| Revision as of 19:50, 16 February 2012 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Saving copy of the {{chembox}} taken from revid 474078001 of page Acetic_anhydride for the Chem/Drugbox validation project (updated: ''). |
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{{short description|Organic compound with formula (CH₃CO)₂O}} |
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{{ambox | text = This page contains a copy of the infobox ({{tl|chembox}}) taken from revid of page ] with values updated to verified values.}} |
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| verifiedrevid = 452568053 |
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| verifiedrevid = 477238827 |
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| Name = Acetic anhydride |
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| Name = Acetic anhydride |
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| ImageFile = Acetic anhydride-2D-skeletal.png |
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| ImageFile = Acetic_anhydride2DACS.svg |
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| ImageClass = skin-invert |
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| ImageSize = 150px |
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| ImageName = Acetic anhydride |
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| ImageSize = 150px |
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| ImageName = Acetic anhydride |
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| ImageFile1 = Acetic-anhydride-3D-vdW.png |
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| ImageFile1 = Acetic-anhydride-from-xtal-2003-3D-balls.png |
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| ImageSize1 = 150px |
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| ImageSize1 = 150px |
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| ImageName1 = Acetic anhydride |
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| ImageName1 = Acetic anhydride |
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| PIN = Acetic anhydride <!-- Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book) --> |
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| ImageFile2 = Acetic anhydride electron density.PNG |
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| SystematicName = Ethanoic anhydride |
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| ImageSize1 = 150px |
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| OtherNames = Ethanoyl ethanoate<br />Acetic acid anhydride<br />Acetyl acetate<br />Acetyl oxide<br />Acetic oxide |
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| ImageName1 = Acetic anhydride |
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|Section1={{Chembox Identifiers |
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| IUPACName = acetic anhydride |
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| ChEBI_Ref = {{ebicite|correct|EBI}} |
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| SystematicName = ethanoic anhydride |
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| OtherNames = Ethanoyl ethanoate<br/>Acetic acid anhydride<br/>Acetyl acetate<br >Acetyl oxide<br/>Acetic oxide |
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| Section1 = {{Chembox Identifiers |
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| ChEBI_Ref = {{ebicite|correct|EBI}} |
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| ChEBI = 36610 |
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| ChEBI = 36610 |
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| SMILES = O=C(OC(=O)C)C |
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| SMILES = O=C(OC(=O)C)C |
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| UNII_Ref = {{fdacite|correct|FDA}} |
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| UNII_Ref = {{fdacite|correct|FDA}} |
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| UNII = 2E48G1QI9Q |
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| UNII = 2E48G1QI9Q |
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| InChIKey = WFDIJRYMOXRFFG-UHFFFAOYAH |
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| InChIKey = WFDIJRYMOXRFFG-UHFFFAOYAH |
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| StdInChIKey = WFDIJRYMOXRFFG-UHFFFAOYSA-N |
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| StdInChIKey = WFDIJRYMOXRFFG-UHFFFAOYSA-N |
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| CASNo = 108-24-7 |
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| CASNo = 108-24-7 |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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| PubChem = 7918 |
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| PubChem = 7918 |
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| EINECS = 203-564-8 |
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| EINECS = 203-564-8 |
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| RTECS = AK1925000 |
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| RTECS = AK1925000 |
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| UNNumber = 1715 |
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| InChI = 1/C4H6O3/c1-3(5)7-4(2)6/h1-2H3 |
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| ChEMBL = 1305819 |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| InChI = 1/C4H6O3/c1-3(5)7-4(2)6/h1-2H3 |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| ChemSpiderID = 7630 |
