Chlorofluorocarburo
Chlorofluorocarburos (CFC) e hydrochlorofluorocarburos (HCFC) son hydrocarburos halogenate que contine carbon (C), hydrogeno (H), chloro e (Cl) e fluor (F). Son volatile derivates de methano, ethano o propano.
Le exemplo le plus consuete es le dichlorodifluoromethano (R-12), alsi appellate Fréon. Essava usate como refrigerante fuido in refrigeratores e alsi como aerosol propulsor, extinctor de incendios gasose, o solvente.
Iste compositos son nocive pro le ozonosphera (strato de ozone) e ha un effecto conservatorio multe importante. In consquentia, lor fabrication ha essite progressivemente abandonate, conformemente al Montreal Protocollo (en). Son reimplaciate per altere productos como hydrofluorocarburos (HFC) o hydrofluoroolefinas (HFO)[1] (includente R-410A, le R-134a e R-1234yf).[2][3][4]
Productos
[modificar | modificar fonte]Freones continente bromo son notate con 4 nummeros. Isomeres, que son consuete pro ethano e propano derivatos, son distinguite per literas post numeros:
| Principal CFC | |||
|---|---|---|---|
| Systematic nomine | Usual nomine, code | Ebullition (°C) | Formula |
| Trichlorofluoromethano | Freon-11, R-11, CFC-11 | 23.77 | CCl3F |
| Dichlorodifluoromethano | Freon-12, R-12, CFC-12 | −29.8 | CCl2F2 |
| Chlorotrifluoromethano | Freon-13, R-13, CFC-13 | −81 | CClF3 |
| Dichlorofluoromethano | R-21, HCFC-21 | 8.9 | CHCl2F |
| Chlorodifluoromethano | R-22, HCFC-22 | −40.8 | CHClF2 |
| Chlorofluoromethano | Freon 31, R-31, HCFC-31 | −9.1 | CH2ClF |
| Bromochlorodifluoromethano | BCF, Halon 1211, H-1211, Freon 12B1 | −3.7 | CBrClF2 |
| 1,1,2-Trichloro-1,2,2-trifluoroethano | Freon 113, R-113, CFC-113, 1,1,2-Trichlorotrifluoroethane | 47.7 | Cl2FC-CClF2 |
| 1,1,1-Trichloro-2,2,2-trifluoroethano | Freon 113a, R-113a, CFC-113a | 45.9 | Cl3C-CF3 |
| 1,2-Dichloro-1,1,2,2-tetrafluoroethano | Freon 114, R-114, CFC-114, Dichlorotetrafluoroethano | 3.8 | ClF2C-CClF2 |
| 1,1-Dichloro-1,2,2,2-tetrafluoroethano | CFC-114a, R-114a | 3.4 | Cl2FC-CF3 |
| 1-Chloro-1,1,2,2,2-pentafluoroethane | Freon 115, R-115, CFC-115, Chloropentafluoroethano | −38 | ClF2C-CF3 |
| 2-Chloro-1,1,1,2-tetrafluoroethano | R-124, HCFC-124 | −12 | CHFClCF3 |
| 1,1-Dichloro-1-fluoroethano | R-141b, HCFC-141b | 32 | Cl2FC-CH3 |
| 1-Chloro-1,1-difluoroethano | R-142b, HCFC-142b | −9.2 | ClF2C-CH3 |
| Tetrachloro-1,2-difluoroethano | Freon 112, R-112, CFC-112 | 91.5 | CCl2FCCl2F |
| Tetrachloro-1,1-difluoroethano | Freon 112a, R-112a, CFC-112a | 91.5 | CClF2CCl3 |
| 1,1,2-Trichlorotrifluoroethano | Freon 113, R-113, CFC-113 | 48 | CCl2FCClF2 |
| 1-bromo-2-chloro-1,1,2-trifluoroethano | Halon 2311a | 51.7 | CHClFCBrF2 |
| 2-bromo-2-chloro-1,1,1-trifluoroethano | Halon 2311 | 50.2 | CF3CHBrCl |
| 1,1-Dichloro-2,2,3,3,3-pentafluoropropano | R-225ca, HCFC-225ca | 51 | CF3CF2CHCl2 |
| 1,3-Dichloro-1,2,2,3,3-pentafluoropropano | R-225cb, HCFC-225cb | 56 | CClF2CF2CHClF |
Reimplaciamente
[modificar | modificar fonte]| Applications and replacements for CFCs | ||
|---|---|---|
| Application | Previe CFC | Reimplacimento |
| Refrigeration | CFC-12 (CCl2F2); CFC-11(CCl3F); CFC-13(CClF3); HCFC-22 (CHClF2); CFC-113 (Cl2FCCClF2); CFC-114 (CClF2CClF2); CFC-115 (CF3CClF2); | HFC-23 (CHF3); HFC-134a (CF3CFH2); HFC-507 (a 1:1 azeotropic mixture of HFC 125 (CF3 CHF2) and HFC-143a (CF3CH3)); HFC 410 (a 1:1 azeotropic mixture of HFC-32 (CF2H2) and HFC-125 (CF3CF2H)) |
| Propulsores in medicinal aerosoles | CFC-114 (CClF2CClF2) | HFC-134a (CF3CFH2); HFC-227ea (CF3CHFCF3) |
| Sufflante agentes pro spumas | CFC-11 (CCl3F); CFC 113 (Cl2FCCClF2); HCFC-141b (CCl2FCH3) | HFC-245fa (CF3CH2CHF2); HFC-365 mfc (CF3CH2CF2CH3) |
| Solventes, disgrassante agentes, nettamento agentes | CFC-11 (CCl3F); CFC-113 (CCl2FCClF2) | HCFC-225cb (C3HCl2F5) |
Presentia in atmosphera
[modificar | modificar fonte]Le CFC ha essite initialemente reimplaciate per hydrochlorofluorocarburos (HCFC), principalemente pro refrigeration e le sufflaje de insulante spuma, quando non nocive alternativas non esseva trovate.
Hodie, gratias al Montreal protocollo, le atmospheric quantitate de HCFC comencia a decrescer.[5]
Referentias
[modificar fonte]- ↑ Climate Change (19 March 2021).
- ↑ "Hydrocarbon pollution of the sea and its influence on marine organisms" (1968). Helgoländer Wissenschaftliche Meeresuntersuchungen 17 (1–4): 335–339. doi:. Bibcode: 1968HWM....17..335M.
- ↑ Darby, Megan (19 August 2014). Ozone layer treaty could tackle super polluting HFCs. Archivo del original create le 19 August 2014. Recuperate le 15 June 2024.
- ↑ Hydrofluoroolefins.
- ↑ Western, L.M., Daniel, J.S., Vollmer, M.K. et al. (2024-06-11cv). "A decrease in radiative forcing and equivalent effective chlorine from hydrochlorofluorocarbons". Nature Climate Change. doi:.
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