Selective ether cleavage synthesis of liquid crystals

• US 7,147,800 B2
• Filed: 12/24/2003
• Issued: 12/12/2006
• Est. Priority Date: 01/23/2001
• Status: Expired due to Term

• Current Assignee: Southwest Research Institute
• Original Assignee: Southwest Research Institute
• Inventors: Hanson, Douglas P., Wellinghoff, Stephen T.
• Primary Examiner(s): WU, SHEAN CHIU
• Application Number:
  US10/746,109
• Publication Number:
  US 20040144954A1
• Time in Patent Office: 1,084 Days
• Field of Search: 252/299.01, 252/299.64, 252/299.67, 560/77, 560/86, 585/25, 585/935, 585/932, 528/176, 528/192
• US Class Current: 252/299.67
• CPC Class Codes: C09K 19/20 linked by a chain containing carbon and oxygen atoms as chain links, e.g. esters or ethers
• CPC Class Codes: C09K 19/2007 the chain containing -COO- or -OCO- groups
• CPC Class Codes: C09K 2019/0448 the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate
• CPC Class Codes: C09K 2019/2078 Ph-COO-Ph-COO-Ph
• CPC Class Codes: Y10S 585/932 Carboxyl-containing, e.g. acid
• CPC Class Codes: Y10S 585/935 Halogen-containing

Abstract

A method for making platform molecules comprising: reacting 4-alkoxy benzoyl chloride with R²-hydroquinone under first conditions effective to produce bis 1,4[4-alkoxy-benzoyloxy]-R²-phenylene comprising bis terminal alkoxy groups wherein R² is a bulky organic group; and, subjecting the bis 1,4[4-alkoxy-benzoyloxy]-R²-phenylene to second conditions effective to selectively cleave the bis terminal alkoxy groups to produce a solution comprising complexes comprising diphenolic platform molecules comprising bis terminal hydroxyl groups, the second conditions also being effective to precipitate the complexes out of the solution.

Claims

1. A method for making platform molecules comprising:

reacting 4-alkoxy benzoyl chloride with R²-hydroquinone under first conditions effective to produce bis 1,4 [4-alkoxy-benzoyloxy]-R²-phenylene comprising bis terminal alkoxy groups wherein R² is a bulky organic group; and

,

subjecting said bis 1,4 [4-alkoxy-benzoyloxy]-R²-phenylene to second conditions effective to selectively cleave said his terminal alkoxy groups to produce a solution comprising complexes comprising diphenolic platform molecules comprising bis terminal hydroxyl groups, said second conditions also being effective to precipitate said complexes out of said solution.

2. The method of claim 1 wherein said bis-terminal alkoxy groups comprise alkyl groups having from about 1 to about 20 carbon atoms.

3. The method of claim 1 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

4. The method of claim 1 wherein said first conditions comprise hydrogen chloride scavenging agent effective to produce said bis 1,4[4-alkoxy-benzoyloxy]-R²-phenylene comprising bis terminal spacer groups.

5. The method of claim 1 wherein said first conditions comprise hydrogen chloride scavenging agent effective to produce bis 1,4[4-alkoxy-benzoyloxy]-R²-phenylene comprising bis terminal alkoxy groups.

6. The method of claim 2 wherein said first conditions comprise hydrogen chloride scavenging agent effective to produce bis 1,4[4-methoxybenzoyloxy]-R²-phenylene comprising bis terminal methoxy groups.

7. The method of claim 3 wherein said first conditions comprise hydrogen chloride scavenging agent effective to produce bis 1,4[4-methoxybenzoyloxy]-R²-phenylene comprising bis terminal methoxy groups.

8. The method of claim 5 wherein said hydrogen chloride scavenging agent comprises one or more basic amines.

9. The method of claim 5 wherein said hydrogen chloride scavenging agent comprises pyridine.

10. The method of claim 9 wherein said first conditions further comprise trialkylamine having from about 2 to about 4 carbon atoms.

