Name: Heptafluoropropane (HFC)
CAS No: 1,1,1,2,3,3,3-Heptafluoropropane [431-89-0]
None adopted
HFA227; HFC227; Dymel 227 ea/P; 2-hydroperfluoropropane; P-227; propellant 227; R-227; Solkane 227; Zephex 227 ea.
1,1,1,2,3,3,3-Heptafluoropropane [431-89-0]
C3HF7 170.0
Heptafluoropropane (P-227) is classified as a hydrofluorocarbon (HFC) aerosol propellant since the molecule consists only of carbon, fluorine, and hydrogen atoms. It does not contain any chlorine and consequently does not affect the ozone layer, nor does it have an effect upon global warming. It is therefore considered as an alternative propellant to CFCs for metered-dose inhalers (MDIs). While some of its physical and chemical properties are known, little has been published in regard to its use as a replacement for CFCs in MDIs. The vapor pressure of heptafluoropropane (P-227) is somewhat lower than that of tetrafluoroethane and dichlorodifluoromethane but considerably higher than the vapor pressure used to formulate most MDIs. When heptafluoropropane (P-227) is used for pharmaceutical aerosols and MDIs, the pharmaceutical grade must be specified. Industrial grades may not be suitable due to their impurity profile. Similarly to tetrafluoroethane, heptafluoropropane is not a good solvent for medicinal agents or for the commonly used surfactants and dispersing agents used in the formulation of MDIs. There are several MDIs formulated with this propellant worldwide that contain a steroid as the active ingredient.
Heptafluoropropane is a liquefied gas and exists as a liquid at room temperature when contained under its own vapor pressure, or as a gas when exposed to room temperature and atmospheric pressure. The liquid is practically odorless and colorless. The gas in high concentration has a faint etherlike odor. Heptafluoropropane is noncorrosive, nonirritating, and nonflammable.
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Boiling point -16.58C Density 1.386 g/cm3 for liquid at 258C Flammability Nonflammable. Freezing point -1318C Solubility Soluble 1 in 1725 parts of water at 208C. Specific gravity 1.41 at 258C Vapor pressure 459.81 kPa (66.69 psia) at 258C
Heptafluoropropane is a nonreactive and stable material. The liquefied gas is stable when used as a propellant and should be stored in a metal cylinder in a cool, dry place.
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Heptafluoropropane is used as a fire extinguisher and is applicable as a non-CFC propellant in various metered-dose inhalers. Heptafluoropropane is regarded as nontoxic and nonirritating when used as directed. No acute or chronic hazard is present when it is used normally. Inhaling high concentrations of heptafluoropropane vapors can be harmful and is similar to inhaling vapors of other propellants. Deliberate inhalation of vapors of heptafluoropropane can be dangerous and may cause death. The same labeling required of CFC aerosols would be required for those containing heptafluoropropane as a propellant (except for the EPA requirement).
Heptafluoropropane is usually encountered as a liquefied gas and appropriate precautions for handling such materials should be taken. Eye protection, gloves, and protective clothing are recommended. Heptafluoropropane should be handled in a wellventilated environment. The vapors are heavier than air and do not support life; therefore, when cleaning large tanks that have contained this propellant, adequate provisions for oxygen supply in the tanks must be made in order to protect workers cleaning the tanks. Although nonflammable, when heated to decomposition heptafluoropropane will emit hydrogen fluoride and carbon monoxide.
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Difluoroethane; tetrafluoroethane.
The main disadvantage of using heptafluoropropane is its lack of miscibility with water and its poor solubility characteristics when used with medicinal agents and the commonly used MDI surfactants. The use of heptafluoropropane as a propellant for MDIs has been the subject of many patents throughout the world. These patents cover the formulation of MDIs, the use of specific surfactants and cosolvents, etc., and the formulator is referred to the patent literature prior to formulating an MDI with any HFC as the propellant. The formulation of MDIs with tetrafluoroethane and heptafluoropropane propellant is complicated since they serve as a replacement for dichlorodifluoromethane or dichlorotetrafluoroethane in MDIs. The use of an HFC as the propellant also requires a change in manufacturing procedure, which necessitates a redesign of the filling and packaging machinery for an MDI. The PubChem Compound ID (CID) for heptafluoropropane is 62442.