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| ChemSpiderID = 7630 |
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}} |
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|Section2={{Chembox Properties |
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| C=4 | H=6 | O=3 |
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| Appearance = colorless liquid |
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| Density = 1.082 g cm<sup>−3</sup>, liquid |
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| Solubility = 2.6 g/100 mL, reacts (''see text'') |
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| MeltingPtC = −73.1 |
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| BoilingPtC = 139.8 |
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| RefractIndex = 1.3901 |
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| VaporPressure = 4 mmHg (20 °C)<ref name=NIOSH/> |
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| MagSus = −52.8·10<sup>−6</sup> cm<sup>3</sup>/mol |
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}} |
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| Section4 = {{Chembox Thermochemistry |
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| Thermochemistry_ref = <ref name="crc">{{cite book |author1=John Rumble |title=CRC Handbook of Chemistry and Physics |date=June 18, 2018 |publisher=CRC Press |isbn=978-1138561632 |pages=5–3 |edition=99th |language=en}}</ref> |
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| HeatCapacity = |
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| Entropy = |
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| DeltaHform = −624.4 kJ/mol |
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| DeltaGfree = |
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}} |
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| Section6 = {{Chembox Pharmacology |
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| Pharmacology_ref = |
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| ATC_Supplemental = |
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| Legal_status = |
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| Legal_AU = S6 |
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| Legal_AU_comment = |
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| Legal_CA = Schedule VI |
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| Dependence_liability = |
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| Section2 = {{Chembox Properties |
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|Section7={{Chembox Hazards |
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| ExternalSDS = |
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| C = 4 |
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| GHSPictograms = {{GHS02}}{{GHS05}}{{GHS07}} |
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| H = 6 |
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| O = 3 |
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| GHSSignalWord = Danger |
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| HPhrases = {{H-phrases|226|302|314|330}} |
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| Appearance = clear liquid |
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| PPhrases = {{P-phrases|210|233|240|241|242|243|260|261|264|270|271|280|301+312|301+330+331|303+361+353|304+312|304+340|305+351+338|310|312|321|330|363|370+378|403+235|405|501}} |
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| Density = 1.082 g cm<sup>−3</sup>, liquid |
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| NFPA-H = 3 |
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| Solubility = 2.6 g/100 mL, ''see text'' |
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| MeltingPtC = −73.1 |
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| NFPA-F = 2 |
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| BoilingPtC = 139.8 |
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| NFPA-R = 1 |
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| NFPA-S = W |
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| RefractIndex = 1.3901 |
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| FlashPtC = 49 |
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}} |
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| AutoignitionPtC = 316 |
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| Section3 = {{Chembox Structure |
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| ExploLimits = 2.7–10.3% |
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| Dipole = |
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| PEL = TWA 5 ppm (20 mg/m<sup>3</sup>)<ref name=NIOSH>{{PGCH|0003}}</ref> |
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| REL = C 5 ppm (20 mg/m<sup>3</sup>)<ref name=NIOSH/> |
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| Section7 = {{Chembox Hazards |
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| IDLH = 200 ppm<ref name=NIOSH/> |
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| ExternalMSDS = |
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| LC50 = 1000 ppm (rat, 4 ])<ref>{{IDLH|108247|Acetic anhydride}}</ref> |
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| EUClass = Corrosive ('''C''') |
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}} |
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| EUIndex = 607-008-00-9 |
