Effect of association of dicarboxylic acids activated by TsCl/DMF/pyridine upon the copolycondensation with bisphenols

Abstract

When a mixture of terephthalic acid (TPA) and various dicarboxylic acids was activated by tosyl chloride (TsCl)/dimethyl‐ formamide (DMF)/pyridine (Py), the resulting mixture became dissolved in Py, although the activated TPA was insoluble even at 120 °C. The temperature at which the mixture became soluble was varied with their compositions and the structure of diacids. Mixing the separately activated TPA and isophthalic acid (IPA) also improved the solubility of the activated TPA to some extent. The interesting phenomena were attributed to associations of the activated diacids through the dipole–dipole interactions between the carbonyl groups. The structures of associates were estimated in terms of transition temperatures of the thermotropic IPA/TPA‐methylhydroquinone and IPA/TPA‐chlorohydroquinone copolymers. The transition temperatures were significantly affected by the temperature of polycondensation, the preparative procedures of a mixture of the activated diacids, and several additives. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 196–201, 2001

Copolycondensations of bisphenols with aggregates of isophthalic acid and terephthalic acid activated by tosyl chloride/dimethylformamide/pyridine in different manners

“…Alternatively, the compositions of I IPA and I TPA in the aggregates were estimated from the sequence distributions of IPA and TPA in the thermotropic copolyesters prepared by II IPA/TPA and IV IPA/TPA , similarly to our previous articles. 3,5,6 For comparison, a separate experiment with III IPA/TPA was done. Copolycondensations of IPA, TPA, and MeHQ or ClHQ were studied because the thermotropic IPA/TPA-MeHQ and IPA/TPA-ClHQ copolymers have been well studied, and the sequences can roughly but easily be estimated from their T m 's, the transition temperature of the solid phase to a nematic mesophase, by DSC and microscopic observation.…”

“…In accordance with our previous article, 6 II IPA and II TPA were separately prepared from IPA (2.5 mmol), TsCl (6.5 mmol), and DMF (5 mmol) in Py (10 mL) and from TPA (2.5 mmol, 50 -30 mol %), TsCl (6.5 mmol), and DMF (5 mmol) in Py (10 mL), respectively, and mixed thoroughly with Py (5 mL). The mixture was aged at room temperature for 10 min and then heated at 120°C for 10 min to effect the solution.…”

“…1,2 Therefore, to our knowledge only a few studies have been done to prepare copolyarylates with modified monomer sequences through control of the copolycondensation. [3][4][5] We reported 6 that when a mixture of terephthalic acid (TPA) and isophthalic acid (IPA) was activated by a tosyl chloride (TsCl)/dimethylformamide (DMF)/pyridine (Py) condensing agent, aggregates of the activated IPA and TPA (II IPA/TPA in Scheme 1) were formed. They were different from those (III IPA/TPA ) prepared by the mixing of the separately activated TPA (II TPA ) and IPA (II IPA ) with regard to the solubility in Py and the thermal properties of the thermotropic IPA/TPAmethylhydroquinone (MeHQ) and IPA/TPA-chlo-rohydroquinone (ClHQ) copolymers produced from them.…”

Copolycondensation of various compositions of isophthalic acid and terephthalic acid with hydroquinones or bisphenols by tosyl chloride/dimethylformamide/pyridine

“…The copolycondensation of various molar ratios of IPA to TPA with BPs was carried out according to earlier procedures. 6,7…”

“…5 It has been assumed that the activated IPA and TPA might associate to form aggregates, the structures of which might control the relative contents of BPs in the aggregates; they have been estimated from the sequence distributions of BPs in the resultant copolymers determined by NMR. The associations have also been examined from the sequences of dicarboxylic acid components in the thermotropic copolyesters evaluated by the transition temperatures of the solid state to a nematic mesophase, 6,7 but not with respect to their influence on the molecular weights of the resulting copolymers.…”