Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: PROCESS FOR CONVERSION OF ACYCLIC C5 COMPOUNDS TO
CYCLIC Cs COMPOUNDS AND CATALYST COMPOSITION FOR USE THEREIN
INVENTOR(s): Larry L. Iaccino, Jeremy W. Bedard, Karl G. Strohmaier, Machteld
M. W.
.. Mertens, Robert T. Carr, and Jane Chi-ya Cheng
FIELD OF THE INVENTION
100011
This invention relates to a process for the conversion of acyclic C5 feedstock
to a
product comprising cyclic C5 compounds, such as for example, cyclopentadiene,
and catalyst
compositions for use in such process.
BACKGROUND OF THE INVENTION
[0002]
Cyclopentadiene (CPD) and its dimer dicyclopentadiene (DCPD) are highly
desired raw materials used throughout the chemical industry in a wide range of
products such
as polymeric materials, polyester resins, synthetic rubbers, solvents, fuels,
fuel additives, etc.
In addition, cyclopentane and cyclopentene are useful as solvents, and
cyclopentene may be
used as a monomer to produce polymers and as a starting material for other
high value
chemicals.
[0003]
Cyclopentadiene (CPD) is currently a minor byproduct of liquid fed steam
cracking (for example, naphtha and heavier feed). As existing and new steam
cracking
.. facilities shift to lighter feeds, less CPD is produced while demand for
CPD is rising. High
cost due to supply limitations impacts the potential end product use of CPD in
polymers. More
CPD-based polymer products and other high value products could be produced, if
additional
CPD could be produced, at unconstrained rates and preferably at a cost lower
than recovery
from steam cracking. Cyclopentane and cyclopentene also have high value as
solvents while
.. cyclopentene may be used as a co-monomer to produce polymers and as a
starting material
for other high value chemicals.
[0004] It
would be advantageous to be able to produce cyclic C5 compounds including
CPD as the primary product from plentiful C5 feedstock using a catalyst system
to produce
CPD while minimizing production of light (C4.) byproducts. While lower
hydrogen content
feedstock (for example, cyclics, alkenes, dialkenes) could be preferred
because the reaction
endotherm is reduced and thermodynamic constraints on conversion are improved,
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non-saturates are more expensive than saturate feedstock. Linear C5 skeletal
structure is
preferred over branched C5 skeletal structures due to both reaction chemistry
and the lower
value of linear C5 relative to branched C5 (due to octane differences). An
abundance of C5 is
available from unconventional gas and shale oil as well as reduced use in
motor fuels due to
stringent fuel regulations. C5 feedstock may also be derived from bio-feeds.
[0005] Dehydrogenation technologies are currently used to produce mono-
olefins and
di-olefins from C3 and C4 alkanes, but not cyclic mono-olefins or cyclic di-
olefins. A typical
process uses Pt/Sn supported on alumina as the active catalyst. Another useful
process uses
chromia on alumina. See, B. V. Vora, "Development of Dehydrogenation Catalysts
and
Processes," Topics in Catalysis, vol. 55, pp. 1297-1308, 2012; and J. C.
Bricker, "Advanced
Catalytic Dehydrogenation Technologies for Production of Olefins", Topics in
Catalysis, vol.
55, pp. 1309-1314, 2012.
[0006] Still another common process uses Pt/Sn supported on Zn and/or Ca
aluminate to
dehydrogenate propane. While these processes are successful in dehydrogenating
alkanes,
they do not perform cyclization which is critical to producing CPD. Pt-
Sn/alumina and
Pt-Sn/aluminate catalysts exhibit moderate conversion of n-pentane, but such
catalyst have
poor selectivity and yield to cyclic C5 products.
[0007] Pt supported on chlorided alumina catalysts are used to reform low
octane naphtha
to aromatics such as benzene and toluene. See, US 3,953,368 (Sinfelt),
"Polymetallic Cluster
Compositions Useful as Hydrocarbon Conversion Catalysts." While these
catalysts are
effective in dehydrogenating and cyclizing C6 and higher alkanes to form C6
aromatic rings,
they are less effective in converting acyclic C5s to cyclic C5s. These Pt on
chlorided alumina
catalysts exhibit low yields of cyclic C5 and exhibit deactivation within the
first two hours of
time on stream. Cyclization of C6 and C7 alkanes is aided by the formation of
an aromatic
ring, which does not occur in C5 cyclization. This effect may be due in part
to the much higher
heat of formation for CPD, a cyclic C5, as compared to benzene, a cyclic C6,
and toluene, a
cyclic C7. This is also exhibited by Pt/Ir and Pt/Sn supported on chlorided
alumina. Although
these alumina catalysts perform both dehydrogenation and cyclization of C6+
species to form
C6 aromatic rings, a different catalyst will be needed to convert acyclic C5
to cyclic C5.
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[0008] Ga-containing ZSM-5 catalysts are used in a process to produce
aromatics from
light paraffins. A study by Kanazirev et al., showed n-pentane is readily
converted over
Ga203/H-ZSM-5. See Kanazirev et al., "Conversion of C8 aromatics and n-pentane
over
Ga203/H-ZSM-5 mechanically mixed catalysts," Catalysis Letters, vol. 9, pp. 35-
42, 1991.
No production of cyclic C5 was reported while upwards of 6 wt% aromatics were
produced at
440 C and 1.8 lu-1 WHSV. Mo/ZSM-5 catalysts have also been shown to
dehydrogenate
and/or cyclize paraffins, especially methane. See, Y. Xu, S. Liu, X. Guo, L.
Wang, and M.
Xie, "Methane activation without using oxidants over Mo/HZSM-5 zeolite
catalysts,"
Catalysis Letters, vol. 30, pp. 135-149, 1994. High conversion of n-pentane
using Mo/ZSM-5
was demonstrated with no production of cyclic C5 and high yield to cracking
products. This
shows that ZSM-5-based catalysts can convert paraffins to a C6 ring, but not
necessarily to
produce a C5 ring.
[0009] US 5,254,787 (Dessau) introduced the NU-87 catalyst used in the
dehydrogenation
of paraffins. This catalyst was shown to dehydrogenate C2-5 and C6+ to produce
their
unsaturated analogs. A distinction between C2-5 and C6+ alkanes was made
explicit in this
patent: dehydrogenation of C2-5 alkanes produced linear or branched mono-
olefins or
di-olefins whereas dehydrogenation of C6+ alkanes yielded aromatics. US
5,192,728 (Dessau)
involves similar chemistry, but with a tin-containing crystalline microporous
material. As
with the NU-87 catalyst, C5 dehydrogenation was only shown to produce linear
or branched,
mono-olefins or di-olefins and not CPD.
[0010] US 5,284,986 (Dessau) introduced a dual-stage process for the
production of
cyclopentane and cyclopentene from n-pentane. An example was conducted wherein
the first
stage involved dehydrogenation and dehydrocyclization of n-pentane to a mix of
paraffins,
mono-olefins and di-olefins, and naphthenes over a Pt/Sn-ZSM-5 catalyst. This
mixture was
then introduced to a second-stage reactor consisting of Pd/Sn-ZSM-5 catalyst
where dienes,
especially CPD, were converted to olefins and saturates. Cyclopentene was were
the desired
product in this process, whereas CPD was an unwanted byproduct.
[0011] US 2,438,398; US 2,438,399; US 2,438,400; US 2,438,401; US
2,438,402;
US 2,438,403, and US 2,438,404 (Kennedy) disclosed production of CPD from
1,3-pentadiene over various catalysts. Low operating pressures, low per pass
conversion, and
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low selectivity make this process undesirable. Additionally, 1,3-pentadiene is
not a readily
available feedstock, unlike n-pentane. See
also, Kennedy et al., "Formation of
Cyclopentadiene from 1,3-Pentadiene," Industrial & Engineering Chemistry, vol.
