Reed reaction

[1] Polyethylene is treated with a mixture of chlorine and sulfur dioxide under UV-radiation.

Vinylsulfonic acid can also be prepared beginning with the sulfochlorination of chloroethane.

Dehydrohalogenation of the product gives vinylsulfonyl chloride, which subsequently is hydrolyzed to give vinylsulfonic acid: The reaction occurs via a free radical mechanism.

UV-light initiates homolysis of chlorine, producing a pair of chlorine atoms: Chain initiation: Thereafter a chlorine atom attacks the hydrocarbon chain, freeing hydrogen to form hydrogen chloride and an alkyl free radical.

The resulting sulfonyl radical attacks another chlorine molecule to produce the desired sulfonyl chloride and a new chlorine atom, which continues the reaction chain.