Atmospheric chemistry and physical fate of HCFCS and HFCS and their degradation products. Interim report, September 1990-September 1992
Laboratory experiments were conducted to determine the fate of the proposed CFC substitutes HCFC-22, HCFC- 123, HCFC-124, HCFC-141b, HCFC-142b, HFC-125, HFC-134a, and HFC-152a. The program consisted of photochemical oxidation experiments to identify stable oxidation products and measure their yields; deposition studies to measure the extent oxidation products are absorbed into aqueous media; and experiments to determine the fate of hydrolysis products during droplet evaporation. Model results, obtained using laboratory derived lower limits estimates for aqueous deposition velocities and assuming a well mixed atmosphere, suggest the uptakes rates to cloudwater and oceans are sufficiently fast such that significant buildup of gas phase products is unlikely. The laboratory studies suggest that product accumulation in aqueous media could be affected by losses during evaporation. Direct loss by evaporation of halogenated acids and/or production of volatile compounds after further reactions of the dissolved acids could return halogenated compounds to the atmosphere.
- Research Organization:
- Environmental Protection Agency, Research Triangle Park, NC (United States). Atmospheric Research and Exposure Assessment Lab.
- OSTI ID:
- 7030737
- Report Number(s):
- PB-93-131449/XAB; EPA-600/R-92/222
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
ORGANIC HALOGEN COMPOUNDS
ECOLOGICAL CONCENTRATION
PHOTOCHEMICAL REACTIONS
RESEARCH PROGRAMS
AIR POLLUTION ABATEMENT
AIR-WATER INTERACTIONS
ATMOSPHERIC CHEMISTRY
BENCH-SCALE EXPERIMENTS
BUILDUP
CHEMICAL ANALYSIS
DEPOSITION
EVAPORATION MODEL
FREONS
HYDROLYSIS
LOSSES
MATHEMATICAL MODELS
METEOROLOGY
OXIDATION
PHYSICAL PROPERTIES
PRECIPITATION
REACTION KINETICS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
HALOGENATED ALIPHATIC HYDROCARBONS
KINETICS
LYSIS
NUCLEAR MODELS
ORGANIC COMPOUNDS
POLLUTION ABATEMENT
SEPARATION PROCESSES
SOLVOLYSIS
400500* - Photochemistry
540120 - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)
540320 - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)