U.S. patent application number 10/782554 was filed with the patent office on 2005-08-25 for olefin oligomerization.
Invention is credited to Kreischer, Bruce E., Small, Brooke L..
Application Number | 20050187418 10/782554 |
Document ID | / |
Family ID | 34861047 |
Filed Date | 2005-08-25 |
United States Patent
Application |
20050187418 |
Kind Code |
A1 |
Small, Brooke L. ; et
al. |
August 25, 2005 |
Olefin oligomerization
Abstract
Provided is a method of oligomerizing alpha olefins. In an
embodiment, an oligomerization catalyst system is contacted in at
least one continuous reactor with a feed comprising olefins; an
effluent comprising product olefins having at least four carbon
atoms is withdrawn from the reactor; the oligomerization catalyst
system comprises iron or cobalt, or combinations thereof; and the
single pass conversion of ethylene is at least about 40 weight
percent among product olefins having at least four carbon atoms. In
another embodiment, the single pass conversion of ethylene
comprises at least about 65 weight percent among product olefins
having at least four carbon atoms. In another embodiment, product
olefins of the effluent having twelve carbon atoms comprise at
least about 95 weight percent 1-dodecene. In another embodiment,
product olefins comprise at least about 80 weight percent linear
1-alkenes. In another embodiment, product olefins comprise at least
about 20 weight percent alpha olefins having from about 8 to about
20 carbon atoms. In another embodiment, the oligomerization
catalyst system provided comprises a selective 1-hexene (S1H)
catalyst.
Inventors: |
Small, Brooke L.; (Kingwood,
TX) ; Kreischer, Bruce E.; (Humble, TX) |
Correspondence
Address: |
CHEVRON PHILLIPS CHEMICAL COMPANY
5700 GRANITE PARKWAY, SUITE 330
PLANO
TX
75024-6616
US
|
Family ID: |
34861047 |
Appl. No.: |
10/782554 |
Filed: |
February 19, 2004 |
Current U.S.
Class: |
585/521 |
Current CPC
Class: |
C07C 2531/30 20130101;
C07C 2531/28 20130101; C07C 2/32 20130101; C07C 11/02 20130101;
C07C 2/32 20130101 |
Class at
Publication: |
585/521 |
International
Class: |
C07C 002/02 |
Claims
What is claimed as our invention is:
1. A method comprising: contacting an oligomerization catalyst
system and a feed comprising olefins; oligomerizing said feed in at
least one continuous reactor; and withdrawing from said at least
one continuous reactor an effluent comprising product olefins
having at least four carbon atoms; wherein the oligomerization
catalyst system comprises iron or cobalt, or combinations thereof;
and wherein oligomerization to product olefins having at least four
carbon atoms comprises a single pass conversion of ethylene of at
least about 40 weight percent.
2. The method of claim 1, wherein the single pass conversion of
ethylene is at least about 65 weight percent.
3. The method of claim 1, wherein product olefins having twelve
carbon atoms comprise at least about 95 weight percent
1-dodecene.
4. The method of claim 1, wherein the effluent comprises at least
about 40 weight percent product olefins having at least four carbon
atoms.
5. The method of claim 1, wherein said product olefins comprise at
least about 80 weight percent linear 1-alkenes.
6. The method of claim 1, wherein said product olefins comprise at
least about 20 weight percent alpha olefins having from about 8 to
about 20 carbon atoms.
7. The method of claim 1, wherein said oligomerization catalyst
system comprises a metal alkyl or metal hydride species.
8. The method of claim 7, wherein said metal alkyl or metal hydride
species comprises one or more Lewis acids; a combination of one or
more Lewis acids and one or more alkylating agents; one or more
alkyl aluminum compounds; one or more alkyl aluminoxanes; methyl
aluminoxane (MAO); modified MAO; tri-alkyl aluminum;
diethylaluminum chloride (DEAC); or combinations thereof.
9. The method of claim 1, wherein said oligomerization catalyst
system comprises triethylaluminum (TEA), trimethylaluminum (TMA),
tri-isobutyl aluminum (TIBA), tri-butyl aluminum, or combinations
thereof.
10. The method of claim 1, wherein the oligomerization catalyst
system comprises a metal complex activated by a co-catalyst and
wherein said metal complex comprises a ligand having chemical
structure I: 11wherein R.sup.1, R.sup.2, and R.sup.3 are each
independently hydrogen, hydrocarbyl, substituted hydrocarbyl, an
inert functional group, or any two of R.sup.1-R.sup.3, vicinal to
one another, taken together may form a ring; R.sup.4 and R.sup.5
are each independently hydrogen, hydrocarbyl, substituted
hydrocarbyl, or inert functional group; and R.sup.6 and R.sup.7 may
be identical or different, and are independently aryl, substituted
aryl, optionally substituted heterohydrocarbyl moiety, optionally
substituted aryl group in combination with and .PI.-coordinated to
a metal, optionally substituted aromatic hydrocarbon ring, or
optionally substituted polyaromatic hydrocarbon moiety.
11. The method of claim 1, wherein said oligomerization catalyst
system is activated in the absence of ethylene.
12. The method of claim 10, further comprising selecting
R.sup.1-R.sup.7 such that said metal complex is symmetrical.
13. The method of claim 10, further comprising selecting
R.sup.1-R.sup.7 such that said metal complex is asymmetrical.
14. The method of claim 1, wherein said oligomerization catalyst
system comprises a metal complex activated by a co-catalyst and
wherein said metal complex comprises a ligand having chemical
structure II: 12wherein R.sub.1, R.sub.2, and R.sub.3 are each
independently hydrogen, hydrocarbyl, substituted hydrocarbyl, or an
inert functional group; R.sub.4 and R.sub.5 are each independently
hydrogen, hydrocarbyl, an inert functional group, or substituted
hydrocarbyl; and Y is a structural bridge, and W, Y, and Z
independently comprise hydrogen, hydrocarbyl, an inert functional
group, or substituted hydrocarbyl having from about 0 to about 30
carbon atoms.
15. The method of claim 1, wherein said oligomerization catalyst
system comprises a metal complex activated by a co-catalyst and
wherein said metal complex comprises a ligand having chemical
structure III: 13wherein R.sub.1-R.sub.5 each comprise,
independently, hydrogen, optionally substituted hydrocarbyl, an
inert functional group, or any two of R.sub.1-R.sub.3 vicinal to
one another taken together may form a ring; Z.sub.1, which is
different from Z.sub.2, is an aryl or substituted aryl group; and
Z.sub.2 comprises an aryl, substituted aryl, optionally substituted
heterohydrocarbyl moiety, or an optionally substituted aryl group
in combination with and .PI.-coordinated to a metal.
16. The method of claim 15, wherein Z.sub.2 is an aryl, substituted
aryl, optionally substituted aromatic heterocyclic moiety, an
optionally substituted polyaromatic heterocyclic moiety, an
optionally substituted aliphatic heterocyclic moiety, or an
optionally substituted aliphatic heterohydrocarbyl moiety.
17. The method of claim 1, wherein said oligomerization catalyst
system comprises a metal complex activated by a co-catalyst and
wherein said metal complex comprises a ligand having chemical
structure IV: 14wherein A.sub.1-A.sub.6 each comprise,
independently, carbon, nitrogen, oxygen, or sulphur; A.sub.1 may be
directly bonded to A.sub.5; R.sub.1-R.sub.12, R.sub.14-R.sub.15,
and, if present, R.sub.13, are each, independently, hydrogen,
optionally substituted hydrocarbyl, or an inert functional group;
any two of R.sub.1-R.sub.15, vicinal to one another, taken together
may form a ring; and conditionally, when A.sub.1-A.sub.5 and
A.sub.6, if present, are all carbon, said atoms constitute the
cyclopentadienyl or aryl part of a .PI.-coordinated metal.
18. The method of claim 1, wherein said oligomerization catalyst
system comprises a metal complex activated by a co-catalyst and
wherein said metal complex comprises a ligand having chemical
structure VI: 15wherein R.sub.1-R.sub.5 and R.sub.7-R.sub.9 and
R.sub.12-R.sub.14 are each, independently, hydrogen, substituted
hydrocarbyl, an inert functional group, or any two of
R.sub.1-R.sub.3, R.sub.7-R.sub.9, and R.sub.12-R.sub.14, vicinal to
one another, taken together may form a ring; and R.sub.6, R.sub.10,
R.sub.11, and R.sub.15 are identical and are selected from fluorine
or chlorine.
