Uses
Phosphorus pentafluoride is a catalyst in ionic polymerization reactions.
Preparation
Phosphorus pentafluoride may be prepared by several methods, among which are:
- Treating phosphorus trifluoride with bromine and then heating the product phosphorus trifluoride dibromide, PF3Br2:
PF3 + Br2 → PF3Br2
5PF3Br2 → 3PF5 + 2PBr5
- Heating phosphorus pentachloride with arsenic trifluoride:
PCl5 + 5AsF3 → 3PF5 + 5AsCl3
- Subjecting phosphorus trifluoride to an electric spark in the absence of air (a disproportion reaction occurs):
5PF3 → 3PF5 + 2P (in the presence of air, the product is phosphorus oxyfluoride, POF3)
- Heating a mixture of phosphorus pentoxide and calcium fluoride:
P2O5 + 5CaF2 → 2PF5 + 5CaO
- Heating a mixture of phosphorus oxyfluoride, hydrogen fluoride and sulfur trioxide:
POF3 + 2HF + SO3 → PF5 + H2SO4
The gas should be stored in steel cylinders in the absence of moisture.
Chemical Properties
colorless gas; nonflammable; fumes strongly in air; high thermal stability; critical temp 144.5°C; critical pressure 3.39MPa; enthalpy of fusion 12.1 kJ/mol; enthalpy of vaporization 17.2 kJ/mol; can be prepared by reaction of PF3 with F2; used as a polymerization catalyst and in electronics industry [AIR87] [HAW93] [MER06] [CRC10] [KIR78]
Physical properties
Colorless gas; fumes in air; density 5.527g/L; heavier than air, density in air 4.35 (air=1); liquefies at -84.6°C; freezes at -93.8°C; reacts with water.
Uses
Phosphorus pentafluoride is usedas a catalyst in polymerization reactions.
Uses
Catalyst in ionic polymerization reactions.
Definition
ChEBI: Phosphorus pentafluoride is a phosphorus halide.
General Description
PHOSPHORUS PENTAFLUORIDE is a colorless, poisonous, nonflammable, compressed gas with a pungent odor. PHOSPHORUS PENTAFLUORIDE is extremely irritating to skin, eyes and mucus membranes. PHOSPHORUS PENTAFLUORIDE is very toxic by inhalation and can cause pulmonary edema. Toxic and corrosive fumes are generated when PHOSPHORUS PENTAFLUORIDE is exposed to water or steam. Prolonged exposure of the containers to fire or heat may result in their violent rupturing and rocketing. PHOSPHORUS PENTAFLUORIDE is used as a polymerization catalyst.
Air & Water Reactions
Fumes strongly in air, with traces of moisture forming POF3 and HF (corrosive). Decomposed in water or moist air to form phosphoric acid and hydrofluoric Acid, corrosive [Merck 11th ed. 1989].
Reactivity Profile
PHOSPHORUS PENTAFLUORIDE is a colorless, toxic gas, when exposed to air PHOSPHORUS PENTAFLUORIDE strongly fumes. Vigorous reaction with water or steam leads to decomposition (hydrolysis) producing toxic and corrosive fumes. When heated to decomposition PHOSPHORUS PENTAFLUORIDE emits toxic fumes of fluoride and oxides of phosphorus [Lewis, 3rd ed., 1993, p. 1034].
Hazard
Phosphorus pentafluoride is a highly toxic gas. Inhalation can cause severe irritation of mucous membrane and pulmonary edema. It is corrosive to skin and can damage eyes.
Health Hazard
TOXIC; may be fatal if inhaled, ingested or absorbed through skin. Vapors are extremely irritating and corrosive. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control may cause pollution.
Health Hazard
Phosphorus pentafluoride is highly irritating to the skin, eyes, and respiratory tract. Exposure to this gas can cause pulmonary edema and lung injury. The LC50 value for this compound is not reported. The concentration in air at which it may be lethal to mice over a 10-minute exposure period is estimated to be about 400 ppm (～2050 mg/m
3).
Fire Hazard
Some may burn but none ignite readily. Vapors from liquefied gas are initially heavier than air and spread along ground. Some of these materials may react violently with water. Cylinders exposed to fire may vent and release toxic and/or corrosive gas through pressure relief devices. Containers may explode when heated. Ruptured cylinders may rocket.
Safety Profile
A poisonous gas.
Violently irritating to skin, eyes, and
-
mucous membranes. Inhalation may cause
pulmonary edema. Reacts with water or
steam to produce toxic and corrosive fumes.
When heated to decomposition it emits
highly toxic fumes of Fand POx. See also
FLUORIDES.
Waste Disposal
Phosphorus pentafluoride is destroyed by bubbling the gas through a solution of caustic soda (in excess) at a cold temperature. The alkaline mixture is neutralized slowly by dilute HCl and washed down the drain.