11. The method of claim 9 wherein said first conditions further comprise triethyl amine.

12. The method of claim 3 wherein R² is selected from the group consisting of methyl groups and t-butyl groups.

13. The method of claim 2 wherein R² is selected from the group consisting of methyl groups and t-butyl groups.

14. The method of claim 1 wherein R² is selected from the group consisting of methyl groups and t-butyl groups.

15. The method of claim 4 wherein R² is selected from the group consisting of methyl groups and t-butyl groups.

16. The method of claim 7 wherein R² is selected from the group consisting of methyl groups and t-butyl groups.

17. The method of claim 9 wherein R² is selected from the group consisting of methyl groups and t-butyl groups.

18. The method of claim 11 wherein R² is selected from the group consisting of methyl groups and t-butyl groups.

19. The method of claim 2 wherein

when said bis 1,4[4-alkoxy-benzoyloxy]-R²-phenylene comprising bis terminal alkoxy groups is to be incorporated into a monomer, R² is selected from the group consisting of t-butyl groups, isopropyl groups, secondary butyl groups, methyl groups, and phenyl groups;

and,

when said bis 1,4[4-alkoxy-benzoyloxy]-R²-phenylene is to be incorporated into a dimer, R² is selected from the group consisting of bulky organic groups and groups having a bulk less than methyl groups.

20. The method of claim 5 wherein

when said bis 1,4[4-alkoxy-benzoyloxy]-R²-phenylene comprising bis terminal alkoxy groups is to be incorporated into a monomer, R² is selected from the group consisting of t-butyl groups, isopropyl groups, secondary butyl groups, methyl groups, and phenyl groups;

and,

when said bis 1,4[4-alkoxy-benzoyloxy]-R²-phenylene is to be incorporated into a dimer, R² is selected from the group consisting of bulky organic groups and groups having a bulk less than methyl groups.

21. The method of claim 1 wherein

when said bis 1,4[4-alkoxy-benzoyloxy]-R 2-phenylene comprising bis terminal alkoxy groups is to be incorporated into a monomer, R² is selected from the group consisting of t-butyl groups, isopropyl groups, secondary butyl groups, methyl groups, and phenyl groups;

and,

when said bis 1,4[4-alkoxy-benzoyloxy]-R²-phenylene is to be incorporated into a dimer, R² is selected from the group consisting of bulky organic groups and groups having a bulk less than methyl groups.

22. The method of claim 3 wherein

when bis 1,4[4-methoxybenzoyloxy]-R²-phenylene is to be incorporated into a monomer, R² is selected from the group consisting of t-butyl groups, isopropyl groups, secondary butyl groups, methyl groups, and phenyl groups;

and,

when bis 1,4[4-methoxybenzoyloxy]-R²-phenylene is to be incorporated into a dimer, R² is selected from the group consisting of bulky organic groups and groups having a bulk less than methyl groups.

23. The method of claim 9 wherein

when bis 1,4[4-methoxybenzoyloxy]-R²-phenylene is to be incorporated into a monomer, R² is selected from the group consisting of t-butyl groups, isopropyl groups, secondary butyl groups, methyl groups, and phenyl groups;

and,

when bis 1,4[4-methoxybenzoyloxy]-R²-phenylene is to be incorporated into a dimer, R² is selected from the group consisting of bulky organic groups and groups having a bulk less than methyl groups.

24. The method of claim 11 wherein

when bis 1,4[4-methoxybenzoyloxy]-R²-phenylene is to be incorporated into a monomer, R² is selected from the group consisting of t-butyl groups, isopropyl groups, secondary butyl groups, methyl groups, and phenyl groups;

and,

when bis 1,4[4-methoxybenzoyloxy]-R²-phenylene is to be incorporated into a dimer, R² is selected from the group consisting of bulky organic groups and groups having a bulk less than methyl groups.

25. The method of claim 1 wherein said bis-terminal alkoxy groups comprise alkyl groups having from about 1 to about 9 carbon atoms.

26. The method of claim 1 wherein said bis-terminal alkyloxy groups comprise alkyl groups having from about 1 to about 6 carbon atoms.

27. The method of claim 1 further comprising reacting one or more of said bis-terminal hydroxyl groups with one or more 4-alkoxy benzoyl chloride molecules under said first conditions effective to produce elongated diphenolic platform molecules.

28. The method of claim 1 further comprising

exposing said diphenolic platform molecules comprising bis-terminal hydroxyl groups to less than a stoichiometric amount of 4-alkoxy benzoyl chloride under third conditions effective to produce a monoester product and a diester product;

and,

separating said monoester product.

