Search results
Results from the WOW.Com Content Network
In this way the two halogens add in an anti addition fashion, and when the alkene is part of a cycle the dibromide adopts the trans configuration. For maximum overlap of the C–Br σ* antibonding molecular orbital (the LUMO , shown to the right in red) and the nucleophile (X − ) lone pair (the HOMO , shown to the right below in green), X − ...
Halogenation of phenols is faster in polar solvents in a basic environment due to the dissociation of phenol, with phenoxide ions being more susceptible to electrophilic attack as they are more electron-rich. Chlorination of toluene with chlorine without catalyst requires a polar solvent as well such as acetic acid.
Since direct sulfonation of the alkanes is hardly possible, this reaction has proven to be useful. Due to chlorine, which is bound directly to the sulfur, the resulting products are highly reactive. As secondary products there are alkyl chlorides formed by pure photochlorination, as well as several sulfochlorinated products in the reaction mixture.
In chemistry, halogenation is a chemical reaction which introduces one or more halogens into a chemical compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, drugs. [1] This kind of conversion is in fact so common that a comprehensive overview is challenging.
In organic chemistry, free-radical halogenation is a type of halogenation. This chemical reaction is typical of alkanes and alkyl-substituted aromatics under application of UV light. The reaction is used for the industrial synthesis of chloroform (CHCl 3), dichloromethane (CH 2 Cl 2), and hexachlorobutadiene. It proceeds by a free-radical chain ...
For alkylbenzene derivatives, e.g. toluene, the alkyl positions tend to be halogenated by free radical conditions, whereas ring halogenation is favored in the presence of Lewis acids. [6] The decolouration of bromine water by electron-rich arenes is used in the bromine test. Reaction between benzene and halogen to form an halogenobenzene
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.
This is due to the abstraction of a hydrogen atom by the alkene from the hydrogen halide (HX) to form the most stable carbocation (relative stability: 3°>2°>1°>methyl), as well as generating a halogen anion. A simple example of a hydrochlorination is that of indene with hydrogen chloride gas (no solvent): [4]