42, pp.
547-552, 1950.
[0012] Fel' dblyum et al. in "Cyclization and dehydrocyclization of C5
hydrocarbons over
platinum nanocatalysts and in the presence of hydrogen sulfide," Doklady
Chemistry, vol.
424, pp. 27-30, 2009, reported production of CPD from 1,3-pentadiene, n-
pentene, and
n-pentane. Yields to CPD were as high as 53%, 35%, and 21% for the conversion
of
1,3-pentadiene, n-pentene, and n-pentane respectively at 600 C on 2%Pt/Si02.
While initial
production of CPD was observed, drastic catalyst deactivation within the first
minutes of the
reaction was observed. Experiments conducted on Pt-containing silica show
moderate
conversion of n-pentane over Pt-Sn/Si02, but with poor selectivity and yield
to cyclic C5
products. The use of H2S as a 1,3-pentadiene cyclization promoter was
presented by
Fel'dblyum, infra, as well as in Marcinkowski, "Isomerization and
Dehydrogenation of
1,3-Pentadiene," M. S., University of Central Florida, 1977. Marcinkowski
showed 80%
conversion of 1,3,-pentadiene with 80% selectivity to CPD with H2S at 700 C.
High
temperature, limited feedstock, and potential of products containing sulfur
that would later
need scrubbing make this process undesirable.
[0013]
Lopez et al. in "n-Pentane Hydroisomerization on Pt Containing HZSM-5, HBEA
and SAPO-11," Catalysis Letters, vol. 122, pp. 267-273, 2008, studied
reactions of n-pentane
on Pt-containing zeolites including H-ZSM-5. At intermediate temperatures (250-
400 C),
they reported efficient hydroisomerization of n-pentane on the Pt-zeolites
with no discussion
of cyclopentenes formation. It is desirable to avoid this deleterious
chemistry as branched C5
do not produce cyclic C5 as efficiently as linear C5, as discussed above.
[0014] Li et al. in "Catalytic dehydroisomerization of n-alkanes to
isoalkenes," Journal of
Catalysis, vol. 255, pp. 134-137, 2008, also studied n-pentane dehydrogenation
on
Pt-containing zeolites in which Al had been isomorphically substituted with
Fe. These
Pti[Fe]ZSM-5 catalysts were efficient dehydrogenating and isomerizing n-
pentane, but under
the reaction conditions used, no cyclic C5 were produced and undesirable
skeletal
isomerization occurred.
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[0015] In view of this state of the art, there remains a need for a
process to convert acyclic
C5 feedstock to non-aromatic, cyclic C5 hydrocarbon, namely CPD, preferably at
commercial
rates and conditions. Further, there is a need for a catalytic process
targeted for the production
of cyclopentadiene which generates cyclopentadiene in high yield from
plentiful C5
feedstocks without excessive production of C4- cracked products and with
acceptable catalyst
aging properties. This invention meets this and other needs.
SUMMARY OF THE INVENTION
[0016] In a first aspect, the invention relates to a process for
conversion of an acyclic C5
feedstock to a product comprising cyclic C5 compounds, particularly CPD. This
process,
comprises the steps of contacting said feedstock and, optionally, hydrogen
under acyclic C5
conversion conditions in the presence of a catalyst composition of this
invention to form said
product.
[0017] In a second aspect, the invention relates to a catalyst
composition for use in the
acyclic CS conversion process. This catalyst composition comprising a
microporous
crystalline aluminosilicate having a constraint index of less than or equal to
5, and a Group 10
metal, and optionally a Group 11 metal in combination with a Group 1 alkali
metal and/or a
Group 2 alkaline earth metal. The microporous crystalline aluminosilicate
which has a
constraint index in the range of less than or equal to 5 preferably is
selected from the group
consisting of zeolite beta, mordenite, faujasite, zeolite L, and mixtures of
two or more thereof
The Group 10 metal is preferably, platinum, and more preferably in the amount
of at least
0.005 wt%, based on the weight of the catalyst composition. The Group 11 metal
is preferably
copper or silver. The Group 1 alkali metal is preferably potassium.
[0018] The crystalline aluminosilicate has a SiO2/A1203 molar ratio of at
least 2,
preferably in the range of from about 2 up to about 20.
[0019] The catalyst composition has a BET surface area of at least 275
m2/g, or in the
range of about greater than about 275 m2/g to less than about 400 m2/g.
[0020] The Group 11 metal content of said catalyst composition is at
least 0.01 molar ratio
to the Group 10 metal, based on the molar quantities of each in the catalyst
composition.
[0021] The molar ratio of the sum of said Group 1 alkali metal and Group
2 alkaline earth
metal to Al is at least 0.5.
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[0022] The
catalyst composition provides (i) a conversion of at least 20% of said acyclic
C5 feedstock and/or (ii) a carbon selectivity to cyclic C5 compounds of at
least about 20%
under acyclic C5 conversion conditions including an n-pentane feedstock with
equimolar H2,
a temperature of about 450 C, an n-pentane partial pressure of about 5 psia
(35 kPa-a), and an
n-pentane weight hourly space velocity of about 2 hr-1.
[0023] In
a third aspect, the invention relates to a method of making the catalyst
composition. The method of making the catalyst composition comprising the
steps of:
(a)
providing a crystalline aluminosilicate comprising a Group 1 alkali metal
and/or a
Group 2 alkaline earth metal and having a constraint index of less than or
equal to 5;
(b) optionally, treating said crystalline aluminosilicate with an acid at a
PH of greater than
or equal to 7 to increase the surface area of said crystalline aluminosilicate
and to form an
acid-treated aluminosilicate; and
(c)
contacting said acid-treated aluminosilicate of step (b) with a source of a
Group 10
metal, and/or optionally said Group 11 metal, to form said catalyst
composition, whereby said
catalyst composition having said Group 10 metal, and/or optionally said Group
11 metal,
deposited thereon.
[0024] In
a fourth aspect, the invention relates to a catalyst composition made by any
one
of the methods of this invention.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0025] For
the purpose of this specification and appended claims, the following terms are
defined.
[0026] The term "saturates" includes, but is not limited to, alkanes and
cycloalkanes.
[0027] The
term "non-saturates" includes, but is not limited to, alkenes, dialkenes,
alkynes, cyclo-alkenes, and cyclo-dialkenes.
[0028] The
term "cyclic C5" or "cC5" includes, but is not limited to, cyclopentane,
cyclopentene, cyclopentadiene, and mixtures of two or more thereof. The term
"cyclic C5" or
"cC5" also includes alkylated analogs of any of the foregoing, e.g., methyl
cyclopentane,
methyl cyclopentene, and methyl cyclopentadiene. It should be recognized for
purposes of
the invention that cyclopentadiene spontaneously dimerizes over time to form
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dicyclopentadiene via Diels-Alder condensation over a range of conditions,
including
ambient temperature and pressure.
[0029] The term "acyclic" includes, but is not limited to, linear and
branched saturates
and non-saturates.
[0030] The term "aromatic" means a planar cyclic hydrocarbyl with
conjugated double
bonds, such as, for example, benzene. As used herein, the term aromatic
encompasses
compounds containing one or more aromatic rings, including, but not limited
to, benzene,
toluene and xylene and polynuclear aromatics (PNAs) which include naphthalene,
anthracene,
chrysene, and their alkylated versions. The term "C6+ aromatics" includes
compounds based
upon an aromatic ring having six or more ring atoms, including, but not
limited to, benzene,
toluene and xylene and polynuclear aromatics (PNAs) which include naphthalene,
anthracene,
chrysene, and their alkylated versions.