19. The method of claim 1, wherein said oligomerization catalyst
system comprises a metal complex activated by a co-catalyst and
wherein said metal complex comprises a ligand having chemical
structure VII: 16wherein R.sub.1-R.sub.5 and R.sub.7-R.sub.9 and
R.sub.12-R.sub.14 are each, independently, hydrogen, substituted
hydrocarbyl, an inert functional group, or any two of
R.sub.1-R.sub.3, R.sub.7-R.sub.9, and R.sub.12-R.sub.14, vicinal to
one another, taken together may form a ring; R.sub.6 is hydrogen,
substituted hydrocarbyl, an inert functional group, or taken
together with R.sub.7 or R.sub.4 to form a ring; R.sub.10 is
hydrogen, substituted hydrocarbyl, an inert functional group, or
taken together with R.sub.9 or R.sub.4 to form a ring; and R.sub.11
and R.sub.15 are, independently, hydrogen or an inert functional
group.
20. The method of claim 1, wherein said oligomerization catalyst
system comprises a selective 1-hexene (S1H) catalyst.
21. The method of claim 20, wherein said oligomerization catalyst
system comprises chromium.
22. The method of claim 1, wherein said at least one continuous
reactor comprises a loop reactor, tubular reactor, continuous
stirred tank reactor, or combinations thereof.
23. The method of claim 1, wherein said at least one continuous
reactor comprises a loop reactor and fluid flow in said loop
reactor comprises a Reynolds number of from about 200,000 to about
700,000.
24. The method of claim 1, wherein said at least one continuous
reactor comprises a tubular reactor and fluid flow in said tubular
reactor comprises a Reynolds number of from about 300,000 to about
2,000,000.
25. The method of claim 1, wherein at steady state the contents of
said reactor are not turbid.
26. The method of claim 1, wherein the effluent comprises a diluent
and wherein said diluent comprising aliphatics, non-aliphatics,
aromatics, saturated compounds having from 4 to 8 carbon atoms, or
combinations thereof.
27. The method of claim 1, wherein the effluent comprises a diluent
and wherein said diluent comprises an aromatic compound having from
about 6 to about 30 carbon atoms, or combinations thereof.
28. The method of claim 1, wherein the effluent comprises a diluent
and wherein said diluent comprises cyclohexane, benzene, toluene,
xylene, ethylbenzene, or combinations thereof.
29. The method of claim 1, wherein the effluent comprises a diluent
and wherein said diluent comprises olefins having from about 4 to
about 30 carbon atoms, or combinations thereof.
30. The method of claim 1, wherein the effluent comprises a diluent
and wherein said diluent comprises 1-butene, 1-dodecene,
1-tetradecene, 1-hexadecene, 1-octadecene, or combinations
thereof.
31. The method of claim 1, further comprising manipulating product
olefin distribution by modifying a pressure of the reactor.
32. The method of claim 1, further comprising injecting said feed
and said catalyst system into said reactor at more than one point
along the length of said reactor wherein said reactor is a tubular
reactor.
33. The method of claim 1, further comprising cooling said reactor
with a coolant more volatile than water.
34. The method of claim 1, further comprising cooling said reactor
with a coolant, wherein said coolant comprises butane, isobutane,
isopentane, or combinations thereof.
35. The method of claim 1, wherein said reactor comprises a
temperature of from about 40 to about 150 degrees Celsius.
36. A method comprising: contacting an oligomerization catalyst
system and a feed comprising olefins; oligomerizing said feed in at
least one continuous reactor; and withdrawing from said at least
one continuous reactor an effluent comprising product olefins
having at least four carbon atoms; wherein oligomerization to
product olefins having at least four carbon atoms comprises a
single pass conversion of ethylene of at least about 65 weight
percent; and wherein product olefins having twelve carbon atoms
comprise at least about 95 weight percent 1-dodecene.
37. The method of claim 36, wherein the catalyst system comprises a
metal complex activated by a co-catalyst and wherein said metal
complex comprises a ligand having chemical structure I: 17wherein
R.sup.1, R.sup.2, and R.sup.3 are each independently hydrogen,
hydrocarbyl, substituted hydrocarbyl, an inert functional group, or
any two of R.sup.1-R.sup.3, vicinal to one another, taken together
may form a ring; R.sup.4 and R.sup.5 are each independently
hydrogen, hydrocarbyl, substituted hydrocarbyl, or inert functional
group; and R.sup.6 and R.sup.7 may be identical or different, and
are independently aryl, substituted aryl, optionally substituted
heterohydrocarbyl moiety, optionally substituted aryl group in
combination with and .PI.-coordinated to a metal, optionally
substituted aromatic hydrocarbon ring, or optionally substituted
polyaromatic hydrocarbon moiety.
38. The method of claim 37, further comprising selecting
R.sup.1-R.sup.7 such that said metal complex is symmetrical.
39. The method of claim 37, further comprising selecting
R.sup.1-R.sup.7 such that said metal complex is asymmetrical.
40. The method of claim 36, wherein the catalyst system comprises a
metal complex activated by a co-catalyst and wherein said metal
complex comprises a ligand having chemical structure II: 18wherein
R.sub.1, R.sub.2, and R.sub.3 are each independently hydrogen,
hydrocarbyl, substituted hydrocarbyl, or an inert functional group;
R.sub.4 and R.sub.5 are each independently hydrogen, hydrocarbyl,
an inert functional group, or substituted hydrocarbyl; and Y is a
structural bridge, and W, Y, and Z independently comprise hydrogen,
hydrocarbyl, an inert functional group, or substituted hydrocarbyl
having from about 0 to about 30 carbon atoms.
41. The method of claim 36, wherein the catalyst system comprises a
metal complex activated by a co-catalyst and wherein said metal
complex comprises a ligand having chemical structure III: 19wherein
R.sub.1-R.sub.5 each comprise, independently, hydrogen, optionally
substituted hydrocarbyl, an inert functional group, or any two of
R.sub.1-R.sub.3 vicinal to one another taken together may form a
ring; Z.sub.1, which is different from Z.sub.2, is an aryl or
substituted aryl group; and Z.sub.2 comprises an aryl, substituted
aryl, optionally substituted heterohydrocarbyl moiety, or an
optionally substituted aryl group in combination with and
.PI.-coordinated to a metal.
42. The method of claim 41, wherein Z.sub.2 is an aryl, substituted
aryl, optionally substituted aromatic heterocyclic moiety, an
optionally substituted polyaromatic heterocyclic moiety, an
optionally substituted aliphatic heterocyclic moiety, or an
optionally substituted aliphatic heterohydrocarbyl moiety.
43. The method of claim 36, wherein the catalyst system comprises a
metal complex activated by a co-catalyst and wherein said metal
complex comprises a ligand having chemical structure IV: 20wherein
A.sub.1-A.sub.6 each comprise, independently, carbon, nitrogen,
oxygen, or sulphur; A.sub.1 may be directly bonded to A.sub.5;
R.sub.1-R.sub.12, R.sub.14-R.sub.15, and, if present, R.sub.13, are
each, independently, hydrogen, optionally substituted hydrocarbyl,
or an inert functional group; any two of R.sub.1-R.sub.15, vicinal
to one another, taken together may form a ring; and conditionally,
when A.sub.1-A.sub.5 and A.sub.6, if present, are all carbon, said
atoms constitute the cyclopentadienyl or aryl part of a
.PI.-coordinated metal.
44. The method of claim 36, wherein the catalyst system comprises a
metal complex activated by a co-catalyst and wherein said metal
complex comprises a ligand having chemical structure VI: 21wherein
R.sub.1-R.sub.5 and R.sub.7-R.sub.9 and R.sub.12-R.sub.14 are each,
independently, hydrogen, substituted hydrocarbyl, an inert
functional group, or any two of R.sub.1-R.sub.3, R.sub.7-R.sub.9,
and R.sub.12-R.sub.14, vicinal to one another, taken together may
form a ring; and R.sub.6, R.sub.10, R.sub.11, and R.sub.15 are
identical and are selected from fluorine or chlorine.
