CATALYSTS AND METHODS FOR POLYMER SYNTHESIS

• US 20140343246A1
• Filed: 11/03/2012
• Published: 11/20/2014
• Est. Priority Date: 11/04/2011
• Status: Active Grant

• Current Assignee: Saudi Aramco Technologies Company
• Original Assignee: Novomer, Inc (Danimer Scientific, Inc.)
• Inventors: Allen, Scott D., Farmer, Jay J., Job, Gabriel
• Granted Patent: US 9,359,474 B2
• Time in Patent Office: Days
• US Class Current: 528/405
• CPC Class Codes: B01J 2540/42 Quaternary ammonium groups
• CPC Class Codes: B01J 31/2217 At least one oxygen and one nitrogen atom present as complexing atoms in an at least bidentate or bridging ligand
• CPC Class Codes: C07F 15/065 without a metal-carbon linkage
• CPC Class Codes: C08G 64/34 and cyclic ethers
• CPC Class Codes: C09B 57/10 Metal complexes of organic compounds not being dyes in uncomplexed form

Abstract

The present invention provides unimolecular metal complexes having increased activity in the copolymerization of carbon dioxide and epoxides. Also provided are methods of using such metal complexes in the synthesis of polymers. According to one aspect, the present invention provides metal complexes comprising an activating species with co-catalytic activity tethered to a multidentate ligand that is coordinated to the active metal center of the complex.

Claims

1. A method for the synthesis of aliphatic polycarbonates comprising the step of contacting an epoxide and carbon dioxide with a metal complex comprising a metal atom coordinated with a salen ligand, the salen ligand comprising two halves each half coordinated to the metal atom via an imine and an oxygen atom, wherein the metal complex is characterized in that one of the two halves of the salen ligand has two or more cationic activating moieties functional groups tethered to it and the other half has no tethered cationic activating groups.

2. The method of claim 1, wherein the cationic activating functional groups tethered to the ligand are independently selected from the group consisting of:

onium salts, nitrogen-containing functional groups;

phosphorous-containing functional groups; and

arsenic-containing functional groups.

3. The method of any one of the preceding claims, wherein at least one cationic activating functional group comprises an ammonium salt.

4. The method of any one of the preceding claims, wherein at least one cationic activating functional group is selected from the group consisting of amidinium salts and guanidinium salts.

5. The method of any one of the preceding claims, wherein the half of the ligand having no tethered cationic activating functional groups is derived from salicylaldehyde optionally substituted with one or more aliphatic groups.

6. The method of any one of the preceding claims, wherein the half of the ligand having no tethered cationic activating functional groups comprises or is derived from a gamma dicarbonyl compound.

7. The method of claim 6, wherein the gamma dicarbonyl compound comprises optionally substituted acetylacetone.

8. The method of any one of the preceding claims, wherein the metal complex has the structure I:

9. The method of claim 8, wherein each Z is independently selected from the group consisting of:

10. The method of any one of the preceding claims, wherein the metal atom is selected from the group consisting of Cr, Mn, V, Fe, Co, Mo, W, Ru, Al, and Ni.

11. The method of any one of the preceding claims, wherein the metal atom is selected from the group consisting of:

Co, Al, and Cr.

12. The method of any one of the preceding claims, wherein the metal atom is Co.

13. The method of any one of the preceding claims, wherein the metal atom is Cr.

14. The method of any one of the preceding claims, wherein the metal atom is Al.

15. The method of any one of the preceding claims, wherein each moiety independently contains 1-30 atoms including at least one carbon atom, and optionally one or more atoms selected from the group consisting of N, O, S, Si, B, and P.

16. The method of any one of the preceding claims, wherein each moiety is independently a C_2-30 aliphatic group wherein one or more methylene units are optionally and independently replaced

by —

NR^y—

, —

N(R^y)C(O)—

, —

C(O)N(R^y)—

, —

O—

, —

C(O)—

, —

OC(O)—

, —

C(O)O—

, —

S—

, —

Si(R^y)₂—

, —

SO—

, —

SO₂—

, —

C(═

S)—

, —

C(═

NR^y)—

, or —

N═

N—

, where each occurrence of R^y is independently —

H, or an optionally substituted radical selected from the group consisting of C_1-6 aliphatic, 3- to 7-membered heterocyclic, phenyl, and 8- to 10-membered aryl.

17. The method of any one of the preceding claims, wherein each moiety is independently selected from the group consisting of:

18. The method of any one of the preceding claims, wherein there is one (Z)_m group present and where the moiety is selected from the group consisting of:

19. The method of claim 18, wherein the moiety is selected from the group consisting of:

20. The method of any one of the preceding claims, wherein there is ones (Z)_m group present and where the moiety is selected from the group consisting of:

21. The method of claim 20, wherein the moiety is selected from the group consisting of:

22. The method of any one of the preceding claims, wherein the metal complex is selected from the group consisting of:

23. The method of claim 22, wherein each of R^1a, R^1a′

is —

H.

