Question

Identify allylic halide and vinylic halide.

Answer 1

Allylic Halides:
An allylic halide is a halogenated organic compound where the halogen atom is bonded to an allylic carbon. An allylic carbon is a carbon atom that is adjacent to a carbon-carbon double bond. This means that the halogen is positioned on a carbon that is one step away from the double bond.

Example of an Allylic Halide:
Consider 3-chloropropene, which is an example of an allylic halide. In this case, the chlorine atom is attached to the carbon atom that is adjacent to the carbon-carbon double bond: \[ \text{CH}_2=\text{CH}-\text{CH}_2\text{Cl} \] Here, the chlorine atom is bonded to the allylic carbon (the carbon next to the double bond), making this compound an allylic halide.

Vinylic Halides:
A vinylic halide is a halogenated organic compound where the halogen atom is bonded directly to a vinyl carbon. A vinyl carbon is a carbon atom that is part of a carbon-carbon double bond, meaning the halogen is attached directly to one of the carbons involved in the double bond.

Example of a Vinylic Halide:
Chloroethene, commonly known as vinyl chloride, is an example of a vinylic halide. In this compound, the chlorine atom is bonded directly to the vinyl carbon: \[ \text{CH}_2=\text{CHCl} \] In this case, the chlorine atom is attached to the carbon involved in the double bond, making this compound a vinylic halide.

Summary:
- An allylic halide has the halogen attached to a carbon adjacent to the double bond (e.g., 3-chloropropene). 
- A vinylic halide has the halogen attached directly to a carbon in the double bond (e.g., chloroethene). 
These two types of halides differ in the position of the halogen relative to the carbon-carbon double bond.