Kølemidlers atmosfærepåvirkning – en historisk gennemgang

Ole John Nielsen

Department of Chemistry, University of Copenhagen [email protected]

1 www.cogci.dk

Plan

• Brug af nye kemiske stoffer – Hvad er de atmosfæriske bekymringer • Historie • Miljømæssige effekter • Konklusioner for HFO-1234yf • Konklusioner generelt og fremtid 2

Brug af nye kemiske forbindelser

Safety low toxicity nonflammable Environmental non-ozone depleting short atmospheric lifetime low global warming potential Performance stability compatibility boiling/freezing point

3

Hvad bekymrer os generelt ved atmosfæriske udslip?

• 1. Skadelige emissioner og/eller skadelige nedbrydningsprodukter – (lokal-regional-global- direkte påvirkning) • 2. Forøgelse af ozon koncentrationen i troposfæren – (lokal-regional-global) • 3. Stratosfærisk ozon nedbrydning – (global) • 4. Ændring af jordens strålingsbalance = global opvarmning – (global) • Hvad er der fælles for disse fire bekymringer ?

• Der er kemi involveret • “Skyldig – indtil det modsatte er bevist" 4

Atmospheric degradation of HFC-134a CF3CFH2 OH.

H2O CF3CFH.

CF3CFHOOH HO2 OH O2 NO2 CF3CFHO2 Decomp/h  CF3CFHOONO2 h  FO x FCO x NO h  h  aq h  FNO O 3 NO NO2 h  CF3CFHO HCOF CF3 O2 CF3O2 NO NO CF3O NO2 RH R O2 HO2 CF3COF aq h  CF3C(O) CF3COOH O2 ?

CF3C(O)O2 NO NO2 CF3C(O)O CF3C(O)O2NO2 FNO 2 CF3OH HF+C(O)F2 5

Historie: Begyndelsen

• 1928 • 1930 Thomas Midgeley opfandt CFCer (CF 2 Cl 2 )?

Sidney Chapman ”opfandt” Chapman mekanismen som fører til ozonlaget 6

Chapman mekanismens konsekvenser:

Dette og supersoniske fly ledte til …..

7

Stratosfærisk O

3

nedbrydning

•1970-71 •1970s Paul Crutzen and Harold Johnston: ”katalyse” ?

James Lovelock: EC detektor og CFC målinger Spørg: “Hvad sker der med …..?” – og få Nobel-prisen “Hvad sker der med CFC-11 (CFCl 3 ) og CFC-12 (CF 2 Cl 2 ) …?” 8

Stratosfærisk O

3

nedbrydning

•1970-71 •1970s Paul Crutzen and Harold Johnston: ”katalyse” ?

James Lovelock: EC detektor og CFC målinger Spørg: “Hvad sker der med …..?” – og få Nobel-prisen • • • • “Hvad sker der med CFC-11 (CFCl 3 ) og CFC-12 (CF 2 Cl 2 ) …?”

1974

Rowland and Molina: Stratosfærisk ozon nedbrydning Cl + O 3 → ClO + O 2 ClO + O → Cl +O 2 ------------------------- O + O 3 → O 2 + O 2 (Nature, 1974) 9

Det Antarktiske Ozon Hul - 1985 10

Stratosfærisk O

3

nedbrydning

• • • • • 1970-71 • 1970s • 1974 • 1985 • 1987 • 1990 • 1992 • 1995 Paul Crutzen and Harold Johnston: ”Catalysis” ?

James Lovelock: EC detektor Rowland og Molina: Ozon nedbrydning Cl + O 3 → ClO + O 2 ClO + O → Cl +O 2 ------------------------- O + O 3 → O 2 + O 2 Joe Farman: Publiserede ozon-hullet Montreal protocol: 1. udgave Montreal protocol: 2. udgave (London) Montreal protocol: 3. udgave (København) Nobelprisen til Rowland, Molina og Crutzen 11

Virkede Montrealprotokollen?

