjournals.org/content/24/2/101.full.pdf Determinations of ethanol, acetaldehyde, and acetate in blood and urine during alcohol oxidation in man]</ref>
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| ====Irritation====
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| Acetaldehyde is an irritant of the skin, eyes, mucous membranes, throat, and respiratory tract. This occurs at concentrations up to 1000 ppm. Symptoms of exposure to this compound include nausea, vomiting, headache. These symptoms may not happen immediately. The perception limit of acetaldehyde in air is in the range between 0.07 and 0.25 ppm.<ref name=Ull/> At such concentrations, the fruity odor of acetaldehyde is apparent. Conjunctival irritations have been observed after a 15-minute exposure to concentrations of 25 and 50 ppm, but transient conjunctivitis and irritation of the respiratory tract have been reported after exposure to 200 ppm acetaldehyde for 15 minutes. It has a general narcotic action and large doses can even cause death by respiratory paralysis. It may also cause drowsiness, delirium, hallucinations, and loss of intelligence. Exposure may also cause severe damage to the mouth, throat, and stomach; accumulation of fluid in the lungs, chronic respiratory disease, kidney and liver damage, throat irritation, dizziness, reddening, and swelling of the skin.
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| ====Carcinogenicity====
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| Acetaldehyde is a probable or possible [[carcinogen]] in humans.<ref name="Chemical Summary For Acetaldehyde">[http://www.epa.gov/chemfact/s_acetal.txt Chemical Summary For Acetaldehyde], US Environmental Protection Agency</ref><ref>{{cite web |url= http://ec.europa.eu/health/ph_risk/committees/sccp/documents/out275_en.pdf|title= Opinion of the Scientific Committee on Cosmetic Products and Non-Food Products Intended for Consumers Concerning Acetaldehyde |author= Scientific Committee on Cosmetic Products and Non-Food Products|date=2004-05-25 |page=11|accessdate=2011-09-28}}</ref> In 1988 the [[International Agency for Research on Cancer]] stated, "There is ''sufficient'' evidence for the carcinogenicity of acetaldehyde (the major metabolite of ethanol) in experimental animals."<ref name="International1988">{{Cite book|title=Alcohol drinking |publisher=[[World Health Organization]], [[International Agency for Research on Cancer]] |location=Lyon |year=1988 |isbn=92-832-1244-4 |url=http://monographs.iarc.fr/ENG/Monographs/vol44/volume44.pdf |author=International Agency for Rescarch on Cancer, World Health Organization.}} p3</ref> In October 2009 the [[International Agency for Research on Cancer]] updated the classification of acetaldehyde stating that acetaldehyde included in and generated endogenously from alcoholic beverages is a Group I human carcinogen.<ref>International Agency for Research on Cancer Monograph Working Group, Special Report: Policy A review of human carcinogens—Part E: tobacco, areca nut, alcohol, coal smoke, and salted fish. The Lancet 2009 10, 1033–1034.</ref> In addition, acetaldehyde is damaging to DNA<ref>http://www.ist-world.org/ResultPublicationDetails.aspx?ResultPublicationId=2c488c559db74d8cae0c14ae5b65e14e</ref> and causes abnormal muscle development as it binds to proteins.<ref name="Nicholas2004">{{Cite journal| journal = [[Alcohol & Alcoholism]] | volume = 39 | issue = 5 | pages = 450–454 | year = 2004 | author = Nicholas S. Aberle, II, Larry Burd, Bonnie H. Zhao and Jun Ren | title = Acetaldehyde-induced cardiac contractile dysfunction may be alleviated by vitamin B<sub>1</sub> but not by vitamins B<sub>6</sub> or B<sub>12</sub> | url = http://alcalc.oxfordjournals.org/cgi/content/full/39/5/450 | doi = 10.1093/alcalc/agh085 | pmid = 15304379}}</ref>
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| ===Aggravating factors===
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| ====Alzheimer's disease====
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| People with a genetic deficiency for the enzyme responsible for the conversion of acetaldehyde into [[acetic acid]] may have a greater risk of [[Alzheimer's disease]]. "These results indicate that the [[ALDH2]] deficiency is a risk factor for LOAD [late-onset Alzheimer's disease] …"<ref name=ohta>{{Cite journal|last= Ohta |first=S |coauthors=Ohsawa I, Kamino K, Ando F, Shimokata H. |date=April 2004 |title=Mitochondrial ALDH2 Deficiency as an Oxidative Stress |trans_title= |journal=Annals of the New York Academy of Sciences |volume=1011 |pages=36–44 |id= |url=http://www3.interscience.wiley.com/journal/118765604/abstract?CRETRY=1&SRETRY=0 |accessdate=13 August 2009 |quote= |doi= 10.1196/annals.1293.004 |pmid= 15126281}}</ref>
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| ====Genetic conditions====
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| A study of 818 heavy drinkers found that those exposed to more acetaldehyde than normal through a defect in the gene for [[acetaldehyde dehydrogenase]] are at greater risk of developing cancers of the upper gastrointestinal tract and liver.<ref>{{cite doi|10.1002/ijc.21583}}</ref>
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| ====Disulfiram====
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| The drug [[disulfiram]] (Antabuse) prevents the oxidation of acetaldehyde to acetic acid, and it has the same{{clarify|date=June 2013}} unpleasant effect on drinkers. Antabuse is sometimes used as a deterrent for alcoholics wishing to stay sober.
