Tetrafluoroethylene

DescriptionTetrafluoroethylene is a synthetic, colorless, flammable gas that is insoluble in water. Tetrafluoroethylene is used primarily in the synthesis of polytetrafluoroethylene resins. It is also used as a monomer in the synthesis of copolymers and as a propellant for food product aerosols. When heated to decomposition, tetrafluoroethylene emits highly toxic fluorocarbon fumes. The primary route of human exposure to this compound is inhalation. Acute inhalation exposure to tetrafluoroethylene may result in irritation of the respiratory tract and buildup of fluid in the lungs (pulmonary edema). Contact with this gas can cause eye irritation. This chemical is reasonably anticipated to be a human carcinogen. (NCI05)

UsesIn manufacture of polymers and synthesis of fluorinated refrigerants, dielectric media and solvents. In vinyl polymerization, cycloalkylation and addition reactions.

General DescriptionTetrafluoroethylene, stabilized appears as a colorless odorless gas. Easily ignited. Vapors are heavier than air. May asphyxiate by the displacement of air. May violently polymerize under prolonged exposure to fire or heat, violently rupturing the container. Under prolonged exposure to fire or heat the containers may rupture violently and rocket. Water insoluble.

PreparationTetrafluoroethylene (TFE) is manufactured from chloroform. Chloroform is fluorinated by reaction with hydrogen fluoride to produce chlorodifluoromethane (R-22). Pyrolysis of chlorodifluoromethane then yields TFE.CHCl3 + 2 HF → CHClF2 + 2 HCl2CHClF2 → C2F4 + 2 HClA laboratory synthesis entails pyrolysis of a PTFE under a vacuum. The PTFE polymer "cracks" and depending on the pressure, produces mainly C2F4.