What Is an Allyl Cation?
An allyl cation is an organic compound with the chemical formula C3H5, and is known for its high stability due to the delocalization of positive charges to the three carbons in the compound by resonance. Although the name originally refers to a single compound, it is sometimes used as a generic term for carbocations with a positive charge on the allylic carbon, rather than the compound itself.
In either case, allyl cation is more stabilized than other carbocations. However, they are usually not isolated and exist as reaction intermediates. Therefore, there is no GHS classification or regulatory requirement for allyl cations themselves. As a result, it is necessary to check the starting material, the allyl compound, and its reaction products.
Uses of Allyl Cation
Allyl cations are used in various ways, including as stable reaction intermediates. Carbocations with a positive charge on a carbon atom exist as intermediates in various reactions, among which allyl cations are stable intermediates that facilitate the progress of reactions. Specifically, they are present as intermediates in the addition reaction of hydrogen halides to allyl compounds and are known to affect the regioselectivity of the addition.
Since allyl cations are polymerizable, the development of allyl cationic polymers using allyl cations themselves as monomers is underway, and these are also uses of the stability of allyl cations themselves.