U.S. patent application number 13/397967 was filed with the patent office on 2014-01-09 for selective catalytical dehydrochlorination of hydrochlorofluorocarbons.
This patent application is currently assigned to E. I. DU PONT DE NEMOURS AND COMPANY. The applicant listed for this patent is Mario Joseph Nappa, Xuehui Sun. Invention is credited to Mario Joseph Nappa, Xuehui Sun.
Application Number | 20140012048 13/397967 |
Document ID | / |
Family ID | 45815964 |
Filed Date | 2014-01-09 |
United States Patent
Application |
20140012048 |
Kind Code |
A9 |
Sun; Xuehui ; et
al. |
January 9, 2014 |
SELECTIVE CATALYTICAL DEHYDROCHLORINATION OF
HYDROCHLOROFLUOROCARBONS
Abstract
A dehydrochlorination process is disclosed. The process involves
contacting R.sub.fCHClCH.sub.2Cl with a carbon catalyst in a
reaction zone to produce a product mixture comprising
R.sub.fCCl.dbd.CH.sub.2, wherein R.sub.f is a perfluorinated alkyl
group.
Inventors: |
Sun; Xuehui; (Swedesboro,
NJ) ; Nappa; Mario Joseph; (Newark, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sun; Xuehui
Nappa; Mario Joseph |
Swedesboro
Newark |
NJ
DE |
US
US |
|
|
Assignee: |
E. I. DU PONT DE NEMOURS AND
COMPANY
Wilmington
DE
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20120215036 A1 |
August 23, 2012 |
|
|
Family ID: |
45815964 |
Appl. No.: |
13/397967 |
Filed: |
February 16, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61444868 |
Feb 21, 2011 |
|
|
|
Current U.S.
Class: |
570/156 |
Current CPC
Class: |
C07C 17/25 20130101;
C07C 17/25 20130101; B01J 37/084 20130101; B01J 21/18 20130101;
C07C 21/18 20130101; B01J 37/06 20130101 |
Class at
Publication: |
570/156 |
International
Class: |
C07C 21/18 20060101
C07C021/18 |
Claims
1. A dehydrochlorination process comprising contacting
R.sub.fCHClCH.sub.2Cl with a carbon catalyst in a reaction zone to
produce a product mixture comprising R.sub.fCCl.dbd.CH.sub.2,
wherein R.sub.f is a perfluorinated alkyl group.
2. The dehydrochlorination process of claim 1 wherein the carbon
catalyst is an activated carbon.
3. The dehydrochlorination process of claim 2 wherein the carbon
catalyst is an acid washed activated carbon.
4. The dehydrochlorination process of claim 2 wherein the carbon
catalyst is a non-acid washed activated carbon.
5. The dehydrochlorination process of claim 1 wherein R.sub.f is
CF.sub.3.
6. The dehydrochlorination process of claim 1 wherein the
temperature in the reaction zone is from about 300.degree. C. to
about 500.degree. C.
7. The dehydrochlorination process of claim 6 wherein the
temperature in the reaction zone is from about 325.degree. C. to
about 450.degree. C.
8. The dehydrochlorination process of claim 1 wherein the product
selectivity to R.sub.fCCl.dbd.CH.sub.2 is at least 90 mole %.
9. The dehydrochlorination process of claim 1 wherein the
dehydrochlorination selectivity to R.sub.fCCl.dbd.CH.sub.2 is at
least 95 mole %.
Description
BACKGROUND
[0001] 1. Field of the Disclosure
[0002] This disclosure relates in general to the selective
catalytic dehydrochlorination of hydrochlorofluorocarbons (HCFCs)
to make hydrochlorofluoroolefins (HCFOs). More specifically, the
catalysts are carbons.
