DEQ-CFW_00000374

DuPont HFPO
Properties, Uses, Storage, and Handling
The miracles of science-
DEQ-CFW 00000374

Introduction
Hexafluoropropylene oxide (HFPO) is a versatile
fluorointermediate that can be used in the synthesis
of fluoromonomers, fluoropolymers and to add fluo-
rine functionality to a variety of organic precursors.
Perfluorinated vinyl ethers utilized in the production
of commercial fluoropolymers are produced using
HFPO as the key intermediate. In addition, the
commercial perfluorinated Krytox® lubricant has
HFPO as the monomer unit. Other useful commer-
cial fluorointermediates produced from HFPO in-
clude hexafluoroisopropanol, hexafluoroisobutylene
and bisphenol AF. All of these FluoroIntermediates
are commercially available through DuPont.
Properties
HFPO supplied by DuPont has a minimum purity of
98.6 wt% (Table 1). When impurities are detected
they generally consist of hexafluoropropene (HFP).
HFP is the key chemical precursor to HFPO which
is synthesized in an oxidation process. This product
may also contain a very low level of hexafluoro-
acetene (HFA), which is a potential reproduction
hazard. The HFA isomer is generated by a metal
catalyzed mechanism that can be initiated by im-
proper storage and handling methods. See Storage
section and MSDS for more information.
Physical properties of HFPO are given in Table 2.
HFPO is a nonflammable gas that is stored as a
pressurized liquid. The vapor pressure equilibrium
curve for HFPO is included in Figure 1.
Table I
Product Data
Property
Unit
Min.
Max.
Organic Purity —HFPO
HFP (Hexafluoropropene)
Weight %
Weight %
98.6
—
1.0
Table 2
Physical Properties
Property
Unit
Typical Value
Chemical Name
—
Oxirane, Trifluoro
(Trifluoromethyl)
CAS No.
—
428-59-1
EINECS No.
—
207-050-4
0
F
Chemical Formula
—
Fzc—C�
\CF,
Molecular Weight
—
166
Boiling Point @ 1 atm
°C (OF)
—27 (-17)
Vapor Pressure @ 25°C
kPa-abs (psia)
660 (96)
Melting Point
°C (OF)
—144 (-227)
I iquiri Density @ 25°C
kg/m3 (Ib/ff3)
VIM (R1.2)
Vapor Heat Capacity @ 25°C
J/mol•K
138
Liquid Heat Capacity @ 25°C
J/mol•K
172 (estimated)
Heat of Vaporization @ NBP
KJ/mol
21.8
Critical Temperature
°C (°F)
86 (186.8)
Critical Pressure
kPa•abs (psia)
2896 (420)
Critical Density
g/cc
0.59
Flammability Limits
Vol%
None
Exposure Limits — HFPO, AEL 8hr. TWA*
ppm
20
* AEL is the DuPont's Internally used Acceptable Exposure Limit. Where governmentally imposed occupational exposure limits
which are lower than the AEL are in effect, such limits shall take precedence.
TWA = Time weighted average
The DuPont Oval Logo, DuPontTm, Krytox®, and The miracles
of scienceTM, are trademarks or registered trademarks of
E.I. du Pont de Nemours and Company.
DEQ-CFW 00000375

Figure 1
Fiaure 2. Infrared Spectrum of Hexafluoropropylene Oxide Vapor at 3.5 kPa in a 10 cm cell
0.7
DuPont Company
HFPO Q 26 Torr. Tua Jul 2311:37:13 2W2
0'8 Tus Jul 2312:02.34 2W2
0.6
0.4
n 0.3
Q
0.2
0.1
.04
Wmnumbara (crrtl)
Figure 3. Infrared Spectrum of Hexafluoroacetone Vapor at 4.6 kPa in a 10 cm cell
1's DuPont Company
HFA34,6 twr In 10 cm call Tua Jul 2315,25:44 2002
1.4 Tuo Jul 23 15:20:012002
1.2
1.0
0,8
0.6
0.4
0.2
0.0
Wwanum6ara (cm 1)
DEQ-CFW 00000376