275 270 265 260 255 250 245 240 235 230 1990 CFC-11 1995 2000 3.0

2.5

1990 220 200 180 160 140 120 100 80 1990 140 120 100 80 60 40 20 0 1990 5.0

4.5

4.0

3.5

CH3CCl3 1995 Halon1211 2000 1995 HCFC-22 1995 2000 2000 2005 2005 2005 2005 550 540 530 520 510 500 490 2010 480 1990 110 105 100 95 90 2010 85 1990 3.5

3.0

2.5

2.0

CFC-12 1995 CCl4 1995 Halon1301 2000 2000 2005 2005 2010 1.5

1990 25 20 1995 HCFC-141b 2000 15 10 5 2010 0 1990 1995 2000 2005 2005 85 80 75 70 2010 65 1990 10.0

CFC-113 1995 2000 2005 9.0

8.0

7.0

CH3Br 2010 6.0

1990 0.6

0.5

0.4

0.3

0.2

0.1

2010 0.0

1990 25 20 1995 Halon2402 1995 HCFC-142b 2000 2000 15 10 5 2010 0 1990 1995 2000 12 2005 2005 HCFC-124 2005 2010 2010 2010 2010

Montreal protokollen medførte bl.a.:

• Freon-12, CFC-12, CF 2 Cl 2 blev erstattet • Hvad kan man gøre for ikke at få Cl i stratosfæren?

• Nedsætte levetiden • HCFC-22, CHFCl 2 og andre • Fjerne chlor • HFC-134a, CF 3 CFH 2 og andre 13

Hvad bestemmer levetiden af halogenerede forbindelser i atmosfæren?

• De fotolyseres ikke i den nederste del af atmosfæren ( l max typisk ≤ 200 nm) • Regner ikke ud da de har lav opløselighed i vand • De fjernes ved reaktion med OH hvis de har et H atom, • som kan abstraheres:

CF 3 • + H 2 O CF 3 H + •OH

•Indsætte H atomer •Indsætte æter-bindinger: –O •Indsætte dobbeltbindinger 14

Historie – teknologispring?

• CFC - chlorofluorocarbons • HCFC – hydrochlorofluorocarbons (↓O 3 ) • HFC – hydrofluorocarbons (↓O 3 ) • HFE – hydrofluoroethers (↓O 3 ) • HFO – hydrofluoroolefin – ( pas på navnet ) ( ↓GWP) • ?

• ?

15

Environmental effects of CFCs and alternatives

formel CFC-12 HCFC-22 HFC-134a HFC-143a HFE-143 HFO-1234yf CF 2 Cl 2 CHClF 2 CF 3 CFH 2 CF 3 CH 3 CF 3 OCH 3 CF 3 CF=CH 2 levetid 100 år 12 år 14 år 52 år 4.3 år 11 dage ODP 1 0.05

0 0 0 0 GWP 10890 1810 1430 4470 756 4 POCP ~0 ~0 0.1

~0 ~0 7 TOXICS None None 15% TFA None None 100% TFA Nu er det klima som styrer udviklingen – GWP<150 16

Direkte strålings påvirkning (klimaeffekt) af alle ODS og forudsigelse for HFCs

17

IPCC/TEAP, 2005

Hvad kan man gøre for at mindske virkningen af en drivhus-gas ?

• 1.

2. En gas der

lever længe nok

i atmosfæren 3.

En gas der absorberer infrarød stråling Der skal være en vis mængde for at der er en effekt: CO 2 , CH 4 , halogenerede gasser (freoner), N 2 O, O 3 , H 2 O ?

18

19

IPCC/TEAP, 2005

Hvad kan man gøre for at mindske virkningen af en drivhus-gas ?

• 1.

2. En gas der

lever længe nok

i atmosfæren 3.

En gas der absorberer infrarød stråling Der skal være en vis mængde for at der er en effekt: CO 2 , CH 4 , halogenerede gasser (freoner), N 2 O, O 3 , H 2 O ?

20

Environmental effects of CFCs and alternatives

formel CFC-12 HCFC-22 HFC-134a HFC-143a HFE-143 HFO-1234yf CF 2 Cl 2 CHClF 2 CF 3 CFH 2 CF 3 CH 3 CF 3 OCH 3 CF 3 CF=CH 2

levetid

100 år 12 år 14 år 52 år 4.3 år 11 dage ODP 1 0.05

0 0 0 0 GWP 10890 1810 1430 4470 756 4 POCP TOXICS ~0 ~0 0.1

~0 ~0 7 None vs 15% TFA Kyoto?