29. The method of claim 28 wherein said method further comprises reacting at least one terminal ester group on said monoester product with a polymerizable group.

30. The method of claim 29 further comprising exposing said monoester product to an alkyloyl chloride solution comprising bifunctional alkyloyl chloride under fourth conditions effective to react said at least one terminal ester group with said bifunctional alkyloyl chloride and to precipitate mesogenic dimer from said monoester solution, wherein said bifunctional alkyloyl chloride comprises an alkyl group having from about 2 to about 20 carbon atoms.

31. The method of claim 29 wherein said bifunctional alkyloyl chloride comprises an alkyl group having from about 6 to about 20 carbon atoms.

32. The method of claim 29 wherein said bifunctional alkyloyl chloride comprises an alkyl group having from about 6 to about 12 carbon atoms.

33. The method of claim 29 wherein said bifunctional alkyloyl chloride is sebacoyl chloride.

34. The method of claim 30 further comprising

preparing a monoester solution comprising said monoester, a quantity of basic amine sufficient to dissolve said monoester, and a first amount of chlorinated organic solvent;

and

preparing said alkyloyl chloride solution comprising a quantity of said bifunctional alkyloyl chloride, a second amount of chlorinated organic solvent, and a concentration of from about 1 to about 100 ppm of benzoquinone inhibitor.

35. The method of claim 34 wherein

said quantity of basic amine is about 10 milliliters per gram of said monoester;

said first amount of said chlorinated organic solvent is substantially the same as said quantity of basic amine on a volume basis;

said second amount of chlorinated organic solvent is about 10 milliliters per gram of said alkyloyl chloride; and

said concentration of benzoquinone inhibitor is about 10 ppm.

36. The method of claim 30 wherein said fourth conditions are effective to precipitate said mesogenic dimer.

37. A method for making platform molecules comprising:

reacting 4-alkoxy benzoyl chloride with a R²-hydroquinone under first conditions effective to produce bis 1,4[4-alkoxybenzoyloxy]-R²-phenylene comprising bis terminal alkoxy groups comprising alkyl groups wherein R² is a bulky organic group;

exposing a quantity of said bis 1,4[4-alkoxybenzoyloxy]-R²-phenylene to second conditions comprising an amount of solvent, a concentration of Lewis acid at a ratio of about 4;

1 or more based on said quantity of bis 1,4[4-alkoxybenzoyloxy]-R²-phenylene, and an amount of nucleophile sufficient to dissolve said Lewis acid in said solvent in the presence of said quantity of bis 1,4[4-alkoxybenzoyloxy]-R²-phenylene, said second conditions being effective to precipitate out of said solution precipitated complexes comprising said platform molecules comprising intact aromatic ester bonds substantially as they are formed, said amount of said solvent being effective to maintain said precipitated complexes in slurry form, said second conditions being effective to selectively cleave said bis terminal alkoxy groups to produce diphenolic platform molecules comprising bis terminal hydroxyl groups.

38. The method of claim 37 wherein said solvent comprises chlorinated solvent, said nucleophile comprises aliphatic thiol, and said amount of said aliphatic thiol is effective to dissolve said concentration of Lewis acid in said chlorinated solvent.

39. The method of claim 38 wherein said 4-alkoxy benzoyl chloride comprises an alkylene group having from about 1 to about 4 carbon atoms.

40. The method of claim 39 wherein said Lewis acid comprises a metal halide.

41. The method of claim 37 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

42. The method of claim 38 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

43. The method of claim 37 wherein said Lewis acid comprises a metal halide and said aliphatic thiol comprises an alkyl group having from about 1 to about 11 carbon atoms.

44. The method of claim 38 wherein said Lewis acid comprises a metal halide and said aliphatic thiol comprises an alkyl group having from about 1 to about 11 carbon atoms.

45. The method of claim 42 wherein said Lewis acid comprises a metal halide and said aliphatic thiol comprises an alkyl group having from about 1 to about 11 carbon atoms.

46. The method of claim 43 wherein said metal halide is selected from the group consisting of aluminum chloride, iron chloride, and zinc chloride.

47. The method of claim 45 wherein said metal halide is selected from the group consisting of aluminum chloride, iron chloride, and zinc chloride.