Uses
Hexafluoropropylene oxide (HFPO) is a key inter-
mediate in the synthesis of organofluorine nnm_
pounds. Many commercial fluoropolymers use
HFPO either as a monomer or a monomer precur-
sor. The epoxide ring is opened by nucleophiles to
give a variety of derivatives. HFPO may be isomer-
ized to either pentafluoropropionyl fluoride (PPF)
or hexatluoroacetone (HFA). The thermolysis
of HFPO can also serve as a source of difluoro-
carbene. A few examples of HFPO chemistry
are given below; the chemistry of HFPO has
been reviewed.','
Reactions of HFPO
HFPO is easily isomerized to pentafluoropropionyl
fluoride (PPF) by nucleophilic catalysts such as
halides or amines."
A) / \ o
/F II
F2C — C � CF,CFZC — F
catalyst
CF3
In the presence of alcohols or secondary amines,
derivatives of PPF are formed. Methyl 2,3,3,3-
tetrafluoro-2-methoxy propionate, prepared from
methanol and HFPO, may be converted to methyl
3,3,3-trifluoropyruvate, auseful building block in
organofluorine chemistry.Ii
O
II
NR,x J, CF3CFZC -NR,
B> / F
F2C C �
\CF3
ROx
O O
II oleum II
CF3CF(OR)C -OR ; CF3C(0)C -OR
Ring -opening the HFPO with halogenating reagents
such as Me3SiI gives halogenated perfluoroalkyl-
propionic acid derivatives such as CF,CFIC(0)F, c
C)
O O
/ \ /F SiWl
F2C = C CF,CFC — F
\CF3 I
HFPO can serve as a source of the heptafluoro-
propoxide ion owing to the equilibrium between
PPF and fluoride ion in solution. The heptafluoro-
propoxide ion, as well as other polyfluorinated
alkoxides, open the HFPO ring to generate oligo-
mers which can be isolated as the acid fluorides.'
The acid fluorides in turn may be converted to
vinyl ethers which are themselves useful chemical
intermediates.
0 0
D) / \/FM II
�FCF O GF C- F
CFZ C� M2=Ne,KF,Cs•
CF3 CF3 CF,
Rfo(FCF20)- CIF
CF3 CFZ
In the presence of Lewis acids such as SbF5, HF or
ACl X173_X (x = 0.05-0.3), HFPO isomerizes to
HFAY This can even happen in storage containers
if precautions are not taken to prevent the rear-
rangement reaction from occurring.
E)
O /\ F O
Lewis Acid I
F2C — C � C
\CF3 CF3 \ CF3
Thermolysis of HFPO gives difluorocarbene and
trifluoroacetyl fluoride.F The difluorocarbene may
be generated in situ to prepare useful intermediates
such as CF2I2 or cyclopropanes.
F)
O O
e
FZC — C � F —� IC + :CFZ
CF3 CF
\� F
DEQ-CFW 00000377

Storage and Handling
Shipping containers in the U.S.
Hexafluoropropylene oxide is a liquefied, nonflammable compressed gas. According to the U.S.
Department of Transportation (DOT), a nonflammable compressed gas is defined as a nonflammable
material having an absolute pressure greater than 40 psia at 21°C (70°F) and/or an absolute pressure
greater than 104 psi at 54°C (1300F).
The appropriate DOT designation is as follows:
Proper shipping name:
Liquefied Gas, N.O.S. Hexafluoropropylene Oxide
Hazard Class:
2.2
UN. No.
3163
DOT Labels
Nonflammable gas
DOT Placards
Nonflammable gas
Containers
Water
DOT
NeightWeight
Liquid Dip
Phase
Capacity
Dimensions
Specification
HFPO
Tube
Available
760 L
208 cm L x 76 cm D
11 OA50OW
818 kg
Yes
Liq or Vap
760 L
208 cm L x 76 cm D
106A500W
818 kg
Yes
Liq or Vap
17,000 L
2.4 m x 2.6 m x 6.1 m L (frame)
51
15,000 kg
Yes
Liq or Vap
ISO
6.1mLx2.4mOD
Smaller sizes are available upon request for developmental purposes.
DEQ-CFW 00000378

There are two types of 760 L cylinders used for shipping HFPO. They are designated by the DOT specifi-
cations I I OA500W and 106A500W and are identical in dimensions and only differentiated by the position of
the valves, relief valves and plugs.
It is important to note the location of the cylinder relief valves (RVs). The relief valve should be positioned
along a vertical axis aligned with the cylinder valves such that the cylinder relief valve is at the highest point.
This ensures that the RV will pass vapor if venting occurs and it will minimize the amount of liquid remaining
in the cylinder after use. The black stripe with "this side up" text is painted on each cylinder to serve as a
reminder.
Valve, Relief Valve, and Plug Placement for 760 L Cylinders
DEQ-CFW 00000379