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| ===Sources of exposure===
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| ====Indoor air====
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| Acetaldehyde is common contaminant in workplace, indoors, and ambient environments. It is also a potential carcinogen. Moreover, humans spend more than 90% of their time in indoor environments, hence increasing any exposure and, as a consequence, the risk to human health.<ref>Spengler, John D.; McCarthy, John F.; Samet, Jonathan M.. Indoor Air Quality Handbook. New York, NY, USA: McGraw-Hill Professional Publishing, 2000. p 761.</ref>
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| In a study in France, the mean indoor concentration of acetaldehydes measured in 16 homes was approximately seven times higher than the outside acetaldehyde concentration. The living room had a mean of 18.1±17.5 μg m<sup>−3</sup> and the bedroom was 18.2±16.9 μg m<sup>−3</sup>, whereas the outdoor air had a mean concentration of 2.3±2.6 μg m<sup>−3</sup>.
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| It has been concluded that VOCs such as benzene, formaldehyde, acetaldehyde, toluene, and xylenes have to be considered as priority pollutants with respect to their health effects. It has been pointed that in renovated or completely new buildings, the VOCs concentration levels are often several orders of magnitude higher. The main sources of acetaldehydes in homes include building materials, laminate, linoleum, wooden varnished, and cork/pine flooring. It is also found in plastic water-based and matt emulsion paints, in wood ceilings, and wooden, particle-board, plywood, pine wood, and chipboard furniture.<ref name = dafni>{{cite journal | author1 = Dafni A. Missia | author2 = E. Demetriou | author3 = N. Michael | author4= E.I. Tolis | author5 = J.G. Bartzis | title = Indoor exposure from building materials: A field study | journal = Atmospheric Environment | year = 2010 | volume = 44 | pages = 4388–4395 | doi = 10.1016/j.atmosenv.2010.07.049 | issue = 35}}</ref>
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| ====Outdoor air====
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| The use of acetaldehyde is widespread in different industries, and it may be released into waste water or the air during production, use, transportation and storage. Sources of acetaldehyde include fuel combustion emissions from stationary internal combustion engines and power plants that burn fossil fuels, wood, or trash, oil and gas extraction, refineries, cement kilns, lumber and wood mills and paper mills. Acetaldehyde is also present in automobile and diesel exhaust.<ref>{{cite doi|10.1016/j.atmosenv.2009.06.044}}</ref>
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| ====Tobacco smoke====
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| Acetaldehyde is a significant constituent of tobacco smoke. It has been demonstrated to have a synergistic effect with [[nicotine]] in rodent models of addiction.<ref>[http://drugabuse.gov/NIDA_notes/NNvol20N3/Study.html Study Points to Acetaldehyde-Nicotine Combination in Adolescent Addiction]</ref><ref>[http://www.universityofcalifornia.edu/news/article/6726 Nicotine's addictive hold increases when combined with other tobacco smoke chemicals, UCI study finds]</ref> Acetaldehyde is also the most abundant carcinogen in tobacco smoke; it is dissolved into the saliva while smoking.
