Dichlorodifluoromethane Montreal Protocol

Economic Aspects. The estimated worldwide production of important industrial CFCs is shown in Table 5. Trichlorofluoromethane, dichlorodifluoromethane, and trichlorotrifluoroethane account for over 95% of the total production. Between 1986 and 1991 the production of CFCs has decreased dramatically due to global adherence to the provisions of the Montreal Protocol and eventually will be phased out entirely. Estimates of the distribution by use in 1986 and subsequent reductions in use are shown in Table 6. 

No information on potentially susceptible populations was located for HCFC-141b. A structurally related chemical, 1,1,1,2-tetrafluoroethane, has been tested in metered-dose inhalers for the treatment of asthma. Test subjects included adult and pediatric asthma patients as well as individuals with severe COPD. No adverse effects were reported (Smith et al. 1994 Taggart et al. 1994 Ventresca 1995 Woodcock 1995). The structurally related chemicals trichlorofluoromethane (CFC-11) and dichlorodifluoromethane (CFC-12) are presently used in metered-dose inhalers for the treatment of asthma but are phased out under the Montreal Protocol of 1987 (Alexander 1995). Structurally related compounds including 1,1,1-trichloroethane and trichlorofluoromethane were also tested for cardiac sensitization in a dog model with experimentally induced myocardial infarction. In these experiments cardiac sensitization occurred under the same conditions as in healthy dogs (Trochimowicz et al. 1976). 

The formed mixture is composed of trichlorofluoromethane (Freon-11) and dichlorodifluoromethane (Freon-12). These compounds are used as aerosols and as refrigerants. Due to the depleting effect of chlorofluorocarbons (CFCs) on the ozone layer, the production of these compounds is to be reduced appreciably (Montreal Protocol). 

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