Chemical properties of tetrafluoroethylene and its application in industry

Chemical properties of tetrafluoroethylene
Tetrafluoroethylene (molecuLar formula: C ₂ F ₄, structural formula: CF ₂=CF ₂) is a highly symmetrical fluoroalkene with the following key chemical properties:
High chemical stability
Resistant to strong acids, strong bases, strong oxidants (such as aqua regia, concentrated nitric acid, etc.), and even difficult to corrode at high temperatures, due to the high bond energy of C-F bonds (about 485 kJ/mol) and the shielding effect of Fluorine atoms on carbon chains.
Insoluble in most organic solvents, only slightly soluble in liquid fluorocarbon compounds.
Polymerization reactivity
Under initiator (such as persulfate) or high temperature and high pressure conditions, free radical polymerization reactions are prone to occur, producing polytetrafluoroethylene (PTFE, commonly known as the "plastic king").
It can also be copolymerized with other fluorinated monomers (such as hexafluoropropylene, vinylidene fluoride, etc.) to form fluoroplastics with different properties (such as FEP, ETFE, etc.).
Thermal stability and decomposition products
Stable at normal operating temperatures (<260 ℃), but decomposition at high temperatures (>400 ℃) can release toxic hydrogen fluoride (Hf) and fluorophosgene (COF ₂), and safety precautions should be taken.
Flame retardancy
It is non combustible and has the characteristic of suppressing combustion, making it a flame-retardant material.
addition reaction
Double bonds can undergo addition reactions with halogens such as fluorine and chlorine, but their reactivity is lower than that of ordinary olefins (due to the electron withdrawing effect of fluorine atoms, which reduces the electron cloud density of double bonds).
Application of Tetrafluoroethylene in Industry
The core application of tetrafluoroethylene is as a monomer for synthesizing fluoroplastics, and its derivative materials have an irreplaceable position in the industrial field:
1. Application of polytetrafluoroethylene (PTFE)
PTFE is the most important polymer of tetrafluoroethylene, widely used for:
Chemical and anti-corrosion fields
Manufacturing corrosion-resistant pipelines, valves, pump bodies, and reactor liners (such as fluoroplastic lined equipment) for the treatment of strong acids, strong alkalis, and strong oxidants.
Sealing materials: such as gaskets and sealing rings, suitable for high temperature, high pressure, or corrosive environments.
In the field of electronics and electrical engineering
The insulation layer of high-frequency communication cables (such as radar and satellite antenna cables) has a low dielectric constant (ε≈ 2.1) and low dielectric loss.
Printed circuit board (PCB) substrate material, used for high temperature resistant and highly reliable electronic devices.
Aerospace and Automotive Industry
Aircraft engine seals, bearing lubricants (utilizing low friction characteristics).
Automotive gearbox seals and suspension bushings enhance wear and oil resistance.
Medical and Food Industry
Medical catheters and artificial blood vessels (with good biocompatibility).
Conveyor belts and coatings for food processing equipment (compliant with FDA standards, anti adhesive, and easy to clean).
2. Application of Fluorocopolymers
The copolymerization of tetrafluoroethylene with other monomers can optimize performance and expand application scenarios:
FEP (fluorinated ethylene propylene copolymer)
Transparency superior to PTFE, used for high-temperature resistant wire insulation (such as oven wiring harnesses) and anti-corrosion coatings (such as chemical tank liners).
ETFE (ethylene tetrafluoroethylene copolymer)
High mechanical strength and good impact resistance, used for photovoltaic cell backboards and building film materials (such as the exterior walls of Beijing Water Cube).
PFA (Perfluoroalkoxy Resin)
Molten processing, used for manufacturing precision valves and high-purity reagent delivery pipelines in the semiconductor industry (low precipitation, corrosion-resistant).
3. Other industrial applications
Surface Treatment
As a coating material, a corrosion-resistant layer is formed on the surface of metals and ceramics through spraying or impregnation processes (such as non stick coatings on cookware, which need to be compounded with other fluororesins).
Semiconductor Manufacturing
Corrosion resistant components in etching equipment (such as reaction chamber liners) are resistant to the erosion of fluorine-containing plasma.
Aerospace propellants
Used as an intermediate for rocket fuel in the early days, but gradually replaced due to environmental issues.
Safety and environmental considerations
Toxicity: Tetrafluoroethylene monomer has certain toxicity, and high concentration inhalation can cause central nervous system inhibition. Therefore, strict ventilation control is required during the production process.
Environmental impact:
Tetrafluoroethylene belongs to the category of greenhouse gases (with extremely high GWP values), and its production and use must comply with environmental regulations (such as the control of fluorinated compounds under the Montreal Protocol).
PTFE is difficult to degrade and needs to be professionally recycled after disposal to avoid white pollution.