Search results
Results From The WOW.Com Content Network
2,4,6-Tribromoaniline can be prepared by treating bromine water with aniline in a solution of acetic acid or dilute hydrochloric acid: [1] By reacting bromine with aniline in water, a white precipitate immediately forms and that is 2,4,6-tribromoaniline
An example of alpha halogenation is the mono-bromination of acetone ((CH 3) 2 C=O), carried out under either acidic or basic conditions, to give bromoacetone: Acidic (in acetic acid): Reaction mechanism for the bromination of acetone while in the presence of acetic acid. Basic (in aqueous NaOH):
Aniline and its ring-substituted derivatives react with nitrous acid to form diazonium salts. One example is benzenediazonium tetrafluoroborate . Through these intermediates, the amine group can be converted to a hydroxyl ( −OH ), cyanide ( −CN ), or halide group ( −X , where X is a halogen ) via Sandmeyer reactions .
The mechanism for bromination of benzene. The mechanism for iodination is slightly different: iodine (I 2) is treated with an oxidizing agent such as nitric acid to obtain the electrophilic iodine ("I +", probably IONO 2). Other conditions for iodination include I 2, HIO 3, H 2 SO 4, and N-iodosuccinimide, H 2 SO 4.
Presence of unsaturation and/or phenol or aniline in the sample is shown by disappearance of the deep brown coloration of bromine when it has reacted with the unknown sample. The formation of a brominated phenol (i.e. 2,4,6-tribromophenol ) or aniline (i.e. 2,4,6-tribromoaniline ) in form of a white precipitate indicates that the unknown was a ...
An example of the Hell–Volhard–Zelinsky reaction can be seen in the preparation of alanine from propionic acid.In the first step, a combination of bromine and phosphorus tribromide is used in the Hell–Volhard–Zelinsky reaction to prepare 2-bromopropionic acid, [3] which in the second step is converted to a racemic mixture of the amino acid product by ammonolysis.
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:
More recently, trifluoromethylation of diazonium salts has been developed and is referred to as a 'Sandmeyer-type' reaction. Diazonium salts also react with boronates, iodide, thiols, water, hypophosphorous acid and others, [6] and fluorination can be carried out using tetrafluoroborate anions (Balz–Schiemann reaction). However, since these ...