Note: Descriptions are shown in the official language in which they were submitted.
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METHOD FOR PRODUCING FLUORINATED ORGANIC COMPOUNDS
BACKGROUND OF INVENTION
(1) Field of Invention:
This invention relates to novel methods for preparing fluorinated organic
compounds.
(2) Description of Related Art:
Hydrofluorocarbons (HFC's), in particular hydrofluoroalkenes such
tetrafluoropropenes (including 2,3,3,3-tetrafluoro-1-propene (HF0-1234yf) and
1,3,3,3-tetrafluoro-l-propene (HF0-1234ze)) have been disclosed to be
effective
refrigerants, fire extinguishants, heat transfer media, propellants, foaming
agents,
blowing agents, gaseous dielectrics, sterilant carriers, polymerization media,
particulate removal fluids, carrier fluids, buffing abrasive agents,
displacement drying
agents and power cycle working fluids. Unlike chlorofluorocarbons (CFCs) and
hydrochlorofluorocarbons (HCFCs), both of which potentially damage the Earth's
ozone layer, HFCs do not contain chlorine and thus pose no threat to the ozone
layer.
Several methods of preparing hydrofluoroalkenes are known. For example,
U.S. Pat. No. 4,900,874 (Ihara et al) describes a method of making fluorine
containing
olefins by contacting hydrogen gas with fluorinated alcohols. Although this
appears to
be a relatively high-yield process, for commercial scale production the
handling of
hydrogen gas at high temperature raises difficult safety related questions.
Also, the cost
of producing hydrogen gas, such as building an on-site hydrogen plant, can be
in many
situations prohibitive.
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U.S. Pat. No. 2,931,840 (Marquis) describes a method of making fluorine
containing olefins by pyrolysis of methyl chloride and tetrafluoroethylene or
chlorodifluoromethane. This process is a relatively low yield process and a
very large
percentage of the organic starting material is converted in this process to
unwanted
and/or unimportant byproducts.
U.S. Pat. No. 2,996,555 (Rausch) describes a method for the vapor phase
manufacture of fluorine containing olefins by a single step process in which
an
oxygen-containing metal catalyst, such as chromium oxyfluoride, is used to
convert a
compound of formula CX3CF2CH3 to 2,3,3,3-tetrafluoropropenen. This examples in
this patent describe a process which produces a relatively low yield, that is,
60%.
The preparation of HF0-1234yf from trifluoroacetylacetone and sulfur
tetrafluoride has been described. See Banks, et al., Journal of Fluorine
Chemistry, Vol.
82, Iss. 2, p. 171-174 (1997). Also, U.S. Pat. No. 5,162,594 (Krespan)
discloses a
process wherein tetrafluoroethylene is reacted with another fluorinated
ethylene in the
liquid phase to produce a polyfluoroolefin product.
SUMMARY
Applicants have discovered a method for producing fluorinated organic
compounds, including hydrofluoropropenes, which preferably comprises
converting at
least one compound of Formula (I):
C(X)3CF2C(X)3 (I)
to at least one compound of Formula (II)
CF3CF=CHZ (II)
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where each X and Z is independently H, F, Cl, I or Br, said process preferably
not
including any substantial amount of oxygen-containing catalyst in certain
embodiments. Preferably Z is H. As used herein and throughout, unless
specifically
indicated otherwise, the term "converting" includes directly converting (for
example,
in a single reaction or under essentially one set of reaction conditions, and
example of
which is described hereinafter) and indirectly converting (for example,
through two or
more reactions or using more than a single set of reaction conditions). .
In certain preferred embodiments of the invention, the compound of Formula
(I) comprises a compound wherein each X on one terminal carbon is H, wherein
each
X on the other terminal carbon is independently selected from F, Cl, I or Br.
Such
preferred embodiments include converting at least one C3 alkane of Formula
(IA):
C(X)3CF2CH3 (IA)
to at least one compound of formula (II)
CF3CF=CHZ (II)
where each X is independently F, Cl, Br or I, said process preferably not
including any
substantial amount of oxygen-containing catalyst in certain embodiments..
Preferably
Z in such embodiments is H.
Preferably the compounds of Formula (I) contain at least four halogen
substituents and even more preferably at least five halogen substituents. In
certainly
highly preferred embodiments, the conversion step of the present invention
comprises
converting a compound of Formula (IA) wherein each X is F. Preferably the
compound of Formula (IA) is a penta-halogenated. Even more preferably the
penta-
halogenated propane of Formula (IA) comprises a trichlorinated, difluorinated
propane,
penta-fluorinated propane, and combinations of these.
