U.S. patent application number 16/196746 was filed with the patent office on 2019-03-21 for process for producing 2,3,3,3-tetrafluoropropene.
This patent application is currently assigned to HONEYWELL INTERNATIONAL INC.. The applicant listed for this patent is HONEYWELL INTERNATIONAL INC.. Invention is credited to Selma BEKTESEVIC, Yuon CHIU, Haluk KOPKALLI, Daniel C. MERKEL, Hsueh Sung TUNG, Haiyou WANG.
Application Number | 20190084906 16/196746 |
Document ID | / |
Family ID | 48192826 |
Filed Date | 2019-03-21 |
United States Patent
Application |
20190084906 |
Kind Code |
A1 |
WANG; Haiyou ; et
al. |
March 21, 2019 |
PROCESS FOR PRODUCING 2,3,3,3-TETRAFLUOROPROPENE
Abstract
The present invention relates, in part, to the discovery that,
during the fluorination of certain fluoroolefin starting reagents,
oligomerization/polymerization of such reagents reduces the
conversion process and leads to increased catalyst deactivation.
The present invention also illustrates that vaporizing such
starting reagents in the presence of one or more organic co-feed
reduces such oligomerization/polymerization and improves catalytic
stability.
Inventors: |
WANG; Haiyou; (Amherst,
NY) ; TUNG; Hsueh Sung; (Getzville, NY) ;
BEKTESEVIC; Selma; (Williamsville, NY) ; MERKEL;
Daniel C.; (West Seneca, NY) ; KOPKALLI; Haluk;
(Staten Island, NY) ; CHIU; Yuon; (Denville,
NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HONEYWELL INTERNATIONAL INC. |
MORRIS PLAINS |
NJ |
US |
|
|
Assignee: |
HONEYWELL INTERNATIONAL
INC.
MORRIS PLAINS
NJ
|
Family ID: |
48192826 |
Appl. No.: |
16/196746 |
Filed: |
November 20, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14355894 |
May 2, 2014 |
10131597 |
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PCT/US2012/063331 |
Nov 2, 2012 |
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16196746 |
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61555732 |
Nov 4, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 27/138 20130101;
B01J 23/745 20130101; C07C 17/087 20130101; B01J 23/755 20130101;
B01J 21/04 20130101; B01J 23/26 20130101; B01J 27/12 20130101; C07C
17/25 20130101; B01J 27/10 20130101; B01J 23/34 20130101; C07C
17/42 20130101; C07C 17/206 20130101; B01J 23/75 20130101; C07C
17/202 20130101; C07C 17/206 20130101; C07C 21/18 20130101; C07C
17/25 20130101; C07C 21/18 20130101; C07C 17/087 20130101; C07C
19/10 20130101; C07C 17/42 20130101; C07C 21/18 20130101 |
International
Class: |
C07C 17/20 20060101
C07C017/20; C07C 17/087 20060101 C07C017/087; C07C 17/42 20060101
C07C017/42; C07C 17/25 20060101 C07C017/25; B01J 27/12 20060101
B01J027/12; B01J 23/26 20060101 B01J023/26; B01J 27/138 20060101
B01J027/138; B01J 21/04 20060101 B01J021/04; B01J 23/34 20060101
B01J023/34; B01J 23/745 20060101 B01J023/745; B01J 23/755 20060101
B01J023/755; B01J 27/10 20060101 B01J027/10; B01J 23/75 20060101
B01J023/75 |
Claims
1. A composition comprising: (i) at least one compound of Formula
I, II or III: CX.sub.2.dbd.CCl--CH.sub.2X (Formula I)
CX.sub.3--CCl.dbd.CH.sub.2 (Formula II) CX.sub.3--CHCl--CH.sub.2X
(Formula III) wherein X is independently selected from F, Cl, Br,
and I provided that at least one X is not F; and (ii) at least one
or more organic compounds selected from trichlorofluoropropene
(1231), 1,2-dichloro-3,3,3-trifluoropropene (1223xd),
2-chloro-3,3,3-trifluoropropene (1233xf),
2-chloro-1,1,1,2-tetrachloropropane (244bb),
1,1,1,2,2-pentafluoropropane (HFC-245cb), difluoromethane (HFC-32),
pentafluoroethane (HFC-125), 1,1,1,2-tetrafluoroethane (HFC-134a),
trifluoroethane (HFC-143) (including all isomers thereof), and
1,1,1,3,3-pentafluoropropane (HFC-245fa) and combinations
thereof.