45. The method of claim 36, wherein the catalyst system comprises a
metal complex activated by a co-catalyst and wherein said metal
complex comprises a ligand having chemical structure VII: 22wherein
R.sub.1-R.sub.5 and R.sub.7-R.sub.9 and R.sub.12-R.sub.14 are each,
independently, hydrogen, substituted hydrocarbyl, an inert
functional group, or any two of R.sub.1-R.sub.3, R.sub.7-R.sub.9,
and R.sub.12-R.sub.14, vicinal to one another, taken together may
form a ring; R.sub.6 is hydrogen, substituted hydrocarbyl, an inert
functional group, or taken together with R.sub.7 or R.sub.4 to form
a ring; R.sub.10 is hydrogen, substituted hydrocarbyl, an inert
functional group, or taken together with R.sub.9 or R.sub.4 to form
a ring; and R.sub.11 and R.sub.15 are, independently, hydrogen or
an inert functional group.
46. The method of claim 36, wherein the effluent comprises at least
about 40 weight percent product olefins having at least four carbon
atoms.
47. The method of claim 36, wherein said product olefins comprise
at least about 80 weight percent linear 1-alkenes.
48. The method of claim 36, wherein said product olefins comprise
at least about 20 weight percent alpha olefins having from about 8
to about 20 carbon atoms.
49. The method of claim 36, wherein said oligomerization catalyst
system comprises a metal alkyl or metal hydride species.
50. The method of claim 49, wherein said metal alkyl or metal
hydride species comprises one or more Lewis acids; a combination of
one or more Lewis acids and one or more alkylating agents; one or
more alkyl aluminum compounds; one or more alkyl aluminoxanes;
methyl aluminoxane (MAO); modified MAO; tri-alkyl aluminum;
diethylaluminum chloride (DEAC); or combinations thereof.
51. The method of claim 36, wherein said oligomerization catalyst
system comprises triethylaluminum (TEA), trimethylaluminum (TMA),
Tri-isobutyl Aluminum (TIBA), Tri-butyl Aluminum, or combinations
thereof.
52. The method of claim 36, wherein the effluent comprises a
diluent and wherein said diluent comprises an aromatic compound
having from about 6 to about 30 carbon atoms, or combinations
thereof.
53. The method of claim 36, wherein the effluent comprises a
diluent and wherein said diluent comprises cyclohexane, benzene,
toluene, xylene, ethylbenzene, or combinations thereof.
54. The method of claim 36, wherein the effluent comprises a
diluent and wherein said diluent comprises olefins having from
about 4 to about 30 carbon atoms, or combinations thereof.
55. The method of claim 36, wherein the effluent comprises a
diluent and wherein said diluent comprises 1-butene, 1-dodecene,
1-tetradecene, 1-hexadecene, 1-octadecene, or combinations
thereof.
56. The method of claim 36, further comprising manipulating product
olefin distribution by modifying a pressure of the reactor.
57. The method of claim 36, further comprising injecting said feed
and said catalyst system into said reactor at more than one point
along the length of said reactor wherein said reactor is a tubular
reactor.
58. The method of claim 36, further comprising cooling said reactor
with a coolant more volatile than water.
59. The method of claim 36, further comprising cooling said reactor
with a coolant, wherein said coolant comprises butane, isobutane,
isopentane, or combinations thereof.
60. The method of claim 36, wherein said reactor comprises a
temperature of from about 40 to about 150 degrees Celsius.
61. The method of claim 36, wherein said catalyst system comprises
a transition metal.
62. The method of claim 36, wherein said catalyst system comprises
iron or cobalt, or combinations thereof.
63. The method of claim 36, wherein said catalyst system comprises
nickel.
64. The method of claim 36, wherein said reactor comprises a loop
reactor, tubular reactor, continuous stirred tank reactor, or
combinations thereof.
65. The method of claim 36, wherein said at least one continuous
reactor comprises a loop reactor and fluid flow in said loop
reactor comprises a Reynolds number of from about 200,000 to about
700,000.
66. The method of claim 36, wherein said at least one continuous
reactor comprises a tubular reactor and fluid flow in said tubular
reactor comprises a Reynolds number of from about 300,000 to about
2,000,000.
67. The method of claim 36, wherein at steady state the contents of
said reactor are not turbid.
68. A method of oligomerizing alpha olefins comprising contacting a
metal complex having chemical structure VIII with a co-catalyst and
a feed comprising olefins: 23wherein R.sub.1, R.sub.2, and R.sub.3
are each independently hydrogen, hydrocarbyl, substituted
hydrocarbyl, or an inert functional group; R.sub.4 and R.sub.5 are
each independently hydrogen, hydrocarbyl, an inert functional
group, or substituted hydrocarbyl; Y is a structural bridge, and W,
Y, and Z are independently hydrogen, hydrocarbyl, an inert
functional group, or substituted hydrocarbyl having from about 0 to
about 30 carbon atoms; wherein M.sub.1 and M.sub.2 are metal atoms
that are independently selected from a group comprising cobalt,
iron, chromium, and vanadium; each X is an anion; and n is 1, 2, or
3, so that the total number of negative charges on X is equal to
the oxidation state of M.sub.1 or M.sub.2.
69. The method of claim 68, further comprising: withdrawing from a
continuous reactor an effluent comprising at least about 25 weight
percent product olefins having at least four carbon atoms.
70. The method of claim 68, further comprising: withdrawing from a
continuous reactor an effluent comprising at least about 40 weight
percent product olefins having at least four carbon atoms.
71. The method of claim 68, further comprising: withdrawing from a
continuous reactor an effluent comprising product olefins having
twelve carbon atoms wherein said product olefins having twelve
carbon atoms comprise at least about 95 weight percent
1-dodecene.
72. The method of claim 68, further comprising: withdrawing product
olefins from a continuous reactor wherein said product olefins
comprise at least about 20 weight percent alpha olefins having from
about 8 to about 20 carbon atoms.
73. The method of claim 68, further comprising: withdrawing product
olefins from a continuous reactor wherein said product olefins
comprise from about 20 to about 80 weight percent olefins having 6
carbon atoms and wherein said product olefins comprise at least
about 20 weight percent olefins having greater than 6 carbon
atoms.
74. The method of claim 68, further comprising: withdrawing from a
continuous reactor product olefins comprising olefins having six
carbon atoms wherein said olefins having six carbon atoms comprise
at least about 98 weight percent 1-hexene.
75. An alpha olefin prepared according to the method of claim
1.
76. An alpha olefin prepared according to the method of claim 36.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The content of this application is related to the content of
patent application Ser. No. 10/379,828, filed Mar. 4, 2003,
entitled "Composition and Method for a Hexadentate Ligand and
Bimetallic Complex for Polymerization of Olefins," which is
incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
[0003] Not applicable.
FIELD OF THE INVENTION
[0004] This invention generally relates to ethylene oligomerization
to alpha olefins.
BACKGROUND OF THE INVENTION
[0005] Olefins, also commonly known as alkenes, are important items
of commerce. Their many applications include employment as
intermediates in the manufacture of detergents, as more
environmentally friendly replacements where refined oils might
otherwise be used, as monomers, and as intermediates for many other
types of products. An important subset of olefins are olefin
oligomers, and one method of making olefin oligomers is via
oligomerization of ethylene, which is a catalytic reaction
involving various types of catalysts.
[0006] Examples of catalysts used commercially in polymerization
and oligomerization of olefins include alkylaluminum compounds,
certain nickel-phosphine complexes, and a titanium halide with a
Lewis acid, such as diethylaluminum chloride. Some examples of
catalysts, and in particular transition metal catalysts, employed
in ethylene polymerization and oligomerization may be found in U.S.
Pat. Nos. 5,955,555, 6,103,946, WO 03/011876, U.S. 2002/0028941, WO
02/28805, and WO 01/58874, which are incorporated herein by
reference.
[0007] Selective 1-hexene (S1H) catalysts are another example of
catalysts employed in the production of olefins. S1H catalysts are
designed to be selective for producton of 1-hexene. Examples of
such S1H catalysts may be found in U.S. Pat. Nos. 6,455,648,
6,380,451, 5,986,153, 5,919,996, 5,859,303, 5,856,257, 5,814,575,
5,786,431, 5,763,723, 5,689,028, 5,563,312, 5,543,375, 5,523,507,
5,470,926, 5,451,645, and 5,438,027, which are incorporated herein
by reference.
[0008] Applications and demand for olefin polymers and oligomers
continue to multiply, and competition to supply them
correspondingly intensifies. Thus, additional novel and improved
catalysts, and methods of olefin polymerization and
oligomerization, are desirable.