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Preferred compounds of Formula (IA) include 1,1,1-trichloro-2,2-
difluoropropane (HCFC-242bb), and 1,1,1,2,2-pentafluoropropane (HFC-245cb).
In certain preferred embodiments, the step of converting a compound of
Formula (I) to at least one compound of Formula (II) comprises directly
converting a
compound of Formula (I). In other embodiments, the step of converting a
compound
of Formula (I) to at least one compound of Formula (II) comprises indirectly
converting a compound of Formula (I).
An example of such indirect conversion embodiments includes converting a
first compound of Formula (I), for example HCFC-242bb, to a second compound of
Formula (I), for example, HFC-245cb, and then converting the second Formula
(I)
compound to a Formula (II) compound. In certain more specific indirect
conversion
embodiments, the step of converting a compound of Formula (I) comprises
providing
at least one trichlorodiflumpropane in accordance with Formula (IA),
preferably
CCI3CF2CH3 (HCFC-242bb) and reacting same under conditions effective to
produce
at least one pentafluorpropane in accordance with Formula (IA), preferably
CF3CF2CH3 (HFC-245cb), which in turn is preferably exposed to reaction
conditions
effective to produce at least one compound in accordance with Formula (II),
preferably
HF0-1234yf. In preferred embodiments said exposing step comprises conducting
one
or more of said reactions in a gas and/or liquid phase in the presence of a
catalyst,
preferably a metal-based catalyst. Examples of such preferred conversion steps
are
disclosed more fully hereinafter. Of course, it is contemplated that in the
broad scope
of the invention that any of the Formula (I) compounds may be converted,
directly or
indirectly, to a compound of Formula (II) in view of the teachings contained
herein.
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In certain preferred embodiments the converting step comprises exposing the
compound of Formula (I), and preferably Formula (1A) to one or more sets of
reaction
conditions effective to produce at least one compound in accordance with
Formula (II).
The preferred conversion step of the present invention is preferably carried
out
under conditions, including the use of one or more reactions, effective to
provide a
Formula (I) conversion of at least about 50%, more preferably at least about
75%, and
even more preferably at least about 90%. In certain preferred embodiments the
conversion is at least about 95%, and more preferably at least about 97%.
Further in
certain preferred embodiments, the step of converting the compound of Formula
(I) to
produce a compound of Formula (II) is conducted under conditions effective to
provide
a formula (II) selectivity of at least about 45%, more preferably at least
about 55%, and
more preferably at least about 75%. In certain preferred embodiments a
selectivity of
about 95% or greater may be achieved.
In other aspects of the present invention, a method is provided for producing
the compound of Formula (I) by converting at least one compound of Formula
(III):
C(X)2=CC1C(X)3 (III)
to at least one compound of Formula (I), as described above, where each X is
independently H, F, Cl, I or Br, provided at least one X is Cl, I or Br. In
preferred
embodiments, at least one X on the unsaturated carbon is Cl, I or Br, and even
more
preferably Cl. The details of exemplary conversion *steps in accordance with
this
aspect of the invention are provided in the examples.
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DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
One beneficial aspect of the present invention is that it enables the
production
of desirable flurookfins, preferably C3. fluoroolefins, using relatively high
conversion
and high selectivity reactions. Furthermore, the present methods in certain
preferred
embodiments permit the production of the desirable fluoroolefins, either
directly or
indirectly, from relatively attractive starting materials.
Preferably the Formula (I) compound is exposed to reaction conditions
effective to produce a reaction product containing one or more of the desired
fluorolefins, preferably one or more compounds of Formula (II). Although it is
contemplated that the exposure step in certain embodiments may effectively be
carried
out in a single reaction stage and/or under a single set of reaction
conditions, as
mentioned above, it is preferred in many embodiments that the conversion step
comprise a series of reaction stages or conditions. In one preferred aspect of
the
present invention, the conversion step comprises: (a) reacting a first
chlorinated
compound of Formula (IA), in a gas and/or liquid phase reaction in the
presence of at
least a first catalyst to produce at least one compound of Formula (IA),
preferably a
compound of Formula (IA) which is penta-fluorinated, and even more preferably
contains no other halogen substituents, such as HFC-245; (b) reacting the
Formula (IA)
compound, preferably the penta-fluorinated Formula (IA) compound, preferably
in a
gas phase and in the presence or absence of catalyst, which if present maybe
the same
or different than the first catalyst to produce at least one compound of
Formula (II)
and even more preferably HF0-1234yf. In certain embodiments, the catalyst does
not
include substantial amounts of oxygen containing catalyst. Each of the
preferred
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reaction steps is described in detail below, with the headings being used for
convenience but not necessarily by way of limitation.