2. The composition of claim 1, wherein the compound of Formula I
comprises 1,1,2,3-tetrachloropropene (1230xa); the compound of
Formula II comprises 2,3,3,3-tetrachloropropene (1230xf); and the
compound of Formula III comprises 1,1,1,2,3-pentachloropropane
(240db).
3. The composition of claim 1, wherein the at least one or more
organic compounds are present in an amount ranging from 1 to 50 wt
%.
4. The composition of claim 3, wherein the at least one or more
organic compounds are present in an amount ranging from 3 to 30 wt
%.
5. The composition of claim 3, wherein the at least one or more
organic compounds are present in an amount ranging from 5 to 15 wt
%.
6. A composition comprising: (i) 2,3-dichloro-3,3-difluoropropene
(1233xf); and (ii) at least one or more organic compounds selected
from 1,2-dichloro-3,3,3-trifluoropropene (1223xd),
trichlorofluoropropene (1231) isomers,
2-chloro-1,1,1,2-tetrafluoropropane (244bb) and unreacted
1,1,2,3-tetrachloropropene (1230xa), 2,3,3,3-tetrachloropropene
(1230xf) and 1,1,1,2,3-pentachloropropane (240db).
7. The composition of claim 6 further comprising HCl.
8. The composition of claim 6 further comprising HF.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a process for preparing
fluorinated organic compounds, more particularly to a process for
preparing fluorinated olefins, and even more particularly to a
process for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf).
BACKGROUND OF THE INVENTION
[0002] Hydrofluoroolefins (HFOs), such as tetrafluoropropenes
(including 2,3,3,3-tetrafluoropropene (HFO-1234yf)), are now known
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, HFOs do
not contain chlorine and, thus, pose no threat to the ozone layer.
HFO-1234yf has also been shown to be a low global warming compound
with low toxicity and, hence, can meet increasingly stringent
requirements for refrigerants in mobile air conditioning.
Accordingly, compositions containing HFO-1234yf are among the
materials being developed for use in many of the aforementioned
applications.
[0003] Several methods of preparing HFOs 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, commercial scale handling of hydrogen gas at
high temperature is hazardous. Also, cost of commercially producing
hydrogen gas, such as building an on-site hydrogen plant, is
economically costly.
[0004] 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 to unwanted and/or
unimportant byproducts, including a sizeable amount of carbon black
which tends to deactivate the catalyst used in the process.
[0005] The preparation of HFO-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.
[0006] However, there remains a need for an economic means of
producing hydrofluoroolefins, such as HFO-1234yf. The present
invention satisfies this need among others.
SUMMARY OF INVENTION
[0007] The present invention relates, in part, to one or more
process steps for improving the reaction efficiency used for the
production of HFOs, such as 2,3,3,3-tetrafluoropropene
(1234yf).
[0008] In one aspect, the present invention relates to a process
for reducing polymerization of a starting reagent during the
manufacture 1234yf by heating a starting reagent composition in a
liquid phase that includes at least one compound of formula I, II,
and/or III
CX.sub.2.dbd.CCl--CH.sub.2X (I)
CX.sub.3--CCl.dbd.CH.sub.2 (II)
CX.sub.3--CHCl--CH.sub.2X (III)
and an effective amount of one or more co-feed compounds other than
the compound of formula I, II, and/or III. "X", as used in any of
formulas I, II, and/or III, is independently selected from F, CI,
Br, and I. At least one X is not fluorine. The starting composition
is heated so as to form a vapor phase composition.
[0009] In a further aspect, the present invention relates to a
process for preparing 2-chloro-3,3,3-trifluoropropene by providing,
in a liquid phase, a starting composition including at least one
compound of formula I, II, and/or III
CX.sub.2.dbd.CCl--CH.sub.2X (I)
CX.sub.3--CCl.dbd.CH.sub.2 (II)
CX.sub.3--CHCl--CH.sub.2X (III)
as defined above, and also an effective amount of one or more
organic co-feed compounds, other than the compound of formulas I,
II, or III. The starting composition is vaporized to form a vapor
phase composition and is then contacted with a fluorinating agent
to produce a final composition comprising
2-chloro-3,3,3trifluoropropene.
[0010] In either of the foregoing embodiments, or any embodiment
provided herein, at least one compound of formula I, II, or III has
at least one X is a chlorine. In further embodiments, at least one
compound of formula I, II, or III has a chlorine at each X
position. In even further embodiments, at least one compound of
formula I includes 1,1,2,3-tetrachloropropene and/or at least one
compound of formula II includes 2,3,3,3-tetrachloropropene and/or
at least one compound of formula III includes
1,1,1,2,3-pentachloropropane.
