Report of the Scientific Assessment Panel
OEWG, 33rd meeting, Bangkok, 24–28 June 2013
ODP and GWP of 1,2-dichlorohexafluoro-cyclobutane
(c-C4F6Cl2, RC-316c)
 Commercial R-316c is as a mixture of 52% (E)- and 48%
(Z)- isomers
Cl
(Z)-R-316c
(E)-R-316c
Cl
Cl
Cl
 lifetime primarily determined by photolysis in the stratosphere
 Isomers have different atmospheric photolysis rates and, hence,
different atmospheric lifetimes, ODP, and GWP
 Both isomers are long-lived; have high ODP and GWP
OEWG Bangkok June 2013 R316c
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UV absorption cross sections of RC316cwork)
Burkholder et al., 2013 (recent
Temperature (K)
296
233
273
213
253
(E)-R-316c
Cl
Cl
(Z)-R-316c
Cl
o Absorption cross sections of
the individual isomers have
been measured.
o Absorption cross sections
were measured as a function
of temperature
o The E-isomer absorbs UV
more than the Z-isomer
Cl
Atmos. l Range
OEWG Bangkok June 2013 R316c
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Infrared cross section of RC-316c
Burkholder et al., 2013 (recent work)
(E)-R-316c
Calculated Radiative
Efficiency(W m-2 ppb1)
Cl
0.282
Cl
(Z)-R-316c
Cl
Cl
0.310
o Measured IR cross sections
are slightly different
o Calculated radiative
efficiency differ by ~10%
OEWG Bangkok June 2013 R316c
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ODP and GWP of RC-316c
Cl
Cl
Cl
(Z)-R-316c
Cl
(E)-R-316c
Atmospheric Lifetime (2-D model)
Fleming et al., 2013
75 years
114 years
ODP (semi-empirical)
~0.5
~0.6-0.7
GWP-20
4885
5615
GWP-100
4360
5800
Bottom Line: ODP and GWP of R-316c is similar to, and
slightly smaller than, CFC-11 and CFC-12
OEWG Bangkok June 2013 R316c
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