I. FLUORINATION OF THE MULTI-HALOGENATED FORMULA I(A)
One preferred reaction step in accordance may be described by those reactions
in which the compound of Formula (IA) contains fluorine and at least one other
halogen, and this compound is fluorinated to produce a compound of Formula
(IA)
which contains at least four, and preferably five, fluorine substituents, and
even more
preferably no other halogen substituents. In certain of such preferred
embodiments,
especially embodiments in which such compound comprises HCFC-242bb, the
present
converting step comprises first reacting said compound(s) by fluorinating said
compound(s), preferably with HF in a gas and/or liquid phase, to produce an
HFC,
preferably an HFC that is at least tetrafluorinated, such as HFC-245.
Preferably this
reaction, whether in the gas phase, the liquid phase, or both is at least
partially
catalyzed. In certain preferred embodiments, the compound of Formula (IA),
such as
HCFC-242bb is contacted with liquid HF in the presence of a catalyst including
but not
limited to SbC15, SbF5, SbF3, TiC14, SnC14, FeC13, AlC13, AlF3, and
combinations of
two or more of these, to synthesize a compound of Formula (IA) having an
increased
number of fluorine substituents, and preferably only fluorine substituents,
such as
CF3CF2CH3. SbC15 is found to be highly preferred in many desirable
embodiments. In
other preferred embodiments, this conversion step is carried out in a
catalytic,
continuous, gas-phase reaction mode using SbC15/C as the solid catalyst. The
preferred
fluorination of the compound of Formula (IA) is preferably carried out under
conditions effective to provide a Formula (IA) conversion of at least about
50%, more
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preferably at least about 75%, and even more preferably at least about 90%. In
certain
preferred embodiments the conversion is at least about 95%, and more
preferably at
least about 97%. Further in certain preferred embodiments, the conversion of
the
compound of Formula (IA) comprises reacting such compound under conditions
effective to produce at least one penta-fluorinated compound (preferably HFC-
245) at
a yield of at least about 70%, more preferably at least about 75%, and even
more
preferably at least about 80%.
In general, it is possible that the fluorination reaction step can be carried
out in
the liquid phase or in the gas phase, or in a combination of gas and liquid
phases, and it
is contemplated that the reaction can be carried out batch wise, continuous,
or a
combination of these.
In preferred gas phase fluorination of Formula (I) compounds, the reaction is
at
least partially a catalyzed reaction, and is preferably carried out on a
continuous basis
by introducing a stream containing the compound of Formula (I) into one or
more
reaction vessels, such as a tubular reactor. In certain preferred embodiments,
the
stream containing the compound of Formula (I), and preferably Formula (IA), is
preheated to a temperature of from about 150 C to about 400 C, preferably
about
300 C, and introduced into a reaction vessel (preferably a tube reactor),
which is
maintained at the desired temperature, preferably from about 40 C to about 200
C,
more preferably from about 50 C to about 150 C, where it is preferably
contacted with
catalyst and fluorinating agent, such as BF.
Preferably the vessel is comprised of materials which are resistant to
corrosion
as Hastelloy, Inconel, Monel and/or fluoropolymers linings.
Preferably the vessel contains catalyst, for example a fixed or fluid catalyst
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bed, packed with a suitable fluorination catalyst, with suitable means to
ensure that the
reaction mixture is maintained with the desired reaction temperature range.
Thus, it is contemplated that the fluorination reaction step may be performed
using a wide variety of process parameters and process conditions in view of
the
overall teachings contained herein. However, it is preferred in certain
embodiments
that this reaction step comprise a gas phase reaction, preferably in the
presence of
catalyst, and even more preferably a Sb-based and/or and Fe-based catalyst
(such as
FeC13 on carbon (designated herein as FeC13/C for convenience), and
combinations of
these.
In general it is also contemplated that a wide variety of reaction pressures
may
be used for the fluorination reaction, depending again on relevant factors
such as the
specific catalyst being used and the most desired reaction product. The
reaction
pressure can be, for example, superatmospheric, atmospheric or under vacuum,
and in
certain preferred embodiments is from about 1 to about 200 psia, and even more
preferably from about 1 to about 120 psia.
In certain embodiments, an inert diluent gas, such as nitrogen, may be used in
combination with the other reactor feed(s).