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|Section8={{Chembox Related |
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| RPhrases = {{R10}}, {{R20/22}}, {{R34}} |
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| OtherFunction_label = ]s |
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| SPhrases = {{S1/2}}, {{S26}}, {{S36/37/39}}, {{S45}} |
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| OtherFunction = ] |
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| NFPA-H = 2 |
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| OtherCompounds = ]<br />] |
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| NFPA-F = 2 |
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}} |
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| NFPA-R = 1 |
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| NFPA-O = W |
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| FlashPt = 49 °C |
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| Autoignition = 316 °C |
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| ExploLimits = 2.7–10.3% |
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}} |
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| Section8 = {{Chembox Related |
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| Function = ]s |
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| OtherFunctn = ] |
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| OtherCpds = ]<br/>] |
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}} |
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'''Acetic anhydride''', or '''ethanoic anhydride''', is the ] with the ] {{chem2|(CH3CO)2O}}. Commonly abbreviated {{chem2|]2O}}, it is the simplest isolable ] of a ] and is widely used as a ] in ]. It is a colorless liquid that smells strongly of ], which is formed by its reaction with moisture in the air. |
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==Structure and properties== |
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] |
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Acetic anhydride, like most acid anhydrides, is a flexible molecule with a nonplanar structure.<ref>{{Citation | doi = 10.1107/S2053229616015047 | title = Acetic anhydride at 100 K: the first crystal structure determination | year = 2016 | last1 = Seidel | first1 = R. W. | last2 = Goddard | first2 = R. | last3 = Nöthling | first3 = N. | last4 = Lehmann | first4 = C. W. | journal = Acta Crystallographica Section C | volume = 72 | issue = 10 | pages = 753–757 | pmid = 27703123 | postscript = .}}</ref> The ] through the central oxygen offers very weak resonance stabilization compared to the ] repulsion between the two ] oxygens. The energy barriers to bond rotation between each of the optimal aplanar conformations are quite low.<ref>{{Citation | doi = 10.1021/jp993131z | title = Acetic Anhydride in the Gas Phase, Studied by Electron Diffraction and Infrared Spectroscopy, Supplemented with ab Initio Calculations of Geometries and Force Fields | year = 2000 | last1 = Wu | first1 = Guang | last2 = Van Alsenoy | first2 = C. | last3 = Geise | first3 = H. J. | last4 = Sluyts | first4 = E. | last5 = Van Der Veken | first5 = B. J. | last6 = Shishkov | first6 = I. F. | last7 = Khristenko | journal = The Journal of Physical Chemistry A | volume = 104 | issue = 7 | pages = 1576–1587 | bibcode = 2000JPCA..104.1576W | postscript = .}}</ref> |
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Like most acid anhydrides, the carbonyl carbon atom of acetic anhydride has ], as the leaving group is ]. The internal asymmetry may contribute to acetic anhydride's potent electrophilicity as the asymmetric geometry makes one side of a carbonyl carbon atom more reactive than the other, and in doing so tends to consolidate the electropositivity of a carbonyl carbon atom to one side (see electron density diagram). |
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==Production== |
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Acetic anhydride was first synthesized in 1852 by the French chemist ] (1816-1856) by heating ] with ].<ref>Charles Gerhardt (1852) (Investigations into the anhydrides of organic acids), ''Comptes rendus'' … , '''34''' : 755-758.</ref> |
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Acetic anhydride is produced by ] of ]:<ref>{{citation | last1 = Zoeller | first1 = J. R. | last2 = Agreda | first2 = V. H. | last3 = Cook | first3 = S. L. | last4 = Lafferty | first4 = N. L. | last5 = Polichnowski | first5 = S. W. | last6 = Pond | first6 = D. M. | title = Eastman Chemical Company Acetic Anhydride Process | journal = Catal. Today | year = 1992 | volume = 13 | issue = 1 | pages = 73–91 | doi = 10.1016/0920-5861(92)80188-S}}</ref> |
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: {{chem2|CH3CO2CH3 + CO -> (CH3CO)2O}} |
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The ] involves the conversion of methyl acetate to ] and an acetate salt. Carbonylation of the methyl iodide in turn produces ], which reacts with acetate salts or acetic acid to give the product. ] in the presence of ] is employed as catalysts. Because acetic anhydride is not stable in water, the conversion is conducted under anhydrous conditions. |
