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Acetic anhydride dissolves in water to approximately 2.6% by weight. [18] 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: [19] (CH 3 CO) 2 O + H 2 O → 2 CH 3 COOH
The analytical method used to determine hydroxyl value traditionally involves acetylation of the free hydroxyl groups of the substance with acetic anhydride in pyridine solvent. After completion of the reaction, water is added, and the remaining unreacted acetic anhydride is converted to acetic acid and measured by titration with potassium ...
The name "Schotten–Baumann reaction conditions" often indicate the use of a two-phase solvent system, consisting of water and an organic solvent. The base within the water phase neutralizes the acid, generated in the reaction, while the starting materials and product remain in the organic phase, often dichloromethane or diethyl ether.
acetyl chloride SOCl 2 acetic acid (i) Li[AlH 4], ether (ii) H 3 O + ethanol Two typical organic reactions of acetic acid Acetic acid undergoes the typical chemical reactions of a carboxylic acid. Upon treatment with a standard base, it converts to metal acetate and water. With strong bases (e.g., organolithium reagents), it can be doubly deprotonated to give LiCH 2 COOLi. Reduction of acetic ...
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]
Hippuric acid, the benzamide derivative of glycine, cyclizes in the presence of acetic anhydride, condensing to give 2-phenyl-oxazolone. [3] This intermediate also has two acidic protons and reacts with benzaldehyde, acetic anhydride and sodium acetate to a so-called azlactone. This compound on reduction gives access to phenylalanine. [4]
Illustrative is the acetylation of aniline. First aniline is dissolved in water using one equivalent of hydrochloric acid. This solution is subsequently treated, sequentially, with acetic anhydride and aqueous sodium acetate. Aniline attacks acetic anhydride followed by deprotonation of the ammonium ion: Acetate then acts as a leaving group:
As examples, a water molecule easily adds to ketene to give 1,1-dihydroxyethene and acetic anhydride is produced by the reaction of acetic acid with ketene. Reactions between diols (HO−R−OH) and bis-ketenes (O=C=CH−R'−CH=C=O) yield polyesters with a repeat unit of (−O−R−O−CO−R'−CO). Ethyl acetoacetate, an important starting ...