It is contemplated that the amount of catalyst use will vary depending on the
particular parameters present in each embodiment.
II. CONVERSION TO FORMULA (H)
One preferred reaction step in accordance may be described by those reactions
in which the compound of Formula (I), preferably Formula (IA) is converted to
a
compound of Formula (II). In certain preferred embodiments, the stream
containing
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the compound of formula (I), and preferably (IA) is preheated to a temperature
of
from about 150 C to about 400 C, preferably about 350 C, and introduced into a
reaction vessel, which is maintained at the desired temperature, preferably
from about
300 C to about 700 C, more preferably from about 450 C to about 650 C.
Preferably the vessel is comprised of materials which are resistant to
corrosion
as Hastelloy, Inconel, Monel and/or fluoropolymers linings. Preferably the
vessel
contains catalyst, for example a fixed or fluid catalyst bed, packed with a
suitable
catalyst, with suitable means to heat the reaction mixture to the desired
reaction
temperature.
Thus, it is contemplated that this reaction step may be preformed using a wide
variety of process parameters and process conditions in view of the overall
teachings
contained herein. However, it is preferred in certain embodiments that this
reaction
step comprise a gas phase reaction, preferably in the presence of catalyst,
and even
more preferably a carbon- and/or metal-based catalyst, preferably activated
carbon, a
nickel-based catalyst (such as Ni-mesh) and combinations of these. Other
catalysts
and catalyst supports may be used, including palladium on carbon, palladium-
based
catalyst (including palladium on aluminum oxides), and it is expected that
many other
catalysts may be used depending on the requirements of particular embodiments
in
view of the teachings contained herein. Of course, two or more any of these
catalysts,
or other catalysts not named here, may be used in combination.
While it is contemplated that a wide variety of reaction temperatures may be
used, depending on relevant factors such as the catalyst being used and the
most
desired reaction product, it is generally preferred that the reaction
temperature for the
step is from about 200 C to about 800 C, more preferably from about 400 C to
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800 C. In certain preferred embodiments, the reaction temperature is from
about
300 C to about 600 C, and even more preferably in certain embodiments from
about
500 C to about 600 C.
In general it is also contemplated that a wide variety of reaction pressures
may
be used, depending again on relevant factors such as the specific catalyst
being used
and the most desired reaction product. The reaction pressure can be, for
example,
superatmospheric, atmospheric or under vacuum and in certain preferred
embodiments
is from about 1 to about 200 psia, and in certain embodiment from about 1 to
about
120 psia.
In certain embodiments, an inert diluent gas, such as nitrogen, may be used in
combination with the other reactor feed(s). It is contemplated that the amount
of
catalyst use will vary depending on the particular parameters present in each
embodiment.
Preferably in such embodiments as described in this section, the conversion of
the formula (I) compound is at least about 30%, more preferably at least about
50%,
and even more preferably at least about 60%. Preferably in such embodiments,
the
'selectivity to compound of Formula (II), preferably HF0-1234y1, is at least
about
70%, more preferably at least about 80% and more preferably at least about
90%.
EXAMPLES
Additional features of the present invention are provided in the following
examples, which should not be construed as limiting the claims in any way.
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EXAMPLES lA
Liquid-phase catalytic fluorination of CC13CE2CH3 (242bb) with HE to
CF3CF2CH3 (R245 cb)
Example 1A
About 327 grams HF, about 50 grams CC13CF2CH3(242bb), and about 75
grams SbC15 were charged into a 1-L autoclave. The reaction mixture was
stirred at
120 C for about 6 hours under about 760 psig of pressure. After the stipulated
reaction
time, the reactor was cooled up to about 0 C, and about 300 ml water was then
added
slowly into the autoclave over a period of about 45 minutes. After complete
addition
of water under stirring, the reactor was heated to about 70 C and then the
overhead
gases were transferred to another collecting cylinder. The yield of CF3CF2CH3
was
about 82% at a 242bb conversion level of about 100%. The other major by-
products
were traces of CF3CFCICH3 and tarry material.
Example 1B
About 327 grams of HF, about 50 graqms of CC13CF2CH3(242bb), and about
75 grams of SbC15 were charged into a 1-L autoclave. The reaction mixture was
stirred
at about 100 C for about 6 hours under about 620 psig of pressure. After the
reaction,
the reactor was cooled to about 0 C, and about 300 ml water was then added
slowly
into the autoclave over a period of about 45 minutes. After complete addition
of water
under stirring, the reactor temperature was raised to 70 C and then the
overhead gases
were transferred to another collecting cylinder. The yield of CF3CF2CH3 was
about
78% at a 242bb conversion level of about 86%. The other major by-products were
traces of CF3CFC1CH3 and and other clorofluoropropanes.
