Description
Strictly speaking, fluorocarbon compounds
contain only the elements carbon, fluorine, and
sometimes hydrogen. However, in industrial
applications such as refrigerants and aerosol
propellants, the term fluorocarbon has been
used to include compounds containing chlorine
and bromine atoms, or both. These industrial
products have somewhat similar chemical and
physical properties. Their relatively inert character
and wide range of vapor pressures and
boiling points make them especially well suited
as refrigerants in a variety of applications,
blowing agents for plastic foams, and aerosols.
Chemical Properties
Colorless gas; ethereal odor. heavier than air. Nonflammable
Uses
The fluorocarbons covered in this monograph
are widely used as refrigerants, polymer intermediates,
and blowing agents in the manufacture
of polymerized foams used in insulation
and comfort cushioning. They are also used for
making packaging foams, as well as aerosol
propellants for products applied in foam or
spray form, and fire extinguishing agents. Special
mixtures of two or more fluorocarbons, or
fluorocarbons and hydrocarbons, are often used
to provide desired special properties in particular
refrigeration or aerosol propellant applications.
While Tetrafluoromethane is also used as a
low-temperature refrigerant gas, it is also widely
used by the electronics industry as a dry etchant
in microchip manufacture. It is blended with
oxygen and used to desmear and etch-back
"through holes" on printed circuit boards.
Uses
Dielectric and aerospace chemical, hardening
of metals, pharmaceutical processing.
General Description
CHLOROTRIFLUOROMETHANE is a colorless odorless gas. CHLOROTRIFLUOROMETHANE is shipped as a liquefied gas under its own vapor pressure. CHLOROTRIFLUOROMETHANE is noncombustible. CHLOROTRIFLUOROMETHANE can asphyxiate by the displacement of air. Contact with the liquid can cause frostbite. Exposure of the container to prolonged heat or fire may cause CHLOROTRIFLUOROMETHANE to rupture violently and rocket.
Reactivity Profile
The reaction of aluminum with various halogenated hydrocarbons produces a self-sustaining reaction with sufficient heat to melt aluminum pieces, examples of other halogenated hydrocarbons are fluorotrichloromethane, dichlorodifluoromethane, chlorodifluoromethane, tetrafluoromethane. The vigor of the reaction appears to be dependent on the combined degree of fluorination and the vapor pressure, [Chem. Eng. News 39(27):44(1961)].
Hazard
Toxic by inhalation; slightly irritant.
Health Hazard
Exposure may cause nausea, dizziness, and headache, and rapid suffocation. Contact with skin may cause frostbite.
Fire Hazard
Special Hazards of Combustion Products: Toxic fumes of Cl and F
Materials Uses
The fluorocarbons are generally compatible
with most of the common metals except at high
temperatures. At elevated temperatures, the
following metals resist fluorocarbon corrosion
(and are named in decreasing order of their corrosive
resistance): Inconel, stainless steel,
nickel, steel, and bronze. Water or water vapor
in fluorocarbon systems will corrode magnesium
alloys or aluminum containing over 2 percent
magnesium. These metals are not recommended
for use with fluorocarbon systems in
which water may be present.
Safety Profile
A mild irritant.
Narcotic in high concentrations. Reacts
violently with Al. When heated to
decomposition it emits highly toxic fumes of
Fand Cl-.
Physiological effects
The fluorocarbons used in industry generally
have low levels of toxicity, and hazards related
to their use are minimal. These compounds have
been extensively studied by many investigators
under a variety of conditions.
storage
Use forced ventilation and local exhaust, or
both, to prevent an accumulation of gas that
could reduce the oxygen level to below 19.5%.
Ensure good floor ventilation. Use a check
valve or trap in the discharge line to prevent
back flow into the cylinder. Where applicable,
use a pressure-reducing regulator when connecting
a cylinder to a low-pressure piping system.
For flammable fluorocarbons, adherence to
pertinent electrical standards is necessary. Personnel
should not weld, solder, braze, or have
an open flame of any type in atmospheres containing
flammable or nonflammable fluorocarbons.
Purification Methods
Main impurities are CO2, O2, and N2. The CO2 is removed by passage through saturated aqueous KOH, followed by conc H2SO4. The O2 is removed using a tower packed with activated copper on Kieselguhr at 200o, and the gas is dried over P2O5. [Miller & Smyth J Am Chem Soc 79 20 1957, Beilstein 1 III 42, 1 IV 34.] TOXIC GAS.
GRADES AVAILABLE
Fluorocarbons are available for commercial and
industrial use in various grades with essentially
the same composition from one producer to
another. Purities of most fluorocarbon products
are a minimum of 99 volume percent. For special
applications very high purity grades are
available.