None None 100% TFA Der er to andre miljømæssige bekymringer man skal være opmærksom på: 1.

2.

Troposfæriske ozon Skadelige nedbrydningsprodukter – trifluoreddikesyre - TFA 21

Environmental effects of CFCs and alternatives

formel CFC-12 HCFC-22 HFC-134a HFC-143a HFE-143 HFO-1234yf CF 2 Cl 2 CHClF 2 CF 3 CFH 2 CF 3 CH 3 CF 3 OCH 3 CF 3 CF=CH 2 levetid 100 år 12 år 14 år 52 år 4.3 år 11 dage ODP 1 0.05

0 0 0 0 GWP 10890 1810 1430 4470 756 4 POCP ~0 ~0 0.1

~0 ~0 7 TOXICS None None 15% TFA None None 100% TFA 22

23

Konklusioner for HFO-1234yf

•Den atmosfæriske nedbrydning af HFO-1234yf, CF 3 CF=CH 2 kortlagt er •Ingen virkning på det stratosfæriske ozonlag.

•Levetiden i atmosfæren er 11 dage som medfører at GWP er 4.

•Photochemical Ozone Creation Potential (POCP) for HFO 1234yf er 7. Betyder at CF 3 CF=CH 2 bidrager ikke til fotokemisk luftforurening.

•Atmosfærisk nedbrydning af HFO-1234yf, CF 3 CF=CH 2 danner, CF CF 3 3 C(O)F som hydrolyserer til CF CF=CH 2 .

3 C(O)OH (trifluoreddikesyre, TFA) i et udbytte på 100%. Der forventes ikke signifikant miljømæssig effekt fra TFA fra det forventede forbrug af 24

Konklusioner og fremtid

• Atm. levetider og GWP for halogenerede forbindelser dækker et stort område • Det er muligt at lave nye halogenerede forbindelser med langt mindre klimaeffekt end tidligere anvendte forbindelser.

• Bidraget til den menneskabte ændring af strålingsbalancen fra halogenerede forbindelser kan bringes tæt på nul.

• HFO-1234yf og andre vil blive brugt i fremtiden • Udgifterne vil være en lille del af de samlede udgifter • Der bliver brug for mange alternativer mange anvendelser • Vi er med til at udvikle nye stoffer og vi bestemmer der nedbrydning i atmosfæren og dermed deres miljøpåvirkning 25

Tak for jeres opmærksomhed

Mads Meshkat Tim Ole John Mike 26

Extra Slides

27

The

Photochemical Reactor

for reaction rates, product distributions and infrared absorption

5.

6.

7.

1. Temperature control: a. Insulation b. Heat exchanger c. Fan 2. Lamps 3. Quartz tube 4. White optics: a. Large mirror b. Smaller mirror 5. Bruker IFS 66v/s 6. Transfer optics 7. Detector (InSb/MCT) 4a.

1a.

UV-A UV-C 3.

1b.

2.

1c.

4b.

Sun lamps 28

Slide by Matthew S. Johnson

Other ways of lowering the atmospheric lifetime

Insert a double bond

Compound CF 3 CF=CF 2

Mads

CF 3 CH=CFH

Roar

CF 3 CF=CH 2

Meshkat

CF 3 CH=CH 2

Anne

CH 3 CH=CH 2

everybody

k Cl (2.7

±

0.3) x 10 11 (4.7

±

0.2) x 10 11 (6.9

±

) x 10 -11 k OH (2.4

±

0.2) x 10 12 (9.3

±

0.5) x 10 -13 (1.06

±

) x 10 -12 k O3 < 3 x 10 -21 (2.8

±

) x 10 -21 (6.6

±

) x 10 -20 τ 18 d 14 d 11 d (9.0

±

1.1) x 10 -11 2.4 x 10 -10 (1.4

±

0.3) x 10 12 2.6 x 10 -11 (3.5

±

0.3) x 10 -19 1.0 x 10 -17 8.5 d 10 h GWP 6 6 4 n.d.

n.d.?