Example 1C
About 327 grams HF, about 50 grams 1233xf, and about 75 grams SbC15 were
charged into a 1-L autoclave. The reaction mixture was stirred at about 80 C
for about
6 hours under about 460 psig of pressure. After the reaction, the reactor was
cooled to
0 C and 300 ml water was then added slowly into the autoclave over a period of
about
45 minutes. After complete addition of water under stirring, the reactor was
cooled to
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room temperature and then the overhead gases were transferred to another
collecting
cylinder. The yield of CF3CF2CH3 was about 67%. The only other major by-
products
includes products resulted from incomplete fluorination and trace of
CF3CFCICH3.
EXAMPLE 2
Gas-phase catalytic fluorination of CC13CF2CH3 (242bb) with HF to CF3CF2CH3
(R245ch)
A 22-inch (1/2-inch diameter) Monel pipe gas phase reactor was charged with
120 cc of 50wt% SbC15/C as the catalyst. The reactor was mounted inside a
heater with
three zones (top, middle and bottom). The reactor temperature was read by
custom
made 5-point thermocouples kept at the middle inside of the reactor. The inlet
of the
reactor was connected to a pre-heater, which was kept at about 300 C by
electrical
heating. The liquid-HF was fed from a cylinder into the pre-heater through a
needle
valve, liquid mass-flow meter, and a research control valve at a substantially
constant
flow of from about 1 to about 1000 grams per hour (g/h). The HF cylinder was
kept at
a constant pressure of 45 psig by applying anhydrous N2 gas pressure into the
cylinder
head space. A feed consisting of organic reactant (242bb) was fed at a rate
ranging
from about 10 to about 120 g/h as a gas from a cylinder kept at about 145 C
through a
regulator, needle valve, and a gas mass-flow-meter. The organic feed stream
was also
fed periodically as liquid at about 105 C from a cylinder into the pre-heater
through a
needle valve, liquid mass-flow meter, and a research control valve at a
substantially
constant flow rate ranging from about 10 to about 150 g/h. The organic line
from the
cylinder to the pre-heater was kept at about 265 C by wrapping with constant
temperature heat trace and electrical heating. All feed cylinders were mounted
on
scales to monitor their weight by difference. The reactions were run at a
substantially
constant reactor pressure of from about 0 to about 100 psig by controlling the
flow of
reactor exit gases by another research control valve. The exit gases coming
out of the
reactor were analyzed by on-line GC and GC/MS connected through a hotbox valve
arrangements to prevent condensation. The reactor temperature was kept at from
about
60 C to about 120 C. The SbC15/C catalyst was pretreated with about 50 g/h HF
at
about the reaction temperature for about 8 hours under about 50 psig
pressures. After
HF pretreatment, the catalyst was further treated with about 20 seem of C12
and about
50 g/h of HF for an additional 4 hours. The pretreated catalyst was then
contacted with
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organic in the presence of about 50 g/h HF. The conversion of 242bb was in the
range
of from about 60 to about 70% and the selectivity to 245cb was about 85% when
the
reaction was performed using 50 wt% SbC15/C as the catalyst at about 120 C
under
about 30 psig pressure in the presence of about 50 g/h HF and about 20 g/h of
242bb.
The product was collected by flowing the reactor exit gases through a solution
of from
about 20wt% to about 60 wt% aqueous KOH scrubber solution and then trapping
the
exit gases from the scrubber into a cylinder kept in dry ice or liquid N2. The
products
were then isolated by distillation. The following catalysts were tested and
found to
have the selecetivity to HFC-245 as indicated in parenthesis: 30 wt% SbC15/C
(Sel.
81%); from about 3 to about 6 wt% FeC13/C (Sel. 52%); SbF5/C (Sel. 87%); 20
wt%
SnC14/C (Sel. 32%); 23 wt% TiC14/C (Sel. 27%). The catalyst temperatures o
used
ranged from about 60 C to about 120 C. SbC15/C is believed to be a preferred
catalyst
for this gas-phase transformation.