SUMMARY OF THE INVENTION
[0009] Provided is a method of oligomerizing alpha olefins. In an
embodiment, an oligomerization catalyst system is contacted in at
least one continuous reactor with a feed comprising olefins; an
effluent comprising product olefins having at least four carbon
atoms is withdrawn from the reactor; the oligomerization catalyst
system comprises iron or cobalt, or combinations thereof; and the
single pass conversion of ethylene is at least about 40 weight
percent among product olefins having at least four carbon atoms. In
another embodiment, the single pass conversion of ethylene
comprises at least about 65 weight percent among product olefins
having at least four carbon atoms. In another embodiment, product
olefins of the effluent having twelve carbon atoms comprise at
least about 95 weight percent 1-dodecene. In another embodiment,
product olefins comprise at least about 80 weight percent linear
1-alkenes. In another embodiment, product olefins comprise at least
about 20 weight percent alpha olefins having from about 8 to about
20 carbon atoms. In another embodiment, the oligomerization
catalyst system provided comprises a selective 1-hexene (S1H)
catalyst.
[0010] In an embodiment, the oligomerization catalyst system
provided comprises a metal complex activated by a co-catalyst
wherein the metal complex comprises a ligand having chemical
structure I: 1
[0011] The components of the ligand having chemical structure I,
labeled R.sup.1 through R.sup.7, may be defined as follows:
[0012] R.sup.1, R.sup.2, and R.sup.3 are each independently
hydrogen, hydrocarbyl, substituted hydrocarbyl, an inert functional
group, or any two of R.sup.1-R.sup.3, vicinal to one another, taken
together may form a ring;
[0013] R.sup.4 and R.sup.5 are each independently hydrogen,
hydrocarbyl, substituted hydrocarbyl, or inert functional
group;
[0014] R.sup.6 and R.sup.7 are each independently aryl, substituted
aryl, optionally substituted heterohydrocarbyl moiety, optionally
substituted aryl group in combination with and .PI.-coordinated to
a metal, optionally substituted aromatic hydrocarbon ring, or
optionally substituted polyaromatic hydrocarbon moiety.
[0015] Also provided is an oligomerization method comprising an
oligomerization catalyst system contacted with a feed comprising
olefins in at least one continuous reactor; a reactor effluent
comprising product olefins having at least four carbon atoms; a
single pass conversion of ethylene of at least about 65 weight
percent among product olefins having at least four carbon atoms;
and at least about 95 weight percent 1-dodecene among product
olefins having twelve carbon atoms. In an embodiment, the
oligomerization catalyst system comprises a metal alkyl or metal
hydride species. In another embodiment, the at least one continuous
reactor comprises a temperature of from about 40 to about 150
degrees Celsius. In another embodiment, the at least one continuous
reactor comprises a loop reactor where fluid flow comprises a
Reynolds number of from about 200,000 to about 700,000. In another
embodiment, the at least one continuous reactor comprises a tubular
reactor where fluid flow comprises a Reynolds number of from about
300,000 to about 2,000,000.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 illustrates an embodiment of an oligomerization
reactor in accordance with the method provided.
[0017] FIG. 2 illustrates an embodiment of a process design for
simultaneous employment of combinations of catalysts in parallel
reactors.
[0018] FIG. 3 illustrates an embodiment of a process design for
simultaneous employment of combinations of catalysts in the same
reactor.
[0019] FIG. 4 illustrates an embodiment of a process design for
consecutive employment of catalysts.
[0020] FIG. 5 illustrates an embodiment of a process design in
accordance with the oligomerization provided.
[0021] FIG. 6 illustrates 1-hexene quality for several embodiments
of the oligomerization provided.
[0022] FIG. 7 illustrates 1-octene quality for several embodiments
of the oligomerization provided.
[0023] FIG. 8 illustrates changes in paraffin content over time
while executing an embodiment of the oligomerization provided.
[0024] FIG. 9 illustrates 1-hexene purity for several embodiments
of the oligomerization provided.
[0025] FIG. 10 illustrates 1-octene purity for several embodiments
of the oligomerization provided.
DETAILED DESCRIPTION OF THE INVENTION
[0026] FIG. 1 illustrates an embodiment of a method for
oligomerization of alpha olefins. A feed 10 comprising olefins may
be contacted with an oligomerization catalyst system. In an
embodiment, the oligomerization catalyst system comprises iron or
cobalt. In another embodiment, the feed 10 comprises ethylene.
Oligomerization of the feed 10 may take place in a continuous
reactor 20, and an oligomerization reactor effluent 30 including at
least three components is withdrawn from the reactor 20. The
components of the oligomerization effluent 30 may comprise diluent,
product olefins, any ethylene not consumed by oligomerization, and
catalyst system constituents. Product olefins of the effluent 30
comprise olefins having at least four carbon atoms that are
produced by the oligomerization reaction in the reactor 20. In an
embodiment, product olefins of the effluent 30 comprise alpha
olefins having at least four carbon atoms that are produced by the
oligomerization reaction in the reactor 20. The diluent comprises
the remaining components of the effluent 30, other than product
olefins, ethylene, and catalyst system constituents.
[0027] In an embodiment, oligomerization to product olefins having
at least four carbon atoms comprises a single pass conversion of
ethylene of at least about 40 weight percent. The single pass
conversion may be expressed as the weight percent of reactant in
the feed, e.g., ethylene, that is oligomerized during a single pass
through the reactor. By calculation, the single pass conversion of
ethylene may be the ratio, expressed as a percentage, of the mass
of product olefins in the effluent divided by the mass of ethylene
in the feed. The single pass conversion may also be expressed as
the probability, expressed as a percentage, that one molecule of
reactant in the feed, e.g., ethylene, will be oligomerized in the
course of a single pass through the reactor. In another embodiment,
oligomerization of ethylene to product olefins having at least four
carbon atoms comprises a single pass conversion of ethylene of at
least about 50 weight percent. In another embodiment, the
oligomerization comprises a single pass conversion of ethylene of
at least about 65 weight percent. In another embodiment, the
oligomerization comprises a single pass conversion of ethylene of
at least about 75 weight percent. In another embodiment, the
oligomerization comprises a single pass conversion of ethylene of
at least about 85 weight percent.
[0028] In addition to ethylene conversion, product quality and
purity characterize the oligomerization described herein. In an
embodiment, the effluent from the oligomerization reactor includes
product olefins having at least four carbon atoms that comprise at
least about 80 weight percent linear 1-alkenes. In another
embodiment, the effluent from the oligomerization reactor includes
from about 25 to about 95 weight percent product olefins having at
least four carbon atoms. In another embodiment, the effluent
includes at least about 40 weight percent product olefins having at
least four carbon atoms. In another embodiment, the effluent
includes from about 30 to about 80 weight percent product olefins
having at least four carbon atoms. In another embodiment, the
effluent includes from about 40 to about 70 weight percent product
olefins having at least four carbon atoms. In another embodiment,
the effluent includes from about 45 to about 65 weight percent
product olefins having at least four carbon atoms. In another
embodiment, the effluent includes from about 50 to about 60 weight
percent product olefins having at least four carbon atoms. In
another embodiment, the effluent comprises from about 50 to about
90 weight percent product olefins having at least four carbon
atoms. In another embodiment, the effluent comprises from about 60
to about 90 weight percent product olefins having at least four
carbon atoms. In another embodiment, the effluent comprises from
about 70 to about 85 weight percent product olefins having at least
four carbon atoms.
[0029] In an embodiment of the oligomerization, product olefins
having at least four carbon atoms comprise olefins having from
about 8 to about 20 carbon atoms. In another embodiment, product
olefins having at least four carbon atoms comprise at least about
20 weight percent olefins having from about 8 to about 20 carbon
atoms. In another embodiment, product olefins having at least four
carbon atoms comprise at least about 30 weight percent olefins
having from about 8 to about 20 carbon atoms. In another
embodiment, product olefins having at least four carbon atoms
comprise at least about 40 weight percent olefins having from about
8 to about 20 carbon atoms. In another embodiment, product olefins
having at least four carbon atoms comprise at least about 20 weight
percent olefins having from about 6 to about 20 carbon atoms. In
another embodiment, product olefins having at least four carbon
atoms comprise at least about 35 weight percent olefins having from
about 6 to about 20 carbon atoms. In another embodiment, product
olefins having at least four carbon atoms comprise at least about
50 weight percent olefins having from about 6 to about 20 carbon
atoms. In another embodiment, product olefins having at least four
carbon atoms comprise at least about 60 weight percent olefins
having from about 6 to about 20 carbon atoms.