Hexafluoropropylene Oxide
Rearrangement Concerns
Hexafluoropropylene oxide can rearrange to the
potential reproductive hazard hexafluoroacetone
(HFA) in the presence of Lewis acids. This can
occur in shipping containers, storage vessels, or
other process equipment. Because higher tempera-
tures cause faster rearrangement, it is highly recom-
mended to maintain the HFPO below 25 °C (77 °F)
unless required for process purposes (i.e. purifica-
tion or chemistry).
Corrosion by-products in carbon steel containers
can catalyze the HFPO rearrangement to HFA. In
order to inhibit the rearrangement reaction, toluene
is commonly added to carbon steel containers. Low
levels of toluene have been shown to be effective
as an inhibitor in this rearrangement reaction. If the
end user requires even lower levels of toluene, a
special low toluene grade can be selected, but it is
strongly recommended that shipping containers be
constructed of stainless steel when toluene is not
intentionally added as an inhibitor.
Because the potential for rearrangement of HFPO
to HFA is always present, it is recommended that
hexafluoropropylene oxide be treated as though
it always contains HFA unless a recent analysis
suggests otherwise.
Material Compatibility Concerns
Most metal components are suitable for use with
HFPO; however, corrosion resistant materials such
as stainless steel are recommended. If less corro-
sion resistant materials, such as carbon steel, are
used in the process equipment, toluene inhibited
HFPO is the preferred product.
Handling Precautions
The following rules for handling hexafluoropro-
pylene oxide containers are strongly recommended:
1. Use proper personal protective equipment, such
as side shield safety glasses, gloves and safety
shoes when handling containers.
2. Exposure to HFPO should be prevented or
minimized using proper ventilation and chemical
hygiene practices.
3. Always treat BFPO containers as though they
contain HFA unless a recent analysis indicates
otherwise.
4. Use proper backflow prevention methods when
connecting and disconnecting HFPO cylinders.
Introduction of water into an HFPO cylinder
can lead to HFA formation by slowly generating
HF, leading to corrosion and ultimately HFA.
5. To reduce the rearrangement of HFPO to
HFA, carbon steel cylinders should be main-
tained below 25°C (7717).
6. To reduce rearrangement of HFPO to HFA, it
is recommended that product shipped in carbon
steel containers be used within 90 days of
shipping..
7. Skin contact with HFPO liquid or escaping
vapor can lead to frostbite.
8. Never heat a container to temperatures higher
than 45°C (113°F).
9. Maintain filled containers with the correct
orientation as indicated on cylinders to ensure
relief protection is located in the vapor phase.
10. Never apply direct flame or live steam to a
container or valve.
11. Never refill disposable cylinders with anything.
The shipment of refilled disposable cylinders is
prohibited by DOT regulations.
NOTE: Disposable cylinders are often used
when supplying lab -scale samples.
12. Never refill returnable cylinders without DuPont
consent. DOT regulations forbid the transporta-
tion of returnable cylinders refilled without
DuPont authorization.
13. Never use a lifting magnet or sling (rope or
chain) when handling containers. A crane may
be used when a safe cradle or platform is used
to hold the container.
14. Never use containers as rollers, supports, or for
any other purpose other than originally intended.
15. Protect containers from any object that will
result in a cut or other abrasion in the surface
of the metal.
16. Never tamper with the safety devices in the
valves or containers.
17. Never attempt to repair either containers or
valves.
18. Never force connectors that do not fit properly.
Make sure threads on the regulators or auxiliary
equipment are the same as those on the con-
tainer valve outlets.
19. Keep valves tightly closed and valve caps and
hoods in place when containers are not in use.
NOTE: Storage and Handling: Store and handle
in accordance with all current regulations and
standards subject to storage regulations:
U.S. OSHA 29 CFR 1910.101.
References
1. Tarrant, P.; Allison, C. G.; Barthold, K. P.
Fluorine Chem. Rev. 1971, 5, 77-113.
2. Millauer, H.; Schwertfeger, W.; Siegemund, G.
Angew. Chem. Int. F,d. Engl. 1985, 24, 161-179.
DEQ-CFW 00000380

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Toll Free: 1-800-207-0756
www.dupont.com/ftuorointermediates
P,O, Box 80713
Customer information Center In Spain: [phone]
Toll Free: 00800 3876 6838
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DEQ-CFW 00000381