EXAMPLE 3
Catalytic conversion of CF3CF2CH3 to CF3CF=CH2
A 22-inch (1/2-inch diameter) Monel tube reactor was charged with about 120
cc of a catalyst. The reactor was mounted inside a heater with three zones
(top, middle
and bottom). The reactor temperature was read by custom made 5-point
thermocouples
kept at the middle inside of the reactor. The inlet of the reactor was
connected to a pre-
heater, which was kept at about 300 C by electrical heating. HFC-245cb was fed
from
a cylinder kept at about 65 C through a regulator, needle valve, and a gas
mass-flow-
meter. The line to the pre-heater was heat traced and kept at a substantially
constant
temperature of from about 65 C to about 70 C by electrical heating to avoid
condensation. The feed cylinder was mounted on scales to monitor their weight
by
difference. The reactions were run at a substantially constant reactor
pressure in the
range of from about 0 to about 100 psig by controlling the flow of reactor
exit gases by
another research control valve. The gas mixture exiting the reactor was
analyzed by on-
line GC and= GC/MS connected through a hotbox valve arrangements to prevent
condensation. The conversion of 245cb was in the range of from about 30% to
about
70% and the selectivity to HF0-1234yf was in the range of from about 90% to
about
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100% depending on the reaction conditions. The products were collected by
flowing
the reactor exit gases through a 20-60-wt% of aqueous KOH scrubber solution
and
then trapping the exit gases from the scrubber into a cylinder kept in dry ice
or liquid
N2. The products were then substantial isolated by distillation. Results are
tabulated in
Table 1.
Table 1: Transformation of CF3CF2CH3 to 1234yf
# Cat T, = 112, CF3CF2CH3 (245cb) Conversion of 245cb 1234yf
C sccm seem (Sel. %).
1 A 575 0 65 79 63
2 B 575 0 68 82 57
3 C 575 0 73 73 61
4 D 575 0 68 84 59
5 D 575 20 68 89 73
6 E 550 0 69 92 53
7 F 550 0 67 93 33
8 G 550 0 69 73 46
Reaction conditions: Pressure about 2.5 to about 5.3 psig; Catalyst, 100 cc"
: A is NORIT RFC 3; B is Shiro-Saga activated carbon; C is Aldrich activated
carbon; D is Calgon activated carbon; E is 0.5 wt% Pd/C; F is 0.5 wt% Pt/C; G
is Ni-
mesh; Organic cylinder temperature about 65 C; CF3CF2CH3 (245cb) line to the
preheater about 50 C; Preheater, 350 C; N2 - 0 SCCM.
EXAMPLE 4A-4C
Preparation of CH3CF2CH2CI from 2,3-dichloropropene using HF/SbC15
Example 4A
A 2-gallon autoclave was charged with about 900 grams (8.1 mol) of 2,3-
dichloropropene, about 405 grams (20.3 mol) of HF, and about 10 grams (0.033
mol)
of SbC15. The contents were heated with stirring to about 100 C for about 19
hours.
The maximum pressure was about 285 psig. (approx. 2000 kPa). The contents were
vented while hot into a fluoropolymer container containing ice, which was
connected
in sequence to a dry ice trap. The organic layer was separated and washed to
remove
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residual acid, giving about 811.9 grams of crude product, which by GC analysis
was
comprised of about 41% CH3CF2CH2C1, about 34.5% CH3CFC1CH2C1, 21 %
CH3CC12CH2C1, and about 1.8 % starting material. The conversion was about 97
%,
while the combined yield of halopropanes was 76.7 %. Substantially pure
CH3CF2CH2C1 was obtained by fractional distillation. The autoclave also
contained
about 77.8 grams of black residue.
Example 4B
Example 4A was repeated except that the reactants were heated to about 120 C
for about 18 hours. The crude organic layer so obtained consisted of about
58.8 %
CH3CF2CH2C1, about 28.3 % CH3CFC1CH2C1, and about 9.8 % CH3CC12CH2C1. The
combined yield of halopropanes was about 74 %.
Example 4C
Example 4A was repeated except that no catalyst was used. The crude organic
layer so obtained consisted of about 58.7 % CH3CF2CH2C1, about 25.9 %
CH3CFC1CH2CI, and about 12.2 % CH3CC12CH2C1. The combined yield of
halopropanes was about 80%. This example demonstrates that SbC15 catalyst was
not
effective in increasing the amount of the desired CH3CF2CH2CI or increasing
the total
yield of useful products.
