Document 9Jne4dBoXG5znjRqzpEZxdZ17

Telomer Research Program AR226-1943 RAelcpoohrotlsTitle: Extended Laboratory Study of the Atmospheric Degradation of Fluorinated Author(s): Professor Georges Le Bras, Geraldine Solignac and Dr. Abdelwahid Mellouki. CSyosntetrmaecstoRre:acCtiefsnt(rCeNNRaStio-nLalCDSRe )La Recherche Scientifique - Laboratoire de Combustion et Study Dates: July 2004 - December 2004 Study Objective The project goal was the determination of the photolysis rate of perfluorinated aldehydes, BaCt6mAFo1l3csCophhHoeOlrsic,aCnpdh6FoCt13ogCFlyiHysiC2sCHoHOf2t,OhpeHrsoeadnaudlcdeCedh8yFind17etChseHmO2aCyHH-ci2onOmitHipa.etetTedhwoexisteihddarateitaoacntaioroefnitwmheiptchoorOtrarHnestprsaoidnnicdceianlsg, Telomer thereby reducing or even eliminating production of the corresponding perfluorocarboxylic acids, in low NOx conditions. Materials and Methods All the photolysis experiments using solar radiation were performed at the outdoor European reactor EUPHORE in Valencia, Spain. The EUPHORE facility consists of two independent h(hetmtpi:s/p/whewriwca.glvoau.etdso./ocerasmim).ulEatUioPnHcOhaRmEbhearss,amvaadreieotyf FoEf iPnsftoriul,mweintths a(ivnoclluumdiengoFf 2T0IR0,mG3Ce-aFcIhD, HPLC) available for in-situ analysis or off-line sampling and the high FTIR detection sensitivity allows use of VOC and NOXconcentration ranges close to those present in the atmosphere. Since the perfluorinated aldehydes were not (and are not) available, the experimental design was tooxipdraotdiounceopfethrfelucoorrirneastpeodnadlidneghyTdeelosminedriBrecAtllycoihnotlhse. ETUhPisHaOppRrEoacchhammebtewr vitiha dthifefiOcuHlt-iiensitaiantded additional experiments were also carried out at EUPHORE using Cl-initiated oxidation of UoCu6nFtivo13enCrstHhite2yOCoHlf-iWinniutaipairpteetodrtadolix.riedcatltyiopnroodf uCc6eF1C3C6FH132COHHOi.n Ianiraudsdinitgiotnh,ee4x8p0eLrimgleanstssphhaovteorbeeaecntocraarrtitehde RprahedosietcoaalrlyscshwisgeorraefdCperloCsad(mOucp)eClde(sOino)-fCstilhtueatbTEyeUlpoPhmHoetOorlRBysEAisalconodfhHboyOlsNpahOnodtooCrly6HFsi21sO3Co2fH. m2COol HlaetcoaumrleasrrweCaedhrileloyrpiranovedaauiltcaebdleb. yOH Wuppertal. All chemicals used were lab grade reagents. Does not contain TSCA CBI 1 TRP (March 30, 2005) ApatthEUlePnHgtOhRFET,IRmaonledcuGlCar-MspSecaiensdcpohnocteonlytrsaitsioenxspearnidmpenrotsduwcetraenpaelyrfsoisrmweedreumseodnnitaotruerdalblyiglhotn. gA- t WFTuIpRpesrpteacl,treoxmpeetreimr (eNnitcsowleetreMpaegrnfoar5m2e0d) winitah4a80pLathdluernagnthgloafss51re.6acmtoarnindtearrfeascoelduttoionanoifn-1scitmu-1. The reactor was surrounded with 20 superactinic lamps (Philips TLA 40W/05, 300 < X< 450 nm, Xmax= 360 nm) used to photochemically initiate the experiments. Findings OH-initiated oxidation of C6F13CH2CH2OH (June 28th at EUPHORE) The experiment was performed using the photolysis of HONO as OH radical source and the ianbistieanlcceoonfcelingthrat twioans