(Difference between pages)

Page 1

Page 1Revision 1

Page 2

Page 2Revision 2

Content deleted Content addedVisualWikitext

Revision as of 15:21, 11 December 2010 editBeetstra (talk | contribs)Edit filter managers, Administrators172,054 edits Script assisted update of identifiers from ChemSpider, CommonChemistry and FDA for the Chem/Drugbox validation project - Updated: StdInChI StdInChIKey.		Latest revision as of 01:40, 30 June 2020 edit Jorge Stolfi (talk | contribs)Autopatrolled, Extended confirmed users, Rollbackers27,608 editsm →top: tweaks
Line 1:		Line 1:
	{{chembox		{{chembox
	| verifiedrevid = 392983950		| verifiedrevid = 401787525
	| Name = Acetic anhydride		| Name = Butyric anhydride
	| ImageFile = Acetic anhydride-2D-skeletal.png		| ImageFile = Butyric_anhydride.svg
	| ImageSize = 150px		| ImageSize = 150px
	| ImageName = Acetic anhydride		| ImageName = Butyric Anhydride
	| ImageFile1 = Acetic-anhydride-3D-vdW.png		| PIN = Butanoic anhydride
			| OtherNames = Butyric anhydride<br />Butanoyl butanoate<br />Butanoic acid anhydride<br />Butyric acid anhydride<br />Butyryl oxide
	| ImageSize1 = 150px
			|Section1={{Chembox Identifiers
	| ImageName1 = Acetic anhydride
			| CASNo = 106-31-0
	| ImageFile2 = Acetic anhydride electron density.PNG
			| CASNo_Ref = {{cascite|correct|CAS}}
	| ImageSize1 = 150px
			| UNII_Ref = {{fdacite|correct|FDA}}
	| ImageName1 = Acetic anhydride
			| UNII = A88LE742VX
	| IUPACName = acetic anhydride
			| PubChem = 7798
	| SystematicName = ethanoic anhydride
			| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
	| OtherNames = Ethanoyl ethanoate<br/>Acetic acid anhydride<br/>Acetyl acetate<br >Acetyl oxide<br/>Acetic oxide
			| ChemSpiderID = 7510
	| Section1 = {{Chembox Identifiers
	| SMILES = O=C(OC(=O)C)C		| SMILES = CCCC(OC(CCC)=O)=O
			| StdInChI = 1S/C8H14O3/c1-3-5-7(9)11-8(10)6-4-2/h3-6H2,1-2H3
	| UNII_Ref = {{fdacite|correct|FDA}}
			| StdInChIKey = YHASWHZGWUONAO-UHFFFAOYSA-N
	| UNII = 2E48G1QI9Q
	| InChIKey = WFDIJRYMOXRFFG-UHFFFAOYAH
	| SMILES1 = CC(=O)OC(=O)C
	| StdInChI = 1S/C4H6O3/c1-3(5)7-4(2)6/h1-2H3
	| StdInChIKey = WFDIJRYMOXRFFG-UHFFFAOYSA-N
	| CASNo = 108-24-7
	| CASNo_Ref = {{cascite|correct|CAS}}
	| PubChem = 7918
	| EINECS = 203-564-8
	| RTECS = AK1925000
	| InChI = 1/C4H6O3/c1-3(5)7-4(2)6/h1-2H3
	| ChemSpiderID = 7630
	}}		}}
	| Section2 = {{Chembox Properties		|Section2={{Chembox Properties
			| C=8
	| Formula = C<sub>4</sub>H<sub>6</sub>O<sub>3</sub>
			| H=14
	| MolarMass = 102.09 g/mol
	| Appearance = clear liquid		| O=3
			| Appearance = Clear liquid
	| Density = 1.082 g/cm<sup>3</sup>, liquid		| Density = .967 g/cm<sup>3</sup>
			| MeltingPtC = −75
	| Solubility = 2.6 g/100 ml, ''see text''
			| MeltingPt_notes =
	| MeltingPt = −73.1 °C
			| BoilingPtC = 198
	| BoilingPt = 139.8 °C
			| BoilingPt_notes =
	| RefractIndex = 1.3901
			| RefractIndex = 1.413
	}}		}}
	| Section3 = {{Chembox Structure		|Section3={{Chembox Hazards
			| ExternalSDS =
	| Dipole =
	}}		}}
	| Section7 = {{Chembox Hazards		|Section8={{Chembox Related
			| OtherFunction_label = ]s
	| ExternalMSDS =
			| OtherFunction = ]<br/>]<br/>]
	| EUClass = Corrosive ('''C''')
			| OtherCompounds = ]<br/>]
	| EUIndex = 607-008-00-9
	| RPhrases = {{R10}}, {{R20/22}}, {{R34}}
	| SPhrases = {{S1/2}}, {{S26}}, {{S36/37/39}}, {{S45}}
	| NFPA-H = 2
	| NFPA-F = 2
	| NFPA-R = 1
	| NFPA-O = W
	| FlashPt = 49 °C
	| Autoignition = 316 °C
	| ExploLimits = 2.7–10.3%
	}}
	| Section8 = {{Chembox Related
	| Function = ]s
	| OtherFunctn = ]
	| OtherCpds = ]<br/>]
	}}		}}