29

30

IPCC/TEAP, 2005

31

IPCC/TEAP, 2005

32

IPCC/TEAP, 2005

33

IPCC/TEAP, 2005

Direct radiative forcing of all ODS and projections for HFCs

34

IPCC/TEAP, 2005

35 IPCC 2001

What determines the importance of a GHG?

1. The intensity and position of infrared absorption 2. The atmospheric lifetime (near term) 3. The amount released EU law will be: GWP 100y < 150 What can we do something about for the halogenated compounds?

36

Replacement of Ozone-Depleting Compounds with hydrofluorocarbons (HFCs) – no Cl!

CFC-11 CFC-12 CFC-113 CCl 3 F CCl 2 F 2 CCl 2 FCClF 2 Also GHG CFC-115 halon 1301 halon 1211 CF 3 CF 2 Cl CF 3 Br CBrClF 2 HFC-23 CF 3 H HFC-125 CF 3 CF 2 H HFC-134a

Slide by John Owens (3M)

CF 3 CF 2 H HFC-227ea CF 3 CFHCF 3 HFC-236fa CF 3 CH 2 CF 3 HFC-365mfc CF 3 CH 2 CF 2 CH 3

Lifetime and GWP of Fluoroalkanes

Compound CF 4 (PFC-14) CHF 3 (HFC-23) CH 2 F 2 (HFC-32)

CH 3 F (HFC-41)

Atm.

GWP (IPCC2007) Lifetime (yrs) (100 yr) 50000 270 7,390 14,800 4.9

3.7

675

140

CF 3 CF 3 (PFC-116) CF 3 CHF 2 (HFC-125) CF 3 CH 2 F (HFC-134a) CF 3 CH 3 (HFC-143a)

CHF 2 CH 3 (HFC-152a) CH 2 FCH 3 (HFC-161)

CF 3 CHFCF 3 (HFC-227ea) CH 2 FCF 2 CHF 2 (HFC-245ca) 10000 29 14 52

1.4

0.25

34.2

6.6

CF 3 CH 2 CF 2 CH 3 (HFC-365mfc) 8.6

CF 3 CHFCHFC 2 F 5 (HFC-43-10mee) 15.9

12,200 3,500 1,430 4,470

124 10

3,220 720 794 1,640

38

Slide by John Owens (3M)

Atmospheric degradation of HFC-134a CF3CFH2 OH.

H2O CF3CFH.

CF3CFHOOH HO2 OH O2 NO2 CF3CFHO2 Decomp/h  CF3CFHOONO2 h  FO x FCO x NO h  O 3 h h   aq FNO NO NO2 O2 CF3CFHO HO2 HCOF h  CF3 O2 CF3COF aq h  CF3C(O) CF3COOH O2 CF3O2 CF3C(O)O2 NO NO2 CF3C(O)O NO NO CF3O NO2 RH R CF3C(O)O2NO2 FNO 2 CF3OH HF+C(O)F2 39

Different Fluorinated Ethers

Potential replacements for CFCs and perfluorocarbons.

Perfluoropolyether (PFPE)

F 3 C O F F F O F F O CF 3 F

Hydrofluoropolyether (HFPE)

F 2 HC O F F F O F F O CHF 2 F

Hydrofluoroether (HFE)

F H F O F F F F F F F H F F F F 3 C O F F F F

Slide by John Owens (3M)

40

Effect of Ether Oxygen on Atmospheric Lifetime Compound CH 3 CF 3 (HFC-143a) CH 3 OCF 3 (HFE-143a) CF 3 CFHCF 3 (HFC-227ea) CF 3 CFHOCF 3 (HFE-227ea) CF 3 CH 2 CF 3 (HFC-236fa) CF 3 CH 2 OCF 3 (HFE-236fa) CF 3 CH 2 CHF 2 (HFC-245fa) CF 3 CH 2 OCHF 2 (HFE-245fa2) Atm.

