Nomenclature of CFC's/Freons/Halons/Coolants

Version 4

    CFC's (chlorofluorocarbons)

    Midgley and Henne developed in 1929 a naming system for halocarbons containing carbon, hydrogen, chlorine and fluorine. Park refined the system some years later. CFC (chlorofluorocarbons) was the group name, which was later divided into sub-groups like HCFC and HFC.

     

    The system contains a body, CFC, a number, 01234, and an alphanumeric suffix, a: CFC-01234a

    • The body stands for the group type
    • The number stands for the molecular formula
    • The suffix stands for different isomers
                                  

    CFC

    ChloroFluoroCarbons

    0

    Number of double bonds, omitted if zero

    1

    Number of carbon atoms minus 1, omitted if zero

    2

    Number of hydrogen atoms plus 1

    3

    Number of fluorine atoms

    4

    Number of chlorine atoms replaced by bromine, always used with prefix "b" (b1, b2), omitted if zero

    a

    Added to identify isomers, the isomer without suffix always has the smallest mass difference on each carbon atom. If there are more isomers the suffix is counting from a - z, omitted if only one isomer exists

     

    Example:

    CFC-12b1 has no double bonds, only 1 carbon atom, no hydrogen atoms, 2 fluorine atoms, one chlorine atom replaced by bromine and no isomers = Bromochlorodifluoromethane

     

    If it is a cyclic structure the number is prefixed with a "C" for cyclic. Sometimes some other bodies are found like FC (fluorocarbon), HC (Halocarbon) or R (refrigerant).

                          

    Abbreviation

    Formula

    Name

    CFC-11

    CCl3F

    trichlorofluoromethane

    CFC-12

    CCl2F2

    dichlorodifluoromethane

    CFC-113

    CCl2F-CClF2

    1,1,2-trichlorotrifluoroethane

    HCFC-22

    CHClF2

    chlorodifluoromethane

    HCFC-123

    CHCl2-CF3

    2,2-dichloro-1,1,1-trifluoroethane

    HCFC-123a

    CHClF-CClF2

    1,2-dichloro-1,1,2-trifluoroethane

    HFC-23

    CHF3

    trifluoromethane

    HFC-134

    CHF2-CHF2

    1,1,2,2-tetrafluoroethane

    HFC-134a

    CH2F-CF3

    1,2,2,2-tetrafluoroethane

    R-20

    CHC3

    chloroform

    R-22B1

    CHBrF2

    bromodifluoromethane

    R-1120

    CHCl=CCl2

    trichloroethylene

    R-1150

    CH2=CH2

    ethylene

    R-C316

    C4Cl2F6

    1,2-dichlorohexafluorocyclobutane

     

    Another technique for naming CFCs has been described in detail in the Journal of Chemical Education [see reference] and is called "The rule of 90". Ninety is added to the CFC number, abc, to give as a result a number, xyz, that corresponds to the Carbon-Hydrogen-Fluorine (CHF) composition. If the carbon atoms are not saturated then additional chlorine atoms are required.


       
    Abbreviation

    Add 90

    Empirical Composition

    Formula

    C

    H

    F

    Added Cl

    CFC-11

    101

    1

    0

    1

    3

    CCl3F

    CFC-12

    102

    1

    0

    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

    0

    CH2F-CF3

    Halons

    The halon nomenclature system was developed by the US Army Corps of Engineers and id totally different from the CFC system. The body prefix is "Halon". There is no number for hydrogen and terminal zeros are omitted. Halon-0123

          
    0

    Number of carbon atoms

    1

    Number of fluorine atoms

    2

    Number of chlorine atoms

    3

    Number of bromine atoms

    Examples:

                  

    Halon Code

    Formula

    Name

    CFC Code

    Halon-1211

    CBrClF2

    bromochlorodifluoromethane

    CFC-12b1

    Halon-1301

    CBrF3

    bromotrifluoromethane

    CFC-13b1

    Halon-2402

    CBrF2-CBrF2

    1,2-dibromo-1,1,2,2-tetrafluoroethane

    CFC-114b2a

     

    Reference:

    A. A. Woolf; J. Chem. Edu. 70 (1993) 35 - 36.