	}}		}}
			'''Butyric anhydride''' or '''butanoic anhydride''' is the ] with the ] (CH<sub>3</sub>CH<sub>2</sub>CH<sub>2</sub>CO)<sub>2</sub>O. The molecule can be described as a ] of two molecules of ] with elimination of one water molecule (hence its name).
	'''Acetic anhydride''', or '''ethanoic anhydride''', is the ] with the ] (CH<sub>3</sub>CO)<sub>2</sub>O.<ref>Acetic anhydride was first synthesized in 1852 by French chemist ] (1816-1856). See: Charles Gerhardt (1852) ''Comptes Rendus'', vol. 34, pages 755-758.</ref> Commonly abbreviated ]<sub>2</sub>O, it is the simplest isolatable ] and is a widely used ] in ]. (] spontaneously decomposes, especially once removed from solution.) It is a colorless liquid that smells strongly of ], formed by its reaction with the moisture in the air.
			Butyric anhydride is a clear colorless liquid that smells strongly of butyric acid, which is formed by its reaction to moisture in the air.
	==Structure==
	Contrary to what its Lewis structure seems to predict, acetic anhydride, like many other acid anhydrides that are free to rotate, has experimentally been found to be aplanar. The pi system linkage through the central oxygen offers very weak resonance stabilisation compared to the dipole-dipole repulsion between the two carbonyl oxygens. However, the energy barriers to bond rotation between each of the optimal aplanar conformations are quite low .
	Like most acid anhydrides, the carbonyl carbon of acetic anhydride is a potent electrophile as the leaving group for each carbonyl carbon (a ]) is a good ] leaving group. The internal asymmetry may contribute to acetic anhydride's potent electrophilicity as the asymmetric geometry makes one side of a carbonyl carbon more reactive than the other, and in doing so tends to consolidate the electropositivity of a carbonyl carbon to one side (see electron density diagram).
	==Production==
	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 | pages = 73–91 | doi = 10.1016/0920-5861(92)80188-S}}</ref>
	: CH<sub>3</sub>CO<sub>2</sub>CH<sub>3</sub> + CO → (CH<sub>3</sub>CO)<sub>2</sub>O
	This process involves the conversion of methyl acetate to ] and an acetate salt. Carbonylation of the methyl iodide in turn affords ], which reacts with acetate salts or acetic acid to give the product. Rhodium and lithium iodides are employed as catalysts. Because acetic anhydride is not stable in water, the conversion is conducted under anhydrous conditions. In contrast, the ], which also involves a rhodium catalyzed carbonylation of methyl iodide, is at least partially aqueous.
	To a decreasing extent, acetic anhydride is also prepared by the reaction of ] with acetic acid at 45–55&nbsp;°C and low pressure (0.05–0.2&nbsp;bar).<ref name="Arpe">{{citation | last = Arpe | first = Hans-Jürgen | title = Industrielle organische Chemie: Bedeutende vor- und Zwischenprodukte | url = http://books.google.com/?id=36kHHvzx6M8C&pg=PA200&dq=wacker+verfahren+essigs%C3%A4ureanhydrid | edition = 6th | publisher = Wiley-VCH | location = Weinheim | year = 2007 | pages = 200–1 | isbn = 3527315403 | date = 2007-01-11}}.</ref>
	:H<sub>2</sub>C=C=O + CH<sub>3</sub>COOH → (CH<sub>3</sub>CO)<sub>2</sub>O (Δ''H'' = −63 kJ/mol)
	Ketene is generated by dehydrating acetic acid at 700–750&nbsp;°C in the presence of ] as a catalyst or (in Switzerland and the CIS) by the thermolysis of ] at 600–700&nbsp;°C in the presence of ] as a catalyst.<ref name="Arpe" />
	:CH<sub>3</sub>COOH {{eqm}} H<sub>2</sub>C=C=O + H<sub>2</sub>O (Δ''H'' = +147 kJ/mol)