[0031] The term "BTX" includes, but is not limited to, a mixture of
benzene, toluene and
xylene (ortho and/or meta and/or para).
[0032] The term "coke" includes, but is not limited to, a low hydrogen
content
hydrocarbon that is adsorbed on the catalyst composition.
[0033] The term "C,," means hydrocarbon(s) having n carbon atom(s) per
molecule,
wherein n is a positive integer.
[0034] The term "Cn+" means hydrocarbon(s) having at least n carbon
atom(s) per
.. molecule.
[0035] The term "Cr," means hydrocarbon(s) having no more than n carbon
atom(s) per
molecule.
[0036] The term "hydrocarbon" means a class of compounds containing
hydrogen bound
to carbon, and encompasses (i) saturated hydrocarbon compounds, (ii)
unsaturated
hydrocarbon compounds, and (iii) mixtures of hydrocarbon compounds (saturated
and/or
unsaturated), including mixtures of hydrocarbon compounds having different
values of n.
[0037] The term "C5 feedstock" includes a feedstock containing n-pentane,
such as, for
example, a feedstock which is predominately normal pentane and isopentane
(also referred to
as methylbutane), with smaller fractions of cyclopentane and neopentane (also
referred to as
2,2-dimethylpropane).
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[0038] All numbers and references to the Periodic Table of Elements are
based on the new
notation as set out in Chemical and Engineering News, 63(5), 27, (1985),
unless otherwise
specified.
[0039] The term "Group 10 metal" means an element in Group 10 of the
Periodic Table
.. and includes, but is not limited to, nickel, palladium, and platinum.
[0040] The term "Group 11 metal" means an element in Group 11 of the
Periodic Table
and includes, but is not limited to, copper, silver, gold, and a mixture of
two or more thereof.
[0041] The term "Group 1 alkali metal" means an element in Group 1 of
the Periodic
Table and includes, but is not limited to, lithium, sodium, potassium,
rubidium, cesium, and a
mixture of two or more thereof, and excludes hydrogen.
[0042] The term "Group 2 alkaline earth metal" means an element in Group
2 of the
Periodic Table and includes, but is not limited to, beryllium, magnesium,
calcium, strontium,
barium, and a mixture of two or more thereof.
[0043] The term "constraint index" is defined in US 3,972,832 and US
4,016,218.
[0044] As used herein, the teiiii "molecular sieve" is used synonymously
with the term
"microporous crystalline material" and zeolite.
[0045] As used herein, the term "carbon selectivity" means the moles of
carbon in the
respective cyclic C5, CPD, C1, and C2-4 formed divided by total moles of
carbon in the pentane
converted. The phrase "a carbon selectivity to cyclic C5 of at least 20%"
means that at least
20 moles of carbon in the cyclic C5 is formed per 100 moles of carbon in the
pentane
converted.
100461 As used herein, the term "conversion" means the moles of carbon
in the acyclic C5
feedstock that is converted to a product. The phrase "a conversion of at least
20% of said
acyclic C5 feedstock to said product" means that at least 20% of the moles of
said acyclic C5
feedstock was converted to a product.
[0047] As used herein, the term "reactor system" refers to a system
including one or more
reactors and all optional equipment used in the production of cyclopentadiene.
[0048] As used herein, the term "reactor" refers to any vessel(s) in
which a chemical
reaction occurs. Reactor includes both distinct reactors as well as reaction
zones within a
single reactor apparatus and as applicable, reactions zones across multiple
reactors. For
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example, a single reactor may have multiple reaction zones. Where the
description refers to
a first and second reactor, the person of ordinary skill in the art will
readily recognize such
reference includes two reactors, as well as a single reactor vessel having
first and second
reaction zones. Likewise, a first reactor effluent and a second reactor
effluent will be
recognized to include the effluent from the first reaction zone and the second
reaction zone of
a single reactor, respectively.
[0049] A reactor/reaction zone may be an adiabatic reactor/reaction zone
or a diabatic
reactor/reaction zone. As used herein the term "adiabatic" refers to a
reaction zone for which
there is essentially no heat input into the system other than by a flowing
process fluid. A
reaction zone that has unavoidable losses due to conduction and/or radiation
may also be
considered adiabatic for the purpose of this invention As used herein the term
"diabatic" refers
to a reactor/reaction zone to which heat is supplied by a means in addition to
that provided by
the flowing process fluid.
[0050] As used herein, the term "moving bed" reactor refers to a zone or
vessel with
contacting of solids (e.g., catalyst particles) and gas flows such that the
superficial gas velocity
(U) is below the velocity required for dilute-phase pneumatic conveying of
solid particles in
order to maintain a solids bed with void fraction below 95%. In a moving bed
reactor, the
solids (e.g., catalyst material) may slowly travel through the reactor and may
be removed from
the bottom of the reactor and added to the top of the reactor. A moving bed
reactor may
operate under several flow regimes including settling or moving packed-bed
regime (U<Umf),
bubbling regime (Umr(U<Umb), slugging regime (Umb<U<Uc), transition to and
turbulent
fluidization regime (Uc<U<Utr), and fast-fluidization regime (U>Utr), where
Umf is minimum
fluidizing velocity, Umb is minimum bubbling velocity, Uc is the velocity at
which fluctuation
in pressure peaks, and tr is transport velocity. These different fluidization
regimes have been
described in, for example, Kunii, D., Levenspiel, 0., Chapter 3 of
Fluidization Engineering,
2nd Edition, Butterworth-Heinemann, Boston, 1991 and Walas, S. M., Chapter 6
of Chemical
Process Equipment, Revised 2nd Edition, Butterworth-Heinemann, Boston, 2010.
[0051] As used herein, the term "settling bed" reactor refers to a zone
or vessel wherein
particulates contact with gas flows such that the superficial gas velocity (U)
is below the
minimum velocity required to fluidize the solid particles (e.g., catalyst
particles), the
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minimum fluidization velocity (Umr), U<Umr, in at least a portion of the
reaction zone, and/or
operating at a velocity higher than the minimum fluidization velocity while
maintaining a
gradient in gas and/or solid property (such as, temperature, gas or solid
composition, etc.)
axially up the reactor bed by using reactor internals to minimize gas-solid
back-mixing.
Description of the minimum fluidization velocity is given in, for example,
Kunii, D.,
Levenspiel, 0., Chapter 3 of Fluidization Engineering, 2" Edition, Butterworth-
Heinemann,
Boston, 1991 and Walas, S. M., Chapter 6 of Chemical Process Equipment,
Revised 2"
Edition, Butterworth-Heinemann, Boston, 2010. A settling bed reactor may be a
"circulating
settling bed reactor," which refers to a settling bed with a movement of
solids (e.g., catalyst
.. material) through the reactor and at least a partial recirculation of the
solids (e.g., catalyst
material). For example, the solids (e.g., catalyst material) may have been
removed from the
reactor, regenerated, reheated, and/or separated from the product stream and
then returned
back to the reactor.
[0052] As used herein, the term "fluidized bed" reactor refers to a zone
or vessel with
contacting of solids (e.g., catalyst particles) and gas flows such that the
superficial gas velocity
(U) is sufficient to fluidize solid particles (i.e., above the minimum
fluidization velocity Unit)
and is below the velocity required for dilute-phase pneumatic conveying of
solid particles in
order to maintain a solids bed with void fraction below 95%. As used herein,
the term
"cascaded fluid-beds" means a series arrangement of individual fluid-beds such
that there can
be a gradient in gas and/or solid property (such as, temperature, gas or solid
composition,
pressure, etc.) as the solid or gas cascades from one fluid-bed to another.