ofofuCn6dFt13oCbHe2cCoHm2pOaHrabwleasto25th0apt pdbuve.toTdhielulotisosno(fcCor6rFe1s3pCoHnd2CinHg2tOoHtheinloss of cSoFn6d) iitniodnicsa. ting that the wall loss of C6F13CH2CH2OH is negligible in our experimental Draudricinaglsthweasexepsetirmimateendt,tothbeecoarnosuunmdp1ti6on%o. fGCC6F-M13CSHa2nCalHy2sOisHshdouweetdo tiwtsoremacatiinonprwodituhctOsHof the reaction. These products could not be not positively identified, however, one of them may be the fToerlmomateiornalodfethhyedreea(Cct6iFo1n3CprHo2dCuHctOs )a.ndTthhee FoTveIrRlaapnoalfytshies wfluaosrrianpaitdeldyccoommppoluicnadtsedwfiothlloswiminilgarthIRe spectra. However, the IR spectra obtained during the experiments showed the presence of an unidentified Figure 1). band 1194-1264 cm-1 which could not be attributed to CF2O nor to C6F 13 C(O)H (see 1100 1150 1200 1250 Wavenumber (cm-1) 1300 1350 Figure 1: Residual spectrum after subtraction of C6F13CH2CH2OH and CF2O Does not contain TSCA CBI 2 TRP (March 30, 2005) OH-initiated oxidation of CsF17CH7CH7OH (June 29th and 30th at EUPHORE) Two runs were performed: in the first one the photolysis of HONO was used as the OH source wpphbilveaHnd2O128w0apspubsve,dreisnptehcetivseeclyo.nd one. The C8F17CH2CH2OH initial concentrations were 130 In both experiments the consumption of C8F17CH2CH2OH was estimated to be 20 %. GC-MS waconhmailcyphsoiuwsnasdsh.oswuFpiegpduotrrweteo2dmsbhyaoiHwn PspLrthoCde-uMccotSns,caeonnnatelryaostifiostnht-ehtmaimt mienadpyircobafetieletdhoethf"eCffi8roFsrt1m"7CaaHtlido2eCnhHyodf2eOaHCca.8Frb1o7CnyHl2CHO csSyoimsmteiplmalircl(yarteetaodcwtbayhnatthtaewndoasvreeoarblcastpeiorpvninepdgrofIoRdrubcCats6nF)d.1s3HCoHefnd2cCifeHf,e2irnOenHatb,fsltuheonercFienTaoItfRedIRacnoasmplyepsciotsurwnadaossfprparupesrideelnypt rinodthuect sparmodpulecstsa. nd reference spectra, it is still difficult to conclusively identify the reaction o144 [C0F 17C H 2C H 2OH] 140 O o O O O O O O O O O136 O OQ. 132 C 0F 17C H 2C H 2O H + HONO 29 06 04 E U P H O R E ooQd OjD 128 -4000 0 time (s) (t = 0: chamber opened) 4000 Figure 2 Cl-Initiated oxidation of C6F13CH7OH at EUPHORE (July 1st and 2nd) uTnhdeearimsunolfigthhetsceonexdpiteiorinms.ents was to generate C6F13CHO directly and check for its photolysis Chlorine atoms were produced using the photolysis of ClC(O)C(O)Cl. Initial concentrations of Cco6nFc13eCntHra2tOioHnswoefreCl1C8(0Op)pCb(vO)aCndl w22e0repcphbovs,ernesinpeocrtdiveerltyooonbtJauilnyd1isftfaenredn2t ncdo.nTsuhme pintiiotinalof C6F13CH2OH in both experiments (85 % and 15 % in the first and second run, respectively). In both experiments, CF2O was the major product observed by FTIR analysis (see Figure 3). Does not contain TSCA CBI 3 TRP (March 30, 2005) 6.2E+012 6E+012 - 1 5.8E+012 _CD rs _CD O Xq 5.6E+012 unTf<q 5.4E+012 5.2E+012 + O CF2OCbF,3CH2OH 0( Q3 0 O 3.0E+011 2.0E+015 =5 _(D ouoET q 1.0E+011 5E+012 0 4000 time (s) t=0 chamber opened 8000 0.0E+000 Figure 3: Concentration-time profiles of C6F13CH2OH and CF2O. The expected mechanism of the Cl-initiated oxidation of C6F13CH2OH leading to the aldehyde C6F 13CHO is: Cl + C6F13CH2OH ^ HCl + C6F 13CHOH C6F C13 HOH + O2 ^ C6F 13CHO + HO2 C6F13CHO then reacts with Cl and could also be photolysed: C6F13CHO + Cl ^ C6F13CO + HCl C6F13CHO + hv ^ C6F13CO + H C6F13CHO + hv ^ C6F13 + HCO C6F13CO and C6F13radicals will ultimately lead to CF2O. nTehxetrsaetceticoonn)swtaenrtes oubsetadintoedfiattthWeuEpUpePrHtaOl RfoEr (ekx(pCelri+mCen6Fta1l3CprHo2fOileHs)toantdenkt(aCtilve+lyC6aFss1e3CssHtOhe)) (see importance of the photolysis of the aldehyde. Again, no definitive conclusion could be drawn because the FTIR analysis was rapidly complicated following the formation of the reaction products and the overlapping of the fluorinated compounds with similar IR spectra. Does not contain TSCA CBI 4 TRP (March 30, 2005) Kinetics & mechanism of the Cl reaction with C6Fi3CH2OH studied at Wuppertal The relative rate technique was used to measure the rate constant of the reaction of Cl with C6F13CH2OH relative to that of Cl with CH3Cl. The relevant reactions in the system were: Cl + C6F13CH2OH ^ products (1) Cl + CH3Cl ^ products (2) Assuming that the fluoroalcohol and the CH3Cl are consumed only by Cl, it can be shown that: ln([C6Fi3CH2OH]o/([C6Fi3CH2OH]t)/ = ki/k2 ln([CH3Cl]o/([CH3Cl]t) where the subscripts 0 and t indicate concentrations before irradiation and at time t, respectively. R2328e2ac0cot--a3an1dt5sd0ecdcomninc-t1eenfroftrerartCoigo6Frnas1m3wCseH. r2eCOmoHnotanronitldoerCxedHpe3urCsimiln, egrnetsthspeeschIRtoivwaeeblydso.trhpIanttiforsanidrfeeedaretsuaprceetcisotr3na5sw5s0eu-rc3eh6d5aes0ripcvhmeod-t1ofalryonsmdis eoxfpCe6rFim13eCnHta2lOcHonadnitdioCnHs.3Cl, as well as heterogenous and dark reactions were negligible in our Uhasvinegdtehreivveadlutheeorfekac(Ctiol+nCrHat3eCclo) n=st4a.n8txo1f0-C13l cwmit3hmCo6Fle1c3uClHe- 1 2 Os-H1 :for the reference reaction, we k (Cl + C6F13CH2OH) = (6.5 0.4) x10-13 cm3 molecule-1 s-1 In Table 1, we have compared this rate constant with the data reported previously for the reactions of Cl with shorter fluorinated l(ekn(Cgtlh+CofnFC2nnF+12Cn+H1 2gOroHu)p does not effect 6.5x10-13 cm3 alcohols with the reactivity molecule-1 s-1 otfhfoeCr fnloa=rtmo1muulsapwCtointFhn2Cn=+n16FC)2.Hn+21OCHH2aOsHshown. The Table 1: Rate constant values for the reaction of Cl with fluoroalcohols Fluoroalcohol k(Cl) CF3CH2OH (6.5 0.5) x10-13 CF3CF2CH2OH (6.5 0.5) x10-13 CF3(CF2)2CH2OH (6.5 0.5) x10-13 CF3(CF2)3CH2OH (6.5 0.5) x10-13 CF3(CF2)5CH2OH (6.5 0.4) x10-13 Does not contain TSCA CBI 5 TRP (March 30, 2005) Product Study of the Cl reaction with QFnCH^OH: ffTCroho6rFemtihC3e-ClC-kHiHniOni2te,i-taaigtcserodsatuluorpedxayfiddo. yalTltoimhoweneerndoetaiCfbocClynti+6eorFdenCia3:6ocCFtfiH1oC32nClOwHwH2iittOwhhHaCOs6^2Finle1v3CaCed6sHFitni12gg3OCattHoHedtOphruHeoscip+neegerHdftlCshuelborysianamabtesetdrsayacslttdieoemnhyoadsfeHth-aattoumsed