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Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH 3 CO) 2 O. Commonly abbreviated Ac 2 O , it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis .
The product of the condensation of two molecules of acetic acid is acetic anhydride. The worldwide production of acetic anhydride is a major application, and uses approximately 25% to 30% of the global production of acetic acid. The main process involves dehydration of acetic acid to give ketene at 700–750 °C. Ketene is thereafter reacted ...
Acetic anhydride. This reagent is common in the laboratory; its use cogenerates acetic acid. [7] [10] Acetyl chloride. This reagent is also common in the laboratory, but its use cogenerates hydrogen chloride, which can be undesirable. [8] Ketene. At one time acetic anhydride was prepared by the reaction of ketene with acetic acid: [11]
However, acetic acid is usually also formed as a by-product of the reaction, so that the solvent is ultimately a mixture of methylene chloride, acetic anhydride and acetic acid. A very rare heterogeneous process is the fiber acetate process, which is only used for the production of cellulose triacetate as an end product.
The addition of the two molecules typically proceeds in a step-wise fashion to the addition product, usually in equilibrium, and with loss of a water molecule (hence the name condensation). [3] The reaction may otherwise involve the functional groups of the molecule, and is a versatile class of reactions that can occur in acidic or basic ...
In one modification, [2] [3] d-glucose is converted to the glucose oxime by reaction with hydroxylamine and sodium methoxide. In the second step the pentaacetyl glycononitrile is formed by reaction with acetic anhydride in acetic acid with sodium acetate.
The Perkin reaction is an organic reaction developed by English chemist William Henry Perkin in 1868 that is used to make cinnamic acids.It gives an α,β-unsaturated aromatic acid or α-substituted β-aryl acrylic acid by the aldol condensation of an aromatic aldehyde and an acid anhydride, in the presence of an alkali salt of the acid.
For example, in reacting ethanol with acetic anhydride, ethyl acetate forms and acetic acid is eliminated as a leaving group, which is considerably less reactive than an acid anhydride and will be left as a byproduct (in a wasteful 1:1 ratio with the ester product) if product is collected immediately. If conditions are acidic enough, the acetic ...