Locus of minimum
fluidization velocity is given in, for example, Kunii, D., Levenspiel, 0.,
Chapter 3 of
Fluidization Engineering 2nd Edition, Butterworth-Heinemann, Boston, 1991 and
Walas, S.
M., Chapter 6 of Chemical Process Equipment, Revised 2" Edition, Butterworth-
Heinemann,
Boston, 2010. A fluidized bed reactor may be a moving fluidized bed reactor,
such as a
"circulating fluidized bed reactor," which refers to a fluidized bed with a
movement of solids
(e.g., catalyst material) through the reactor and at least a partial
recirculation of the solids
(e.g., catalyst material). For example, the solids (e.g., catalyst material)
may have been
removed from the reactor, regenerated, reheated and/or separated from the
product stream and
then returned back to the reactor.
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[0053] As used herein, the term "riser" reactor (also known as a
transport reactor) refers
to a zone or vessel (such as, vertical cylindrical pipe) used for net upwards
transport of solids
(e.g., catalyst particles) in fast-fluidization or pneumatic conveying
fluidization regimes. Fast
fluidization and pneumatic conveying fluidization regimes are characterized by
superficial gas
velocities (U) greater than the transport velocity WO. Fast fluidization and
pneumatic
conveying fluidization regimes are also described in Kunii, D., Levenspiel,
0., Chapter 3 of
Fluidization Engineering, 2" Edition, Butterworth-Heinemann, Boston, 1991 and
Walas, S.
M., Chapter 6 of Chemical Process Equipment, Revised 2" Edition, Butterworth-
Heinemann,
Boston, 2010. A fluidized bed reactor, such as a circulating fluidized bed
reactor, may be
operated as a riser reactor.
[0054] As used herein, the term "fired tubes" reactor refers to a furnace
and parallel
reactor tube(s) positioned within a radiant section of the furnace. The
reactor tubes contain a
catalytic material (e.g., catalyst particles), which contacts reactant(s) to
form a product.
[0055] As used herein, the term "convectively heated tubes" reactor
refers to a conversion
system comprising parallel reactor tube(s) containing a catalytic material and
positioned
within an enclosure. While any known reactor tube configuration or enclosure
may be used,
preferably the conversion system comprises multiple parallel reactor tubes
within a convective
heat transfer enclosure. Preferably, the reactor tubes are straight rather
than having a coiled
or curved path through the enclosure (although coiled or curved tubes may be
used).
Additionally, the tubes may have a cross section that is circular, elliptical,
rectangular, and/or
other known shapes. The tubes are preferentially heated with a turbine exhaust
stream
produced by a turbine burning fuel gas with a compressed gas comprising
oxygen. In other
aspects, the reactor tubes are heated by convection with hot gas produced by
combustion in a
furnace, boiler, or excess air burner. However, heating the reactor tubes with
turbine exhaust
is preferred because of the co-production of shaft power among other
advantages.
[0056] As used herein, the term "fixed bed" or "packed bed" reactor
refers to a zone or
vessel (such as, vertical or horizontal, cylindrical pipe or a spherical
vessel) and may include
transverse (also known as cross flow), axial flow and/or radial flow of the
gas, where solids
(e.g., catalyst particles) are substantially immobilized within the reactor
and gas flows such
that the superficial velocity (U) is below the velocity required to fluidize
the solid particles
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(i.e., below the minimum fluidization velocity Umf) and/or the gas is moving
in a downward
direction so that solid particle fluidization is not possible.
[0057] As used herein, the term "cyclical" refers to a periodic recurring
or repeating event
that occurs according to a cycle. For example, reactors (e.g., cyclic fixed
bed) may be
cyclically operated to have a reaction interval, a reheat interval and/or a
regeneration interval.
The duration and/or order of the interval steps may change over time.
[0058] As used herein, the term "co-current" refers to a flow of two
streams (e.g., stream
(a), stream (b)) in substantially the same direction. For example, if stream
(a) flows from a
top portion to a bottom portion of at least one reaction zone and stream (b)
flows from a top
portion to a bottom portion of at least one reaction zone, the flow of stream
(a) would be
considered co-current to the flow of stream (b). On a smaller scale within the
reaction zone,
there may be regions where flow may not be co-current.
[0059] As used herein, the term "counter-current" refers to a flow of two
streams (e.g.,
stream (a), stream (b)) in substantially opposing directions. For example, if
stream (a) flows
from a top portion to a bottom portion of the at least one reaction zone and
stream (b) flows
from a bottom portion to a top portion of the at least one reaction zone, the
flow of stream (a)
would be considered counter-current to the flow of stream (b). On a smaller
scale within the
reaction zone, there may be regions where flow may not be counter-current.
Fecdstock
100601 A cyclic CS feedstock useful herein is obtainable from crude oil or
natural gas
condensate, and can include cracked CS (in various degrees of unsaturation:
alkenes,
dialkenes, alkynes) produced by refining and chemical processes, such as fluid
catalytic
cracking (FCC), reforming, hydrocracking, hydrotreating, coking, and steam
cracking.
[0061] The acyclic C5 feedstock useful in the process of this invention
comprises pentane,
pentene, pentadiene and mixtures of two or more thereof. Preferably, the
acyclic C5 feedstock
comprises at least about 50 wt%, or 60 wt%, or 75 wt%, or 90 wt% n-pentane, or
in the range
from about 50 wt% to about 100 wt% n-pentane.
[0062] The acyclic CS feedstock, optionally, does not comprise benzene,
toluene, or
xylene (ortho, meta, or para), preferably the benzene, toluene, or xylene
(ortho, meta, or para)
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CA 03004308 2018-05-03
compounds are present at less than 5 wt%, preferably less than 1 wt%,
preferably present at
less than 0.01 wt%, preferably at 0 wt%.
[0063] The acyclic C5 feedstock, optionally, does not comprise C6+
aromatic compounds,
preferably C6+ aromatic compounds are present at less than 5 wt%, preferably
less than 1 wt%,
.. preferably present at less than 0.01 wt%, preferably at 0 wt%.
[0064] The acyclic C5 feedstock, optionally, does not comprise C4-
compounds, any C4
compounds are present at less than 5 wt%, preferably less than 1 wt%,
preferably present at
less than 0.01 wt%, preferably at 0 wt%.
Acyclic C5 Conversion Process
[0065] The first aspect of the invention is a process for conversion of an
acyclic C5
feedstock to a product comprising cyclic C5 compounds. The process comprising
the steps of
contacting said feedstock and, optionally, hydrogen under acyclic C5
conversion conditions
in the presence of any one of the catalyst compositions of this invention to
form said product.
The catalyst composition comprises a microporous crystalline aluminosilicate
having a
constraint index less than about 5, a Group 10 metal in combination with a
Group 1 alkali
metal and/or a Group 2 alkaline earth metal and, optionally, a Group 11 metal.
[0066] The first aspect of the invention is also a process for conversion
of an acyclic C5
feedstock to a product comprising cyclic Cs compounds, the process comprising
the steps of
contacting said feedstock and, optionally, hydrogen under acyclic CS
conversion conditions
.. in the presence of any one of the catalyst compositions made by any one of
the methods of
this invention to form said product.