[0003] 2. Description of Related Art
[0004] Hydrochlorofluoroolefins (HCFOs), having low ozone depletion
potential and low global warming potentials, are regarded as
candidates for replacing saturated CFCs (chlorofluorocarbons) and
HCFCs (hydrochlorofluorocarbons). HCFOs can be employed in a wide
range of applications, including their use as refrigerants,
solvents, foam expansion agents, cleaning agents, aerosol
propellants, dielectrics, fire extinguishants and power cycle
working fluids. For example, HCFO-1233xf (CF.sub.3CCl.dbd.CH.sub.2)
can be used as a foam expansion agent, fire extinguishant,
refrigerant, et al. HCFO-1233xf is also an intermediate in the
production of 2,3,3,3-tetrafluoropropene (HFO-1234yf) which is a
refrigerant with zero ozone depletion potential and low global
warming potential.
BRIEF SUMMARY OF THE DISCLOSURE
[0005] The present disclosure provides a dehydrochlorination
process. The process comprises contacting R.sub.fCHClCH.sub.2Cl
with a carbon catalyst in a reaction zone to produce a product
mixture comprising R.sub.fCCl.dbd.CH.sub.2, wherein R.sub.f is a
perfluorinated alkyl group.
DETAILED DESCRIPTION
[0006] The foregoing general description and the following detailed
description are exemplary and explanatory only and are not
restrictive of the invention, as defined in the appended claims.
Other features and benefits of any one or more of the embodiments
will be apparent from the following detailed description, and from
the claims.
[0007] As used herein, the terms "comprises," "comprising,"
"includes," "including," "has," "having" or any other variation
thereof, are intended to cover a non-exclusive inclusion. For
example, a process, method, article, or apparatus that comprises a
list of elements is not necessarily limited to only those elements
but may include other elements not expressly listed or inherent to
such process, method, article, or apparatus. Further, unless
expressly stated to the contrary, "or" refers to an inclusive or
and not to an exclusive or. For example, a condition A or B is
satisfied by any one of the following: A is true (or present) and B
is false (or not present), A is false (or not present) and B is
true (or present), and both A and B are true (or present).
[0008] Also, use of "a" or "an" are employed to describe elements
and components described herein. This is done merely for
convenience and to give a general sense of the scope of the
invention. This description should be read to include one or at
least one and the singular also includes the plural unless it is
obvious that it is meant otherwise.
[0009] Unless otherwise defined, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
methods and materials similar or equivalent to those described
herein can be used in the practice or testing of embodiments of the
present invention, suitable methods and materials are described
below. All publications, patent applications, patents, and other
references mentioned herein are incorporated by reference in their
entirety, unless a particular passage is cited. In case of
conflict, the present specification, including definitions, will
control. In addition, the materials, methods, and examples are
illustrative only and not intended to be limiting.
[0010] When an amount, concentration, or other value or parameter
is given as either a range, preferred range or a list of upper
preferable values and/or lower preferable values, this is to be
understood as specifically disclosing all ranges formed from any
pair of any upper range limit or preferred value and any lower
range limit or preferred value, regardless of whether ranges are
separately disclosed. Where a range of numerical values is recited
herein, unless otherwise stated, the range is intended to include
the endpoints thereof, and all integers and fractions within the
range.
[0011] The term "dehydrochlorination", as used herein, means a
process during which hydrogen and chlorine on adjacent carbons in a
molecule are removed.
[0012] The term "hydrochlorofluoroolefin", as used herein, means a
molecule containing hydrogen, carbon, fluorine, chlorine, and at
least one carbon-carbon double bond. Exemplary
hydrochlorofluoroolefins in this disclosure include
HCFO-1233xf.
[0013] The term "alkyl", as used herein, either alone or in
compound words such as "perfluorinated alkyl group", includes
cyclic or acyclic and straight-chain or branched alkyl groups, such
as, methyl, ethyl, n-propyl, i-propyl, or the different isomers
thereof.
[0014] The term "perfluorinated alkyl group", as used herein, means
an alkyl group wherein all hydrogens on carbon atoms have been
substituted by fluorines. Examples of a perfluorinated alkyl group
include --CF.sub.3 and --CF.sub.2CF.sub.3.
