A facile cesium fluoride-mediated synthesis of aromatic polyethers from bisphenols and activated aromatic dihalides

Imai, Yoshio; Ishikawa, Hironobu; Park, Kihong; Kakimoto, Masa–aki

doi:10.1002/(sici)1099-0518(19970730)35:10<2055::aid-pola21>3.0.co;2-e

Cited by 21 publications

(19 citation statements)

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“…The presence of trace amounts of water in association with fluoride ions produced during the reaction in the solution will cause serious polymer degradations by side reactions such as hydrolysis and chain scission. [17][18][19][20] It has been reported that the introduction of calcium or magnesium carbonates into the reaction associated with an alkali metal carbonate facilitates the polycondensation. [21][22][23][24][25] Very high molecular weight poly(arylene ether)s have been synthesized when a mixture of calcium carbonate and a small amount of potassium carbonate is used, whereas only low molecular weight polymers are produced using potassium carbonate alone.…”

Section: Introductionsupporting

confidence: 70%

“…A set of Microstyragel columns (10 3 , 10 4 , and 10 5 Å ) were used and calibrated with polystyrene standards in THF. The values of polystyrene equivalent number average molecular weight (M n ) are found very close to those determined from the end-group analysis by 19 F NMR. In this regard, see also the GPC analysis of the cyclic fraction in ref.…”

Section: Instrumentationmentioning

confidence: 99%

“…[3] Consequently, in M n and M w =M n calculations, this portion was eliminated from the GPC curve using a peak resolution technique. NMR spectra were recorded in CDCl 3 using a Varian Unity Inova spectrometer at a resonance frequency of 400 MHz for 1 H and 376 MHz for 19 F. CFCl 3 was used as an internal standard (0 ppm) for the 19 F NMR measurements. IR spectra were collected using a Scheme 1.…”

Section: Instrumentationmentioning

confidence: 99%

“…This is extremely advantageous since the presence of F À in the reaction solution can attack the polymer and degrade the polymer chain in addition to hydrolysis and cyclization reactions. [14][15][16][17][18][19][20] …”

Section: Introductionmentioning

confidence: 99%

“…However, under these conventional reaction conditions with the use of K 2 CO 3 , [5][6][7] water is produced during the reaction and has to be removed due to the potential hydrolysis of the polymer. [16] Therefore, a low boiling, non-polar co-solvent such as toluene has been introduced into the reaction medium to facilitate the removal of water by azeotropic distillation [5][6][7] or by refluxing. [3,13] Unfortunately, this approach reduces the polarity of the polymerization medium and results in a lower selectivity of the reaction.…”

Section: Introductionmentioning

confidence: 99%

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Highly Fluorinated Poly(arylene ether ketone) Prepared by a CaH₂‐Mediated Polycondensation Reaction

Ding

Day

Robertson

et al. 2004

Macro Chemistry & Physics

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Summary: A new reaction procedure has been developed for the polycondensation of hexafluorobisphenol A (6F‐BPA) with bis(pentafluorophenyl) ketone (BPK) in dimethylacetamide (DMAc). In this reaction, CaH2 has been used as a base to facilitate the formation of the phenolate; an alkali metal fluoride was used as a catalyst. Unlike the conventional polycondensation reactions, this procedure avoided producing water during the reaction, and hence, azeotropic distillation with the assistant of a low‐polar co‐solvent is not required. This improvement maintains the high polarity of the reaction medium; consequently, the selectivity of the reaction at the para‐position of BPK is significantly enhanced and polymers with high molecular weights ($\overline M _{\rm n}$ ca. 30 000 Da) can be obtained with very low branching contents (less than 3 mol‐%) and free of any cross‐linked gel particles. In addition to avoiding the formation of water in the reaction, the use of CaH2 also reduced the concentration of the fluoride ion in the solution. These effects minimize chain degradation reactions such as hydrolysis. The use of CaO instead of CaH2 for this reaction produces similar effects. In the case of CaO, traces of water can be introduced into the reaction. The presence of trace amounts of water increases the polycondensation rate, probably due to the enhanced ionization of the phenolate. However, it also causes a hydrolysis of polymer chains, resulting in the elimination of the ketone group in the polymer backbone. Fortunately, this side reaction is highly water and temperature dependent, and can be efficiently prevented by using CaH2 or conducting the reaction at a lower temperature (<65 °C).CaH2‐mediated polycondensation for the preparation of highly fluorinated poly(arylene ether ketone).imageCaH2‐mediated polycondensation for the preparation of highly fluorinated poly(arylene ether ketone).