[0067] The acyclic Cs conversion process can be conducted in a wide range
of reactor
configurations including: convectively heated tubes (as described in US
9,926,242), fired
tubes (as described in US 9,914,678), a riser reactor (as described in US
2017/0121252), a
circulating fluidized bed or a circulating settling bed with counter-current
flow (as described
in US 9,908,825), and a cyclic fluidized bed reactor or a cyclic fixed bed
reactor (as described
in US 2017/0121251). In addition, the CS conversion process can be conducted
in a single
reaction zone or in a plurality of reaction zones, such as an adiabatic
reaction zone followed
by a diabatic reaction zone (as described in US 9,873,647).
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[0068] Typically, the acyclic C5 hydrocarbon(s) contained in the C5
feedstock is fed into
a first reactor loaded with a catalyst, where the acyclic C5 hydrocarbons
contact the catalyst
under conversion conditions, whereupon at least a portion of the acyclic Cs
hydrocarbon(s)
molecules are converted into CPD molecules, and a reaction product containing
CPD and,
optionally, other cyclic hydrocarbons (e.g., C5 cyclic hydrocarbons such as
cyclopentane and
cyclopentene) exits the first reactor as a first reactor hydrocarbon effluent.
Preferably, a
hydrogen co-feedstock comprising hydrogen and, optionally, light hydrocarbons,
such as
CI-Ca hydrocarbons, is also fed into the first reactor. Preferably, at least a
portion of the
hydrogen co-feedstock is admixed with the C5 feedstock prior to being fed into
the first
reactor. The presence of hydrogen in the feed mixture at the inlet location,
where the feed
first comes into contact with the catalyst, prevents or reduces the formation
of coke on the
catalyst particles.
[0069] The product of the process for conversion of an acyclic C5
feedstock comprises
cyclic C5 compounds. The cyclic CS compounds comprise one or more of
cyclopentane,
cyclopentene, cyclopentadiene, and includes mixtures thereof The cyclic C5
compounds
comprise at least about 20 wt%, or 30 wt%, or 40 wt%, or 50 wt%
cyclopentadiene, or in the
range of from about 10 wt% to about 80 wt%, alternately 10 wt% to 80 wt% of
cyclopentadiene.
[0070] The acyclic C5 conversion conditions include at least a
temperature, a partial
pressure, and a weight hourly space velocity (WHSV). The temperature is in the
range of
about 450 C to about 650 C, or in the range from about 500 C to about 600 C,
preferably, in
the range from about 545 C to about 595 C. The partial pressure is in the
range of about 3
psia to about 100 psia (21 to 689 kPa-a), or in the range from about 3 psia to
about 50 psia (21
to 345 kPa-a), preferably, in the range from about 3 psia to about 20 psia (21
to 138 kPa-a).
The weight hourly space velocity is in the range from about 1 hr-1 to about 50
hr-1, or in the
range from about 1 hr-Ito about 20 hr4. Such conditions include a molar ratio
of the optional
hydrogen co-feed to the acyclic CS hydrocarbon in the range of about 0 to 3
(e.g., 0.01 to 3.0),
or in the range from about 0.5 to about 2. Such conditions may also include co-
feed CI¨Ca
hydrocarbons with the acyclic C5 feed.
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CA 03004308 2018-05-03
[0071] In any embodiments, this invention relates to a process for
conversion of n-pentane
to cyclopentadiene comprising the steps of contacting n-pentane and,
optionally, hydrogen (if
present, typically H2 is present at a molar ratio of hydrogen to n-pentane of
0.01 to 3.0) with
one or more catalyst compositions, including but not limited to the catalyst
compositions
described herein, to form cyclopentadiene at a temperature of 400 C to 700 C,
a partial
pressure of 3 psia to about 100 psia (21 to 689 kPa-a), and a weight hourly
space velocity of
1 hr l to about 50 hr-I.
[0072] In the presence of the catalyst, a number of desired and
undesirable side reactions
may take place. The net effect of the reactions is the production of hydrogen
and the increase
of total volume (assuming constant total pressure). One particularly desired
overall reaction
(i.e., intermediate reaction step that is not shown) is:
n-pentane CPD + 3H2.
[0073] Additional overall reactions include, but are not limited to:
n-pentane --> 1,3-pentadiene + 2112,
n-pentane - 1-pentene + Hz,
n-pentane --> 2-pentene + Hz,
n-pentane - 2-methyl-2-butene + H2,
n-pentane - cyclopentane + H2,
cyclopentane 4 cyclopentene + H2, or
cyclopentene - CPD + H2.
[0074] Fluids inside the first reactor are essentially in gas phase. At
the outlet of the first
reactor, a first reactor hydrocarbon effluent, preferably in gas phase, is
obtained. The first
reactor hydrocarbon effluent may comprise a mixture of the following
hydrocarbons, among
others: heavy components comprising more than 8 carbon atoms such as multiple-
ring
aromatics; C8, C7, and C6 hydrocarbons such as one-ring aromatics; CPD (the
desired
product); unreacted C5 feedstock material such as n-pentane; C5 by-products
such as pentenes
(1-pentene, 2-pentene, e.g.), pentadienes (1,3-pentadiene, 1,4-pentadiene,
e.g.), cyclopentane,
cyclopentene, 2 -methylbutane, 2-methyl-1-butene, 3-methyl-1 -butene , 2-
methy1-1,3-
butadiene, 2,2-dimethylpropane, and the like; C4 by-products such as butane, 1-
butene,
2-butene, 1,3-butadiene, 2-methylpropane, 2-methyl-1-propene, and the like; C3
by-products
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such as propane, propene, and the like; C2 by-products such as ethane and
ethene, methane,
and hydrogen.
[0075] The first reactor hydrocarbon effluent may comprise CPD at a
concentration of
C(CPD)1 wt%, based on the total weight of the C5 hydrocarbons in the first
reactor
.. hydrocarbon effluent; and al < C(CPD)1 < a2, where al and a2 can be,
independently, 15, 16,
18, 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 36, 38, 40, 45, 50, 55, 60, 65,
70, 75, 80, or 85 as
long as al< a2.
[0076] The first reactor hydrocarbon effluent may comprise acyclic
diolefins at a total
concentration of C(ADO)1 wt%, based on the total weight of the C5 hydrocarbons
in the first
reactor hydrocarbon effluent; and b 1 < C(ADO)1 < b2, where b 1 and b2 can be,
independently, 20, 18, 16, 15, 14, 12, 10, 8, 6, 5, 4, 3, 2, 1, or 0.5, as
long as b 1 < b2.
Preferably, 0.5 < C(ADO) < 10.
[0077] As a result of the use of the catalyst and the choice of reaction
conditions in the
first reactor, a high CPD to acyclic diolefin molar ratio in the first reactor
hydrocarbon effluent
can be achieved such that C(CPD)1/C(ADO)1 > 1.5, preferably 1.6, 1.8, 2.0,
2.2, 2.4, 2.5, 2.6,
2.8, 3.0, 3.2, 3.4, 3.5, 3.6, 3.8, 4.0, 5.0, 6.0, 8.0, 10, 12, 14, 15, 16, 18,
or 20. The high ratio
of C(CPD)1/C(ADO)1 significantly reduces CPD loss as a result of Diels-Alder
reactions
between CPD and acyclic dienes in subsequent processing steps, and therefore,
allows the
processes of the present invention to achieve high DCPD yield and high DCPD
purity for the
subsequently produced DCPD fractions.
[0078] Desirably, the total absolute pressure and temperature of the
first reactor
hydrocarbon effluent should be maintained at levels such that the dimerization
of CPD to form
DCPD is substantially avoided, and the Diels-Alder reactions between CPD and
acyclic dienes
are substantially inhibited.
