Document 4vy7X465mv1DK0LGyyXpRqR9j
AR226-2702
24
AR226-2702
TORONTO WORKSHOP MATERIALS
September 13-14,2004
Atmospheric Chemistry of
Fluorotelomer Alcohols
(Part 2)
Robert Waterland DuPont Engineering Research & Technol
Wilmington, DE
Outline
do we
for
a initial gas phase reaction kinetics
m photolysis of FTOHs
do we
a
role of HOx and N0^
photolysis of fluoroaldehydes
we
heterogeneous chemistry
know?
competition between HOx and NOx hydrates & fluorotelomer olefins
What we know for certain
FTOH, C^n+iCH^OH (n=l,10) are sufficiently
be present in the atmosphere.
[Stock etal., 2004; Krusic etal., 2004
They do not photodissociate in the gas phase.
[S. Mello etal., in preparation]
The sole gas phase oxidation product is CpF^+iCH FTOH lifetime is approx. 11 days:
transport
[Hurley etal., 2004; Le Bras etai, SE
CpF^n+iCH^CHO oxidises primarily to CnF^+iCHO.
[Hurley etal., 2004; Le Bras etal., 5F
What we know a little abou
(PFAL) A. It depends on what else is around: NOx and HO
A7. It depends on where you are: urban/suburban
What we know a little abou
A. What else is around: NOX..' A7. Where you are:
This is baseic |-n=|||^,,'
For the high^
are unknown.
jstnFPAN^^^
What we know a little abou
A, What else is around: HO^
A\ Where you are:
This is based on n
For the higher
are unknown.
1,2,3,4 in smog chamber.
(n>4), yi^ PFCA an
What we know a little abou
What we know a little abou
Competition from photolysis.
Do the fluoroaldehydes photolyze? Competition with chemica
What is known:
':l.:,:l:,'.l;l/,l,;l/::';';;:\:l^\;l',::.^:,1,.-;,,1,:.,
The fluoroaldehydes absorb in^^tt
They absorb a Ijttl^^^^r^
The normal aldehyctes photodissod readily (hours/days).
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missing that we
Heterogeneous physical chemistry
FTOH
to
FTOH?
(condense/surfectent/separa^^
organic phase (condense/surfactant/separated
graphitic soot & mineral fraction
'^^^y
What's missing that we must k
H eteroae neous reaction chem istrv
What is the chemistry on sol id surfaces and liqu
e.g. Ellls etai [2004] reported -5% PFCAs yield from FTOH + -Cl
a suite of lower PFCAs were observed
Proposed mechanism is HF elimination from perfluoroalco
CFsCCF^CFpH --^ CF3(CF2),-iCFO + HF
We knowWs^esii^^pf^
So, it must be heterogeneous chemistry (but where?) Probably on quartz walls of small smog chamber
Smog Chamber at Ford Motor C
UPHORE Chamber in Valenci
What's missing that we must k
Perfluoroaldehyde hydrates
nF^,iCHO.H^=C^
n= 1-4 fluoroatdehydes are commercially available only as hyd Do the n>4 fluoroaldehydes react wit^^v^^
If so, what is the chemistry of these hydrates?
'^issHn^-
What's missing that we must k
Telomer B Olefin?
''
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'l,^^
Residual levels of TBO and FTOH in polymers comparable
.... 8-2 Vapor pressures of TBO and FTOH are comparable
FTOH = 3 Pa at 21 C
\ :
:: : .:,;'
8-2TBO ^ISPaatlS'QC.:.1';; \/:-.,:
,:
TBO much less water soluble (less in water phase?) 8-2 FTOH = 0.130 mg/L (Clariant)
^ 8-2 TBO = 0,001 mg/L(aariant)
Little known about TBO chemistry
Le Bras (2000) studied CnF2n+iCH=CH2(n^,6)wi^
OH chemistry appears to be similar to^^F^
-:'' '
w
Conclusions
we
for
initial gas phase reaction kinetics
we know a little about - and need to know
competition between HOx and N0^ chemical fate of fluoroaldehydes photolysis of fluoroaldehydes
we must know?
sorbing of FTOH to atmospheric aerosol heterogeneous chemistry hydrates & fluorotelomer olefins