[0015] The term "product selectivity to R.sub.fCCl.dbd.CH.sub.2",
as used herein, means the molar percentage of
R.sub.fCCl.dbd.CH.sub.2 obtained in the process compared to the
total molar amounts of all products obtained.
[0016] The term "dehydrochlorination selectivity to
R.sub.fCCl.dbd.CH.sub.2", as used herein, means the molar
percentage of R.sub.fCCl.dbd.CH.sub.2 based on the total molar
amount of R.sub.fCCl.dbd.CH.sub.2 and R.sub.fCH.dbd.CHCl obtained
in the dehydrochlorination reaction of R.sub.fCHClCH.sub.2Cl.
[0017] The term "an elevated temperature", as used herein, means a
temperature higher than the room temperature.
[0018] Disclosed is a dehydrochlorination process comprising
contacting R.sub.fCHClCH.sub.2Cl with a carbon catalyst in a
reaction zone to produce a product mixture comprising
R.sub.fCCl.dbd.CH.sub.2, wherein R.sub.f is a perfluorinated alkyl
group.
[0019] In some embodiments of this invention, R.sub.f is --CF.sub.3
or --CF.sub.2CF.sub.3. In some embodiments of this invention,
R.sub.fCHClCH.sub.2Cl is CF.sub.3CHClCH.sub.2Cl (HCFC-243 db), and
R.sub.fCCl.dbd.CH.sub.2 is CF.sub.3CCl.dbd.CH.sub.2
(HCFO-1233xf).
[0020] Some hydrochlorofluoroolefins of this disclosure, e.g.,
CF.sub.3CH.dbd.CHCl (HCFO-1233zd), exist as different
configurational isomers or stereoisomers. When the specific isomer
is not designated, the present disclosure is intended to include
all single configurational isomers, single stereoisomers, or any
combination thereof. For instance, HCFO-1233zd is meant to
represent the E-isomer, Z-isomer, or any combination or mixture of
both isomers in any ratio.
[0021] The starting materials for the dehydrochlorination processes
in this disclosure, i.e., R.sub.fCHClCH.sub.2Cl, can be synthesized
by methods known in the art. For example, HCFC-243 db may be
prepared by chlorinating CF.sub.3CH.dbd.CH.sub.2 or by the addition
reaction of CF.sub.2.dbd.CHCl with CFClH.sub.2.
[0022] The dehydrochlorination process can be carried out in liquid
phase or vapor phase using well-known chemical engineering
practice, which includes continuous, semi-continuous or batch
operations. The temperature in the reaction zone is typically from
about 300.degree. C. to about 500.degree. C. In some embodiments of
this invention, the temperature in the reaction zone is from about
325.degree. C. to about 450.degree. C. The dehydrochlorination
process can be conducted at superatmospheric, atmospheric, or
subatmospheric pressures. The contact time of the starting material
R.sub.fCHClCH.sub.2Cl with the catalyst can be largely varied.
Typically, the contact time is from about 10 seconds to about 150
seconds. In some embodiments of this invention, the contact time is
from about 20 seconds to about 80 seconds.
[0023] The contacting step of this invention may be carried out by
methods known in the art. In some embodiments of this invention,
starting material R.sub.fCHClCH.sub.2Cl, optionally with an inert
gas, is fed to a reactor containing the catalyst. In some
embodiments of this invention, starting material
R.sub.fCHClCH.sub.2Cl, optionally with an inert gas, is passed
through the catalyst bed in a reactor. In some embodiments of this
invention, starting material R.sub.fCHClCH.sub.2Cl, optionally with
an inert gas, may be mixed with the catalyst in a reactor with stir
or agitation.
[0024] The dehydrochlorination process may be conducted in the
presence of an inert gas such as He, Ar, or N.sub.2. In some
embodiments of this invention, the inert gas is co-fed into the
reactor with the starting material.
