Propellant 12 dichlorodifluoromethane

Propellant 12, see Dichlorodifluoromethane Propenal, see Acrolein Prop-2-en-l-al, see Acrolein 2-Propenal, see Acrolein Propenamide, see Acrylamide 2-Propenamide, see Acrylamide Propenenitrile, see Acrylonitrile 2-Propenenitrile, see Acrylonitrile Propene oxide, see Propylene oxide Propenitrile, see Acrylonitrile... 

Salmeterol xinafoate inhalation aerosol contains salmeterol xinafoate as the racemic form of the 1-hydroxyl-naphthoic acid salt of salmeterol. It is a pressurized, metered-dose aerosol unit for oral inhalation. It contains a microcrystalline suspension of salmeterol xinafoate in a mixture of two chlorofluorocarbon propellants (trichlorofluoromethane and dichlorodifluoromethane)... 

A group of compounds were discovered in the 1930s and were called the chlorofluorocarbons (CFCs). Because of their inertness they found many uses, especially as a propellant in aerosol cans. CFC-12 or dichlorodifluoromethane, CF2C12, was one of the most popular CFCs in use in aerosols. Scientists believe that CFCs released from aerosols are destroying the ozone layer and steps are being taken to reduce this threat. 

Owing to the extreme chemical activity of fluorine, the chief uses of this element arise in connection with the production of its compounds. Thus, sodium fluoride is commonly used as a flux, as an insecticide, and as a wood preservative. Ammonium fluoride is sometimes used as a disinfectant. The compound dichlorodifluoromethane (CC12F2) is used as an insecticide propellent and is an important commercial refrigerant (Freon), particularly well suited for use in domestic refrigeration units. 

Dichlorodifluoromethane, dichlorotetrafluoroethane, and trichloromonofluoromethane are chlorofluorocarbon (CFC) aerosol propellants used in pharmaceutical formulations. 

Dichlorodifluoromethane is used as an aerosol propellant in metered-dose inhaler (MDI) formulations, either as the sole propellant or in combination with dichlorotetrafluoroethane, trichloromonofluoromethane, or mixtures of these chlorofluorocarbons. Dichlorodifluoromethane may also be used as a propellant in an aerosolized sterile talc used for intrapleural administration and is also used alone in some MDIs containing a steroid. 

Dichlorotetrafluoroethane is used in combination with dichlorodifluoromethane, and in several cases with dichlorodifluoromethane and trichloromonofluoromethane, as the propellant in metered-dose oral and nasal aerosols. 

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. 

Both dichlorodifluoromethane and dichlorotetrafluoro-ethane are compatible with most ingredients used in pharmaceutical aerosols. Because of their poor miscibility with water, most MDIs are formulated as suspensions. However, solution MDIs can be prepared through the use of ethanol as a cosolvent for water and propellant, resulting in a clear solution (provided the water content is less than 5%). 

Dichlorodifluoromethane, dichlorotettafluoroethane, and trichloromonofluoromethane have been used for over 40 years as propellants in topical, oral, and nasal aerosol formulations and are generally regarded as nontoxic and nonittitant materials when used as directed. 

Dichlorodifluoromethane and dichlorotetrafluoroethane are usually encountered as a liquefied gas and appropriate precautions for handling such materials should be taken. Eye protection, gloves, and protective clothing are recommended. These propellants should be handled in a well-ventilated environment. Chlorofluorocarbon vapors are heavier than air and do not support life therefore, when cleaning large tanks that have contained chlorofluorocarbons, adequate provisions for supply of oxygen in the tanks must be made in order to protect workers cleaning the tanks. 

Fluorocarbon (FC) aerosol propellants may be identified by a standardized numbering nomenclature for example, dichlorodifluoromethane is known as propellant 12, while dichlorotetrafluoroethane is known as propellant 114. 

Niazi S, Chiou WL. Fluorocarbon aerosol propellants XI pharmacokinetics of dichlorodifluoromethane in dogs following single dose and multiple dosing. Pharm Sci 1977 66 49-53. 

In aerosol vehicles that include water, the addition of polyoxyl 40 hydrogenated castor oil improves the solubility of the propellant in the aqueous phase. This enhancement applies both to dichlorodifluoromethane and to propane/butane mixtures. 

Dichlorodifluoromethane (Freon 12) [75-71-8] M 120.9, m -158 , b -29.8°/atm, 42.5 /10atm. Passage through saturated aqueous KOH then cone H2SO4, and a tower packed with activated copper on Kielselguhr at 200° removed CO2 and O2. A trap cooled to -29° removed a trace of high boiling material. It is a non-flammable propellant. 

Large quantities of dichlorodifluoromethane and other chlorofluorocarbons ( Freons ) are used as aerosol propellants, and it has been calculated that there is a danger of reducing the earth s protective ozone layer following photolysis to produce chlorine atoms in the upper atmosphere.184 Milstein and Rowland185 have now measured quantum yields of unity for CF2C12 dissociation [reaction (36)] and for appearance of photo-oxidation products in oxygen. Studies of the... 

Dichlorodifluoromethane and other Freons were once used for many commercial applications as refrigerants for air conditioners and refrigerators as an aerosol propellant for hair sprays, insecticides, paints, adhesives, and cleaners ... 

Propei . See Lactic acid Propellant 11. See Trichlorofluoromethane Propellant 12. See Dichlorodifluoromethane Propellant 22. See Chlorodifluoromethane Propellant 23. See Trifluoromethane Propellant 114. See 1,2-Dichlorotetrafluoroethane Propellant 142b. See 1,1,1-Chlorodifluoroethane Propellant 152a. See 1,1-Difluoroethane Propellant C-318. See Octafluorocyclobutane Prop-2-enal 2-Propenal. See Acrolein... 

Carbon dioxide Dichlorodifluoromethane Nitrogen Nitrous oxide Propane propellant, hydrocarbon Cyclopentane... 

Fluorine compounds have many uses. One of the most notable of these is the manufacture of chlorofluorocarbon compounds known by the trade name Freon. These are chemical combinations of chlorine, fluorine, and carbon, an sample of which is dichlorodifluoromethane, CI2CF2. These compounds used to be widely employed as refrigerant fluids and blowing agents to make foam plastics they were also once widely used as propellants in aerosol spray cans. Uses of chlorofluorocarbons have now been phased out because of their role in destroying stratospheric ozone (discussed with oxygen, above). 

Dichlorodifluoromethane, CCI2F2, is a gas used as a refrigerant and aerosol propellant. Write the Lewis formula for CCI2F2. 

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