[0011] The organic co-feed compound may be any organic compound
that improves the foregoing process, particularly by decreasing
starting reagent oligomerization/polymerization and/or reducing
catalyst deactivation over the course of the process. In one
embodiment, the organic co-feed compound has a boiling point that
is lower than the compound of Formula I, II, or III. Such compounds
include halocarbons or haloolefins, of which one or more of the
following may be included: trichlorofluoropropene (1231),
2,3-dichloro-3,3-difluoropropene (1232xf),
1,2-dichloro-3,3,3-trifluoropropene (1223xd),
2-chloro-3,3,3-trifluoropropene (1233xf),
2-chloro-1,1,1,2-tetrachloropropene (244bb),
1,1,1,2,2-pentafluoropropane (HFC-245cb), difluoromethane (HFC-32),
pentafluoroethane (HFC-125), 1,1,1,2-tetrafluoroethane (HFC-134a),
trifluoroethane (HFC-143) (including all isomers thereof),
1,1,1,3,3-pentafluoropropane (HFC-245fa).
[0012] The effective amount of the co-feed compound may be any
amount provided herein. While not limited thereto, in certain
aspects, it is between about 0.1 to about 99.9 wt %, between about
1 to about 50 wt %, between about 3 to about 30 wt %, or between
about 5 to about 15 wt %, each based on the total amount of organic
feed provided to the reaction.
[0013] The step of contacting the starting composition with a
fluorinating agent may occur in the presence of a catalyst. In one
aspect, the contacting step occurs in a vapor phase with or without
the presence of a vapor phase catalyst. Vapor phase catalysts used
for such a reaction include, but are not limited to, a chromium
oxide, a chromium hydroxide, a chromium halide, a chromium
oxyhalide, an aluminum oxide, an aluminum hydroxide, an aluminum
halide, an aluminum oxyhalide, a cobalt oxide, a cobalt hydroxide,
a cobalt halide, a cobalt oxyhalide, a manganese oxide, a manganese
hydroxide, a manganese halide, a manganese oxyhalide, a nickel
oxide, a nickel hydroxide, a nickel halide, a nickel oxyhalide, an
iron oxide, an iron hydroxide, an iron halide, an iron oxyhalide,
inorganic salts thereof, fluorinated derivatives thereof and
combinations thereof. In certain embodiments, the catalyst includes
a chromium oxide, such as, but not limited to, Cr.sub.2O.sub.3.
[0014] In even further aspects, the present invention relates to a
process for preparing 2,3,3,3-tetrafluoroprop-1-ene by [0015] a.
providing a starting composition including a compound of formula I,
II, and/or III
[0015] CX.sub.2.dbd.CCl--CH.sub.2X (I)
CX.sub.3--CCl.dbd.CH.sub.2 (II)
CX.sub.3--CHCl--CH.sub.2X (III) wherein X is independently selected
from F, Cl, Br, and I, provided that at east one X is not fluorine;
[0016] b. vaporizing said starting composition with an effective
amount of one or more organic co-feed compounds, other than the
compound of formula I, II, or III; [0017] c. contacting the
starting composition with a first fluorinating agent to produce a
first intermediate composition including
2-chloro-3,3,3-trifluoropropene and a first chlorine-containing
byproduct; [0018] d. contacting the first intermediate composition
with a second fluorinating agent to produce a second intermediate
composition including 2-chloro-1,1,1,2-tetrafluoropropane; and
[0019] e. dehydrochlorinating at least a portion of the
2-chloro-1,1,1,2-tetrafluoropropane to produce a reaction product
including 2,3,3,3-tetrafluoroprop-1-ene.
[0020] Additional embodiments and advantages to the present
invention will be readily apparent to one of skill in the art,
based on the disclosure provided herein.
DETAILED DESCRIPTION OF THE INVENTION
[0021] According to one embodiment, the present invention includes
a manufacturing process for making 2,3,3,3-tetrafluoroprop-1-ene
using a starting material according to any one or combination of
formulas I, II, and/or III:
CX.sub.2.dbd.CCl--CH.sub.2X (I)
CX.sub.3--CCl.dbd.CH.sub.2 (II)
CX.sub.3--CHCl--CH.sub.2X (III)
wherein X is independently selected from F, Cl, Br, and I, provided
that at least one X is not fluorine. In certain embodiments, the
compound(s) of Formula I, II and/or III contains at least one
chlorine, a majority of the Xs as chlorine, or all Xs as chlorine.
