Nomenclature of CFC's/Freons/Halons/Coolants

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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.

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