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How are organohalogen compounds classified as alkyl, vinylic, aryl, or acyl halides?
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organohalogen compound
Vinyl chloride is an organohalogen compound that has important industrial applications. When treated with certain catalysts, vinyl chloride monomers undergo polymerization and form the larger compound known as polyvinyl chloride, or PVC. PVC is used in the manufacture of numerous products, including packaging films and water pipes.
Organohalogen compounds are classified based on the specific type of carbon atom to which the halogen is directly bonded. This classification is primarily responsible for the characteristic chemical properties of each class.1
The four main categories are:
- Alkyl halides: The carbon atom bearing the halogen is bonded to four other atoms via single bonds. Even if a double bond or an aromatic ring exists elsewhere in the molecule, the compound is classified as an alkyl halide if the halogen-bearing carbon itself is only involved in single bonds.1
- Vinylic halides: The carbon atom that bears the halogen is directly involved in a double bond with another carbon atom.1
- Aryl halides: The halogen-bearing carbon atom is part of an aromatic ring.1
- Acyl halides: The halogen-bearing carbon atom is double-bonded to an oxygen atom.1
For alkyl halides, further classification into primary, secondary, or tertiary types is determined by the degree of substitution at the halogen-bearing carbon—specifically, how many other carbon atoms are directly attached to it.2