EXAMPLE 5
Conversion of 2,3-diehloropropene to CH3CFCICH2C1
A two-gallon autoclave was evacuated and charged with about 1500 grams of
2,3-dichloropropene (about 13.4 mol). It was then cooled to about -5 C by
means of
internal cooling coils connected to a chiller. About 1500 grams (75 mol) was
added,
the chiller turned off, and the contents slowly heated to a temperature in the
range of
from about 20 to about 25 C with stirring. After approximately 18 hours, the
contents
were cooled to about 5 C before discharging into iced water. The organic phase
was
separated and washed with about 1 L of water, dried (MgSO4) and filtered to
give
about 1554 grams of the product mixture. GC analysis indicated that the crude
product
contained about 86.5 % CH3CFC1CH2C1, about 3.8 % CH3CF2CH2C1, and about 2.8 %
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CH3CC12CH2C1. Similar results were obtained at a temperature of about 50 C,
although the amount of CH3CFCICH2CI decreased slightly, while the amount of
CH3CF2CH2C1 marginally increased.
EXAMPLE 6
Conversion of CH3CCI2CH2C1 to CH3CF2CH2C1
An autoclave was charged with about 100 grams of CH3CC12CH2C1 and about .
44 grams of HF and the contents heated with stirring to about 130 C for about
20.5
hours. The products were process substantially in accordance with the
description in
Example 1, which resulted in about 70 grams of crude product which was
comprised,
based on GC area %, about 43.8 % CH3CF2CH2C1, about 23.1 % CH3CFCICH2C1, and
about 30.3 % CH3CC12CH2C1. The autoclave also contained about 1.9 grams of
dark
residue.
EXAMPLE 7
Conversion of a mixture of CH3CFCICH2CI and CH3CC12CH2C1 to
CH3CF2CH2C1
A mixture of about 666 grams of CH3CFC1CH2C1, about 268 grams of
CH3CC12CH2C1, about 474 grams of HF and about 11 grams of SnCI.4 were heated
together with stirring to about 114 C for about 18 hours. The crude product
was
comprised of about 89 % CH3CF2CH2C1.
Based on the results of Examples 4 ¨ 7, the use of chlorinated antimony
catalyst, such as. SbC15, may not be preferred in certain embodiments due to
an added
cost that may not provide the desired improvement in yield or conversion in
some
embodiments, and may produce considerable by-product residue. In certain
embodiments, therefore, it is preferred to run the reaction without catalyst.
However,
the use of SnC14 may be preferred in embodiments in which CH3CF2CH2CI is the
desired product, since its use may allow a lower temperature to be used and
result in a
higher percentage of CH3CF2CH2C1 in the crude product.
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EXAMPLES 8A ¨ 8C
Preparation of Cli3CF2CC13
The photochlorination of CH3CF2CH3 to CH3CF2CCI3 has been mentioned in
JACS, 59 (1937) 2436
Example 8A - Photoehlorination of CIJACE&CH2C1
The photochlorination was done using a 100-W Hg lamp placed in a quartz
jacket that was cooled with the use of a circulating cooling bath set at about
-5 C. The
quartz jacket was inserted into a glass reactor of about 400 mL capacity. The
reactor
was cooled externally by placing it in a glycol-water bath which was cooled
with the
use of cooling coils connected to a second circulating bath set at -8.5 C. The
reactor
was fitted with a thermocouple, stir bar, and a gas inlet tube for introducing
chlorine
gas from a cylinder via a calibrated flowmeter. Exiting gases passed through a
water-
cooled condenser, an air trap, and a scrubber containing NaOH and Na2S03 to
remove
HC1 and chlorine.
The reactor was charged with about 250.5 grams of CH3CF2CH2C1 of about
98.6 % purity and allowed to cool to a substantially constant temperature of
about -5.5
C. The chlorine cylinder was then opened and the flow rate set at 23 g/h.
Immediately
thereafter, the lamp was then turned on. After approximately 0.5 hours, the
temperature
of the reactor contents stabilized at about -3 10.5 C.
The photochlorination was continued for about 7 hours and a
conversion of about 79.4% was achieved. The composition of the crude product,
which
amounted to about 309.3 grams, was about 19.2 % CH3CF2CH2C1 , about 50.9 %
CH3CF2CHC12 and about 24.8 % CH3CF2CC13. Substantially pure CH3CF2CC13 was
obtained by fractional distillation.
A 450-W Hg lamp could also be used. The ratios of CH3CF2CHC12 to
CH3CF2CCI3vs. time were essentially the same as with a 100-watt lamp.
Examole 88 -õPhotochlorination of CH3CF2C11C12
In a manner similar to that described in Example 8A, about 296.8 grams of
CH3CF2CHC12 (about 97.4 % pure, containing about 1.9 % CH3CF2CC13) was
photochlorinated using a l 00-W Hg lamp at a temperature of about -4 C and
chlorine
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feed rate of about 22.3 g/h. After about 2.5 hours, the composition of the
reactor
contents was about 58.2 % CH3CF2CHC12 and about 39.9 % CH3CF2CC13. Thus the
selectivity for CH3CF2CC13 was about 97 % at a CH3CF2CHC12 conversion of about
40
%.
