12.3 What is the nomenclature system for CFCs/HCFCs/HFCs? (Chemistry)
Description
This article is from the Chemistry FAQ, by Bruce Hamilton B.Hamilton@irl.cri.nz with numerous contributions by others.
12.3 What is the nomenclature system for CFCs/HCFCs/HFCs? (Chemistry)
The CFC naming system was developed by T.Midgley,Jr. and A.L.Henne in 1929,
and further refined by J.D.Park. Originally, organic molecules that contained
Chlorine and Fluorine were all referred to as CFCs. Today, the group is
subdivided into CFCs, HCFCs, and HFCs. The naming system consists of:-
CFC-01234a where 0 = number of double bonds ( omitted if zero )
1 = Carbon atoms - 1 ( omitted if 0 )
2 = Hydrogen atoms + 1
3 = Fluorine atoms
4 = Chlorine atoms replaced by Bromine ("B" prefix added )
a = letter added to identify isomers, the "normal" isomer
in any number has the smallest mass difference on each
carbon, and a, b, or c are added as the masses diverge
from normal.
If the compound is cyclic, then the number is prefixed with "C". There are
several other refrigerants, some of which are hydrocarbons, hydrocarbon
blends, or CFC blends. Full details of the nomenclature system are specified
in ANSI/ASHRAE Standard 34-1992 with additional annual supplements. Chemical
names are frequently used in place of the numbers for common materials
- such as trichloroethylene and chloroform. The specified ANSI/ASHRAE
prefixes were FC ( FluoroCarbon ), or R ( Refrigerant ), but today most are
prefixed by more specific classifications - such as CFC, HCFC, and HFC.
CFC-11 CCl3F trichlorofluoromethane [75-69-4] CFC-12 CCl2F2 dichlorodifluoromethane [75-71-8] CFC-113 CCl2F-CClF2 1,1,2-trichlorotrifluoroethane [76-13-1] HCFC-22 CHClF2 chlorodifluoromethane [75-45-6] HCFC-123 CHCl2-CF3 2,2-dichloro-1,1,1-trifluoroethane [306-83-2] HCFC-123a CHClF-CClF2 1,2-dichloro-1,1,2-trifluoroethane [354-23-4] HFC-23 CHF3 trifluoromethane [75-46-7] HFC-134 CHF2-CHF2 1,1,2,2-tetrafluoroethane [359-35-3] HFC-134a CH2F-CF3 1,2,2,2-tetrafluoroethane [811-97-2] R-20 CHCl3 chloroform [67-66-3] R-22B1 CHBrF2 bromodifluoromethane [1511-62-2] R-1120 CHCl=CCl2 trichloroethylene [79-01-6] R-1150 CH2=CH2 ethylene [74-85-1] R-C316 C4Cl2F6 1,2-dichlorohexafluorocyclobutane
Another technique for naming CFCs uses the addition of 90 to the CFC number
to produce a "def" number which corresponds to the CHF composition. If
(e + f) < (2d + 2), then additional atoms are required for saturation. This
technique has been described in detail in the Journal of Chemical Education
[3].
ASHRAE +90 Empirical Composition Formula
C H F (+Cl)
CFC-11 101 1 - 1 3 CCl3F
CFC-12 102 1 - 2 2 CCl2F2
HCFC-22 112 1 1 2 1 CHClF2
HCFC-123 213 2 1 3 2 CHCl2-CF3
HFC-134a 224 2 2 4 - CH2F-CF3
Halons are numbered according to a totally different system developed by
the US Army Corps of Engineers, and the prefix term is always "Halon".
Hydrogen is not numbered, and terminal zeros are not expressed.
Halon-0123 where 0 = number of carbon atoms
1 = number of fluorine atoms
2 = number of chlorine atoms
3 = number of bromine atoms
Halon-1211 CBrClF2 bromochlorodifluoromethane [353-59-3]
Halon-1301 CBrF3 bromotrifluoromethane [75-63-8]
Halon-2402 CBrF2-CBrF2 1,2-dibromo-1,1,2,2-tetrafluoroethane [124-73-2]
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