Perfluoroisobutene
Perfluoroisobutene (PFIB), also known as 1,1,3,3,3-pentafluoro-2-(trifluoromethyl)prop-1-ene, is a fluorinated olefine. It is a hydrophobic reactive gas with boiling point at 7 °C. It is a strong electrophile.
PFIB is about 10 times as toxic as phosgene. Its inhalation can lead to pulmonary edema, which may be fatal. Onset of symptoms can take 1-4 hours after inhalation. Treatment is based on managment of the pulmonary edema (usualy with high-dose corticoids and other medication/measures) and associated disorders (e.g. heart failure, hypocalcemia etc.). Many cases resolve within 72 hours without major long-term effects.
In contact with water PFIB undergoes rapid hydrolysis, producing various reactive compounds and fluorophosgene.
PFIB is a product of pyrolysis of polytetrafluoroethylene (PTFE), one of the substances causing polymer fume fever.
It is a Schedule 2 substance of the Chemical Weapons Convention.