Lifetime (yrs) 52 4.3

GWP (100 Yr ITH) 4,470 756 34.2

11 240 3.7

7.6

4.9

3,220 1,500 9,810 470 1,030 659 GWP still too high!

alkane ether

41

Slide by John Owens (3M)

Atmospheric Lifetimes of Segregated HFEs

R f

-

O

-

R h

n-C 4 F 9 - OCH 3 i-C 4 F 9 - OCH 3 n-C 4 F 9 - OC 2 H 5 i-C 4 F 9 - OC 2 H 5 C 4 F 9 -O-(CH 2 ) 3 -O-C 4 F 9

k OH (cm 3 molecules -1 s -1 )

1.20 x 10 -14 1.54 x 10 6.4 x 10 7.7 x 10 -14 -14 -14 1.44 x 10 -13 

(GWP) (years)

4.7 (~404) 3.7 (~404) 0.9 (~

57

) 0.7 (~

57

) 0.4 (n.d.) CF 3 CF 3 CF O F F F CF 3 CF CF 3 O CH 2 CH 3 F F 5.93 x 10 -14 1.0 (

55

) 42

Slide partly by John Owens (3M)

Atmospheric Impact of HFO-1234yf (CF

3

CF=CH

2

)

T.J. Wallington 1 , M.D. Hurley 1 , M.P.S. Andersen 2 , M.S. Javadi 3 , O.J. Nielsen 3 3 1 Ford Motor Company, USA 2 University of California, Irvine, USA University of Copenhagen, Denmark 43

Background

• CFC-12 (CF 2 Cl 2 ) replaced by HFC-134a (CH 2 FCF 3 ) in 90s.

• HFC-134a has GWP 100 of 1430 • Regulations developed by the European Union require refrigerants with GWPs<150 for all new vehicles by 2017.

• HFO-1234yf (CF 3 CF=CH 2 ) under consideration as replacement for R-134a.

44

Ford Smog Chamber Experimental study of kinetics of reactions with OH radicals, Cl atoms, O 3 .

Measurement of products of OH radical and Cl atom initiated oxidation.

IR spectrum, radiative efficiency, and global warming potential.

Trifluoroacetic acid formation and impacts. (delete) 45

Chlorine atom kinetics

Cl + CF 3 CF=CH 2 Cl + C 2 H 4 → products (1) → products (2) Cl + C 2 H 2 → products (3) Linear least squares analysis gives

k 1 /k 2

= 0.76 ± 0.04 and

k 1 /k 3

= 1.38

±0.06. Using

k 2

= (9.29 ± 0.51) x 10 -11 0.34) x 10 -11 gives x 10 -11

k 1

= (7.06 ± 0.54) x 10 -11 cm 3 molecule -1 s -1 . and

k 3 =

(5.07 ± and (7.00 ± 0.56) Hence

k 1

= (7.03

±0.59) x 10 -11

k

(Cl + CH 3 CH=CH 2 ) = 2.4 x 10 -10

k

(Cl + CF 3 CH=CH 2 ) = (9.07 ± 1.08) x 10 -11

k

(Cl + CF 3 CF=CF 2 ) = (2.7 ± 0.3) x 10 -11 Reaction with Cl atoms not major atmospheric loss of CF 3 CF=CH 2 .

46

OH radical kinetics

47

Ozone kinetics

Pseudo first order decays of CF 3 CF=CH 2 experiments.

observed in all Second order plot gives

k

=(2.77 ± 0.21) x 10 -21 molecule -1 s -1 .

cm 3 Combining with [O 3 ] = 35 ppb gives lifetime of 13 years with respect to reaction with O 3 .

48

IR spectrum, radiative efficiency, and GWP Integrated IR absorption cross section (800 –2000 cm -1 ) = (1.63 ± 0.09) x 10 -16 cm molecule -1 Instantaneous cloudy-sky radiative efficiency estimated using method of Pinnock et al. to be 0.22 W m -2 ppb -1 .

Global warming potential (100 year time horizon) = 4.

49

Oxidation products

OH radical initiated oxidation gives CF 3 C(O)F in a molar yield of 91 ± 6%.

Atmospheric fate of CF 3 C(O)F is hydrolysis to give CF 3 C(O)OH (trifluoroacetic acid).

Oxidation of CF 3 CF=CH 2 gives trifluoroacetic acid in yield close to 100%.

50

Impact on climate change Degradation is initiated by reaction with OH radicals (Orkin et al., 1997; Nielsen et al. 2007, Papadimitriou et al.2008) We estimate an atmospheric lifetime of approximately 11 days and a GWP of approximately 4.

