Difference Between Allyl Chloride and Vinyl Chloride

The key difference between allyl chloride and vinyl chloride is that ally chloride contains its chlorine atom bonded to the carbon atom that is adjacent to the double bond, whereas vinyl chloride contains its chlorine atom bonded to one of the two carbon atoms in the double bond.

The terms allyl and vinyl are common in organic chemistry because we can use these terms to name compounds using the positions of specific atoms with regard to the double bonds present in that compound.

CONTENTS

1. Overview and Key Difference
2. What is Allyl Chloride 
3. What is Vinyl Chloride
4. Side by Side Comparison – Allyl Chloride vs Vinyl Chloride in Tabular Form
5. Summary

What is Allyl Chloride?

Allyl chloride is an organic compound containing its chlorine atom bonded to the carbon atom that is adjacent to the double bond in the molecule. That means; the allyl chlorides are alkenes containing a chlorine atom. The chlorine atom is bound to the carbon atom that is nearest to the double bond of the alkene. Although the carbon atoms having the double bond are sp2 hybridized, the carbon atom bearing the chlorine atom is sp3 hybridized.

Furthermore, this carbon atom bonds with the double-bonded carbon atom through a single bond. Therefore, the electron density around this carbon atom is lower than that of the carbon atoms in the double bond. If a molecule contains two double bonds, then the allylic carbon that bears the chlorine atom can act as a bridge for two double bonds.

What is Vinyl Chloride?

Vinyl chloride is an organic compound containing its chlorine atom bonded to one of the two carbon atoms in the double bond of the molecule. These are alkenes containing a chlorine atom at the double bond. Therefore, the carbon atom containing the chloride atom has sp2 hybridization, and its geometry around the carbon atom is trigonal planar. These carbon atoms in the double bond are named as vinylic carbon. The electron density around these carbon centres are higher; however, the carbon atom containing the chlorine atom has more electron density than the other carbon atom because the chlorine atom is an electron-rich species.

The vinyl chloride compound exists as a colourless gas at room temperature and it has a pleasant odour as well. This compound is important as the monomer for the production of polyvinyl chloride polymer. Therefore, it is a chemical intermediate, rather than a final product. The polymer product of vinyl chloride (polyvinyl chloride) is stable, storable and non-toxic. However, vinyl chloride is mostly unstable, thus difficult to store and shows acute toxicity. We can produce vinyl chloride via thermal decomposition of dichloroethane, from acetylene, and from ethane.

What are the Similarities between Allyl Chloride and Vinyl Chloride?

• Allyl chloride and vinyl chloride are two-carbon compounds.
• They are alkenes containing a double bond.
• Both are highly toxic compounds.

What is the Difference Between Allyl Chloride and Vinyl Chloride?

The key difference between allyl chloride and vinyl chloride is that ally chloride contains its chlorine atom bonded to the carbon atom that is adjacent to the double bond, whereas vinyl chloride contains its chlorine atom bonded to one of the two carbon atoms in the double bond. Furthermore, the allyl chloride occurs as a liquid, while vinyl chloride is a colourless gas at room temperature. Moreover, allyl chloride has an unpleasant odour, while vinyl chloride has a pleasant odour.

Below infographic tabulates the differences between allyl chloride and vinyl chloride.

Summary – Allyl Chloride vs Vinyl Chloride

The terms allyl and vinyl are common in organic chemistry. The key difference between allyl chloride and vinyl chloride is that ally chloride contains its chlorine atom bonded to the carbon atom that is adjacent to the double bond, whereas vinyl chloride contains its chlorine atom bonded to one of the two carbon atoms in the double bond.

Reference:

1. Johnson, Todd. “PVC Plastics: Polyvinyl Chloride.” ThoughtCo, Feb. 11, 2020, Available here.

Image Courtesy:

1. “Allyl chloride” By Cwbm (commons) – standard textbook (Public Domain) via Commons Wikimedia
2. “Vinyl-chloride-2D” (Public Domain) via Commons Wikimedia