Acetic anhydride
IUPAC name	Ethanoyl ethanoate
Other names	Acetic anhydride Acetic acid anhydride Acetylacetate Acetyl oxide Acetic oxide Ethanoic anhydride
Identifiers
CAS number	[108-24-7]
RTECS number	AK1925000
SMILES	CC(=O)OC(=O)C
InChI	1/C4H6O3/c1-3(5) 7-4(2)6/h1-2H3
Properties
Molecular formula	C4H6O3
Molar mass	102. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to Registry of Toxic Effects of Chemical Substances ( RTECS) is a Database of Toxicity information compiled from the open scientific literature without reference The IUPAC International Chemical Identifier ( InChI, pronounced "INchee" is a textual Identifier for Chemical substances designed to provide a A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 1 g/mol
Appearance	clear liquid
Density	1. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 08 g/cm³, liquid
Melting point	−73. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. 1 °C
Boiling point	139. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid 8 °C
Solubility in water	2. Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. Water is a common Chemical substance that is essential for the survival of all known forms of Life. 6% by weight; rapidly reacts to form acetic acid
Hazards
EU classification	Corrosive (C)
R-phrases	R10, R20/22, R34
S-phrases	(S1/2), S26, S36/37/39, S45
Flash point	54 °C
Related compounds
Related acid anhydrides	Propionic anhydride
Related compounds	Acetic acid Acetyl chloride
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Acetic anhydride is the chemical compound with the formula (CH₃CO)₂O. Acetic acid, also known as ethanoic acid, is an organic chemical compound, giving Vinegar its sour taste Council Directive 67/548/EEC of 27 June 1967 on the approximation of laws regulations and administrative provisions relating to the classification packaging and labelling R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. The flash point of a flammable liquid is the lowest Temperature at which it can form an ignitable mixture in air An acid anhydride is an Organic compound that has two Acyl groups bound to the same Oxygen atom Propanoic anhydride, also called propionic anhydride, is a simple Acid anhydride. Acetic acid, also known as ethanoic acid, is an organic chemical compound, giving Vinegar its sour taste Acetyl chloride, also known as ethanoyl chloride, is an Acid chloride (also known as an Acyl chloride) derived from Acetic acid ( Ethanoic In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by Mass. A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Commonly abbreviated Ac₂O, it is one of the simplest acid anhydrides and is a widely used reagent in organic synthesis. In Organic chemistry, acetyl (ethanoyl is a Functional group, the Acyl of Acetic acid, with Chemical formula - C[[Oxygen An acid anhydride is an Organic compound that has two Acyl groups bound to the same Oxygen atom A reagent or reactant is a substance or compound consumed during a Chemical reaction. Organic synthesis is a special branch of Chemical synthesis and is concerned with the construction of Organic compounds via Organic reactions Organic It is a colorless liquid that smells strongly of acetic acid, which is formed by its reaction with the moisture in the air. Acetic acid, also known as ethanoic acid, is an organic chemical compound, giving Vinegar its sour taste

Contents 1 Production 2 Organic chemistry 2.1 Hydrolysis 3 Applications 4 Safety 5 Notes and references 6 See also

Production

Acetic anhydride is produced by carbonylation of methyl acetate:^[1]

CH₃CO₂CH₃ + CO → (CH₃CO)₂O

This process involves the conversion of methyl acetate to methyl iodide and an acetate salt. Carbonylation refers to reactions that introduce Carbon monoxide into organic and inorganic substrates Methyl acetate, also known as acetic acid methyl ester or methyl ethanoate, is a clear flammable liquid with a characteristic not unpleasant smell like certain Iodomethane, commonly called Methyl iodide and commonly abbreviated "MeI" is the Chemical compound with the formula CH3I Carbonylation of the methyl iodide in turn affords acetyl iodide, 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 Monsanto acetic acid synthesis, which also involves a rhodium catalyzed carbonylation of methyl iodide, is at least partially aqueous. The Monsanto process is an important method for the manufacture of Acetic acid.

To a decreasing extent, acetic anhydride is also prepared by the reaction of ketene with acetic acid. A ketene is an Organic compound of the form R2C=C=O Hermann Staudinger pioneered the research of ketenes Ketene is generated by dehydrating acetic acid at elevated temperatures. This production method was developed by Wacker Chemie in 1922, when the demand for acetic anhydride increased due to the production of acetic fibre. Wacker Chemie AG ( is a worldwide operating company in the chemical business

Due to its low cost, acetic anhydride is purchased, not prepared, for use in research laboratories.

