Hexafluoroisobutylene is an organofluorine compound with the formula (CF<sub>3</sub>)<sub>2</sub>C=CH<sub>2</sub>. This colorless gas is structurally similar to isobutylene. It is used as a comonomer in the production of modified polyvinylidene fluoride. It is produced in a multistep process starting with the reaction of acetic anhydride with hexafluoroacetone. It is oxidized by sodium hypochlorite to hexafluoroisobutylene oxide. As expected, it is a potent dienophile.