C6F C13 HOH + O2 ^ C6F 13CHO + HO2 Tcohme paolduenhdysdaesmenayd upnroddeurgctos.further reaction with Cl atoms leading to other fluorinated Figure 4 shows C6F 13CH2OH. an example of the experimental concentration profile of C6F 13CHO versus [C6F, 3 CH2OH] t /[C6 F, 3 CH2OH]0 Figure 4: Formation of C6F3CHO versus loss of C6Fi3CH2OH The reaction rate constant of Cl with C6F13CHO was derived by fitting these profiles: k(Cl + C6F13CHO) = (2.8 0.7)x10"12 cm3 molecule-1 s-1 Conclusion cTohueldrenaocttiboen nooftCp6oFsii3tCivHel2yCiHd2eOntHifiwedi,thhoOwHevraedr,icoanlse pwrioldl ulickeeslytwboe tmheainTeplroomduecrtasl.deThhyedsee products m(Ca6iFni3pCroHd2uCctHs.O)G. CS-MimSilaarnlaylythsiesrsehaocwtioend towfoCm8Faii7nCHpr2oCdHuc2tOs,HowneitohfOthHemradmicaaylsbeprtohdeu"cfeirssttw" o faoldrmehaytidoenCo8fFai7cCaHrb2oCnHylOcwomhipcohuwnda.s supported by HPLC-MS analysis that indicated the Does not contain TSCA CBI 6 TRP (March 30, 2005) The C for its lp-IhnoittoialytesdisouxniddaetriosnunolifgCh6tFc1o3nCdHit2ioOnHs. wLaasrugseecdotnovgeersnieornatoefCth6Fe 1a3lCcoHhOold(iurepcttoly8a5n%d)cwheacsk observed and CF2O was the major product observed by FTIR analysis. Experimental rate constants obtained at Wuppertal were used to fit the EUPHORE experimental profiles to tentatively assess the importance of the photolysis of the aldehyde but no definitive conclusions could be drawn.. At Wuppertal, the rate CH3Cl was measured. constant o f the reaction o f Cl with C6F 13 CH2OH relative to th at o f Cl w ith Uhasvinegdtehreivveadlutheeorfekac(Ctiol+nCrHat3eCclo) n=st4a.n8txo1f0-C13l cwmit3hmCo6Fle1c3uClHe- 1 2 Os-H1 :for the reference reaction, we k (Cl + C6F13CH2OH) = (6.5 0.4) x10-13 cm3 molecule-1 s-1 In addition, the reaction rate constant of Cl with C6F13CHO was derived: k(Cl + C6F13CHO) = (2.8 0.7)x10-12 cm3 molecule-1 s-1 Unfortunately, the experiments performed at EUPHORE and in Wuppertal are inconclusive. Dpousesitbolethteo aqbusaenntcifeyotfhespfeocrtmraatoiof npuorfetshaemseptlwe oofaCld6eFh1y3CdeHs2dCuHriOnganthdeCe6xFp1e3rCimHeOn,tsi.t wOatshenrot experiments are planned in the near future at EUPHORE to look directly at the photolysis of cshoorrretespr oanlddeihnygdheysd(rCat3eFs7.CHAO smog chamber. faenwdtCes4tFs9hCaHveOb) ewehnicahlreaardeyavcaoinladbulcetecdomonmCer3cFi7aCllHy Othurosuinggh their an indoor Publications / Presentations tAJTSr..iIPfDkKlhiuEnEyoBesLrt.oOiLcpCTYrahoT,nepOdmVaM.nm. oBA,elOcGu(hS2.naS0dLn0OeiEs5rUt)BiacTt7Rm,RsAt3oOu3SsdTp4yh-,3eoI4.rfi1McthcAeoGrnedNaictEitoiRonOnssNo,fKO.HWrIaRdTicZa,lsJ.anTdRECAl aCtoYm, sAw. MithE3L,L3,O3-UKI, H. A MELLOUKI, G. SOLIGNAC, G. LE BRAS, I. BARNES, R.L. WATERLAND TThoebaetmproesspenhteerdicacththeme iSsEtrTyAoCf nE-Cur6oFp1e3C1H52thOAHnnual Meeting, Lille, 22-26 May 2005. (This work will also be submitted for publication) Does not contain TSCA CBI 7 TRP (March 30, 2005)