[0030] Selectivity for hexene may be of interest among the product
olefins. In an embodiment, product olefins comprise at least about
20 weight percent olefins having 6 carbon atoms. In another
embodiment, product olefins comprise from about 25 to about 70
weight percent olefins having 6 carbon atoms. In another
embodiment, product olefins comprise from about 30 to about 60
weight percent olefins having 6 carbon atoms. In another
embodiment, product olefins comprise from about 40 to about 50
weight percent olefins having 6 carbon atoms. In another
embodiment, of the product olefins having 6 carbon atoms, at least
about 98 weight percent are 1-hexene.
[0031] The purity of octenes and dodecenes among product olefins
may also be of interest. In an embodiment, product olefins having 8
carbon atoms comprise at least about 95 weight percent 1-octene. In
another embodiment, product olefins having 8 carbon atoms comprise
at least about 96 weight percent 1-octene. In another embodiment,
product olefins having 8 carbon atoms comprise at least about 97
weight percent 1-octene. In another embodiment, product olefins
having 8 carbon atoms comprise at least about 98 weight percent
1-octene. In another embodiment, product olefins having 8 carbon
atoms comprise at least about 99 weight percent 1-octene. In
another embodiment, product olefins having 12 carbon atoms comprise
at least about 93 weight percent 1-dodecene. In another embodiment,
product olefins having 12 carbon atoms comprise at least about 95
weight percent 1-dodecene. In another embodiment, product olefins
having 12 carbon atoms comprise at least about 96 weight percent
1-dodecene. In another embodiment, product olefins having 12 carbon
atoms comprise at least about 97 weight percent 1-dodecene. In
another embodiment, product olefins having 12 carbon atoms comprise
at least about 98 weight percent 1-dodecene.
[0032] An oligomerization catalyst system is employed in the
oligomerization provided. The oligomerization catalyst system may
be homogeneous, heterogeneous, supported, or unsupported, as those
terms are known in the art. In an embodiment, the oligomerization
catalyst system comprises a co-catalyst, and a ligand complexed
with a metal. In another embodiment, the oligomerization catalyst
system comprises a metal complex activated by a co-catalyst,
wherein the metal complex comprises a ligand having chemical
structure I: 2
[0033] The components of the ligand having chemical structure I,
labeled R.sup.1 through R.sup.7, may be defined as follows:
[0034] R.sup.1, R.sup.2, and R.sup.3 are each independently
hydrogen, hydrocarbyl, substituted hydrocarbyl, an inert functional
group, or any two of R.sup.1-R.sup.3, vicinal to one another, taken
together may form a ring;
[0035] R.sup.4 and R.sup.5 are each independently hydrogen,
hydrocarbyl, substituted hydrocarbyl, or inert functional
group;
[0036] R.sup.6 and R.sup.7 are each independently aryl, substituted
aryl, optionally substituted heterohydrocarbyl moiety, optionally
substituted aryl group in combination with and .PI.-coordinated to
a metal, optionally substituted aromatic hydrocarbon ring, or
optionally substituted polyaromatic hydrocarbon moiety.
[0037] The metal complex provided may be formed by complexing a
ligand, such as, for example, the ligand having chemical structure
I, with a metal. In an embodiment, the metal selected for
complexing with a ligand to form the metal complex provided
comprises a transition metal. In other embodiments, the metal
selected to form the metal complex comprises iron, nickel,
palladium, cobalt, vanadium, chromium, or combinations thereof. In
another embodiment, the metal comprises iron, cobalt, or
combinations thereof. In another embodiment, the oligomerization
catalyst system comprises chromium.
[0038] Other variations on the oligomerization catalyst system are
presented. For example, the order of addition of reagents may vary.
In an embodiment, activating the metal complex, occurs in the
absence of ethylene.
[0039] Referring to chemical structure I, the configuration of the
ligand may vary with selection of R.sup.1 through R.sup.7. In an
embodiment, R.sup.1-R.sup.7 are selected such that the ligand
having chemical structure I is symmetrical. A symmetrical ligand as
provided herein is symmetrical if it possesses symmetry higher than
`C.sub.1` symmetry, where C.sub.1 refers to the C.sub.1 point
group. In an embodiment, R.sup.1-R.sup.7 are selected such that the
ligand having chemical structure I is asymmetrical. An asymmetrical
ligand as provided herein is asymmetrical if it possesses only
`C.sub.1` symmetry, i.e., possesses no mirror plane, no rotational
axis of symmetry, and no inversion center.
[0040] The oligomerization catalyst system further comprises a
co-catalyst, which may be involved in catalyst activation. In an
embodiment, the co-catalyst comprises a metal alkyl or metal
hydride species. In another embodiment, the co-catalyst comprises
one or more Lewis acids; a combination of one or more Lewis acids
and one or more alkylating agents; one or more alkyl aluminum
compounds; one or more alkyl aluminoxanes; methyl aluminoxane
(MAO); modified MAO; tri-alkyl aluminum; diethylaluminum chloride
(DEAC); or combinations thereof. In another embodiment, the
co-catalyst comprises triethylaluminum (TEA), trimethylaluminum
(TMA), tri-isobutyl aluminum (TIBA), tri-butyl aluminum, or
combinations thereof. In an embodiment, where the catalyst system
comprises an iron catalyst, the molar ratio of aluminum to iron in
the oligomerization ranges from about 1:1 to about 10,000:1. In
another embodiment, where the catalyst system comprises an iron
catalyst, the molar ratio of aluminum to iron in the
oligomerization ranges from about 100:1 to about 3,000:1. In
another embodiment, where the catalyst system comprises an iron
catalyst, the molar ratio of aluminum to iron in the
oligomerization ranges from about 200:1 to about 2,000:1.
[0041] Components of the oligomerization catalyst system may vary.
In an embodiment, the oligomerization catalyst system comprises a
metal complex activated by a co-catalyst, wherein the metal complex
comprises a ligand having chemical structure II: 3
[0042] The components of the ligand having chemical structure II,
labeled R.sub.1-R.sub.5, W, Y, and Z, may be defined as
follows:
[0043] R.sub.1, R.sub.2, and R.sub.3 are each independently
hydrogen, hydrocarbyl, substituted hydrocarbyl, or an inert
functional group;
[0044] R.sub.4 and R.sub.5 are each independently hydrogen,
hydrocarbyl, an inert functional group, or substituted
hydrocarbyl;
[0045] Y is a structural bridge, and W, Y, and Z independently
comprise hydrogen, hydrocarbyl, an inert functional group, or
substituted hydrocarbyl having from about 0 to about 30 carbon
atoms.
[0046] In another embodiment of the oligomerization catalyst
system, a metal complex is activated by a co-catalyst, wherein the
metal complex may include a ligand having chemical structure III:
4
[0047] The components of the ligand having chemical structure III,
labeled R.sub.1-R.sub.5, Z.sub.1, and Z.sub.2, may be defined as
follows:
[0048] R.sub.1-R.sub.5 each comprise, independently, hydrogen,
optionally substituted hydrocarbyl, an inert functional group, or
any two of R.sub.1-R.sub.3 vicinal to one another taken together
may form a ring;
[0049] Z.sub.1, which is different from Z.sub.2, is an aryl or
substituted aryl group; and
[0050] Z.sub.2 comprises an aryl, substituted aryl, optionally
substituted heterohydrocarbyl moiety, or an optionally substituted
aryl group in combination with and .PI.-coordinated to a metal.
[0051] In another embodiment of the ligand having chemical
structure III, Z.sub.2 may be defined as an aryl, substituted aryl,
optionally substituted aromatic heterocyclic moiety, an optionally
substituted polyaromatic heterocyclic moiety, an optionally
substituted aliphatic heterocyclic moiety, or an optionally
substituted aliphatic heterohydrocarbyl moiety.
[0052] In another embodiment of the oligomerization catalyst
system, a metal complex is activated by a co-catalyst, wherein the
metal complex may include a ligand having chemical structure IV:
5
[0053] The components of the ligand having chemical structure IV,
labeled R.sub.1-R.sub.15 and A.sub.1-A.sub.6, may be defined as
follows:
[0054] A.sub.1-A.sub.6 each comprise, independently, carbon,
nitrogen, oxygen, or sulphur;
[0055] in the absence of A.sub.6, A.sub.1 may be directly bonded to
A.sub.5;
[0056] R.sub.1-R.sub.12, R.sub.14-R.sub.15, and, if present,
R.sub.13, are each, independently, hydrogen, optionally substituted
hydrocarbyl, or an inert functional group;
[0057] any two of R.sub.1-R.sub.15, vicinal to one another, taken
together may form a ring; and
[0058] conditionally, when A.sub.1-A.sub.5 and A.sub.6, if present,
are all carbon, said atoms constitute the cyclopentadienyl or aryl
part of a .PI.-coordinated metal.