Organic chemistry

Acetic anhydride is a versatile reagent for acetylations, the introduction of acetyl groups to organic substrates. Acetylation (or in IUPAC nomenclature ethanoylation) describes a reaction that introduces an Acetyl Functional group into an Organic compound In these conversions, acetic anhydride is viewed as a source of CH₃CO⁺. Alcohols and amines are readily acetylated. In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon Amines are Organic compounds and Functional groups that contain a basic Nitrogen Atom with a Lone pair. ^[2] For example, the reaction of acetic anhydride with ethanol is:

(CH₃CO)₂O + CH₃CH₂OH → CH₃CO₂CH₂CH₃ + CH₃CO₂H

Often a base such as pyridine is added to function as catalyst. Ethyl acetate ( systematically, ethyl ethanoate commonly abbreviated EtOAc or EA is the Organic compound with the formula CH3COOCH2CH3 Pyridine is a Chemical compound with the formula C5[[Hydrogen H5]] N. In specialized applications, Lewis acidic scandium salts have also proven effective catalysts. ^[3]

Aromatic rings are acetylated, usually in the presence of an acid catalyst. Illustrative is the conversion of benzene to acetophenone:

(CH₃CO)₂O + C₆H₆ → CH₃COC₆H₅ + CH₃CO₂H

Hydrolysis

Acetic anhydride dissolves in water to approximately 2. Acetophenone is the Organic compound with the formula C6H5C(OCH3 6% by weight. ^[4] Aqueous solutions have limited stability because, like most acid anhydrides, acetic anhydride hydrolyses to give acetic acid:^[5]

(CH₃CO)₂O + H₂O → 2 CH₃CO₂H

Applications

As indicated by its organic chemistry, Ac₂O is mainly used for acetylations leading to commercially significant materials. Its largest application is for the conversion of cellulose to cellulose acetate, which is a component of photographic film and other coated materials. Cellulose acetate, first prepared in 1865 is the Acetate Ester of Cellulose. Similarly it is used in the production of aspirin, acetyl salicylic acid, which is prepared by the acetylation of salicylic acid. Aspirin, or acetylsalicylic acid (ASA (əˌsɛtɨlsælɨˌsɪlɨk ˈæsɨd is a Salicylate drug, often used as an Analgesic to relieve Salicylic acid (from the Latin word for the willow tree Salix, from whose bark it can be obtained is a Beta hydroxy acid (BHA with the formula It ia also used as a wood preservative via autoclave impregnation to to make a longer lasting timber. Because of its use for the synthesis of heroin by the diacetylation of morphine, acetic anhydride (known as 'AA' in clandestine chemistry circles) is listed as a U. Heroin ( INN: diacetylmorphine, BAN: diamorphine) is a semi-synthetic opioid synthesized from Morphine, a derivative Medical uses Morphine can be used as an analgesic in hospital settings to relieve pain in Myocardial infarction pain in Clandestine chemistry generally refers to Chemistry carried out in illegal drug Laboratories (known colloquially as labs) but can include any S. DEA List II Precursor,^[6] and restricted in many other countries.

Safety

Acetic anhydride is an irritant and flammable. Because of its reactivity toward water, alcohol foam or carbon dioxide are preferred for fire suppression. ^[7] The vapour of acetic anhydride is harmful. ^[8]

Notes and references

1. ^ Zoeller, J. R. ; Agreda, V. H. ; Cook, S. L. ; Lafferty, N. L. ; Polichnowski, S. W. ; Pond, D. M. "Eastman Chemical Company Acetic Anhydride Process" Catalysis Today (1992), volume 13, pp. 73-91. doi:10. 1016/0920-5861(92)80188-S
2. ^ Science is Fun…. Chemical of the Week. Retrieved on 2006-03-25. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1199 - Richard I is wounded by a crossbow bolt while fighting France which leads to his death on April 6.
3. ^ Macor, J. ; Sampognaro, A. J. ; Verhoest, P. R. ; Mack, R. A. "(R)-(+)-2-Hydroxy-1,2,2-Triphenylethyl Acetate" Organic Syntheses, Collected Volume 10, p. 464 (2004). http://www.orgsyn.org/orgsyn/pdfs/V77P0045.pdf
4. ^ British Petroleum. Acetic Anhydride: Frequently Asked Questions (PDF). Retrieved on 2006-05-03. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1491 - Kongo monarch Nkuwu Nzinga is baptised by Portuguese missionaries adopting the baptismal name of João
5. ^ Celanese. Acetic Anhydride: Material Safety Data Sheet (PDF). Retrieved on 2006-05-03. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1491 - Kongo monarch Nkuwu Nzinga is baptised by Portuguese missionaries adopting the baptismal name of João
6. ^ ChemGuide. Acid Anhydrides. Retrieved on 2006-03-25. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1199 - Richard I is wounded by a crossbow bolt while fighting France which leads to his death on April 6.
7. ^ Data Sheets. International Occupational Safety and Health Information Centre. Retrieved on 2006-04-13. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1111 - Henry V is crowned Holy Roman Emperor. 1204 - The Fourth Crusade sacks Constantinople
8. ^ NIOSH. Pocket Guide to Chemical Hazards. Retrieved on 2006-04-13. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1111 - Henry V is crowned Holy Roman Emperor. 1204 - The Fourth Crusade sacks Constantinople

See also

• Acid anhydride

An acid anhydride is an Organic compound that has two Acyl groups bound to the same Oxygen atom

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