48. The method of claim 43 wherein said Lewis acid comprises aluminum chloride and said aliphatic thiol is ethane thiol.

49. The method of claim 44 wherein said metal halide comprises aluminum chloride and said aliphatic thiol is ethane thiol.

50. The method of claim 45 wherein said metal halide comprises aluminum chloride and said aliphatic thiol is ethane thiol.

51. The method of claim 38 wherein said amount of aliphatic thiol comprises at least one mole of aliphatic thiol per mole of bis 1,4[4-alkoxybenzoyloxy]-R²-phenylene.

52. The method of claim 43 wherein said amount of aliphatic thiol comprises at least one mole of aliphatic thiol per mole of bis 1,4[4-alkoxybenzoyloxy]-R²-phenylene.

53. The method of claim 49 wherein said amount of ethane thiol comprises at least one mole of ethane thiol per mole of bis 1,4[4-alkoxybenzoyloxy]-R²-phenylene.

54. The method of claim 50 wherein said amount of ethane thiol comprises at least one mole of ethane thiol per mole of bis 1,4[4-alkoxybenzoyloxy]-R²-phenylene.

55. The method of claim 37 further comprising exposing said precipitated complexes to a quenching agent having a pH effective to produce bis terminal hydroxyl groups, said pH being ineffective to cleave aromatic ester bonds in said precipitate.

56. The method of claim 39 further comprising exposing said precipitated complexes to a quenching agent having a pH effective to produce bis terminal hydroxyl groups, said pH being ineffective to cleave aromatic ester bonds in said precipitate.

57. The method of claim 38 further comprising exposing said precipitated complexes to a quenching agent having a pH effective to produce bis terminal hydroxyl groups, said pH being ineffective to cleave aromatic ester bonds in said precipitate.

58. The method of claim 42 further comprising exposing said precipitated complexes to a quenching agent having a pH effective to produce bis terminal hydroxyl groups, said pH being ineffective to cleave aromatic ester bonds in said precipitate.

59. The method of claim 45 further comprising exposing said precipitated complexes to a quenching agent having a pH effective to produce bis terminal hydroxyl groups, said pH being ineffective to cleave aromatic ester bonds in said precipitate.

60. The method of claim 50 further comprising exposing said precipitate to a quenching agent having a pH effective to produce bis terminal hydroxyl groups, said pH being ineffective to cleave aromatic ester bonds in said precipitate.

61. The method of claim 55 wherein said quenching agent is an acidic aqueous solution having a pH of from about 5 to about 7.

62. The method of claim 57 wherein said quenching agent is an acidic aqueous solution having a pH of from about 5 to about 7.

63. The method of claim 60 wherein said quenching agent is an acidic aqueous solution having a pH of from about 5 to about 7.

64. The method of claim 56 wherein said amount of chlorinated solvent comprises a molar excess of from about 3 to about 7 relative to said aliphatic thiol.

65. The method of claim 56 wherein said amount of chlorinated solvent comprises a molar excess of 5 or more relative to said ethane thiol.

66. The method of claim 60 wherein said amount of chlorinated solvent comprises a molar excess of 5 or more relative to said ethane thiol.

67. The method of claim 55 wherein said chlorinated solvent is methylene chloride.

68. The method of claim 60 wherein said chlorinated solvent is methylene chloride.

69. The method of claim 63 wherein said chlorinated solvent is methylene chloride.

70. The method of claim 37 wherein said second conditions comprise a an initial temperature of about 0°

C.

71. The method of claim 37 wherein said second conditions comprise maintaining a temperature of about 25°

C. or less.

72. The method of claim 70 wherein second conditions comprise maintaining a temperature of about 25°

C. or less.

73. The method of claim 55 wherein said second conditions comprise an initial temperature of about 0°

C.

74. The method of claim 55 wherein said second conditions comprise maintaining a temperature of about 25°

C. or less.

75. The method of claim 73 wherein said second conditions comprise maintaining a temperature of about 25°

C. or less.

76. The method of claim 60 wherein said second conditions comprise an initial temperature of about 0°

C.

77. The method of claim 60 wherein said second conditions comprise maintaining a temperature of about 25°

C. or less.

78. The method of claim 76 wherein said second conditions comprise maintaining a temperature of about 25°

C. or less.

79. The method of claim 37 wherein said 4-alkoxy benzoyl chloride comprises an alkyl group having from about 1 to about 20 carbon atoms.