In certain embodiments, the compound(s) of formula I includes
1,1,2,3-tetrachloropropene (1230xa). In certain embodiments, the
compound(s) of formula II includes 2,3,3,3-tetrachloropropene
(1230xf). In further embodiments, the compound(s) of formula III
includes 1,1,1,2,3-pentachloropropane (240db). Processes applicable
to the present invention include, without limitation, integrated
multistep processes as described in U.S. Pat. No. 8,084,653 and US
Published Patent Application 2009/0240090, the contents of each of
which are incorporated herein by reference.
[0022] The method generally includes at least three reaction steps.
In the first step, a starting composition of Formulas I, II, and/or
III (such as 1,1,2,3-tetrachloropropene,
2,3,3,3-tetrachloropropene, and/or 1,1,1,2,3-pentachloropropane is
reacted with anhydrous HF in a first vapor phase reactor
(fluorination reactor) to produce a mixture of
2-chloro-3,3,3-trifluoropropene (1233xf) and HCl. In certain
embodiments, the starting reagents are provided as a liquid phase
and, prior to the reaction, are heated in a vaporizer to form a
vapor phase. To this end, the conversion of the compounds of
formulas I, II, and/or III occurs in the vapor phase and in the
presence of a vapor phase catalyst. One non-limiting catalyst may
include, but is not limited to, a fluorinated chromium oxide. The
catalyst may (or may not) have to be activated with anhydrous
hydrogen fluoride HF (hydrogen fluoride gas) before use depending
on the state of the catalyst. In one embodiment, there is no
oxygen-containing agent or gas feed, e.g. air, pure oxygen, or
diluted oxygen gas, such as an oxygen/inert gas (e.g. nitrogen), to
the first vapor phase reactor.
[0023] While fluorinated chromium oxides are disclosed as the vapor
phase catalyst, the present invention is not limited to this
embodiment. Any fluorination catalysts known in the art may be used
in this process. Suitable catalysts include, but are not limited to
chromium, aluminum, cobalt, manganese, nickel and iron oxides,
hydroxides, halides, oxyhalides, inorganic salts thereof and their
mixtures and any one of which may be optionally fluorinated.
Combinations of catalysts suitable for the present invention
nonexclusively include Cr.sub.2O.sub.3, FeCl.sub.3/C,
Cr.sub.2O.sub.3/Al.sub.2O.sub.3, Cr.sub.2O.sub.3/AlF.sub.3,
Cr.sub.2O.sub.3/carbon, CoCl.sub.2/Cr.sub.2O.sub.3/Al.sub.2O.sub.3,
NiCl.sub.2/Cr.sub.2O.sub.3/Al.sub.2O.sub.3, CoCl.sub.2/AlF.sub.3,
NiCl.sub.2/AlF.sub.3 and mixtures thereof. Chromium oxide/aluminum
oxide catalysts are described in U.S. Pat. No. 5,155,082 which is
incorporated herein by reference. Chromium (III) oxides such as
crystalline chromium oxide or amorphous chromium oxide are
preferred with amorphous chromium oxide being most preferred.
Chromium oxide (Cr.sub.2O.sub.3) is a commercially available
material which may be purchased in a variety of particle sizes.
Fluorination catalysts having a purity of at least 98% are
preferred. The fluorination catalyst is present in an excess but in
at least an amount sufficient to drive the reaction.
[0024] The compound of formulas I, II, and/or III is also provided
to the vaporizer with at least one co-feed organic compound and,
optionally but preferably, hydrogen fluoride. The compound
preferably, though not exclusively, has a boiling point that is
lower than the compound of Formula I, or II, or III and should be
chemically compatible with both the compound of these formulas and
hydrogen fluoride. Generally speaking, such compounds may include
any halocarbon or haloolefin that exhibits the desired improvement
in the reaction and/or improvement in the catalyst life.
