Polycondensation of Terephthalic Acid and 3,3′-Dimethyl Bisphenol A with TsCl/DMF/Py in the Presence of Salts

Higashi, Fukuji; Shirai, Takayo

doi:10.1002/1521-3927(200102)22:2<109::aid-marc109>3.0.co;2-t

Cited by 10 publications

(14 citation statements)

References 5 publications

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“…Separately prepared, II IPA and II TPA were insoluble at room temperature in Py, but a mixture of II IPA and II TPA , obtained by the acti- vation of a mixture of 70 mol % IPA and 30 mol % TPA, was soluble even at room temperature. In addition, II TPA was insoluble at the boiling point of Py but became readily soluble at 100°C by the activation of TPA in the presence of LiCl or ammonium and phosphonium salts 10 and when heated in the presence of these salts.…”

Section: Resultsmentioning

confidence: 99%

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

Higashi

Takakura

Sumi

2004

J. Polym. Sci. A Polym. Chem.

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The polycondensation of isophthalic acid (IPA)/terephthalic acid (TPA) with aromatic diols by tosyl chloride/dimethylformamide/pyridine in solution was examined through changes in the IPA/TPA compositions, the kinds of dihydroxyl components, the periods of their addition, and the reaction temperatures. The reaction proceeded favorably at IPA/TPA ratios of 70/30 to 50/50, similarly to an earlier report on the interfacial reaction. The effects of the compositions were significant in the reactions with monosubstituted hydroquinones. The results were examined from distributions of the resulting oligomers prepared at a reaction extent of 0.7, determined by gel permeation chromatography. The reaction producing better results exhibited distributions closer to the theoretical ones. The period of addition also favorably affected the distributions as well as the results of the polycondensation. These results were attributed to the change in the reaction method, in which the diols reacted with the aggregates that formed from the activated IPA and TPA. The change was likely caused by the degree of association of IPA and TPA in the aggregates, on the basis of melting points and IR spectra of mixtures of dimethyl esters of IPA and TPA prepared by the quenching of the aggregates with methanol. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2321–2328, 2004

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Section: Resultsmentioning

confidence: 99%

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

Higashi

Takakura

Sumi

2004

J. Polym. Sci. A Polym. Chem.

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“…Numerous types of preparation procedures have been reported7–27 for aromatic polyester besides polycondensation with eliminating acetic acid. Among them, direct polycondensation15–27 is very attractive to control the morphology of aromatic polyesters because the condensation reagent must influence significantly the morphology. The direct copolycondensation of p ‐hydroxybenzoic acid (HBA) and other monomers has been reported 15–24.…”

Section: Introductionmentioning

confidence: 99%

“…Among them, direct polycondensation15–27 is very attractive to control the morphology of aromatic polyesters because the condensation reagent must influence significantly the morphology. The direct copolycondensation of p ‐hydroxybenzoic acid (HBA) and other monomers has been reported 15–24. However, the direct homopolymerization of HBA has not been examined in detail because of the precipitation during polymerization, and research on the morphology of POB has not been conducted to our knowledge.…”

Section: Introductionmentioning

confidence: 99%

Viability of Möbius Topologies in [26]‐ and [28]Hexaphyrins

Alonso

Geerlings

Proft

2012

Chemistry A European J

101

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Recently, hexaphyrins have emerged as a promising class of π-conjugated molecules that display a range of interesting electronic, optical, and conformational properties, including the formation of stable Möbius aromatic systems. Besides the Möbius topology, hexaphyrins can adopt a variety of conformations with Hückel and twisted Hückel topologies, which can be interconverted under certain conditions. To determine the optimum conditions for viable Möbius topologies, the conformational preferences of [26]- and [28]hexaphyrins and the dynamic interconversion between the Möbius and Hückel topologies were investigated by density functional calculations. In the absence of meso substituents, [26]hexaphyrin prefers a planar dumbbell conformation, strongly aromatic and relatively strain free. The Möbius topology is highly improbable: the most stable tautomer is 33 kcal mol(-1) higher in energy than the global minimum. On the other hand, the Möbius conformer of [28]hexaphyrin is only 6.5 kcal mol(-1) higher in energy than the most stable dumbbell conformation. This marked difference is due to aromatic stabilization in the Möbius 4n electron macrocycle as opposed to antiaromatic destabilization in the 4n+2 electron system, as revealed by several energetic, magnetic, structural, and reactivity indices of aromaticity. For [28]hexaphyrins, the computed activation barrier for interconversion between the Möbius aromatic and Hückel antiaromatic conformers ranges from 7.2 to 10.2 kcal mol(-1), in very good agreement with the available experimental data. The conformation of the hexaphyrin macrocycle is strongly dependent on oxidation state and solvent, and this feature creates a promising platform for the development of molecular switches.

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“…An equivalent of LiCl with respect to the carboxyl groups of the diacids was used because it was most effective. 6 LiCl participated during several stages of the reaction (Scheme 1). (TPA) m and (TPA) n denote hydrogen-bonded aggregates of unactivated terephthalic acid, m and n being the degrees of aggregation (m Ͼ n).…”

Section: Resultsmentioning

confidence: 99%

“…[2][3][4][5] However, the reaction with dicarboxylic acids, such as terephthalic acid (TPA), does not proceed smoothly and produces only low-molecular-weight polyesters because the dicarboxylic acids activated by TsCl/DMF/Py do not dissolve in the reaction medium (Py), even at high temperatures. Recently, we have reported that activated TPA of difficult solubility in Py becomes soluble when the activation is carried out in the presence of salts, 6 such as lithium chloride (LiCl) or phosphonium and ammonium salts, or other dicarboxylic acids, 7,8 and that the reaction yields satisfactory results.…”

Section: Introductionmentioning

confidence: 99%

Polyesterification of aromatic dicarboxylic acids and bisphenols with tosyl chloride/dimethylformamide/pyridine promoted by the improvement of the difficult solubility of the activated diacids with lithium chloride

Higashi

Kira

2004

J. Polym. Sci. A Polym. Chem.

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The solution polyesterification of dicarboxylic acids in pyridine, the activated intermediates of which were difficult to dissolve in tosyl chloride/dimethylformamide/pyridine, was investigated in the presence of lithium chloride. The solubility of the activated dicarboxylic acids was largely improved by the presence of the salt, and the polycondensation with bisphenols was greatly facilitated. The salt was more effectively added to a pyridine solution of dicarboxylic acids than to the activated dicarboxylic acids in pyridine. The favorable additive effect on the improved solubility was attributed to a lowered degree of association of the activated dicarboxylic acids, which led to distributions of the resulting oligomers from bisphenols at an earlier stage closer to the theoretical ones and yielded better polycondensation results. The reaction, which proceeded through favorable distributions of the co-oligomers, produced copolymers of higher inherent viscosities and slightly block sequence distributions determined by NMR.

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Polycondensation of Terephthalic Acid and 3,3′-Dimethyl Bisphenol A with TsCl/DMF/Py in the Presence of Salts

Cited by 10 publications

References 5 publications

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

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

Viability of Möbius Topologies in [26]‐ and [28]Hexaphyrins

Polyesterification of aromatic dicarboxylic acids and bisphenols with tosyl chloride/dimethylformamide/pyridine promoted by the improvement of the difficult solubility of the activated diacids with lithium chloride

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