80. The method of claim 38 wherein said 4-alkoxy benzoyl chloride comprises an alkyl groups having from about 1 to about 9 carbon atoms.

81. The method of claim 37 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

82. The method of claim 38 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

83. The method of claim 57 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

84. The method of claim 72 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

85. The method of claim 78 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

86. The method of claim 38 further comprising reacting one or more of said bis-terminal hydroxyl groups with one or more 4-alkoxy benzoyl chloride molecules under said first conditions effective to produce elongated diphenolic platform molecules.

87. The method of claim 86 further comprising

exposing said diphenolic platform molecules comprising bis-terminal hydroxyl groups to less than a stoichiometric amount of 4-alkoxy benzoyl chloride under third conditions effective to produce a monoester product and a diester product;

and,

separating said monoester product.

88. The method of claim 87 further comprising reacting at least one terminal ester group on said monoester product with a polymerizable group.

89. The method of claim 88 wherein said method further comprises exposing a monoester solution comprising said monoester product to an alkyloyl chloride solution comprising bifunctional alkyloyl chloride under fourth conditions effective to react said at least one terminal ester group with said bifunctional alkyloyl chloride and to precipitate mesogenic dimer from said monoester solution, wherein said bifunctional alkyloyl chloride comprises an alkyl group having from about 2 to about 20 carbon atoms.

90. The method of claim 89 wherein said bifunctional alkyloyl chloride comprises an alkyl group having from about 6 to about 20 carbon atoms.

91. The method of claim 89 wherein said bifunctional alkyloyl chloride comprises an alkyl group having from about 6 to about 12 carbon atoms.

92. The method of claim 89 wherein said bifunctional alkyloyl chloride is sebacoyl chloride.

93. The method of claim 89 further comprising

preparing said monoester solution comprising said monoester, a quantity of basic amine sufficient to dissolve said monoester, and a first amount of chlorinated organic solvent;

and

preparing said alkyloyl chloride solution comprising a quantity of said bifunctional alkyloyl chloride, a second amount of chlorinated organic solvent, and a concentration of from about 1 to about 100 ppm of benzoquinone inhibitor.

94. The method of claim 93 wherein

said quantity of basic amine is about 10 milliliters per gram of said monoester;

said first amount of said chlorinated organic solvent is substantially the same as said quantity on a volume basis;

said second amount of chlorinated organic solvent is about 10 milliliters per gram of said alkyloyl chloride; and

said concentration of benzoquinone inhibitor is about 10 ppm.

95. The method of claim 89 wherein said fourth conditions are effective to precipitate said mesogenic dimer.

96. A method of making platform molecules comprising:

reacting 4-alkoxy benzoyl chloride with R²-hydroquinone under first conditions effective to produce bis 1,4[4-alkoxybenzoyloxy]-R²-phenylene comprising bis terminal alkoxy groups comprising alkyl groups having from about 1 to 6 carbon atoms wherein R² is a bulky organic group;

exposing a quantity of said bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene to second conditions to produce a final solution, said second conditions comprising an amount of methylene chloride, a concentration of aluminum chloride at a ratio of 4;

1 or more to said quantity of bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene, and at least one mole of ethane thiol per mole of said bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene, said second conditions being effective to precipitate complexes out of said final solution substantially as they are formed, the precipitated complexes comprising said platform molecules comprising intact aromatic ester bonds, said amount of said methylene chloride being effective to maintain said precipitated complexes in slurry form.

97. The method of claim 96 wherein said amount of ethane thiol comprises at least two moles of ethane thiol per mole of said bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene.

98. The method of claim 96 further comprising exposing said precipitate to a quenching agent having a pH effective to produce bis terminal hydroxyl groups, said pH being ineffective to cleave aromatic ester bonds in said precipitate.

99. The method of claim 97 further comprising exposing said precipitate to a quenching agent having a pH effective to produce bis terminal hydroxyl groups, said pH being ineffective to cleave aromatic ester bonds in said precipitate.

100. The method of claim 98 wherein said quenching agent is an acidic aqueous solution having a pH of from about 5 to about 7.

101. The method of claim 99 wherein said quenching agent is an acidic aqueous solution having a pH of from about 5 to about 7.

102. The method of claim 96 wherein said amount of methylene chloride comprises a molar excess of from about 3 to about 7 relative to said ethane thiol.