Non-limiting examples of such halocarbons and haloolefins include
one or any combination of trichlorofluoropropene (1231),
2,3-dichloro-3,3-difluoropropene (1232xf),
1,2-dichloro-3,3,3-trifluoropropene (1223xd),
2-chloro-3,3,3-trifluoropropene (1233xf),
2-chloro-1,1,1,2-tetrachloropropane (244bb),
1,1,1,2,2-pentafluoropropane (HFC-245cb), difluoromethane (HFC-32),
pentafluoroethane (HFC-125), 1,1,1,2-tetrafluoroethane (HFC-134a),
trifluoroethane (HFC-143) (including all isomers thereof),
1,1,1,3,3-pentafluoropropane (HFC-245fa). In certain embodiments,
the halocarbons and haloolefins include one or more organic
compounds that are typically generated during the fluorination
reaction of 1230xa with HF, such as, but not limited to, 1231,
1232xf, 1223xd, 1233xf, 244bb, HFC-245cb, and combinations
thereof
[0025] The amount of co-feed compounds or an "effective amount," as
used herein, relates to any amount of co-feed provided to the
vaporizer that may be used to improve the conversion of a compound
of formula I, II, and/or III (particularly 1230xa, 1230xf, and/or
240db) to 1233xf in the downstream reaction. In one aspect, the
effective amount of co-feed organic compound may be any amount that
measurably reduces the occurrence of oligomerization/polymerization
of the compound of the forgoing formulas during steam vaporization
or during the fluorination reaction. Similarly, an effective amount
may also, or independently, include any amount of the organic
co-feed that results in a measurable reduction of catalyst
deactivation, particularly deactivation caused by starting reagent
oligomerization/polymerization. In one non-limiting embodiment, the
percentage of co-feed organic(s) in total organic feed can be
ranged from 0.1 to 99.9 wt %, from 1 to 50 wt %, from 3 to 30 wt %,
or from 5 to 15 wt %, each based upon the total weight of organic
reagents used. While not intending to be bound by theory, it is
believed that co-feeding at least an organic compound with a
boiling point lower than the compound of formula I, II, or III
(particularly 1230xa, 1230xf, or 240db) can facilitate the
vaporization of the starting compounds since the bubble point of
the mixture is lower than that of the starting compounds and can
help avoid or at least reduce the formation of starting reagent
oligomers and/or polymer.
[0026] A vaporizer, as described herein, relates to a heat
exchanger designed to convert a chemical compound from liquid form
into vapor form. Often the heating medium is steam, and hence steam
vaporizer is preferred. The vaporizer is preferably, though not
exclusively, made from corrosion-resistant materials. Non-limiting
examples of corrosion-resistant materials include Hastelloy,
Nickel, Incoloy, Inconel, Monel and fluoropolymer linings.
[0027] In a certain embodiments, liquid 1230xa, HF, and one or more
of the co-feeds are fed continuously to a steam vaporizer. The
steam pressure can be varied in a wide range from 30 to 250 psig,
preferably from 100-200 psig, and even more preferably from 140-160
psig. The mol ratio of HF to HCO-1230xa is 1:1 to 50:1 and
preferably from about 10:1 to about 20:1. Depending on the pressure
of down-stream reactor, the vaporizer can be operated at a pressure
of 200 psig or lower, preferably 100 psig or lower, and even more
preferably 70 psig or lower. The process temperature at the outlet
of the vaporizer is inherently determined by its dimension and
efficiency as well as steam and process conditions.
[0028] In further embodiments, liquid 1230xf, HF, and one or more
of the co-feeds are fed continuously to a steam vaporizer. The
steam pressure can be varied in a wide range from 30 to 250 psig,
preferably from 100-200 psig, and even more preferably from 140-160
psig. The mol ratio of HF to HCO-1230xf is 1:1 to 50:1 and
preferably from about 10:1 to about 20:1. Depending on the pressure
of down-stream reactor, the vaporizer can be operated at a pressure
of 200 psig or lower, preferably 100 psig or lower, and even more
preferably 70 psig or lower. The process temperature at the outlet
of the vaporizer is inherently determined by its dimension and
efficiency as well as steam and process conditions.
[0029] In even further embodiments, liquid 240db, HF, and one or
more of the co-feeds are fed continuously to a steam vaporizer. The
steam pressure can be varied in a wide range from 30 to 250 psig,
preferably from 100-200 psig, and even more preferably from 140-160
psig. The mol ratio of HF to 240db is 1:1 to 50:1 and preferably
from about 10:1 to about 20:1. Depending on the pressure of
down-stream reactor, the vaporizer can be operated at a pressure of
200 psig or lower, preferably 100 psig or lower, and even more
preferably 70 psig or lower. The process temperature at the outlet
of the vaporizer is inherently determined by its dimension and
efficiency as well as steam and process conditions.
[0030] In any of the foregoing embodiments, the vaporized mixture
is then fed into a fluorination reactor charged with a fluorinated
chromia catalyst to convert the starting material(s) into 1233xf.
The fluorination reaction may be carried out at a temperature from
about 150.degree. C. to about 400.degree. C. (preferably from about
180.degree. C. to about 300.degree. C.) and at a pressure from
about 0 psig to about 200 psig, preferably from about 0 psig to
about 100 psig, and even more preferably from 0 psig to 70 psig.
Contact time of organic feeds with the catalyst may range from
about 1 second to about 60 seconds, however, longer or shorter
times can be used.