24. The method of any one of claims 22-23, wherein each R^4a, R^4a′

, R^5a, R^5a′

, R^6a, R^6a′

, R^7a, and R^7a′

is independently selected from the group consisting of;

—

H, optionally substituted C_1-20 aliphatic, optionally substituted phenyl, and optionally substituted 8- to 10-membered aryl.

25. The method of any one of claims 22-24, wherein each R^4a, R^4a′

, R^6a, and R^6a′

is —

H.

26. The method of any one of claims 22-25, wherein each of R^1a, R^1a′

, R^4a, R^4a′

, R^6a, and R^6a′

is —

H and each R^5a, R^5a′

, R^7a, and R^7a′

is independently —

H, (Z)_m, or an optionally substituted C_1-20 aliphatic.

27. The method of any one of claims 22-26, wherein at least one salicylaldehyde-derived portion of the metal complex is selected from the group consisting of:

28. The method of any one of claims 22-27, wherein at least one salicylaldehyde-derived portion of the metal complex is selected from the group consisting of:

29. The method of any one of the preceding claims, wherein the half of the salen ligand having two or more tethered cationic activating groups comprises:

30. The method of any one of claims 8 to 29, wherein one or more Z groups is a cationic moiety independently selected from the group consisting of:

31. The method of claim 20, wherein each Z is

32. The method of claim 31, wherein each R¹, R², and R³ group is an alkyl group.

33. The method of claim 31, wherein each R¹, R², and R³ group is independently a C₁-C₂₀ straight chain, branched, or cyclic alkyl group.

34. The method of claim 31, wherein each R¹, R², and R³ group is independently a C₁-C₁₂ straight or branched alkyl group.

35. The method of claim 31, wherein each R¹, R², and R³ group is independently a C₁-C₈ straight or branched alkyl group.

36. The method of claim 31, wherein each R¹, R², and R³ group is independently selected from the group consisting of:

methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl.

37. The method of claim 31, wherein each R¹, R², and R³ group is n-butyl.

38. The method of any one of the preceding claims, wherein the metal complex comprises any one or more of those appearing in Table 1, hereinabove.

39. The method of claim 38, wherein M is selected from the group consisting of cobalt, aluminum, and chromium.

40. The method of claim 38, wherein M is selected from the group consisting of cobalt and chromium.

41. The method of claim 38, wherein M is cobalt.

42. The method of claim 40, wherein the cobalt has a 3+ oxidation state.

43. The method of any one of claims 8-42, wherein X is selected from the group consisting of:

chlorine, bromine, an optionally substituted C_1-12 carboxylate, azide, nitrate, an optionally substituted phenoxide, a sulfonate salt, and a combination of any two or more of these.

44. The method of any one of the preceding claims, wherein the metal complex contains a total of 2 to 4 cationic activating functional groups.

45. The method of any one of the preceding claims, wherein the metal complex contains a total of 2 cationic activating functional groups.

46. The method of any one of the preceding claims, wherein the metal complex contains a total of 3 cationic activating functional groups.

47. The method of any one of the preceding claims, wherein the metal complex contains a total of 4 cationic activating functional groups.

48. The method of any one of the preceding claims, wherein the epoxide has the formula:

49. The method of claim 48, wherein a polymer formed has a formula selected from the group consisting of:

50. The method of any one of claims 48-49, wherein R^b′

, R^c′

, and R^d′

are each hydrogen.

51. The method of any one of claims 48-50, wherein R^a′

is optionally substituted C_1-12 aliphatic.

52. The method of any one of the preceding claims, wherein the epoxide is selected from the group consisting of:

ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, 1,2 octene oxide, 3-vinyl cyclohexene oxide, epichlorohydrin and mixtures of any two or more of these.

53. The method of any one of the preceding claims, wherein the epoxide is propylene oxide.

54. The method of any one of the preceding claims, wherein the CO₂ pressure is between about 50 and 800 psi.

55. The method of any one of the preceding claims, wherein a molar ratio of the metal complex to the epoxide is between about 1:

1000 and about 1;

100,000.

56. The method of any one of the preceding claims, further comprising the steps of letting the polymerization proceed until a desired polymer molecular weight has been achieved, quenching the polymerization reaction and isolating the polymer.

57. A metal complex of formula I:

58. The metal complex of claim 57, wherein M is selected from the group consisting of Cr, Mn, V, Fe, Co, Mo, W, Ru, Al, and Ni.

59. The metal complex of any one of claims 57-58, wherein M is selected from the group consisting of:

Co, Al, and Cr.

60. The metal complex of any one of claims 57-59, wherein M is Co.

61. The metal complex of any one of claims 57-60, wherein M is Cr.

62. The metal complex of any one of claims 57-61, wherein the moiety contains 1-30 atoms including at least one carbon atom, and optionally one or more atoms selected from the group consisting of N, O, S, Si, B, and P.

