Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
  • C07C69/76—Esters of carboxylic acids having a carboxyl group bound to a carbon atom of a six-membered aromatic ring
  • C07C69/84—Esters of carboxylic acids having a carboxyl group bound to a carbon atom of a six-membered aromatic ring of monocyclic hydroxy carboxylic acids, the hydroxy groups and the carboxyl groups of which are bound to carbon atoms of a six-membered aromatic ring
  • C07C69/90—Esters of carboxylic acids having a carboxyl group bound to a carbon atom of a six-membered aromatic ring of monocyclic hydroxy carboxylic acids, the hydroxy groups and the carboxyl groups of which are bound to carbon atoms of a six-membered aromatic ring with esterified hydroxyl and carboxyl groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
  • C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
  • C08G63/16—Dicarboxylic acids and dihydroxy compounds
  • C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
  • C08G63/19—Hydroxy compounds containing aromatic rings
  • C08G63/193—Hydroxy compounds containing aromatic rings containing two or more aromatic rings
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K19/00—Liquid crystal materials
  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/38—Polymers
  • C09K19/3804—Polymers with mesogenic groups in the main chain
  • C09K19/3809—Polyesters; Polyester derivatives, e.g. polyamides

Definitions

• Fig. 1 which forms a portion of the instant specification, illustrates the structure of this known aromatic ester triad.
• References which related to the synthesis and evaluation of such known structure include: C. Ober et al.. Polymer J. 14, 9 (1982); G. Galli et al., Makromol. Chem. 183, 2693 (1982); and A. Y. Bilibin et al., Makromol. Chem. 186, 1575 (1985).
• the polymers just described have been shown to be thermotropic liquid crystalline polymers which can exhibit either a nematic or a smectic mesophase.
• Liquid crystalline polyesters can be synthesized by step-growth polymerization techniques. Two basic methods are generally used. The first involves growing the polymer from solution involving the reaction of a diol with a diacid chloride. The problem of polymer solubility, however, can be a limiting factor in the preparation of high molecular weight polymers, especially in the case of aromatic polyesters. The second method avoids such problems by carrying out the reaction in the absence of solvent. Such bulk (or melt) polymerization techniques (see V. V. Korshak et al., "Experimental Methods of Bulk Polymerization", Comprehensive Polymer Science, Vol. 5, G.
• the present invention relates, in one aspect, to novel monomers which can be used as precursors in the synthesis of the triad polymers previously described.
• Fig. 2 shows a synthesis route which can be used to make these monomers which are alkylene bis(p-acetoxybenzoate) compounds. It is contemplated that the phenyl rings in these compounds can be independently substituted with such substituents as lower alkyl, aryl, halogen and the like.
• the monomers which are intended to be the subject of the invention can have r range from about 3 to about 8.
• the instant invention in another aspect, also relates to preparation of the aforementioned type of aromatic triad liquid crystalline polymer by reaction of the foregoing type of alkylene bis(a ⁇ etoxybenzoate) monomer with an aromatic dicarboxylic acid monomer to form the desired aromatic triad polyester with liberation of acetic acid by-product.
• a representative alkylene bis(acetoxybenzoate) monomer is depicted by (A) in Fig. 3 with the alkylene group being hexamethylene, namely -(CH 2 ) 6 -.
• the phenyl rings can be independently substituted with such substituents as lower alkyl, aryl, halogen, and the like.
• the alkylene group can be varied in its length, as described before, and can be generically depicted as -(CH 2 ) r with r ranging from 3 to 8. As depicted in Fig.
• this monomer (A) can be reacted with a dicarboxylic acid compound, such as terephthalic acid, in the absence of or, preferably, in the presence of a catalyst such as zinc acetate, using heat to produce the desired aromatic triad liquid crystalline polyester (B) with acetic acid by-product which is easily removed.
• the dicarboxylic acid reactant can have its phenyl ring substituted by the same substituents described above.
• Copolymers with mixtures of monomers e.g., with 50 mole % of a monomer where r is 4 and 50 mole % of a monomer where r is 6 may be prepared. These ratios can be widely varied to cover the entire compositional range (e.g., l%-99% to 99%-l%) .