[0031] The fluorination reaction is preferably carried out to
attain a conversion of about 50% or, preferably, about 90% or
higher. Conversion is calculated by the number of moles of reactant
consumed divided by number of moles of reactant fed to the reactor
multiplied by 100. The selectivity for 1233xf attained is
preferably about 60% or higher and more preferably about 80% or
higher. Selectivity is calculated by number of moles of product
(1233xf) formed divided by number of moles of reactant
consumed.
[0032] This first step of the reaction may be conducted in any
reactor suitable for a vapor phase fluorination reaction. In
certain embodiments, the reactor is constructed from materials
which are resistant to the corrosive effects of hydrogen fluoride
and catalyst such as Hastalloy, Nickel, Incoloy, Inconel, Monel and
fluoropolymer linings. The vessel is a fixed catalyst bed or
fluidized bed. If desired, inert gases such as nitrogen or argon
may be employed in the reactor during operation.
[0033] In general, the effluent from the fluorination reaction
step, including any intermediate effluents that may be present in
multi-stage reactor arrangements, may be processed to achieve
desired degrees of separation and/or other processing. For example,
in embodiments in which the reactor effluent includes 1233xf, the
effluent will generally also include HCl and one or more of HF,
2,3-dichloro-3,3-difluoropropene (1232xf),
1,2-dichloro-3,3,3-trifluoropropene (1223xd),
trichlorofluoropropene (1231) isomers,
2-chloro-1,1,1,2-tetrachloropropane (244bb), and unreacted 1230xa,
1230xf, and/or 240db. Sonic portion or substantially all of these
components of the reaction product may be recovered from the
reaction mixture via any separation or purification method known in
the art such as neutralization and distillation. It is expected
that unreacted starting materials and HF could be recycled,
completely or partially, to improve the overall yield of the
desired 1233xf. 1232xf and any 1231 formed may also be
recycled.
[0034] Optionally, hydrogen chloride is then recovered from the
result of the fluorination reaction. Recovering of hydrogen
chloride is conducted by conventional distillation where it is
removed from the distillate. Alternatively, HCl can be recovered or
removed by using water or caustic scrubbers. When a water extractor
is used, HCl is removed as an aqueous solution. When caustic
scrubbers are used, HCl is just removed from system as a chloride
salt in aqueous solution.
[0035] In the second step of the process for forming
2,3,3,3-tetrafluoroprop-1-ene, 1233xf is converted to
2-chloro-1,1,1,2-tetrafluoropropane (244bb). In one embodiment,
this step may be performed in the liquid phase in a liquid phase
reactor, which may be TFE or PFA-lined. Such a process may be
performed in a temperature range of about 70-120.degree. C. and
about 50-120 psig.
[0036] Any liquid phase fluorination catalyst may be used in the
invention. A non-exhaustive list include Lewis acids, transition
metal halides, transition metal oxides, Group IVb metal halides, a
Group Vb metal halides, or combinations thereof. Non-exclusive
examples of liquid phase fluorination catalysts are an antimony
halide, a tin halide, a tantalum halide, a titanium halide, a
niobium halide, and molybdenum halide, an iron halide, a
fluorinated chrome halide, a fluorinated chrome oxide or
combinations thereof. Specific non-exclusive examples of liquid
phase fluorination catalysts are SbCl.sub.5, SbCl.sub.3, SbF.sub.5,
SnCl.sub.4, TaCl.sub.5, TiCl.sub.4, NbCl.sub.5, MoCl.sub.6,
FeCl.sub.3, a fluorinated species of SbCl.sub.5, a fluorinated
species of SbCl.sub.3, a fluorinated species of SnCl.sub.4, a
fluorinated species of TaCl.sub.5, a fluorinated species of
TiCl.sub.4, a fluorinated species of NbCl.sub.5, a fluorinated
species of MoCl.sub.6, a fluorinated species of FeCl.sub.3, or
combinations thereof. Antimony pentachloride is most preferred.
[0037] These catalysts can be readily regenerated by any means
known in the art if they become deactivated. One suitable method of
regenerating the catalyst involves flowing a stream of chlorine
through the catalyst. For example, from about 0.002 to about 0.2 lb
per hour of chlorine can be added to the liquid phase reaction for
every pound of liquid phase fluorination catalyst. This may be
done, for example, for from about 1 to about 2 hours or
continuously at a temperature of from about 65.degree. C. to about
100.degree. C.
[0038] This second step of the reaction is not necessarily limited
to a liquid phase reaction and may also be performed using a vapor
phase reaction or a combination of liquid and vapor phases, such as
that disclosed in U.S. Published Patent Application No.
20070197842, the contents of which are incorporated herein by
reference. To this end, the 1233xf containing feed. stream is
preheated to a temperature of from about 50.degree. C. to about
400.degree. C., and is contacted with a catalyst and fluorinating
agent. Catalysts may include standard vapor phase agents used for
such a reaction and fluorinating agents may include those generally
known in the art, such as, but not limited to, hydrogen
fluoride.