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To a decreasing extent, acetic anhydride is also prepared by the reaction of ketene (]) with acetic acid at 45–55 °C and low pressure (0.05–0.2 bar).<ref name="Arpe">{{citation | last = Arpe | first = Hans-Jürgen | title = Industrielle organische Chemie: Bedeutende vor- und Zwischenprodukte | url = https://books.google.com/books?id=36kHHvzx6M8C&q=wacker+verfahren+essigs%C3%A4ureanhydrid&pg=PA200 | edition = 6th | publisher = Wiley-VCH | location = Weinheim | pages = 200–1 | isbn = 978-3-527-31540-6 | date = 2007-01-11 }}{{Dead link|date=July 2023 |bot=InternetArchiveBot |fix-attempted=yes }}.</ref> |
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:{{chem2|H2C\dC\dO + CH3COOH -> (CH3CO)2O}} |
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:(Δ''H'' = −63 kJ/mol) |
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The route from acetic acid to acetic anhydride via ketene was developed by ] in 1922,<ref>{{citation | title = Milestones in the history of WACKER | url = http://www.wacker.com/cms/en/wacker_group/wacker_facts/history/history.jsp | publisher = Wacker Chemie AG | access-date = 2009-08-27}}.</ref> when the demand for acetic anhydride increased due to the production of ]. |
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Due to its low cost, acetic anhydride is usually purchased, not prepared, for use in research laboratories. |
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==Reactions== |
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Acetic anhydride is a versatile reagent for ]s, the introduction of acetyl groups to organic substrates.<ref>{{citation | title = Acid Anhydrides | url = http://www.chemguide.co.uk/organicprops/anhydridemenu.html | work = Understanding Chemistry | access-date = 2006-03-25}}.</ref> In these conversions, acetic anhydride is viewed as a source of {{chem2|CH3CO+}}. |
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===Acetylation of alcohols and amines=== |
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]s and ]s are readily acetylated.<ref>{{citation | first = Bassam Z. | last = Shakhashiri | title = Acetic Acid & Acetic Anhydride | url = http://scifun.chem.wisc.edu/CHEMWEEK/AceticAcid/AceticAcid.html | work = Science is Fun… | publisher = Department of Chemistry, University of Wisconsin | access-date = 2006-03-25 | archive-url = https://web.archive.org/web/20060303081507/http://scifun.chem.wisc.edu/chemweek/AceticAcid/AceticAcid.html | archive-date = 2006-03-03 | url-status = dead }}.</ref> For example, the reaction of acetic anhydride with ] yields ]: |
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:{{chem2|(CH3CO)2O + CH3CH2OH -> CH3CO2CH2CH3 + CH3COOH}} |
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Often a base such as ] is added to function as catalyst. In specialized applications, ]ic ] salts have also proven effective catalysts.<ref>{{OrgSynth | last1 = Macor | first1 = John | last2 = Sampognaro | first2 = Anthony J. | last3 = Verhoest | first3 = Patrick R. | last4 = Mack | first4 = Robert A. | title = (''R'')-(+)-2-Hydroxy-1,2,2-Triphenylethyl Acetate | prep = V77P0045 | year = 2000 | volume = 77 | pages = 45 | collvol = 10 | collvolpages = 464 | doi = 10.15227/orgsyn.077.0045 }}</ref> |
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===Acetylation of aromatic rings=== |
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Aromatic rings are acetylated by acetic anhydride. Usually acid catalysts are used to accelerate the reaction. Illustrative are the conversions of ] to ]<ref>Roger Adams and C. R. Noller "p-Bromoacetophenone" Org. Synth. 1925, vol. 5, p. 17. {{doi|10.15227/orgsyn.005.0017}}</ref> and ] to acetylferrocene:<ref>{{citation | last = Taber | first = Douglass F. | title = Column chromatography: Preparation of Acetyl Ferrocene | url = http://valhalla.chem.udel.edu/ferroc.html | publisher = Department of Chemistry and Biochemistry, University of Delaware | access-date = 2009-08-27 | archive-url = https://web.archive.org/web/20090502011406/http://valhalla.chem.udel.edu/ferroc.html | archive-date = 2009-05-02 | url-status = dead }}.</ref> |
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:{{chem2|(C5H5)2Fe + (CH3CO)2O -> (C5H5)Fe(C5H4COCH3) + CH3CO2H}} |
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===Preparation of other acid anhydrides=== |
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Dicarboxylic acids are converted to the anhydrides upon treatment with acetic anhydride.<ref>B. H. Nicolet and J. A. Bender "3-Nitrophthalic Anhydride" Org. Synth. 1927, vol. 7, 74. |
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{{doi|10.15227/orgsyn.007.0074}}</ref> It is also used for the preparation of mixed anhydrides such as that with nitric acid, ]. |
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===Precursor to geminal diacetates=== |
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]s react with acetic anhydride in the presence of an acidic ] to give geminal diacetates.<ref>R. T. Bertz "Furfuryl Diacetate" Org. Synth. 1953, 33, 39. {{doi|10.15227/orgsyn.033.0039}}</ref> A former industrial route to ] involved the intermediate ], the geminal diacetate obtained from ] and acetic anhydride:<ref>G. Roscher "Vinyl Esters" in ''Ullmann's Encyclopedia of Chemical Technology'', 2007 John Wiley & Sons: New York. {{doi|10.1002/14356007.a27_419}}</ref> |
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:{{chem2|CH3CHO + (CH3CO)2O -> (CH3CO2)2CHCH3}} |
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===Hydrolysis=== |