[0025] It was found through experiments that carbons are suitable
for selective dehydrochlorination process of this disclosure.
Carbon used in the embodiments of this invention may come from any
of the following sources: wood, peat, coal, coconut shells, bones,
lignite, petroleum-based residues and sugar. Commercially available
carbons which may be used include those sold under the following
trademarks: Barneby & Sutcliffe.TM., Darco.TM., Nucharm,
Columbia JXN.TM., Columbia LCK.TM., Calgon.TM. PCB, Calgon.TM. BPL,
Westvaco.TM., Norit.TM., Takeda.TM. and Barnaby Cheny NB.TM..
[0026] The carbon also includes three dimensional matrix porous
carbonaceous materials. Examples are those described in U.S. Pat.
No. 4,978,649. In one embodiment of the invention, carbon includes
three dimensional matrix carbonaceous materials which are obtained
by introducing gaseous or vaporous carbon-containing compounds
(e.g., hydrocarbons) into a mass of granules of a carbonaceous
material (e.g., carbon black); decomposing the carbon-containing
compounds to deposit carbon on the surface of the granules; and
treating the resulting material with an activator gas comprising
steam to provide a porous carbonaceous material. A carbon-carbon
composite material is thus formed.
[0027] Embodiments of carbon in this invention include both
non-acid washed and acid-washed carbons. In some embodiments of
this invention, suitable carbon catalysts may be prepared by
treating the carbon with acids such as HNO.sub.3, HCl, HF,
H.sub.2SO.sub.4, HClO.sub.4, CH.sub.3COOH, and combinations
thereof. Acid treatment is typically sufficient to provide carbon
that contains less than 1000 ppm of ash. Some suitable acid
treatments of carbon are described in U.S. Pat. No. 5,136,113. In
some embodiments of this invention, an activated carbon is dried at
an elevated temperature and then is soaked for 8 to 24 hours with
occasional stirring in 1 to 12 weight percent of HNO.sub.3. The
soaking process can be conducted at temperatures ranging from room
temperature to 80.degree. C. The activated carbon is then filtered
and washed with deionized water until the washings have a pH
greater than 4.0 or until the pH of the washings does not change.
Finally, the activated carbon is dried at an elevated
temperature.
[0028] In some embodiments of this invention, carbon is an
activated carbon. In some embodiments of this invention, carbon is
a non-acid washed activated carbon. In some embodiments of this
invention, carbon is an acid washed activated carbon. The carbon
can be in the form of powder, granules, or pellets, et al.
[0029] The effluent from the reaction zone typically includes
residual starting materials R.sub.fCHClCH.sub.2Cl, desired
hydrochlorofluoroolefin product R.sub.fCCl.dbd.CH.sub.2,
dehydrochlorination byproduct R.sub.fCH.dbd.CHCl and some other
byproducts. The desired product R.sub.fCCl.dbd.CH.sub.2 may be
recovered from the product mixture by conventional methods. In some
embodiments of this invention, product R.sub.fCCl.dbd.CH.sub.2 may
be purified or recovered by distillation.
[0030] It was found through experiments that the catalytic
dehydrochlorination processes of this disclosure produced desired
products with high selectivity. In some embodiments of this
invention, the product selectivity to R.sub.fCCl.dbd.CH.sub.2 is at
least 90 mole %.
[0031] It was also found through experiments that the
dehydrochlorination reaction of this disclosure is highly
selective. The dehydrochlorination reaction of
R.sub.fCHClCH.sub.2Cl may generate both isomers
R.sub.fCCl.dbd.CH.sub.2 and R.sub.fCH.dbd.CHCl. It was found that
the dehydrochlorination processes of this disclosure generate
substantially more R.sub.fCCl.dbd.CH.sub.2 than R.sub.fCH.dbd.CHCl.
In some embodiments of this invention, the dehydrochlorination
selectivity to R.sub.fCCl.dbd.CH.sub.2 is at least 95 mole %.
