classify the following reaction on the basis of the type Phosphorus reacts with chlorine to give Phosphorus pentachloride
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Answer:
In synthetic chemistry, two classes of chlorination are usually of interest: oxidative chlorinations and substitutive chlorinations. Oxidative chlorinations entail the transfer of Cl2 from the reagent to the substrate. Substitutive chlorinations entail replacement of O or OH groups with chloride. PCl5 can be used for both processes.
Upon treatment with PCl5, carboxylic acids convert to the corresponding acyl chloride.
It also converts alcohols to alkyl chlorides. Thionyl chloride is more commonly used in the laboratory because the resultant sulfur dioxide is more easily separated from the organic products than is POCl3.
PCl5 reacts with a tertiary amides, such as dimethylformamide (DMF), to give dimethylchloromethyleneammonium chloride, which is called the Vilsmeier reagent, [(CH3)2N=CClH]Cl. More typically, a related salt is generated from the reaction of DMF and POCl3. Such reagents are useful in the preparation of derivatives of benzaldehyde by formylation and for the conversion of C−OH groups into C−Cl groups.
It is especially renowned for the conversion of C=O groups to CCl2 groups. For example, benzophenone and phosphorus pentachloride react to give the diphenyldichloromethane :
(C6H5)2CO + PCl5 → (C6H5)2CCl2 + POCl3
The electrophilic character of PCl5 is highlighted by its reaction with styrene to give, after hydrolysis, phosphonic acid derivatives