[0039] In the third step of 1234yf production, the 244bb is fed to
a second vapor phase reactor (dehydrochlorination reactor) to be
dehydrochlorinated to make the desired product
2,3,3,3-tetrafluoroprop-1-ene (1234yf). This reactor contains a
catalyst that can catalytically dehydrochlorinate HCFC-244bb to
make HFO-1234yf.
[0040] The catalysts may be metal halides, halogenated metal
oxides, neutral (or zero oxidation state) metal or metal alloy, or
activated carbon in bulk or supported form. Metal halide or metal
oxide catalysts may include, but are not limited to, mono-, bi-,
and tri-valent metal halides, oxides and their
mixtures/combinations, and more preferably mono-, and bi-valent
metal halides and their mixtures/combinations. Component metals
include, but are not limited to, Cr.sup.3+, Fe.sup.3+, Mg.sup.2+,
Ca.sup.2+, Ni.sup.2+, Zn.sup.2+, Pd.sup.2+, Li.sup.+, Na.sup.+,
K.sup.+, and Cs.sup.+. Component halogens include, but are not
limited to, F.sup.-, Cl.sup.-, Br.sup.-, and I.sup.-. Examples of
useful mono- or bi-valent metal halide include, but are not limited
to, LiF, NaF, KF, CsF, MgF.sub.2, CaF.sub.2, LiCl, NaCl, KCl, and
CsCl. Halogenation treatments can include any of those known in the
prior art, particularly those that employ HF, F.sub.2, HCl,
Cl.sub.2, HBr, Br.sub.2, HI, and I.sub.2 as the halogenation
source.
[0041] When neutral, i.e., zero valent, metals, metal alloys and
their mixtures are used. Useful metals include, but are not limited
to, Pd, Pt, Rh, Fe, Co, Ni, Cu, Mo, Cr, Mn, and combinations of the
foregoing as alloys or mixtures. The catalyst may be supported or
unsupported. Useful examples of metal alloys include, but are not
limited to, SS 316, Monel 400, Inconel 825, Inconel 600, and
Inconel 625.
[0042] Preferred, but non-limiting, catalysts include activated
carbon, stainless steel (e.g. SS 316), austenitic nickel-based
alloys (e.g. Inconel 625), nickel, fluorinated 10% CsCl/MgO, and
10% CsCl/MgF.sub.2. The reaction temperature is preferably about
300-550.degree. C. and the reaction pressure may be between about
0-150 psig. The reactor effluent may be fed to a caustic scrubber
or to a distillation column to remove the by-product of HCl to
produce an acid-free organic product which, optionally, may undergo
further purification using one or any combination of purification
techniques that are known in the art.
[0043] In one embodiment, the organic co-feed compounds are
provided as fresh feeds in effective amounts, i.e. they are not
obtained from recycle streams derived from the multistep
process.
[0044] In another embodiment, the organic co-feeds compounds are
present in one or more recycle streams derived from the multistep
process as described in U.S. Pat. No. 8,084,653 and US Published
Patent Application 2009/0240090. In a practice of this embodiment,
the invention is directed to a multistep process for preparing
2,3,3,3-tetrafluoropropene (1234yf) comprising a.) providing, in a
liquid phase, 1,1,2,3-tetrachloropropene (1230xa), a fluorinating
agent, and at least one organic co-feed compound, to a vaporizer;
b.) vaporizing said 1,1,2,3-tetrachloropropene (1230xa), said
fluorinating agent, and said at least one organic co-feed compound,
to form a vaporized mixture; c.) contacting, in a first vapor phase
reactor, said vaporized mixture with at least one compound of
formula (I)
CX.sub.2.dbd.CCl--CH.sub.2X (I)
wherein X is independently selected from F, Cl, Br, and I, provided
that at least one X is not fluorine, optionally in the presence of
a vapor phase catalyst, to produce a first intermediate composition
comprising 2-chloro-3,3,3trifluoropropene (1233xf) and HCl; b.)
separating said HCl and said 2-chloro-3,3,3trifluoropropene
(1233xf) from said first intermediate composition; c.) contacting,
in a liquid phase reactor, said separated
2-chloro-3,3,3trifluoropropene (1233xf) with a second fluorinating
agent to produce a second intermediate composition comprising
2-chloro-1,1,1,2-tetrafluoropropane (244bb); and e).
dehydrochlorinating, in a second vapor phase reactor, at least a
portion of said 2-chloro-1,1,1,2-tetrafluoropropane (244bb) to
produce a reaction product comprising 2,3,3,3-tetrafluoropropene.