63. The metal complex of any one of claims 57-62, wherein the moiety is a C_2-30 aliphatic group wherein one or more methylene units are optionally and independently replaced

by —

NR^y—

, —

N(R^y)C(O)—

, —

C(O)N(R^y)—

, —

O—

, —

C(O)—

, —

OC(O)—

, —

C(O)O—

, —

S—

, —

Si(R^y)₂—

, —

SO—

, —

SO₂—

, —

C(═

S)—

, —

C(═

NR^y)—

, or —

N═

N—

, where each occurrence of R^y is independently —

H, or an optionally substituted radical selected from the group consisting of C_1-6 aliphatic, 3- to 7-membered heterocyclic, phenyl, and 8- to 10-membered aryl.

64. The metal complex of any one of claims 57-63, wherein the moiety is selected from the group consisting of:

65. The metal complex of any one of claims 57-64, wherein the moiety is selected from the group consisting of:

66. The metal complex of any one of claims 57-65, wherein the moiety is selected from the group consisting of:

67. The metal complex of any one of claims 57-66, wherein the moiety is selected from the group consisting of:

68. The metal complex of any one of claims 57-67, wherein the moiety is selected from the group consisting of:

69. The metal complex of any one of claims 57-68, wherein the metal complex has a structure selected from the group consisting of:

70. The metal complex of claim 69, wherein only one (Z)_m group is present and m is greater than 1.

71. The metal complex of any one of claims 69-70, wherein more than one (Z)_m group is present.

72. The metal complex of any one of claims 69-71, wherein the metal complex is selected from the group consisting of:

73. The metal complex of any one of claims 69-72, wherein the metal complex is selected from the group consisting of:

74. The metal complex of any one of claims 69-73, wherein the metal complex is selected from the group consisting of:

75. The metal complex of any one of claims 69-74, wherein each R^4a, R^4a′

, R^5a, R^5a′

, R^6a, R^6a′

, R^7a, and R^7a′

is independently selected from the group consisting of;

—

H, optionally substituted C_1-20 aliphatic, optionally substituted phenyl, and optionally substituted 8- to 10-membered aryl.

76. The metal complex of any one of claims 69-75, wherein each R^4a, R^4a′

, R^6a, and R^6a′

is —

H.

77. The metal complex of any one of claims 69-76, wherein each R^4a, R^4a′

, R^6a, and R^6a′

is —

H and each R^5a, R^5a′

, R^7a, and R^7a′

is independently —

H, or an optionally substituted C_1-20 aliphatic.

78. The metal complex of claim 72, wherein the ring denoted “

B”

has a structure selected from the group consisting of;

79. The metal complex of claim 72, wherein the ring denoted “

B”

has a structure selected from the group consisting of;

80. The metal complex of claim 72, wherein the ring denoted “

B”

has a structure;

81. The metal complex of any one of claims 57-80, wherein one or more Z group is a cationic moiety independently selected from the group consisting of:

82. The metal complex of any one of claims 57-80, wherein each Z is

83. The metal complex of any one of claims 57-82, wherein each R¹, R², and R³ group is an alkyl group.

84. The metal complex of any one of claims 57-83, wherein each R¹, R², and R³ group is independently a C₁-C₂₀ straight chain, branched, or cyclic alkyl group.

85. The metal complex of any one of claims 57-84, wherein each R¹, R², and R³ group is independently a C₁-C₁₂ straight or branched alkyl group.

86. The metal complex of any one of claims 57-85, wherein each R¹, R², and R³ group is independently a C₁-C₈ straight or branched alkyl group.

87. The metal complex of any one of claims 57-86, wherein each R¹, R², and R³ group is independently selected from the group consisting of:

methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl.

88. The metal complex of any one of claims 57-87, wherein each R¹, R², and R³ group is n-butyl.

95. The metal complex of any one of claims 57-94, wherein the polymerization catalyst contains a total of 2 to 4 Z groups.

96. The metal complex of any one of claims 57-95, wherein the polymerization catalyst contains a total of 2 Z groups.

97. The metal complex of any one of claims 57-95, wherein the polymerization catalyst contains a total of 3 Z groups.

98. The metal complex of any one of claims 57-95, wherein the polymerization catalyst contains a total of 4 Z groups.

89. A metal complex comprising any one or more of the metal complexes appearing in Table 1, hereinabove.

90. The metal complex of claim 89, wherein M is selected from the group consisting of cobalt, aluminum, and chromium.

91. The metal complex of claim 89, wherein M is selected from the group consisting of cobalt and chromium.

92. The metal complex of claim 89, wherein M is cobalt.

93. The metal complex of claim 92, wherein the cobalt has a 3+ oxidation state.

94. The metal complex of any one of claims 89-93, wherein X is selected from the group consisting of:

chlorine, bromine, an optionally substituted C_1-12 carboxylate, azide, nitrate, an optionally substituted phenoxide, a sulfonate salt, and a combination of any two or more of these.