Papadimitriou et al. (2008) estimated an atmospheric lifetime of approximately 12 days and a GWP of < 4.4.

Atmospheric lifetime and GWP of HFO-1234yf are well established. No significant contribution to radiative forcing of climate change.

References O.J. Nielsen, M.S. Javadi, M.P. Sulbaek Andersen, M.D. Hurley, T.J. Wallington, R. Singh, Chem. Phys. Lett., 439, 18 (2007); V. L. Orkin, R. E. Huie and M. J. Kurylo, J. Phys. Chem. A, 1997, 101, 9118 –9124; V.C. Papadimitriou, R.K. Talukdar, R.W. Portman, A.R. Ravishankara, J.B. Burkholder, Phys. Chem. Chem. Phys., 10, 808 (2008).

51

Impact on Stratospheric Ozone HFO-1234yf does not contain chlorine or bromine and hence will not contribute to the well established Cl- and Br-based catalytic ozone destruction cycles.

Papadimitriou et al. (2008) concluded that ozone-depletion potential for HFO 1234yf is “nearly zero”.

References V.C. Papadimitriou, R.K. Talukdar, R.W. Portman, A.R. Ravishankara, J.B. Burkholder, Phys. Chem. Chem. Phys., 10, 808 (2008).

52

Impact on Tropospheric Ozone CF 3 CF=CH 1.1 x 10 -12 2 reacts with OH radicals with rate constant of approximately cm 3 molecule -1 s -1 at 298 K. The peroxy radicals formed will oxidize NO 2 which will photolyze and contribute to ozone formation. Using method of Jenkin (1998) the photochemical ozone creation potential (POCP) for CF 3 CF=CH 2 can be estimated to be 7. The POCP for CF 3 CF=CH 2 lies between those for methane and ethane. CF 3 CF=CH not expected to make a significant contribution to tropospheric ozone formation.

2 is Derwent, R.G., M.E. Jenkin, S.M. Saunders, and M.J. Pilling,

Atmos. Environ

., 32, 2429 –2441, 1998. Hayman, G.D., and R.G. Derwent,

Environ. Sci. Technol.

, 31, 327-336, 1997; Jenkin, M.E.,

Photochemical Ozone and PAN Creation Potentials: Rationalisation and Methods of Estimation

, AEA Technology plc, Report AEAT-4182/ 20150/003, 1998 53

Impact of trifluoroacetic acid Atmospheric oxidation of CF 3 CF=CH 2 gives CF 3 C(O)OH (TFA). Tang et al. conclude “no significant risk is anticipated from TFA produced by atmospheric degradation of the present and future production of HFCs and HCFCs as there is a 1000 fold difference between the PNEC (Predicted No Effect Concentration) and the PEC (Predicted Environmental Concentration)”. Based on risk assessment of CF 3 C(O)OH by Tang et al. (1988) and analysis by WMO (2006), Hurley et al. conclude that “the products of the atmospheric oxidation of CF 3 CF=CH 2 have negligible environmental impact”.

It has been shown that trifluoroacetic acid is ubiquitous in precipitation and ocean water even in remote areas (Berg et al., 2000; Frank et al., 2002; Scott et al, 2005, 2006; Von Sydow et al. 2000). Contribution of CF 3 CF=CH 2 expected to be negligible.

References Berg. M., S.R. Müller, J. Mühlemann, A. Wiedmer, and R.P. Scharzenbach,

Environ. Sci. Technol.

34, 2675-2683, 2000; M.D. Hurley, T.J. Wallington, M.S. Javadi, O.J. Nielsen, Chem. Phys. Lett., 450, 263 (2008); X. Tang, S. Madronich, T. J. Wallington, D. Calamari, , J. Photochem. Photobiol., B 46, 83, (1998); WMO, Scientific Assessment of Stratospheric Ozone: 2006, World Meteorological Organization, Geneva (2007); Frank, H., E.H. Christoph, O. Holm-Hansen, J.L. Bullister,

Environ. Sci. Technol.