EXAMPLE 10C
Photoehlorination of a mixture of CH3CF2CH2CI and CH3CF2CHC12
The selectivity found in Examples 8A and 8C is considered to be desirably for
many embodiments of the invention. However, limiting the conversion achieved
in
those examples may be less than desired in certain applications. It is
believed that the
conversions may be limited in those example by two factors. One factor is the
melting
point of CH3CF2CC13 (53 C) and the other is lower selectivity at high
conversion. The
latter may be a problem in connection with certain commercial embodiments
where
such yield losses may be unacceptable. Therefore to keep selectivity high with
relatively high conversion, it is advantageous in certain embodiments to run
the
photochlorination with less than 100 % conversion of CH3CF2CHC12 and recycle
this
material along with fresh CH3CF2CH2C1, preferably in the next batch. In
preferred
embodiments, the amount of CH3CF2CHC12 made is approximately equal to the
amount added as recycled material.
A mixture of about 202.4 grams of CH3CF2CH2C1 and about 110.7 g of
CH3CF2CHC12 was photochlorinated using a 100-watt Hg lamp at a temperature of
about -4 C with a chlorine feed rate of about 22.2 g/h as described in Example
10A.
= After an irradiation time of about 8.4 hours the conversion of
CH3CF2CH2C1 exceeded
about 90 %. The composition of the crude product was about 6.9 wt%
CH3CF2CH2C1,
45.2 wt% CH3CF2CHC12, and 43.5 wt% CH3CF2CC13. The amount of CH3CF2CHC12
initially increased with time, reaching a maximum of about 55 wt % after about
5
hours.
EXAMPLE 90A ¨ 90C
Conversion of 2,3-dichloropropene
Example 10A
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=
About 65 cc of 50 weight% SbC15 on activated carbon support is provided at a
temperature of about 96 C. The catalyst was loaded into the 'A" OD x 36" L
mortal
tube. 2,3-dichloropropene was used for the organic feed stock. After normal
catalyst
activation with HF and C12, the C12 flow was stopped and the HF feed was
adjusted to
a rate of about 47 g/hr. Shortly thereafter, the 2,3-dichloropropene feed was
started at
a rate of about 20 ¨.25 g/hr. The HF/organic mole ratio was 11.5/1. The
pressure was
about 20 psig. The contact time was about 6.73 sec. Reactor effluent samples
were
collected in Tedlar gas sample bags containing DI water to absorb the acid
before
analysis. The bags were then heated to about 60 C to ensure that the organic
present in
the bag was completely vaporized. GC/MS results showed the major product to be
1-
chloro-2,2-difluoropropane (262ca) with an area of about 93.3%. Also present
are
about 3.7 area% of 1,2,2-trifluoropropane (263ca) and about 3.4 area% of
272ca. The
conversion of the 2,3-dichloropropene was about 100%.
Ex pie 100
This example was run similarly to Example 10A but the reaction temperature
was about 135 C. The contact time was about 6.07 sec. The GC,/MS results of
the bag
sample show about 72.8 area% for 1-chloro-2,2-difluoropropane (262ca), about
15.11
area% for 1,2-dichloro-2-fluoropropane (26 lba), about 4.8 area% for 263ca,
about 4.1
area% for 2,2-difluoropropane (272ca) and about 2.6 area% for
1,1,1,2,2,3,3,4,4-
nanofluorohexane.
Example 14)C
This Example was run similarly to Example 10A but the reaction temperature
was about 195 C. The contact time was about 5.29 sec. The GC,/MS results of
the bag
sample show about 38.59 area% for 1-chloro-2,2-difluoropropane (262ca), about
29.3
area% for 1,2-dich1oro-2-fluompropane (261ba), about 4.7 area% for 263ca,
about
20.12 area% for 272.ca and about 7.3 area% for 1,1,1,2,2,3,3,4,4-
nanofluorohexane.
Having thus described a few particular embodiments of the invention, various
alterations, modifications, and improvements will readily occur to those
skilled in the
art. Such alterations, modifications, and improvements are made obvious by
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CA 02635806 2013-10-09
disclosure, and it will be understood that the scope of the claims will not be
limited
by any preferred embodiments or examples set forth, but should be given the
broadest
interpretation consistent with the description as a whole.
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