[0079] Because the overall conversion from acyclic C5 hydrocarbons to CPD
and
hydrogen results in substantial volume increase (assuming constant total
system pressure), a
low partial pressure of CPD and/or a low partial pressure of hydrogen in the
reaction mixture
favors the conversion of acyclic C5 hydrocarbons. The total partial pressure
of C5
hydrocarbons and hydrogen in the first reactor effluent at the outlet is
desired to be lower than
.. atmospheric pressure. Thus, where insufficient co-feedstock of a CI-C4
hydrocarbon or other
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co-feedstock is introduced into the first reactor, the total overall pressure
of the first reactor
effluent is desirably sub-atmospheric, in order to achieve a level of
satisfactory conversion
from acyclic C5 hydrocarbons to CPD. However, direct separation of a sub-
atmospheric
stream has the disadvantage of potential oxygen/air ingress into the system,
resulting in
oxidation of CPD and other hydrocarbons and formation of undesirable species
in the system.
Thus, it is desirable that the first reactor hydrocarbon effluent is processed
to a higher total
pressure before separation thereof Eductor systems, can be used for that
purpose (as
described in US 9,893,396).
Catalyst Composition
[0080] The second aspect of the invention is a catalyst composition for the
conversion of
an acyclic C5 feedstock and, optionally, hydrogen to a product comprising
cyclic C5
compounds including cyclopentadiene. The catalyst composition comprises a
microporous
crystalline aluminosilicate having a constraint index of less than about 5,
and a Group 10 metal
in combination with a Group 1 alkali metal and/or a Group 2 alkaline earth
metal and,
optionally, a Group 11 metal.
[0081] Suitable aluminosilicates having a constraint index of less than
or equal to 5
include, or and are selected from the group consisting of zeolite beta,
mordenite, faujasite,
zeolite L, and mixtures of two or more thereof Preferably, the crystalline
aluminosilicate that
has a constraint index of less than or equal to 5 is zeolite L. Constraint
index and a method
for its determination are described in US 4,016,218, referenced above.
[0082] Zeolite L may be synthesized in various crystal morphologies; the
"hockey puck"
morphology is preferred where the channel direction is parallel to the shorter
axis of the
crystal. See, US 5,491,119. Zeolite L is described in US 3,216,789. Zeolite
beta is described
in US 3,308,069, and US Reissue 28,341. Mordenite is a naturally occurring
material, but is
also available in synthetic forms, such as TEA-mordenite (i.e., synthetic
mordenite prepared
from a reaction mixture comprising a tetraethylammonium directing agent). TEA-
mordenite
is disclosed in US 3,766,093 and US 3,894,104. Faujacite is a naturally
occurring material
but is also available in synthetic forms, such as zeolite Y, Ultrastable Y
(USY), Dealuminized
Y (Deal Y), Ultrahydrophobic Y (UHP-Y) and Rare earth exchanged Y (REY). Low
sodium
Ultrastable Y molecular sieve (USY) is described in US 3,293,192 and US
3,449,070.
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CA 03004308 2018-05-03
Dealuminized Y zeolite (Deal Y) may be prepared by the method found in US
3,442,795.
Ultrahydrophobic Y (UHP-Y) is described in US 4,401,556. Rare earth exchanged
Y (REY)
is described in US 3,524,820.
[0083] The microporous crystalline aluminosilicate has a SiO2/A1203
molar ratio greater
of at least about 2, or at least about 3, or preferably in the range of from
about 2 up to about
20.
[0084] The crystalline aluminosilicate has a BET surface area of at
least 275 m2/g, or in
the range of about greater than about 275 m2/g to less than about 400 m2/g.
[0085] The Group 10 metal includes, or is selected from the group
consisting of, nickel,
palladium and platinum, preferably platinum. The Group 10 metal content of
said catalyst
composition is at least 0.005 wt%, based on the weight of the catalyst
composition.
Alternatively, the Group 10 content is in the range from about 0.005 wt% to
about 10 wt%, or
from about 0.005 wt% up to about 1.5 wt%, based on the weight of the catalyst
composition.
[0086] The Group 1 alkali metal includes, or is selected from the group
consisting of,
lithium, sodium, potassium, rubidium, cesium, and mixtures of two or more
thereof,
preferably potassium.
[0087] The Group 2 alkaline earth metal includes, or is selected from
the group consisting
of beryllium, magnesium, calcium, strontium, barium, and mixtures of two or
more thereof.
[0088] The molar ratio of the sum of said Group 1 alkali metal and said
Group 2 alkaline
earth metal to Al is at least about 0.5, or in the range from at least about
0.5 up to about 2,
preferably at least about 1, more preferably at least about 1.5.
[0089] Alternatively, the Group 1 alkali metal and/or said Group 2
alkaline earth metal is
present as an oxide. The Group 1 alkali metal oxide is an oxide of lithium,
sodium, potassium,
rubidium, cesium and mixtures of two or more thereof. The Group 2 alkaline
earth metal
oxide is an oxide of beryllium, magnesium, calcium, strontium, barium, and
mixtures of two
or more thereof.
[0090] The use of the catalyst compositions of this invention provides a
conversion of at
least about 10%, or at least about 20%, or at least about 30%, or in the range
of from about
20% to about 50%, of said acyclic Cs feedstock under acyclic C5 conversion
conditions of an
n-pentane containing feedstock with equimolar Hz, a temperature in the range
of from 400 C
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to about 500 C, or about 450 C, an n-pentane partial pressure of about 5 psia
(35 kPa-a), or
about 7 psia (48 kPa-a), or from about 4 psia to about 6 psia at the reactor
inlet (28 to 41
kPa-a), and an n-pentane weight hourly space velocity of about 2 hr", or
between 1 hr-1 and 5
hr-1.
[0091] The use of any one of the catalyst compositions of this invention
provides a carbon
selectivity to cyclic C5 compounds of at least about 10%, or at least about
20%, or at least
about 30%, or in the range from about 20% to about 50%, under acyclic C5
conversion
conditions including an n-pentane feedstock with equimolar Hz, a temperature
in the range of
about 400 C to about 500 C, or about 450 C, an n-pentane partial pressure
between 3 psia
and 10 psia (21 to 69 kPa-a), and an n-pentane weight hourly space velocity
between 10 hr-'
and 20 hr".
[0092] The use of any one of the catalyst compositions of this invention
provides a carbon
selectivity to cyclopentadiene of at least about 20%, or at least about 30%,
or at least about
40%, or at least about 50%, or in the range from about 30% to about 50%, under
acyclic C5
conversion conditions including an n-pentane feedstock with equimolar Hz, a
temperature in
the range of about 550 C to about 600 C, an n-pentane partial pressure of
about 7 psia (48
kPa-a), or about 5 psia (35 kPa-a), or from about 4 psia to about 6 psia (28
to 41 kPa-a), and
an n-pentane weight hourly space velocity of about 2 hr-1, or between 1 hr-1
and 5 hr".
[0093] The catalyst compositions of this invention can be combined with
a matrix or
binder material to render them attrition resistant and more resistant to the
severity of the
conditions to which they will be exposed during use in hydrocarbon conversion
applications.
The combined compositions can contain 1 wt% to 99 wt% of the materials of the
invention
based on the combined weight of the matrix (binder) and material of the
invention. The
relative proportions of zeolite crystalline material and matrix may vary
widely, with the crystal
content ranging from about 1 wt% to about 90 wt% and more usually,
particularly when the
composite is prepared in the form of beads, in the range of about 2 wt% to
about 80 wt% of
the composite.
[0094] During the use of the catalyst compositions in the processes of
this invention, coke
may be deposited on the catalyst compositions, whereby such catalyst
compositions lose a
portion of its catalytic activity and become deactivated. The deactivated
catalyst compositions
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CA 03004308 2018-05-03
may be regenerated by conventional techniques including high pressure hydrogen
treatment
and combustion of coke on the catalyst compositions with an oxygen-containing
gas.