36, 12-15, 2002. Scott, B.F., C. Spencer, S.A. Mabury, and D.C.G. Muir,

Environ. Sci. Technol

., 40, 7167-7174, 2006; Scott, B.F., R.W. Macdonald, K. Kannan, A. Fisk, A. Witter, N, Yamashita, L. Durham, C. Spencer, D.C.G. Muir,

Environ. Sci. Technol.

, 39, 6555-6560, 2005; Von Sydow, L.M., A.B. Grimvall, H.B. Borén, K. Laniewski, and A.T. Nielsen,

Environ. Sci. Technol.

, 34, 3115-3118, 2000.

54

Table 1-6. Direct Global Warming Potentials (mass basis) for gases that have adequately characterized lifetimes.

Industrial designation or common name

Carbon dioxide Methane Nitrous oxide

Chlorofluorocarbons

CFC-11 CFC-12 CFC-13 CFC-113 CFC-114 CFC-115

Hydrochlorofluorocarbons

HCFC-21 Chemical formula CO CH N 2 CCl CCl 2 4 O CCl 3 2 CClF 2 CClF CClF F F FCClF CHCl 3 2 2 2 2 CClF CF F 3 2 2 Lifetim e (years)  12.0 114 45 100 640 85 300 1700 1.7 HCFC-22 HCFC-123 HCFC-124 HCFC-141b CHClF CHCl CHClFCF CH 3 2 2 CF CCl 2 3 3 F 12.0 1.3 5.8 9.3 HCFC-142b HCFC-225ca HCFC-225cb

Hydrofluorocarbons

HFC-23 HFC-32 HFC-41 HFC-125 CH CHCl CHClFCF CHF CH CH 3 2 3 CHF CClF 3 F F 2 2 2 CF CF 2 2 3 2 CF 3 CClF 2 17.9 1.9 5.8 270 4.9 2.4 29 HFC-134 HFC-134a HFC-143 HFC-143a HFC-152 HFC-152a HFC-227ea HFC-236cb CHF CH CH CH CH CH CF CH 2 2 3 2 3 3 2 2 CHF FCF FCHF CF 3 FCH CHF FCF 3 2 2 2 2 2 F CHFCF CF 3 3 9.6 14.0 3.5 52 0.60 1.4 34.2 13.6 ODP 0.043 0.017 0.017 <1.5x10

-5 HFC-236ea HFC-236fa HFC-245ca HFC-245fa HFC-365mfc HFC-43-10mee CHF CF CH CF 3 2 3 2 CHFCF CH 2 FCF CF 2 3 CHF CHF 2 CH 2 CF 3 3 2 CH 3 CF 2 CH 2 CF 3 CHFCHFCF 2 CF 3 10.7 240 6.2 7.6 8.6 15.9 1 0.82 0.90 0 0.85 0.40 .0.034 0.012 0.026 0.086

Fully fluorinated

Sulfur hexafluoride Trifluoromethylsulfurpentafluoride FC-14 FC-116 FC-218 FC-31-10 FC-318 FC-41-12 FC-51-14

Halogenated alcohols ethers

SF 6 SF 5 CF 3 CF 4 C 2 F 6 C 3 F 8 C 4 F 10 c-C 4 F 8 C 5 F 12 C 6 F 14 3200 800 50000 10000 2600 2600 3200 4100 3200 GWP (100 years) 1 23.

d 300 4680 10720 14190 6030 9880 7250 148 1780 76 599 713 2270 120 586 12240 543 90 3450 1090 1320 347 4400 52 122 3660 1320 1350 9650 682 1020 782 1610 22450 17500 5820 12010 8690 8710 10090 9010 9140 55

Hvorfor interesserer man sig for F-forbindelser?