103. The method of claim 101 wherein said amount of methylene chloride comprises a molar excess of from about 3 to about 7 relative to said ethane thiol.

104. The method of claim 101 wherein said amount of methylene chloride comprises a molar excess of 5 or more relative to said ethane thiol.

105. The method of claim 96 wherein said temperature comprises an initial temperature of about 0°

C.

106. The method of claim 99 wherein said temperature comprises an initial temperature of about 0°

C.

107. The method of claim 100 wherein said temperature comprises an initial temperature of about 0°

C.

108. The method of claim 103 wherein said temperature comprises an initial temperature of about 0°

C.

109. The method of claim 104 wherein said temperature comprises an initial temperature of about 0°

C.

110. The method of claim 96 wherein said quantity of said bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene is about 150 mmolar or more.

111. The method of claim 108 wherein said quantity of said bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene is 150 mmolar or more.

112. The method of claim 96 wherein said quantity of said bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene is from about 150 mmolar to about 250 mmolar.

113. The method of claim 109 wherein said quantity of said bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene is from about 150 mmolar to about 250 mmolar.

114. The method of claim 109 wherein said quantity of said bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene is about 220 mmolar.

115. The method of claim 96 wherein said quantity of said bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene is about 7 millimoles (mmol) per milliliter (ml) of ethane thiol.

116. The method of claim 113 wherein said quantity of said bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene is about 7 mmol of methyl ether per ml of ethane thiol.

117. The method of claim 114 wherein said quantity of said bis 1,4[4-alkoxy benzoyloxy]-R²-phenylene is about 7 mmol of methyl ether per ml of ethane thiol.

118. The method of claim 96 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

119. The method of claim 98 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

120. The method of claim 100 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

121. The method of claim 103 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

122. The method of claim 104 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

123. The method of claim 116 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

124. The method of claim 117 wherein said 4-alkoxy benzoyl chloride is 4-methoxy benzoyl chloride.

125. The method of claim 98 further comprising reacting one or more of said bis-terminal hydroxyl groups with one or more 4-alkoxy benzoyl chloride molecules under said first conditions effective to produce elongated diphenolic platform molecules.

126. The method of claim 125 further comprising

exposing said diphenolic platform molecules comprising bis-terminal hydroxyl groups to less than a stoichiometric amount of 4-alkoxy benzoyl chloride under third conditions effective to produce a monoester product and a diester product;

and,

separating said monoester product.

127. The method of claim 126 wherein said method further comprises reacting at least one terminal ester group on said monoester product with a polymerizable group.

128. The method of claim 127 wherein said method further comprising exposing a monoester solution comprising said monoester product to an alkyloyl chloride solution comprising bifunctional alkyloyl chloride under fourth conditions effective to react said at least one terminal ester group with said bifunctional alkyloyl chloride and to precipitate mesogenic dimer from said monoester solution, wherein said bifunctional alkyloyl chloride comprises an alkyl group having from about 2 to about 20 carbon atoms.

129. The method of claim 128 wherein said bifunctional alkyloyl chloride comprises an alkyl group having from about 6 to about 20 carbon atoms.

130. The method of claim 128 wherein said bifunctional alkyloyl chloride comprises an alkyl group having from about 6 to about 12 carbon atoms.

131. The method of claim 128 wherein said bifunctional alkyloyl chloride is sebacoyl chloride.

132. The method of claim 128 further comprising

preparing said monoester solution comprising said monoester, a quantity of basic amine sufficient to dissolve said monoester, and a first amount of chlorinated organic solvent;

and

preparing said alkyloyl chloride solution comprising a quantity of said bifunctional alkyloyl chloride, a second amount of chlorinated organic solvent, and a concentration of from about 1 to about 100 ppm of benzoquinone inhibitor.

133. The method of claim 132 wherein

said quantity of basic amine is about 10 milliliters per gram of said monoester;

said first amount of said chlorinated organic solvent is substantially the same as said quantity on a volume basis;

said second amount of chlorinated organic solvent is about 10 milliliters per gram of said alkyloyl chloride; and

said concentration of benzoquinone inhibitor is about 10 ppm.

134. The method of claim 128 wherein said fourth conditions are effective to precipitate said mesogenic dimer.