Method of Making the Catalyst Compositions
[0095] In the third aspect of the invention, the method of making the
catalyst composition
comprising the steps of:
(a) providing a crystalline aluminosilicate comprising a Group 1 alkali
metal and/or a Group
2 alkaline earth metal and having a constraint index of less than or equal to
5;
(b) optionally, treating said crystalline aluminosilicate with an acid at a
PH of greater than
or equal to 7 to increase the surface area of said crystalline aluminosilicate
and to form an
acid-treated aluminosilicate; and
(c) contacting said acid-treated aluminosilicate of step (b) with a source
of a Group 10 metal
to form said catalyst composition, whereby said catalyst composition having
said Group 10
metal, and/or, optionally, said Group 11 metal, deposited thereon.
[0096] The Group 10 metal may be added to the catalyst composition
during or after
synthesis of the crystalline molecular sieve as any suitable Group 10 metal
compound.
[0097] One Group 10 metal is platinum, and a source of platinum
includes, but is not
limited to, one or more platinum salts, such as, for example, platinum
nitrate, chloroplatinic
acid, platinous chloride, platinum amine compounds, particularly, tetraamine
platinum
hydroxide, and mixtures of two or more thereof. Alternatively, a source of
platinum is
selected from the group consisting of chloroplatinic acid, platinous chloride,
platinum amine
compounds, particularly, tetraamine platinum hydroxide, and mixtures of two or
more thereof.
[0098] The source of Group 11 metal is a source of copper or silver. The
source of copper
is selected from the group consisting of copper nitrate, copper nitrite,
copper acetate, copper
hydroxide, copper acetylacetonate, copper carbonate, copper lactate, copper
sulfate, copper
phosphate, copper chloride, and mixtures of two or more thereof. The source of
silver is
selected from the group consisting of silver nitrate, silver nitrite, silver
acetate, silver
hydroxide, silver acetylacetonate, silver carbonate, silver lactate, silver
sulfate, silver
phosphate, and mixtures of two or more thereof. When Group 10 and/or Group 11
metals are
added post-synthesis, they may be added by incipient wetness, spray
application, solution
exchange, and chemical vapor disposition or by other means known in the art.
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[0099] The amount deposited of said Group 10 metal and/or said Group 11
metal is at
least 0.005 wt%, based on the weight of the catalyst composition, or in the
range from 0.005
wt% to 10 wt%, based on the weight of the catalyst composition.
[00100] In the fourth aspect of the invention, the catalyst composition is
made by the
method of this invention.
Industrial Applicability
[00101] The first hydrocarbon reactor effluent obtained during the the acyclic
C5
conversion process containing cyclic, branched and linear C5 hydrocarbons and,
optionally,
containing any combination of hydrogen, C4 and lighter byproducts, or C6 and
heavier
byproducts is a valuable product in and of itself Preferably, CPD and/or DCPD
may be
separated from the reactor effluent to obtain purified product streams, which
are useful in the
production of a variety of high value products.
[00102] For example, a purified product stream containing 50 wt% or greater,
or preferably
60 wt% or greater of DCPD is useful for producing hydrocarbon resins,
unsaturated polyester
resins, and epoxy materials. A purified product stream containing 80 wt% or
greater, or
preferably 90 wt% or greater of CPD is useful for producing Diels-Alder
reaction products
formed in accordance with the following reaction Scheme (I):
Scheme I
440 4+2 cycloaddition
R Diels-
Alder reaction product.
where R is a heteroatom or substituted heteroatom, substituted or
unsubstituted Ci-Cso
hydrocarbyl radical (often a hydrocarbyl radical containing double bonds), an
aromatic
radical, or any combination thereof. Preferably, substituted radicals or
groups contain one or
more elements from Groups 13-17, preferably from Groups 15 or 16, more
preferably
nitrogen, oxygen, or sulfur. In addition to the monoolefin Diels-Alder
reaction product
depicted in Scheme (I), a purified product stream containing 80 wt% or
greater, or preferably
90 wt% or greater of CPD can be used to form Diels-Alder reaction products of
CPD with one
or more of the following: another CPD molecule, conjugated dienes, acetylenes,
allenes,
disubstituted olefins, trisubstituted olefins, cyclic olefins, and substituted
versions of the
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foregoing. Preferred Diels-Alder reaction products include norbornene,
ethylidene
norbornene, substituted norbomenes (including oxygen containing norbomenes),
norbomadienes, and tetracyclododeccne, as illustrated in the following
structures:
0
norbornene ethyl idene norbornene tetracyclododecene
norbomadiene oxygen substituted
norbornene.
[00103] The foregoing Diels-Alder reaction products are useful for producing
polymers
and copolymers of cyclic olefins copolymerized with olefins such as ethylene.
The resulting
cyclic olefin copolymer and cyclic olefin polymer products are useful in a
variety of
applications, e.g., packaging film.
[001041 A purified product stream containing 99 wt% or greater of DCPD is
useful for
producing DCPD polymers using, for example, ring opening metathesis
polymerization
(ROMP) catalysts. The DCPD polymer products are useful in forming articles,
particularly
molded parts, e.g. wind turbine blades and automobile parts.
[00105] Additional components may also be separated from the reactor effluent
and used
in the formation of high value products. For example, separated cyclopentene
is useful for
producing polycyclopentene, also known as polypentenamer, as depicted in
Scheme (II).
Scheme II
ROMP
catalyst
[00106] Separated cyclopentane is useful as a blowing agent and as a solvent.
Linear and
branched C5 products are useful for conversion to higher olefins and alcohols.
Cyclic and
non-cyclic C5 products, optionally, after hydrogenation, are useful as octane
enhancers and
transportation fuel blend components.
Examples
[00107] The following examples illustrate the present invention. Numerous
modifications
and variations are possible and it is to be understood that within the scope
of the appended
claims, the invention may be practiced otherwise than as specifically
described herein.
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Measurement of Total Surface Area by BET
[00109] The total BET was measured by nitrogen adsorption/desorption with a
Micromeritics Tristar II 3020 instrument after degassing of the calcined
zeolite powders for
4 hrs at 350 C. More information regarding the method can be found, for
example, in
"Characterization of Porous Solids and Powders: Surface Area, Pore Size and
Density", S.
Lowell et al., Springer, 2004.
X-ray diffraction patterns
1001101 The X-ray diffraction data (powder XRD or XRD) were collected with a
Bruker
D4 Endeavor diffraction system with a VANTEC multichannel detector using
copper K-alpha
radiation. The diffraction data were recorded by scanning mode with 0.018
degrees two-theta,
where theta is the Bragg angle, and using an effective counting time of about
30 seconds for
each step.
Example 1 ¨ Zeolite L Catalyst Composition Synthesis
[00111] A zeolite synthesis gel of composition, 3 K20: A1203: 9 Si02: 135
H20, was
prepared by first making a potassium aluminate solution. To 1750 ml of
distilled water was
added 1450.3 g of K0H.1/2H20 (86.8% KOH) and 1166.7 g of A1203.3H20 (ALCOA C-
31).
The mixture was heated to a mild boil with stirring until alumina dissolved.
The mixture was
then allowed to cool down to room temperature. Final weight of mixture was
3991 g. An
alum solution was prepared by dissolving 1820.1 g of Al2(SO4)3.17H20 in 2672
ml of distilled
water. Twelve zeolite slurries were then prepared by slowly adding 1762 g of
Kasil-6
potassium silicate (PQ Corp. 12.5% K2O, 26.3% SiO2), 332 g of potassium
aluminate solution,
374 g of alum solution and 532 ml of distilled 1120 to a 1 gallon Hobart mixer
with stirring.