CH 4 9% 2005 Globale GHG Emissioner % Bidrag på CO 2 basis N 2 O 6% FCs 2% Ændring siden 1990

+1.6%

CO 2 83%

CO 2 CH 4 N 2 O FCs -18% -20% +19% HFCs +154% PFCs SF 6 -45% -62% 56

Halogenerede forbindelser i atmosfæren 57

IPCC 2007

HFC134a at Mace Head BAU and reduced emissions 58

IPCC/TEAP, 2005

Levetider og GWP af F-forbindelser

Forbindelse CF 4 (PFC-14) CHF 3 (HFC-23) CH 2 F 2 (HFC-32) CH 3 F (HFC-41) CF 3 CF 3 (PFC-116) CF 3 CHF 2 (HFC-125) CF 3 CH 2 F (HFC-134a) CF 3 CH 3 (HFC-143a) CHF 2 CH 3 (HFC-152a) CH 2 FCH 3 (HFC-161) Atm. Levetid (år) GWP 100 50000 7,390 270 14,800 4.9

3.7

675 140 10000 29 14 52 1.4

0.25

12,200 3,500 1,430 4,470 124 10

GWP<150 59

Hvad betyder en æter-gruppe for levetiden?

Forbindelse CH 3 CF 3 (HFC-143a) CH 3 OCF 3 (HFE-143a) Atm. Levetid (år) 52 4.3

GWP 100 4,470 756 CF 3 CFHCF 3 (HFC-227ea) CF 3 CFHOCF 3 34.2

(HFE-227ea) 11 CF 3 CH 2 CF 3 (HFC-236fa) CF 3 CH 2 OCF 3 (HFE-236fa) 240 3.7

3220 1500 9810 470 CF 3 CH 2 CHF 2 (HFC-245fa) 7.6

1030 CF 3 CH 2 OCHF 2 (HFE-245fa) 4.9

GWP er stadig for høj!

659

60

Levetider af andre typer F ætere

•

R f

-

O

-

R h

• n-C 4 F 9 - OCH 3 • i-C 4 F 9 - OCH 3 • n-C 4 F 9 - OC 2 H 5 • i-C 4 F 9 - OC 2 H 5

Atm. Levetid (år)

• C 4 F 9 -O-(CH 2 ) 3 -O-C 4 F 9 0.4 • • CF 3 CF 3 CF O F F F CF 3 CF CF 3 O CH 2 CH 3 F F 4.7

3.7

0.9

0.7

1.0

GWP

404 404

57 57

ikke bestemt

55

61

100

Effekten af en dobbeltbinding

• •

CF 3 CX=CYZ Atm. Levetid ( dage )

•

CF 3 CF=CF 2 (interessant)

•

CF 3 CH=CFH 18 14

•

CF 3 CF=CH 2 (HFO1234yf) 11

•

CF 3 CH=CH 2 8.5

GWP 100 6 6 4 ikke bestemt

62

End with the bad news and the good news

The Montreal Protocol have reduced net GWP-weighted emissions from ODSs in 2010 by 5-6 times the reduction target of the first commitment period (2008-2012) of the Kyoto Protocol.

The Montreal Protocol will have reduced net GWP-weighted emissions from ODSs in 2010 by about 11 Gt CO 2 -eq yr -1 . • Greenhouse gases: CO 2 , CH 4 , N 2 O, HFCs, PFCs, SF 6 63 G. Velders

et al.

, PNAS, 2007

The bad news

2004-2007: 30% increase in global CO 2 -weighted HCFC emissions.

2007: HCFC emissions were 2.6% of fossil-fuel and cement related CO 2 emissions (30 Gt/yr) 64 Montzka et al. GRL 2008

Stratosfærisk O

3

nedbrydning

• 1970-71 P. Crutzen and H. Johnston: ”katalyse” ?

• X + O 3 → XO + O 2 • XO + O → X + O 2 • ------------------------- • O + O 3 → 2O 2 X = H, OH,

NO, NO 2

, F, Cl, Br, (og andet ?) 65

Ole John Nielsen • 1954 Født, gift og har 2 børn på 20 og 22 år • 1973 Begyndte at læse kemi og fysik på KU • 1974 Vigtigt atmosfærekemisk år • 1978 Færdig som cand scient og læste videre (PhD) på RISØ • 1978-95 på 96-99 på Forskningscenter RISØ • 1995-96 Ford’s Forskningscenter i Aachen, Tyskland • 1999-? Professor på Kemisk Institut på KU (det bedste) Mit speciale er nedbrydning af stoffer i atmosfæren (hvor hurtigt og hvordan og hvorfor) IPCC – Intergovernmental Panel of Climate Change Nobels Fredspris 2007 66