Vapor pressure dichlorodifluoromethane

Blends of trichloromonofluoromethane and dichlorodifluoromethane (propellant 11/12) or propellant 11/114/12 produce vapor pressures of 103 84 kPa (15-70 psig) at 21°C, which adequately cover the range of pressures required to produce the proper particle-size distribution for satisfactory aerosol products. Trichloromonofluoromethane is unique among the chlorofluorocarbon propellants in that it is a liquid at room temperature and atmospheric pressure and can be used to prepare a slurry with insoluble medicinal agents. 

Dichlorodifluoromethane 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 concentrations has a faint etherlike odor. Dichlorodifluoromethane is noncorrosive, nonirritating, and nonflammable. 

Dichlorodifluoromethane (Freon 12, Fluorocarbon 12 [CAS 75-71-81) Mild eye and respiratory tract irritant. Extremely high exposures (eg, 100,000 ppm) can cause coma and cardiac arrhythmias. See also p 209. 1000 ppm 15,000 ppm Colorless gas. Ether-llke odor Is a poor warning property. Vapor pressure is 5.7 mm Hg at 20°C (68°F). Not combustible. Decomposes slowly on contact with water or heat to produce hydrogen chioride, hydrogen fluoride, and phosgene. 

TEMPERATURE Degrees Fahrenheit Fig. 1. Vapor pressure curve for dichlorodifluoromethane (R12). 

TEMPERATURE -- Degrees Fahrenheii Fig. 1. Vapor Pressure Curve for Dichlorodifluoromethane (R-12). 

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