The mixtures were then thoroughly homogenized in a laboratory blender and
transferred to
two 6 gallon HDPE plastic containers. The plastic containers were sealed and
placed in a
100 C oven for three days. The product was recovered by vacuum filtration,
washed
thoroughly with distilled water and then dried in an oven at 125 C. Analysis
by powder X-ray
diffraction showed the product to be pure zeolite L. Yield = 6.0 Kg, Si/Al=
2.65, KJA1 = 1.04,
crystal size (SEM) = 0.2 ¨ 0.1 p.m, BET surface area = 291 m2/g.
[00112] A portion of the acid washed zeolite L was pressed, crushed and
sieved to 20/40
mesh. Then 98.3 g of dried sieved zeolite was added to a 28 cm column. A
solution of 1.539
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g of Pt(NH3)4C12.1420 and 0.783 g of KCl in 190 ml of deionized water was
prepared and
added to the column. The solution was circulated from the bottom to the top
with a peristalic
pump for 75 minutes. Initial pH = 6.78, temperature = 24.0 C. Final pH = 8.31,
temperature
= 27.0 C. The solution and zeolite was then aged for 3 days at 50 C. The
sample was
separated from the excess liquid and air dried 50 C for 1 hr, 70 C for 1 hr,
90 C for 1 hr, and
at 20 C/hr ramp. The sample was then calcined by placing in 100 C furnace and
then ramping
to 200 C for 2 hr, 350 C in 3 hr with 500 cc/min air flow rate. Pt content was
measured and
determined to be 0.5 wt% of total catalyst weight.
Example 2 - Catalyst Composition Performance Evaluation
[00113] The above material of Example 1 was evaluated for performance. The
catalyst
composition (0.25 g, 20-40 mesh) was physically mixed with quartz (6.5 g, 60-
80 mesh) and
loaded into a reactor. The catalyst composition was dried for 1 hour under H2
(200 mL/min,
50 psia (345 kPa-a), 250 C) then reduced for 5 hours under H2 (200 mL/min, 50
psia (345
kPa-a), 500 C). The catalyst composition was then tested for performance with
feed of
n-pentane, H2, and balance Ar, typically at 451 C, 7.0 psia (48 kPa-a) C5F112,
1.0 molar
H2:C5H12, 1.9 hr-1 and 19.9 hrl WHSV, and 50 psia (345 kPa-a) total. Catalyst
composition
stability and regenerability was tested post initial tests by treating with H2
at 650 C (200
mL/min, 50 psia (345 kPa-a) for 5 Ins then retesting performance at 451 C.
[00114] Cyclopentadiene, and three equivalents of hydrogen, are produced
by the
conversion of n-pentane (Equation 1). This is achieved by flowing n-pentane
over a
solid-state, Pt containing catalyst composition at elevated temperature. The
performance of
ZSM-5(Si/A1 = 2.65Si)/0.5%Pt of Example 1 was evaluated based on n-pentane
conversion,
cyclic C5 production (cC5), cracking yields, and stability.
C5 H12 --) C5 H6 + 3H2 Equation (1)
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Table 1A
WHS TO Temperature Conversion Selectivity (mol %)
Yield (mol %)
V S ( C) (0/0)
(hr-1) (hr)
C511112 cC5 CPD CI C2-4 cC5 CPD CI C2-4
19.9 0.9 451 12.7 21.6 1.0 8.1 11.0 2.8 0.1
1.0 1.4
1.9 1.9 451 30.2
18.0 0.7 25.3 28.2 5.4 0.2 7.6 8.5
19.9 4.9 451 10.2 15.1 1.1 8.9 11.0 1.5 0.1
0.9 1.1
19.9 6.1 451, Post H2 10.4 24.5 1.1 2.7 4.8 2.6
0.1 0.3 0.5
1.9 7.1 451, Post H2 19.8 30.6 0.7 10.4 15.4
6.0 0.1 2.1 3.0
19.9 9.2 451, Post H2 8.2 16.3 1.2 2.7 4.4 1.3
0.1 0.2 0.4
Table 1B
Conversion
(%) Selectivity (C %)
Yield (C %)
WHSV TOS Temperature CP cC CP
(hr'') (hr) ( C) C51112
cC5 D CI C2-4 5 D CI C2-4
19.9 0.9 451 12.7 29.0 1.3 2.2 9.1
3.7 0,2 0.3 1.2
1,9 1.9 451 30.2 30.9 1.3 8.7
29.3 9.3 0.4 2.6 8.8
19.9 4.9 451 10.2 19.0 1.3 2.2 8.4 1.9 0.1 0.2
0.9,
19.9 6.1 451, Post H2 10.4 31.2 1.4 0.7 3.7 3.3
0.1 0.1 0.4
1.9 7.1 451, Post H2 19.8 48.2 1.1 3.3 14.8 9.5 0.2
0.6 2.9
19.9 9.2 451, Post H2 8.2 18.7 1.4 0.6 3.1 1.5
0.1 0.1 0.3
1001151 Table IA and Table 1B show the conversion of n-pentane and
selectivity and yield
of cyclic CS, CPD, C1, and C24 cracking products at varying space velocities
(average values
at each space velocity).
[00116] In Table 1A, the selectivities and yields are expressed on a molar
percentage basis
for the respective cyclic C5, CPD, C1, and C2-4 of hydrocarbons formed; i.e.,
the molar
selectivity is the moles of the respective cyclic C5, CPD, CI, and C2-4 formed
divided by total
moles of pentane converted. In Table 1B, the selectivities and yields are
expressed on a carbon
percentage basis for the respective cyclic C5, CPD, CI, and C2-4 of
hydrocarbons formed; i.e.,
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the carbon selectivity is the moles carbon in the respective cyclic C5, CPD,
CI, and C2-4 formed
divided by total moles of carbon in the pentane converted. The data sets in
Table 1A
correspond to those in Table 1B.
[00117] As can be seen, Table lA and Table 1B show that near equilibrium
yield of cyclic
C5 and CPD is possible at 1.9 WHSV. Some decline in cyclic yield is seen while
on oil (data
sets 1 vs. 3 and 4 vs. 6), but it is demonstrated that the 650 C H2 exposure
can restore at least
a portion of the cyclization activity (hypothesized to be due to removal of
coke); the 650 C
H2 exposure has the additional beneficial effect of reducing the selectivity
to cracked products
so that the thermodynamic constrained yield of cyclic products is increased.
This performance
is greatly superior to other dehydrogenation catalysts, such as aluminas and
aluminates.
[00118] Certain embodiments and features have been described using a set
of numerical
upper limits and a set of numerical lower limits. It should be appreciated
that ranges from any
lower limit to any upper limit are contemplated unless otherwise indicated.
Certain lower
limits, upper limits, and ranges appear in one or more claims below. All
numerical values
take into account experimental error and variations that would be expected by
a person having
ordinary skill in the art.
[00119] As is apparent from the foregoing general description and the
specific
embodiments, while forms of the invention have been illustrated and described,
various
modifications can be made without departing from the spirit and scope of the
invention.
Accordingly, it is not intended that the invention be limited thereby.
Likewise, the term
"comprising" is considered synonymous with the term "including." Likewise,
whenever a
composition, an element or a group of elements is preceded with the
transitional phrase
"comprising," it is understood that we also contemplate the same composition
or group of
elements with transitional phrases "consisting essentially of," "consisting
of," "selected from
the group of consisting of," or "is" preceding the recitation of the
composition element, or
elements and vice versa.
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