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| ====Cannabis smoke====
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| Acetaldehyde has been found in cannabis smoke. This finding emerged through the use of new chemical techniques that demonstrated the acetaldehyde present was causing DNA damage in laboratory settings.<ref>Stacy, Kelli Miller. "Marijuana Smoke Linked to Cancer." WebMD – Better Information. Better Health. WebMD.com, 23 June 2009. Web. 23 Nov. 2011. <http://www.webmd.com/cancer/news/20090623/marijuana-smoke-linked-to-cancer>.</ref> However, UCLA pulmonologist Dr. Donald Tashkin, supported by other research, concluded that the active ingredient [[tetrahydrocannabinol]], or THC, has an “anti-tumoral effect” in which “cells die earlier before they age enough to develop mutations that might lead to lung cancer” from acetaldehyde and other carcinogens.<ref>http://stash.norml.org/cannabis-alters-human-dna-bogus-claim</ref>
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| ====Alcohol consumption====
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| Many microbes produce acetaldehyde from ethanol, but they have a lower capacity to eliminate the acetaldehyde, which can lead to the accumulation of acetaldehyde in saliva, stomach acid, and intestinal contents. Fermented food and many alcoholic beverages can also contain significant amounts of acetaldehyde. Acetaldehyde, derived from mucosal or microbial oxidation of ethanol, tobacco smoke, and diet, appears to act as a cumulative carcinogen in the upper digestive tract of humans.<ref name="SALASPURO M 2011">{{cite journal | author = Salaspuro, M. | title = Acetaldehyde as a common denominator and cumulative carcinogen in digestive tract cancers. Scandinavian Journal Of Gastroenterology | year = 2009 | volume = 44 | issue = 8 | pages = 912–925 | doi = 10.1080/00365520902912563 | journal = Scandinavian Journal of Gastroenterology | pmid = 19396661}}</ref>
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| ==See also==
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| {{Commons category|Acetaldehyde}}
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| * [[Wine fault]]
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| * [[Alcohol dehydrogenase]]
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| Some major acetaldehyde producers include Celanese Chemicals Europe GmbH ( Germany ), Eastman Chemical Company( USA ), ECROS( SA, Spain ), Japan Aldehyde Company Ltd.( Japan ),Jilin Chemical Industrial Company( China ), Kyowa Yuka Company Ltd.( Japan ), Showa Denko K.K.( Japan ), Sinopec Yangzi Petrochemical Co.( China ), and Wacker Chemie AG,( Germany ).
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| ==References==
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| {{Reflist|2}}
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| ==External links==
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| * SEKAB, a producer of green Acetaldehyde [http://www.sekab.com/chemistry/acetaldehyde]
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| * [http://www.inchem.org/documents/icsc/icsc/eics0009.htm International Chemical Safety Card 0009]
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| * [http://www.npi.gov.au/database/substance-info/profiles/1.html National Pollutant Inventory – Acetaldehde]
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| * [http://www.cdc.gov/niosh/npg/npgd0001.html NIOSH Pocket Guide to Chemical Hazards]
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| * [http://www.cdc.gov/niosh/nmam/pdfs/2018.pdf Methods for sampling and analysis]
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| * [http://monographs.iarc.fr/ENG/Monographs/vol71/index.php IARC Monograph: "Acetaldehyde"]
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| * Hal Kibbey, [http://www.indiana.edu/~rcapub/v17n3/p18.html Genetic Influences on Alcohol Drinking and Alcoholism], Indiana University Research and Creative Activity, Vol. 17 no. 3.
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| * [http://www.grokfood.com/additives/2.htm United States Food and Drug Administration (FDA) information for acetaldehyde]
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| *[http://www.inclusive-science-engineering.com/acetaldehyde-production-ethylene-oxidation-stage-process/ Acetaldehyde production process flow sheet by ethylene oxidation method]
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| {{Use dmy dates|date=March 2012}}
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| [[Category:Flavors]]
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| [[Category:Aldehydes]]
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| [[Category:Hazardous air pollutants]]
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| [[Category:IARC Group 2B carcinogens]]
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