• the instant process is one which is deemed to allow for synthesis of the type of aromatic triad polyester (B) in increased molecular weight as compared to solution methods.
• the acidolysis reaction does not occur to any extent between the carboxylic acid function and the internal diol ester groups so that essentially no scrambling of the units occurs.
• the process produces acetic acid as a by-product which can easily be removed under vacuum (see U.S. Patent No. 3,772,405 of F. L. Hamb) .
• This Example illustrates the preparation of butylene bis(p-acetoxybenzoate) which is the final compound depicted by 3a in the equation shown in Fig. 2.
• An amount equalling 93.5 grams of 4-acetoxybenzoic acid (Compound 1 in the reaction shown in Fig. 2) was mixed with 150 ml of thionyl chloride and stirred at 50°C for 3.5 hours. The excess thionyl chloride was removed under reduced pressure, and the remaining oil was vacuum distilled, and was then recrystallized in hexane, giving pure 4-acetoxybenzoyl chloride (Compound 2 in Fig. 2) with a melting point of 28°C at 75% yield.
• This Example shows preparation of hexamethylene bis(acetoxybenzoate) which is compound 3b in Fig. 2.
• Hexamethylene bis(acetoxybenzoate) was prepared and purified in a manner similar to the preparation described in Example 1 for the analogous butylene compound.
• 4-acetoxybenzoyl chloride (34.5 grams, 0.174 mole) was reacted with hexanediol (8.92 grams, 0.075 mole), to give the desired compound in 63% yield. It had a melting point of 84-85 ⁇ C.
• Analysis for (3b, C 24 H 26 0 8 ) Calculated: C, 65.15; H, 5.92. Found: C, 65.28; H, 5.93.
• the product was removed and ground, then treated at 215°C for twenty hours under vacuum to induce further reaction and increase the molecular weight of the product (see German Offen. No. 2,520,820, U.S. Patent No. 3,991,013, and H. R. Dicke et al., J. Poly . Sci., Polym. Chem. Ed., 21, 2581, 1983) .
• the product was then extracted with methanol and dried in a vacuum oven, to give 2.0 grams of polymer.
• the product was examined under an optical polarizing microscope and found to display a nematic schlieren texture.
• the polymer (B) exhibited a melting point of 241°C, and an isotropization temperature of 345°C, as determined by DSC.
• the inherent viscosity was measured to be 0.540 dl/g at 45.5°C in p-chlorophenol.
• the product was removed and ground, then treated at 180-192°C for six hours under vacuum to induce further reaction and increase molecular weight.
• the product was then extracted with methanol and dried in a vacuum oven, to give 2.8 grams of polymer.
• the product was examined under an optical polarizing microscope and found to display a nematic schlieren texture.
• the isotropization temperature was above the decomposition temperature, which began at 308°C as determined by TGA.
• the inherent viscosity was 0.42 dl/g at 45.7°C in p-chlorophenol.
• This Example shows preparation of a triad polymer of the general structure B in Fig. 3 where the repeating methylene unit is four carbons rather than six.
• the solid mixture was then placed into a reaction tube and was flushed with argon and a slow stream of argon was passed through the reaction tube.
• This reaction tube was then placed in a hot salt bath at 180°C, and the temperature was slowly raised to 285°C over a period of five hours.
• a high vacuum (less than 0.1 mm Hg) was applied, and the reaction temperature was raised to 295°C for one and one-half hours.
• the product was then removed, was ground and was then treated at 250°C for two hours under a high vacuum (less than 0.1 mm Hg) .
• the product was then extracted with methanol and was dried in a vacuum oven to give 3.4 gm of polymer.
• the product was examined under an optical polorizing microscope and was found to display a nematic schlieren texture.
• the polymer exhibited a melting point of 243°C.
• the isotropization temperature which was 340°C, as determined by TGA.
• the inherent viscosity was to be 0.524 dl/g at 45.6°C in p-chlorophenol.

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• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Crystallography & Structural Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Polyesters Or Polycarbonates (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 1991
  • 1991-04-26 JP JP91509149A patent/JPH05507514A/ja active Pending
  • 1991-04-26 EP EP19910909643 patent/EP0527201A4/en not_active Withdrawn
  • 1991-04-26 CA CA002082830A patent/CA2082830A1/en not_active Abandoned
  • 1991-04-26 WO PCT/US1991/002883 patent/WO1991017137A1/en not_active Application Discontinuation

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