[0059] In another embodiment of the oligomerization catalyst
system, a metal complex is activated by a co-catalyst, wherein the
metal complex may include a ligand having chemical structure V:
6
[0060] The components of the ligand having chemical structure V,
labeled R.sub.1-R.sub.5 and Z, may be defined as follows:
[0061] R.sub.1-R.sub.5 are each, independently, hydrogen,
substituted hydrocarbyl, an inert functional group, or any two of
R.sub.1-R.sub.3, vicinal to one another, taken together may form a
ring; and
[0062] each Z, selected independent of the other, is a substituted
aryl, an optionally substituted polyaromatic hydrocarbon moiety, an
optionally substituted heterohydrocarbyl moiety, or a substituted
aryl group in combination with a metal, said optionally substituted
aromatic hydrocarbon ring being .PI.-coordinated to the metal.
[0063] In another embodiment of the oligomerization catalyst
system, a metal complex is activated by a co-catalyst, wherein the
metal complex may include a ligand having chemical structure VI:
7
[0064] The components of the ligand having chemical structure VI,
labeled R.sub.1-R.sub.15, may be defined as follows:
[0065] R.sub.1-R.sub.5 and R.sub.7-R.sub.9 and R.sub.12-R.sub.14
are each, independently, hydrogen, substituted hydrocarbyl, an
inert functional group, or any two of R.sub.1-R.sub.3,
R.sub.7-R.sub.9, and R.sub.12-R.sub.14, vicinal to one another,
taken together may form a ring; and
[0066] R.sub.6, R.sub.10, R.sub.11, and R.sub.15 are identical and
are selected from fluorine or chlorine.
[0067] In another embodiment of the oligomerization catalyst
system, a metal complex is activated by a co-catalyst, wherein the
metal complex may include a ligand having chemical structure VII:
8
[0068] The components of the ligand having chemical structure VII,
labeled R.sub.1-R.sub.15, may be defined as follows:
[0069] R.sub.1-R.sub.5 and R.sub.7-R.sub.9 and R.sub.12-R.sub.14
are each, independently, hydrogen, substituted hydrocarbyl, an
inert functional group, or any two of R.sub.1-R.sub.3,
R.sub.7-R.sub.9, and R.sub.12-R.sub.14, vicinal to one another,
taken together may form a ring;
[0070] R.sub.6 is hydrogen, substituted hydrocarbyl, an inert
functional group, or taken together with R.sub.7 or R.sub.4 to form
a ring;
[0071] R.sub.10 is hydrogen, substituted hydrocarbyl, an inert
functional group, or taken together with R.sub.9 or R.sub.4 to form
a ring; and
[0072] R.sub.11 and R.sub.15 are each, independently, hydrogen or
an inert functional group.
[0073] The oligomerization catalyst system may include combinations
of catalysts, which may modify the distribution of product olefins
in the effluent. In an embodiment, the oligomerization catalyst
system comprises a selective one hexene (S1H) catalyst. In another
embodiment, the oligomerization catalyst system comprises a S1H
catalyst; a metal complex including a ligand having chemical
structure I, II, III, IV, V, VI, or VII, or combinations thereof,
as provided herein; and at least one co-catalyst. In an embodiment
where a combination of catalysts makes up the oligomerization
catalyst system, an S1H catalyst; a metal complex including a
ligand having chemical structure I, II, III, IV, V, VI, or VII, or
combinations thereof; and said co-catalyst may be employed
simultaneously. FIG. 2 illustrates an embodiment of a process
design where combinations of different catalysts and co-catalysts
may be employed simultaneously. A transition metal catalyst
oligomerization may be executed in a first reactor 200, and
simultaneously a S1H catalyst oligomerization may be executed in a
parallel reactor 210. Alternatively, two different transition metal
catalysts may be employed simultaneously in the two parallel
reactors 200, 210, or a combination of transition metal and S1H
catalysts may be employed simultaneously in the two parallel
reactors 200, 210. The effluents 205, 215 of the reactors 200, 210
may be combined into a single process output stream 220. FIG. 3
illustrates another embodiment of a process design for simultaneous
employment of combinations of transition metal and S1H catalysts
and co-catalysts. Combinations of different transition metal
catalysts, or combinations of transition metal catalysts and S1H
catalysts, may be employed in the same reactor 100. Thus, the
effluent 110 would include product olefins generated by each of the
oligomerization catalysts employed in the reactor 100.
[0074] In another embodiment where a combination of catalysts makes
up the oligomerization catalyst system, an S1H catalyst; a metal
complex including a ligand having chemical structure I, II, III,
IV, V, VI, or VII, or combinations thereof; and said co-catalyst
may be employed consecutively. FIG. 4 illustrates an embodiment of
a process design where catalysts may be employed consecutively. One
type of oligomerization catalyst or combination of catalysts may be
employed in a first reactor 300, and a second type of
oligomerization catalyst or combination may be employed in a second
reactor 310. The first 300 and second 310 reactors are operated in
series. The first reactor effluent 305 is fed to the second reactor
310, so the second reactor effluent 315 comprises a mixture of the
two reactor effluents 305, 315.
[0075] The particular combination of catalysts employed in a
particular process design, such as, for example, those combinations
and designs illustrated by FIGS. 2-4, may modify the distribution
of product olefins in the effluent of an oligomerization process.
Such a modification may cause the distribution of product olefins
to vary from a typical Schulz-Flory distribution, and, therefore,
also adjust the Schulz-Flory constant, or K-value associated with
such a product olefin distribution. In an embodiment where an
oligomerization catalyst system comprises a combination of
catalysts, the product olefins of the oligomerization comprise a
1-hexene content of from about 20 to about 80 weight percent. In
another embodiment, product olefins comprise a 1-hexene content of
from about 50 to about 80 weight percent.
[0076] The lifetimes of the components of the oligomerization
catalyst system may vary. For example, the lifetime of a catalyst
including a metal complex may be different than the lifetime of an
S1H-type catalyst. Thus, designing the oligomerization method as
provided herein to account for such variances may be advantageous.
In an embodiment, where the continuous reactor includes a tubular
reactor, the oligomerization catalyst system is injected at more
than one point along the length of the reactor. In another
embodiment, a metal complex is injected at more than one point
along the length of the reactor. In another embodiment, the
oligomerization catalyst system and olefins are injected at more
than one point along the length of the reactor.
[0077] The oligomerization provided may be a continuous process
carried out in one or more reactors. In an embodiment, the reactor
comprises a loop reactor, tubular reactor, continuous stirred tank
reactor (CSTR), or combinations thereof.
[0078] The oligomerization may be further characterized by the
velocity of reaction components in the continuous reactor, and
associated Reynolds numbers. In an embodiment, the continuous
reactor may be a loop reactor where fluid flow in the loop reactor
comprises a Reynolds number of from about 100,000 to about
1,000,000. In another embodiment, the continuous reactor may be a
loop reactor where fluid flow in the loop reactor comprises a
Reynolds number of from about 200,000 to about 700,000. In another
embodiment, the continuous reactor may be a tubular reactor where
fluid flow in the tubular reactor comprises a Reynolds number of
from about 100,000 to about 10,000,000. In another embodiment, the
continuous reactor may be a tubular reactor where fluid flow in the
tubular reactor comprises a Reynolds number of from about 300,000
to about 2,000,000.
[0079] In various embodiments, the continuous reactor may be
employed in the form of different types of reactors in combination,
and in various arrangements. In an embodiment, the continuous
reactor may be a combination of a tubular reactor and a CSTR. In
other embodiments, the continuous reactor may be employed as
reactors in series, reactors in parallel, or combinations thereof.
In an embodiment, the continuous reactor may be more than one CSTR
in series. In another embodiment, the continuous reactor may be a
tubular reactor and a loop reactor in series.
