Practicing Success
Practicing Success
CUET Preparation Today
Case: Read the passage and answer the questions There are several methods to prepare halo alkanes and haloarenes. One of the methods is to prepare from alcohol. The hydroxyl group of an alcohol is replaced by halogen on reaction with concentrated halogen acids, phosphorus halides or thionyl chloride. The halo alkanes are prepared by treating alkane with a limited amount of halogen in presence of halogen carrier and sunlight or heat. Adding hydrogen halide to alkene also results in the formation of halo alkanes. Haloarenes are prepared from hydrocarbons by electrophilic substitution and amines by Sandmeyer’s reaction. |
| What is the catalyst used in the electrophilic substitution of arenes with chlorine and bromine to prepare aryl chlorides and bromides? |
Platinum Palladium Lewis acid catalysts like iron or iron(III) chloride.
Nickel |
| Lewis acid catalysts like iron or iron(III) chloride. |
| Aryl chlorides and bromides can be easily prepared by electrophilic substitution of arenes with chlorine and bromine respectively in the presence of Lewis acid catalysts like iron or iron(III) chloride. |