In another practice of this embodiment, said first intermediate
composition further comprises at least one organic co-feed
compound. In another practice, the process further comprised, in
step b.), separating said at least one organic co-feed compound
from said first intermediate composition, and recycling an
effective amount of said separated at least one organic co-feed
compound to said vaporizer in step a.). In one embodiment of this
practice, said recycle is substantially free of 244bb and/or 245cb,
or contains these materials in amounts that are not effective
amounts. In another practice, the organic co-feed compounds are
provided to the vaporizer as a combination of fresh feeds and
recycle. In another practice, the process comprises, step a.), said
at least one organic co-feed be present in an effective amount and
thereby reducing the formation of oligomers and/or polymers in said
vaporizer. In another practice, said fluorinating agent is HF, and
said optional vapor phase catalyst is a chromium oxide, a chromium
hydroxide, a chromium halide, a chromium oxyhalide, an aluminum
oxide, an aluminum hydroxide, an aluminum halide, an aluminum
oxyhalide, a cobalt oxide, a cobalt hydroxide, a cobalt halide, a
cobalt oxyhalide, a manganese oxide, a manganese hydroxide, a
manganese halide, a manganese oxyhalide, a nickel oxide, a nickel
hydroxide, a nickel halide, a nickel oxyhalide, an iron oxide, an
iron hydroxide, an iron halide, an iron oxyhalide, inorganic salts
thereof, fluorinated derivatives thereof and combinations
thereof.
[0045] The following are examples of the invention and are not to
be construed as limiting.
EXAMPLES
Example 1
[0046] This example illustrates the effect of co-feeding 1232xf or
1233xf together with 1230xa and HF on the vaporization of 1230xa
and the formation of non-volatile residue.
[0047] A system consisting of N.sub.2, HF, and organic feed
systems, steam vaporizer, 3/4'' OD U-shaped super-heater (immersed
in sandbath), and acid scrubber was used for the vaporization
study. High pressure (150 psig) steam at full rate was used to heat
up the vaporizer. The process pressure was controlled by
controlling the pressure in U-shaped super-heater, which was kept
at 180.degree. C. HF and organic (1230xa, 10% 1232xf/90% 1230xa, or
10% 1233xf/90% 1230xa) were introduced to the steam vaporizer and
then the U-shaped super-heater at feed rates of 2.0 lb/h and 1.0
lb/h, respectively. After eight hours, the mixed feed and the steam
were stopped, and the vaporizer was cooled down in nitrogen flow.
At room temperature, the content accumulated in the steam vaporizer
was drained and weighed. After that water and methylene chloride
were added into the drained sample and phase separation was
performed. A fraction of the separated organic phase was subject to
non-volatile residual (NVR) determination. As shown in Table 1, the
co-feeding of 1232xf or 1233xf significantly reduced the build-up
in steam vaporizer except for 20 psig pressure point and the total
amount of NVR in all pressures.
TABLE-US-00001 TABLE 1 % of drained org. in total fed org. Total
residue System 20 psig 70 psig 100 psig 20 psig 70 psig 100 psig
1230xa/HF 2.8 11.6 10.5 6964 5223 8771 10% 1232xf- 3.7 3.4 3.4 3502
1790 1546 90% 1230xa/HF 10% 1233xf- 3.6 2.6 3.0 1524 1106 1386 90%
1230xa/HF
Example 2
[0048] The 1230xa used in this example contained 5 ppm di-isopropyl
amine. A mixture of 10 wt % 1233xf-90 wt % 1230xa was made as
feedstock. 6.5 L of pre-fluorinated chromium oxide catalyst was
loaded into a 4 inch Monel 400 reactor. The reactor was heated up
to about 180.degree. C. in nitrogen flow. Anhydrous HF feed was
then started at a flow rate of 1.9 lb/h. After passing though a Mol
Sieve 3A column at a flow rate of 1.1 lb/h, organic feed was
combined with HF feed. The mixed. HF and organic feed was
introduced to a vaporizer for vaporization and then to the reactor
for reaction. The reaction temperature (hot spot temperature) was
increased to about 200.degree. C. once the reaction was initiated.
The reactor pressure was set at 70 psig. Samples were periodically
taken from the product stream and were analyzed by GC and GC-MS
during reaction. The results showed that 1230xa conversion was
almost 100% and the average selectivities to 1233xf, 1232xf, 244bb
were about 97.9%, 0.3%, and 1.5%, respectively, during the period
of time of the reaction study that lasted for about 300 hours.
* * * * *