[0080] It is known in the art that the temperatures associated with
oligomerization may vary depending on the oligomerization catalyst
system employed. For example, oligomerizations employing transition
metal catalysts typically involve lower temperatures. Such lower
reactor temperatures, however, may make precipitation of waxes and,
therefore, plugging more problematic. Such waxes that cause
plugging may be, for example, the insoluble portion of wax products
from the oligomerization reaction that have at least 20 carbon
atoms. The turbidity, or clarity of the reactor contents upon
visual inspection may be an indicator of the presence of
precipitated waxes. As the level of precipitated waxes in the
reactor increases, the turbidity of the reactor contents also
typically increases. Thus, lower reactor temperatures and potential
increases in wax precipitation and plugging may be characteristic
of oligomerization. In an embodiment, at least one oligomerization
reactor comprises a temperature of from about 40 to about 150
degrees Celsius. In another embodiment, at least one reactor
comprises a temperature of from about 40 to about 90 degrees
Celsius. In another embodiment, at least one reactor comprises a
temperature of from about 80 to about 150 degrees Celsius. In
another embodiment, the contents of the reactor at steady state,
even without substantial turbulence, are not turbid.
[0081] A diluent, or solvent is among the components of the
oligomerization. At lower oligomerization temperatures, such as
those associated with late transition metal catalysts, selection of
diluent may contribute to prevention of wax precipitation and,
therefore, affect the turbidity of reactor contents, and plugging.
In embodiments, the diluent comprises aliphatics, non-aliphatics,
aromatics, saturated compounds having from 4 to 8 carbon atoms, or
combinations thereof. In other embodiments, the diluent comprises
cyclohexane, heptane, benzene, toluene, xylene, ethylbenzene, or
combinations thereof. In another embodiment, the diluent comprises
an aromatic compound having from about 6 to about 30 carbon atoms.
In another embodiment, the diluent comprises olefins. In another
embodiment, the diluent comprises alpha olefins. In another
embodiment, the diluent comprises olefins having from about 4 to
about 30 carbon atoms. In another embodiment, the diluent comprises
olefins having from about 4 to about 12 carbon atoms. In another
embodiment, the diluent comprises olefins having from about 10 to
about 30 carbon atoms. In another embodiment, the diluent comprises
olefins having from about 12 to about 18 carbon atoms. In yet other
embodiments, the diluent comprises 1-butene, 1-dodecene,
1-tetradecene, 1-hexadecene, 1-octadecene, or combinations thereof.
In another embodiment, the diluent comprises 1-tetradecene. In
another embodiment, the diluent comprises no more than about 30
weight percent of the oligomerization reactor effluent. In another
embodiment, the diluent comprises no more than about 20 weight
percent of the reactor effluent. In another embodiment, the diluent
comprises no more than about 10 weight percent of the reactor
effluent.
[0082] As is known in the art, coolants may be employed when
operating oligomerization reactors. For example, vaporized water
may be used to cool an oligomerization reactor. Accordingly, as
oligomerization temperature may vary with the type of catalyst
employed, so may the coolant employed to cool the reactor. In an
embodiment, a coolant more volatile than water is used in cooling
the continuous reactor. In another embodiment, the coolant employed
comprises butane, isobutane, isopentane, or combinations
thereof.
[0083] Reactor, or ethylene pressure may impact the product olefins
of the oligomerization. In an embodiment, the distribution of
product olefins in the effluent is manipulated via modifying
reactor pressure. In an embodiment, where reactor pressure is
modified in order to manipulate product olefin distribution, the
oligomerization catalyst system includes a transition metal complex
and a co-catalyst, and the co-catalyst is a tri-alkyl aluminum.
[0084] Further provided is a method that comprises contacting a
feed comprising olefins and an oligomerization catalyst system. The
feed is oligomerized in at least one continuous reactor, and an
effluent comprising product olefins that have at least four carbon
atoms is withdrawn from the reactor. In an embodiment, the method
of oligomerization to product olefins having at least four carbon
atoms is further characterized by a single pass conversion of
ethylene of at least about 65 weight percent. Additionally, the
product olefins from the oligomerization that have twelve carbon
atoms comprise at least about 95 weight percent 1-dodecene.
[0085] In embodiments of the method comprising a single pass
conversion of ethylene of at least about 65 weight percent, and
product olefins having twelve carbon atoms that comprise at least
about 95 weight percent 1-dodecene, the oligomerization catalyst
system may comprise a metal complex activated by a co-catalyst
where the metal complex comprises a ligand having one or more of
chemical structures I-VIII, or combinations thereof. In another
embodiment, the oligomerization catalyst system may comprise an S1H
catalyst. In other embodiments, the oligomerization catalyst system
may comprise iron, cobalt, chromium, nickel, vanadium, or
combinations thereof.
[0086] The present application further discloses a method of
oligomerizing alpha olefins where a metal complex having chemical
structure VIII is contacted with a co-catalyst and a feed
comprising olefins. 9
[0087] The metal complex having chemical structure VIII may be
produced from a ligand having chemical structure II as provided
herein. The metal complex VIII may be formed as a result of a
coordination reaction between the ligand II and a metal salt. In an
embodiment, the components of the metal complex of chemical
structure VIII, labeled as R.sub.1-R.sub.5, W, Y, Z, M, and X.sub.n
are as follows:
[0088] wherein R.sub.1, R.sub.2, and R.sub.3 are each independently
hydrogen, hydrocarbyl, substituted hydrocarbyl, or an inert
functional group;
[0089] R.sub.4 and R.sub.5 are each independently hydrogen,
hydrocarbyl, an inert functional group, or substituted hydrocarbyl;
and
[0090] Y is a structural bridge, and W, Y, and Z are independently
hydrogen, hydrocarbyl, an inert functional group, or substituted
hydrocarbyl having from about 0 to about 30 carbon atoms.
[0091] wherein M.sub.1 and M.sub.2 are metal atoms that are
independently selected from a group comprising cobalt, iron,
chromium, and vanadium;
[0092] each X is an anion; and
[0093] n is 1, 2, or 3, so that the total number of negative
charges on X is equal to the oxidation state of M.sub.1 or
M.sub.2.
EXAMPLES
[0094] The following examples, 1 through 3, are merely
representative of aspects of the present invention and, as one
skilled in the art would recognize, the present invention may be
practiced without many of the aspects illustrated by the examples.
Data in examples 2 and 3 that represent process components, and
compositions of reaction mixtures and products were determined by
gas chromatography using a standard boiling point capillary column
and flame ionization detector (GC/FID).
Example 1
[0095] Several .alpha.-olefin mixtures were mixed separately with
two diluents, cyclohexane and 1-tetradecene. The level of diluent
in each mixture was varied between 10 and 27 percent to simulate a
reactor effluent, excluding unreacted ethylene, with from 90 to 73
percent product composition, respectively. The amounts of wax in
the mixtures were gradually increased such that the total amount of
wax in the mixtures ranged from 10 to 15 percent. The temperatures
of the mixtures were then varied from 35 to 65.degree. C. for each
mixture, in order to determine when each mixture would become a
clear solution.
[0096] Using a typical commercial Schulz-Flory chain growth factor
of K=0.7, where
K=(moles C.sub.n+2)/(moles C.sub.n),
[0097] 500 g of a mixture containing 135 g of diluent (either
cyclohexane or 1-tetradecene) and 365 g of .alpha.-olefins were
prepared in a 1 L flask fitted with a heating mantle. A stirbar was
added to the flask, which was sealed and then connected to a
bubbler via a needle in order to relieve pressure. Due to the
volatility of 1-butene and 1-hexene, their masses were combined
with the mass of 1-octene for preparing the solutions, such that
1-octene was used to simulate the presence of 1-butene, 1-hexene
and 1-octene (see Table 1). Similarly, 1-dodecene was used to
represent the C.sub.10, C.sub.12, and C.sub.14 fractions, and
1-octadecene was used to represent the C.sub.16 and C.sub.18
fractions. For the waxes, C.sub.20/24, C.sub.26/28, and C.sub.30
were chosen to represent the wax products made by the catalysts of
interest. In addition to these two mixtures, a third mixture was
prepared in which only 50 g of 1-tetradecene diluent was used in
506 g of the mixture.
[0098] The three prepared mixtures, shown in columns 1-3 in Table
1, were then heated slowly with rapid stirring to determine the
point at which each solution became clear. For the solution
containing 73 percent product olefins and 27 percent C.sub.14
diluent, the solution became clear at 55.degree. C. (col. 1), and
when the diluent concentration was lowered to 10.3 percent (col.
3), the solution became clear at 60.degree. C. Contrasting these
results, the mixture containing cyclohexane (col. 2) did not become
clear under any of the temperature conditions studied. The results
would suggest that a mid-range .alpha.-olefin fraction, such as
1-tetradecene, may be a better solvent and less likely to promote
reactor plugging than cyclohexane. Also, the high level of product
in the effluent suggests that it may be possible to run an
oligomerization of this sort at low temperatures and high
conversions without causing lines to plug.