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Acetic anhydride dissolves in water to approximately 2.6% by weight.<ref>{{citation|title=Acetic Anhydride: Frequently Asked Questions |url=http://www.bp.com/liveassets/bp_internet/globalbp/STAGING/global_assets/downloads/pdfs/acetyls_aromatics_pta/AceticAnhydrideFAQ.pdf |publisher=British Petroleum |access-date=2006-05-03 |url-status=dead |archive-url=https://web.archive.org/web/20071011104749/http://www.bp.com/liveassets/bp_internet/globalbp/STAGING/global_assets/downloads/pdfs/acetyls_aromatics_pta/AceticAnhydrideFAQ.pdf |archive-date=2007-10-11 }}.</ref> Aqueous solutions have limited stability because, like most acid anhydrides, acetic anhydride hydrolyses to give carboxylic acids. In this case, acetic acid is formed, this reaction product being fully water miscible:<ref>{{citation|title=Acetic Anhydride: Material Safety Data Sheet (PDF) |url=http://www.celanese.com/msds/pdf/570-22027587.pdf |publisher=Celanese |access-date=2006-05-03 |url-status=dead |archive-url=https://web.archive.org/web/20070927025258/http://www.celanese.com/msds/pdf/570-22027587.pdf |archive-date=2007-09-27 }}.</ref> |
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:{{chem2|(CH3CO)2O + H2O -> 2 CH3COOH}} |
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=== Cinnamic acid synthesis === |
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In the last third of the 19th century the main application for the acetic anhydride was the ].<ref>{{Cite book |last=Lassar-Cohn |first=Dr |url=https://books.google.com/books?id=KxhIAAAAIAAJ&pg=PA104 |title=A Laboratory Manual of Organic Chemistry: A Compendium of Laboratory Methods for the Use of Chemists, Physicians, and Pharmacists |last2=Smith |first2=Alexander |date=1895 |publisher=Macmillian and Company Limited |language=en}}</ref> |
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==Applications== |
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As indicated by its organic chemistry, acetic anhydride is mainly used for acetylations leading to commercially significant materials. Its largest application is for the conversion of cellulose to ], which is a component of photographic film and other coated materials, and is used in the manufacture of cigarette filters. Similarly it is used in the production of ] (acetylsalicylic acid), which is prepared by the acetylation of ].<ref name="SIDS">{{SIDS-ref|name=Acetic anhydride|id=108247|page=5}}{{Dead link|date=January 2024}}</ref> It is also used as an active modification agent via ] impregnation and subsequent acetylation to make a durable and long-lasting timber.<ref>{{cite news |last1=Tullo | first1=Alexander |title=Making Wood Last Forever With Acetylation |url=https://cen.acs.org/articles/90/i32/Making-Wood-Last-Forever-Acetylation.html |access-date=2022-09-17 |work=Chemical and Engineering News |issue=32 |publisher=American Chemical Society|date=2012-08-06 |issn=0009-2347 }}</ref> |
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In starch industry, acetic anhydride is a common acetylation compound, used for the production of ]es (E1414, E1420, E1422) |
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== Legal status == |
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Because of its use for the synthesis of ] by the diacetylation of ], acetic anhydride is listed as a U.S. DEA List II precursor, and restricted in many other countries.<ref>{{Cite web|date=2022-02-15|title=§ 1310.02 - Substances Covered|url=https://www.ecfr.gov/current/title-21/chapter-II/part-1310/section-1310.02|url-status=live|archive-url=https://web.archive.org/web/20220215120955/https://www.ecfr.gov/current/title-21/chapter-II/part-1310/section-1310.02|archive-date=2022-02-15|website=]}}</ref><ref>{{citation | title = UN Intercepts Taliban's Heroin Chemical in Rare Afghan Victory | url = https://www.bloomberg.com/apps/news?pid=20670001&refer=home&sid=aY1eg_RtBNNU | publisher = ] | access-date = 2008-10-07 |archive-url=https://web.archive.org/web/20121022213218/http://www.bloomberg.com/apps/news?pid=newsarchive&refer=home&sid=aY1eg_RtBNNU |archive-date=22 October 2012|url-status=dead}}.</ref> |
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==Safety== |
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Acetic anhydride is an irritant and combustible liquid; it is highly corrosive to skin and any direct contact will result in severe burns. Because of its reactivity toward water and alcohol, foam or carbon dioxide are preferred for fire suppression.<ref>{{cite web | title=Data Sheets | work=International Occupational Safety and Health Information Centre | url=http://www.inchem.org/documents/icsc/icsc/eics0209.htm | access-date=2006-04-13}}</ref> The vapour of acetic anhydride is harmful.<ref> |
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{{cite web | title=NIOSH | work=Pocket Guide to Chemical Hazards | url=https://www.cdc.gov/niosh/npg/npgd0003.html | access-date=2006-04-13| archive-url= https://web.archive.org/web/20060422144317/http://www.cdc.gov/niosh/npg/npgd0003.html| archive-date= 22 April 2006 | url-status= live}}</ref> |
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==References== |
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{{reflist}} |
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==External links== |
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{{Authority control}} |
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{{DEFAULTSORT:Acetic Anhydride}} |
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