	:CH<sub>3</sub>COCH<sub>3</sub> → H<sub>2</sub>C=C=O + CH<sub>4</sub>
	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 | accessdate = 2009-08-27}}.</ref> when the demand for acetic anhydride increased due to the production of cellulose acetate.
	Due to its low cost, acetic anhydride is purchased, not prepared, for use in research laboratories.
	==Reactions==
	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 | accessdate = 2006-03-25}}.</ref> In these conversions, acetic anhydride is viewed as a source of CH<sub>3</sub>CO<sup>+</sup>. ]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 | accessdate = 2006-03-25}}.</ref> For example, the reaction of acetic anhydride with ] yields ]:
	: (CH<sub>3</sub>CO)<sub>2</sub>O + CH<sub>3</sub>CH<sub>2</sub>OH → CH<sub>3</sub>CO<sub>2</sub>CH<sub>2</sub>CH<sub>3</sub> + CH<sub>3</sub>COOH
	Often a base such as ] is added to function as catalyst. In specialized applications, ]ic scandium 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}}</ref>
	Aromatic rings are acetylated, usually in the presence of an acid catalyst. Illustrative is the conversion of benzene to ]:
	: (CH<sub>3</sub>CO)<sub>2</sub>O + C<sub>6</sub>H<sub>6</sub> → CH<sub>3</sub>COC<sub>6</sub>H<sub>5</sub> + CH<sub>3</sub>CO<sub>2</sub>H
	] may be acetylated too:<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 | accessdate = 2009-08-27}}.</ref>
	: Cp<sub>2</sub>Fe + (CH<sub>3</sub>CO)<sub>2</sub>O → CpFe(C<sub>5</sub>H<sub>4</sub>COCH<sub>3</sub>)
	===Hydrolysis===
	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 | accessdate = 2006-05-03}}.</ref> Aqueous solutions have limited stability because, like most acid anhydrides, acetic anhydride hydrolyses to give acetic acid:<ref>{{citation | title = Acetic Anhydride: Material Safety Data Sheet (PDF) | url=http://www.celanese.com/msds/pdf/570-22027587.pdf | publisher = Celanese | accessdate=2006-05-03}}.</ref>
	: (CH<sub>3</sub>CO)<sub>2</sub>O + H<sub>2</sub>O → 2 CH<sub>3</sub>CO<sub>2</sub>H
	==Applications==
	As indicated by its organic chemistry, Ac<sub>2</sub>O 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. 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}}.</ref> It is also used as a wood preservative via autoclave impregnation to make a longer lasting timber.
	In starch industry, acetic anydride is a common acetylation compound, used for the production of ]es (E1414, E1420, E1422)
	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>{{citation | title = UN Intercepts Taliban's Heroin Chemical in Rare Afghan Victory | url = http://www.bloomberg.com/apps/news?pid=20670001&refer=home&sid=aY1eg_RtBNNU | publisher = ] | accessdate = 2008-10-07}}.</ref>
	==Safety==		==Safety==
	Acetic anhydride is an irritant and flammable. Because of its reactivity toward water, 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.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc02/icsc0209.htm | accessdate=2006-04-13}}</ref> The vapour of acetic anhydride is harmful.<ref>		Butyric anhydride is a combustible, corrosive liquid. It is considered water sensitive.<ref>{{cite web | title=MSDS Information | work=Butyric Anhydride MSDS | url=http://www.coleparmer.com/catalog/Msds/96914.htm | accessdate=2011-01-07}}</ref>
	{{cite web | title=NIOSH | work=Pocket Guide to Chemical Hazards | url=http://www.cdc.gov/niosh/npg/npgd0003.html | accessdate=2006-04-13}}</ref>
	==References==		==References==
	{{reflist}}		{{reflist}}
			]
	==External links==
			]
	*
	*
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]