[0099] To test the limits of reactor composition, further
experiments were performed in which the amount of wax in the
reactor was artificially inflated. Columns 4, 5, and 6 in Table 1
illustrate the respective changes that were made to solutions 1, 2,
and 3. In each mixture the amount of diluent and non-wax olefins
was held constant, but the amount of C.sub.20+waxes was increased
by about 30 percent. As expected, the cyclohexane mixture 5 was
cloudy at all of the temperatures studied. However, the 26 percent
diluent (col. 4) and the 10 percent diluent (col. 6) mixtures were
completely clear at 40 and 45.degree. C., respectively. For
solutions 1 and 3, the "clear" point was determined by slowly
raising the temperature, but for solutions 4 and 6, the point of
total clarity was determined by slowly lowering an already elevated
temperature. As a final incremental change, solutions 7 and 8 were
prepared, in which the amount of wax in solutions 4 and 6 was
increased. In the case, all of the additional wax was C.sub.30 or
higher, so that the amount of higher molecular weight material
could be exaggerated. With these elevated amounts of wax, the
solutions were still clear at 40 and 45.degree. C.,
respectively.
1 TABLE 1 Mixture 1 2 3 4 5 6 7 8 Component (all in grams) C8 166
166 227 166 166 227 166 227 C12 109 109 135 109 109 135 109 135
Cyclohexane 0 135 0 0 135 0 0 0 C14 135 0 50 135 0 50 135 50 C18 39
39 42 39 39 42 39 42 C20/24 30 30 32 40 40 43 40 43 C26/28 9 9 9.2
12 12 12.7 12 12.7 C30 11 11 11.2 14.6 14.6 15 22 22.4 Total (g)
499 499 506 516 516 525 523 532 % Diluent 27 27 10 26 26 10 26 9 %
Wax 10 10 10.3 12.9 12.9 13.5 14.1 14.7 T (.degree. C.) 35 a a a b
a b b b 40 a a a c a b c b 45 b a a c a c c c 50 b b b c a c c c 55
c b b c a c c c 60 c b c c a c c c 65 c b c c a c c c a = very
cloudy b = slightly cloudy c = totally clear
Example 2
[0100] Two specific iron catalysts were tested under
semi-continuous operating conditions. FIG. 5 illustrates the
process design for the test. 120 g of solvent was pumped into a 1.0
L reactor under inert conditions, and the reactor was then
pressurized with ethylene to either 500 or 1000 psig. Next, high
pressure pumps were used to quickly transfer the first hour's
amounts of catalyst, which was the iron dichloride complex of
either structure IX or X, and co-catalyst (TEA) to the reactor.
10
[0101] The catalyst was introduced as an anhydrous methylene
chloride solution (0.1 mg/ml), and the co-catalyst was diluted in
anhydrous heptane. The reaction was allowed to exotherm to the run
temperature of 50.degree. C., and this temperature was maintained
by internal cooling coils in the reactor. The catalyst and
co-catalyst pumps were allowed to continue running at the hourly
rates shown in Table 2, and the ethylene was fed "on demand" using
a pre-set regulator. The reaction was periodically sampled via the
sampling port, and the data in Table 2 were generated via GC
analysis. Entries 1-8 reflect data collected employing an iron
catalyst formed from a ligand having chemical structure IX and
FeCl.sub.2, while Entry 9 reflects data collected under similar
conditions but employing an iron catalyst formed from a ligand
having chemical structure X and FeCl.sub.2. The data shown for the
product distributions and the product purities are from the last
samples taken for each reaction, i.e. at the highest conversion
level. Each reaction was run for approximately 3 hours after the
reaction had exothermed to 50.degree. C. The catalyst
productivities in Table 2 are based on the total amount of product
formed and the total amount of catalyst and co-catalyst fed to the
reactor. The cyclohexane solvent was used as the internal standard
for calculating the catalyst productivities.
2 TABLE 2 Entry 1 2 3 4 5 6 7 8 9 Solvent (120 g) C.sub.6H.sub.12
C.sub.6H.sub.12 C.sub.6H.sub.12 C.sub.6H.sub.12 C.sub.6H.sub.12
C.sub.6H.sub.12 C.sub.6H.sub.12 1-Butene C.sub.6H.sub.12 Catalyst
IX IX IX IX IX IX IX IX X Flowrate (mg/hr) 0.4 0.4 0.2 0.2 0.4 0.4
0.2 0.2 0.2 Yield (g) of product AOs 322 214 459 326 329 343 118
312 374 lb prod/lb Al 4464 2321 5200 6170 3193 2997 1518 4227 5004
lb prod/lb Fe cat (.times.10.sup.3) 224 116 521 620 321 301 76 424
509 TEA:Fe ratio 1000 1000 2000 2000 2000 2000 1000 2000 2000
K(C20/C18) 0.68 0.77 0.67 0.74 0.68 0.78 0.76 0.69 0.68 K(C16/C14)
0.68 0.76 0.69 0.76 0.68 0.78 0.77 0.69 0.69 K(C10/C8) 0.68 0.76
0.67 0.76 0.68 0.78 0.77 0.69 0.69 P ethylene (psig) 500 1000 500
1000 500 1000 1000 500 500 1-C6 Purity 99.35 99.16 99.34 99.26
99.29 98.88 98.97 98.87 99.34 C6 % branched AO 0.16 0.03 0.19 0.14
0.16 0.07 0.03 0.47 0.17 C6 % Paraffin 0.24 0.29 0.19 0.15 0.38
0.27 0.38 0.19 0.21 1-C8 Purity 99.13 99.16 99.07 99.05 99.17 98.69
98.98 98.27 99.05 C8 % branched AO 0.30 0.25 0.32 0.24 0.29 0.66
0.27 0.83 0.29
[0102] In examining Table 2, some additional observations are
noted. First, the product distribution, as expressed by the
Schulz-Flory K value, was approximately 0.67-0.69 at 500 psig
ethylene pressure, and reflected pressure dependence. Upon
increasing the pressure to 1000 psig, the K value increased to
0.75-0.77 (compare entries 1 and 2). Also, using the data in entry
3 of Table 2, FIGS. 6, 7, and 8 were created. FIG. 6 shows that
when increasing the concentration of 1-butene in the reactor, the
1-hexene quality remains near 99.3 percent at 12 percent 1-butene
concentration. FIG. 7 shows that the 1-octene purity remains over
99 percent with 25 percent 1-butene and 1-hexene in the reactor.
FIG. 8 illustrates how the overall paraffin content in the reactor
decreases with increasing conversion and run length.
Example 3
[0103] The tests described in entry 8 of Example 2 are furthered
described in Example 3. To examine the impact of ethylene
conversion on product olefin quality, product olefin content was
simulated utilizing 1-butene as a diluent, which is also one of the
product olefins produced in the oligomerization reactor, rather
than cyclohexane. See entries 3 and 8 of Table 2. Thus, 120 g of
1-butene was introduced into the reactor, followed by catalyst and
cocatalyst. Ethylene was fed to the reactor by demand and the
semi-continuous oligomerization experiment was performed at 500
psig of ethylene. In FIGS. 9 and 10, conversion, measured as the
amount of product olefins formed, increases as the percentage of
butene present decreases. In the single run oligomerization, the
mass of the diluent, 1-butene, decreases from 100 percent due to
ethylene oligomerization to product olefins. FIG. 9 indicates that
a high 1-hexene purity was obtained in this run. The lowest
1-hexene purity point, near 50 mass percent 1-butene, is due to
increased paraffin content (0.7 percent vs 0.2 percent for other
points) resulting from low ethylene conversion. In FIG. 10,
1-Octene purity remains over 98 percent when running the reaction
in 1-butene. As in FIG. 9, the elevated level of paraffin at low
conversion artificially lowers the olefin purity. FIGS. 9 and 10,
which were composed using data from the 500 psig run, may be viewed
as extensions of FIGS. 6 and 7, respectively. When using 1-butene
as the solvent, the product quality remains high, approaching 99
percent for 1-hexene and exceeding 98.2 percent for 1-octene.
[0104] While the present invention has been illustrated and
described above in terms of particular apparatus and methods of
use, it is apparent that, having the benefit of the teachings
herein, equivalent techniques and ingredients may be substituted
for those shown, and other changes can be made within the scope of
the present invention as defined by the appended claims.
* * * * *