[0032] The reactors, distillation columns, and their associated
feed lines, effluent lines, and associated units used in applying
the processes of embodiments of this invention may be constructed
of materials resistant to corrosion. Typical materials of
construction include Teflon.TM. and glass. Typical materials of
construction also include stainless steels, in particular of the
austenitic type, the well-known high nickel alloys, such as
Monel.TM. nickel-copper alloys, Hastelloy.TM. nickel-based alloys
and, Inconel.TM. nickel-chromium alloys, and copper-clad steel.
[0033] Many aspects and embodiments have been described above and
are merely exemplary and not limiting. After reading this
specification, skilled artisans appreciate that other aspects and
embodiments are possible without departing from the scope of the
invention.
EXAMPLES
[0034] The concepts described herein will be further described in
the following examples, which do not limit the scope of the
invention described in the claims.
Example 1
[0035] Example 1 demonstrates that contacting HCFC-243 db with
carbon generates HCFO-1233xf.
[0036] 5 cc (cubic centimeter) (2.78 gm) of Calgon.TM. non-acid
washed PCB carbon (an activated carbon with surface area ranging
from about 900 m.sup.2/g to about 1200 m.sup.2/g) (12-30 mesh) were
filled into an Inconel.TM. reactor tube (0.43 inch ID) to form a
catalyst bed.
[0037] The reactor tube temperature was then raised to about
400.degree. C. HCFC-243 db was fed into a vaporizer at 1.62 ml/hour
and was vaporized at 94.degree. C. Nitrogen was flowed through the
vaporizer at 3.6 sccm and carried vaporized HCFC-243 db to the
reactor tube. Product samples were taken at one hour intervals and
analyzed by GC-MS and tabulated as mole percentage. The remaining
percentages were unknown byproducts.
TABLE-US-00001 TABLE 1 Prod Prod Prod Sel DHC Conv Sel Sel Mole Sel
Temp 243db N.sub.2 CT Mole % Mole % Mole % % Mole % .degree. C.
ml/hr sccm sec 243db 1233xf 1233zd 253fb 1233xf 401 1.62 3.6 32
100.0% 91.1% 4.9% 0.6% 95 401 1.62 3.6 32 100.0% 91.0% 4.8% 0.6% 95
400 1.62 3.6 32 100.0% 90.5% 4.8% 0.6% 95 Note: Temp = Temperature;
ml = milliliter; hr = hour; CT = Contact Time; Conv = Conversion;
Sel = Selectivity; Prod = Product; DHC = Dehydrochlorination; 243db
= HCFC-243db; 1233xf = HCFO-1233xf; 1233zd = HCFO-1233zd; 253fb =
HCFC-253fb = CH.sub.2ClCH.sub.2CF3.
[0038] Note that not all of the activities described above in the
general description or the examples are required, that a portion of
a specific activity may not be required, and that one or more
further activities may be performed in addition to those described.
Still further, the order in which activities are listed are not
necessarily the order in which they are performed.
[0039] In the foregoing specification, the concepts have been
described with reference to specific embodiments. However, one of
ordinary skill in the art appreciates that various modifications
and changes can be made without departing from the scope of the
invention as set forth in the claims below. Accordingly, the
specification is to be regarded in an illustrative rather than a
restrictive sense, and all such modifications are intended to be
included within the scope of invention.
[0040] Benefits, other advantages, and solutions to problems have
been described above with regard to specific embodiments. However,
the benefits, advantages, solutions to problems, and any feature(s)
that may cause any benefit, advantage, or solution to occur or
become more pronounced are not to be construed as a critical,
required, or essential feature of any or all the claims.
[0041] It is to be appreciated that certain features are, for
clarity, described herein in the context of separate embodiments,
may also be provided in combination in a single embodiment.
Conversely, various features that are, for brevity, described in
the context of a single embodiment, may also be provided separately
or in any subcombination.
* * * * *