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Section: Introductionsupporting

confidence: 70%

Section: Instrumentationmentioning

confidence: 99%

Section: Instrumentationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Highly Fluorinated Poly(arylene ether ketone) Prepared by a CaH₂‐Mediated Polycondensation Reaction

Ding

Day

Robertson

et al. 2004

Macro Chemistry & Physics

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A Low Temperature Polycondensation for the Preparation of Highly Fluorinated Poly(arylene ether sulfone)s Containing Crosslinkable Pentafluorostyrene Moieties

Ding¹,

Qi²,

Day³

et al. 2005

Macro Chemistry & Physics

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Summary: The polycondensation of pentafluorophenyl sulfone (PPSO) with hexafluorobisphenol A (6F‐BPA), or a model compound, 4‐phenoxylphenol (POPOH), has been studied in order to find optimized reaction conditions for the preparation of fluorinated poly(arylene ether sulfone)s (FPAESs). It was found that PPSO had a very high reactivity in N,N‐dimethylacetamide (DMAc), allowing the reaction to occur at temperatures as low as 22 °C, even in the absence of any catalyst. This reaction was promoted by the addition of a trace amount of potassium fluoride (KF). Increasing the amount of KF to 1.05 equiv enhanced the conversion and allowed the reaction to be completed in a short time. Under this reaction condition, KF acted as a catalyst to activate the phenol group and also acted as a base to absorb the HF, which was a by‐product of the polycondensation, to produce high molecular weight polymer. The use of calcium hydride (CaH2) instead of KF as a base in this reaction produced a similar effect with a slightly lower reaction rate. Both base systems were also applicable to the reaction of pentafluorostyrene (FSt) with 6F‐BPA. However, a much higher reaction temperature (125 °C) was required due to the low reactivity of FSt. Reacting FSt with an excess of 6F‐BPA produced a mixture of mono‐ and di‐substituted products of FSt with a controllable ratio, which could further react with PPSO to produce a polymer containing crosslinkable FSt moieties both as end‐capping groups and inserting units. This structure allowed the molecular weight of the polymer and the content of FSt to be adjusted independently. Crosslinked films of this polymer demonstrated an excellent processability and performance in waveguide applications, having refractive indices of 1.5061 (TE) and 1.5038 (TM), and a straight waveguide loss of 0.7 dB · cm−1.

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Synthesis and properties of new aromatic poly‐(ether benzoxazole)s from 2,2′‐bis(4‐amino‐3‐hydroxyphenoxy)biphenyl and aromatic dicarboxylic acid chlorides

Imai

Maeda

Takeuchi

et al. 2002

J. Polym. Sci. A Polym. Chem.

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A new bis(o‐aminophenol) with a crank and twisted noncoplanar structure and ether linkages, 2,2′‐bis(4‐amino‐3‐hydroxyphenoxy)biphenyl, was synthesized by the reaction of 2‐benzyloxy‐4‐fluoronitrobenzene with biphenyl‐2,2′‐diol, followed by reduction. Biphenyl‐2,2′‐diyl‐containing aromatic poly(ether benzoxazole)s with inherent viscosities of 0.52–1.01 dL/g were obtained by a conventional two‐step procedure involving the polycondensation of the bis(o‐aminophenol) monomer with various aromatic dicarboxylic acid chlorides, yielding precursor poly(ether o‐hydroxyamide)s, and subsequent thermal cyclodehydration. These new aromatic poly(ether benzoxazole)s were soluble in methanesulfonic acid, and some of them dissolved in m‐cresol. The aromatic poly(ether benzoxazole)s had glass‐transition temperatures of 190–251 °C and were stable up to 380 °C in nitrogen, with 10% weight losses being recorded above 520 °C. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2656–2662, 2002

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A facile cesium fluoride-mediated synthesis of aromatic polyethers from bisphenols and activated aromatic dihalides

Cited by 21 publications

References 0 publications

Highly Fluorinated Poly(arylene ether ketone) Prepared by a CaH₂‐Mediated Polycondensation Reaction

Highly Fluorinated Poly(arylene ether ketone) Prepared by a CaH₂‐Mediated Polycondensation Reaction

A Low Temperature Polycondensation for the Preparation of Highly Fluorinated Poly(arylene ether sulfone)s Containing Crosslinkable Pentafluorostyrene Moieties

Synthesis and properties of new aromatic poly‐(ether benzoxazole)s from 2,2′‐bis(4‐amino‐3‐hydroxyphenoxy)biphenyl and aromatic dicarboxylic acid chlorides

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A facile cesium fluoride-mediated synthesis of aromatic polyethers from bisphenols and activated aromatic dihalides

Cited by 21 publications

References 0 publications

Highly Fluorinated Poly(arylene ether ketone) Prepared by a CaH2‐Mediated Polycondensation Reaction

Highly Fluorinated Poly(arylene ether ketone) Prepared by a CaH2‐Mediated Polycondensation Reaction

A Low Temperature Polycondensation for the Preparation of Highly Fluorinated Poly(arylene ether sulfone)s Containing Crosslinkable Pentafluorostyrene Moieties

Synthesis and properties of new aromatic poly‐(ether benzoxazole)s from 2,2′‐bis(4‐amino‐3‐hydroxyphenoxy)biphenyl and aromatic dicarboxylic acid chlorides

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Product

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Highly Fluorinated Poly(arylene ether ketone) Prepared by a CaH₂‐Mediated Polycondensation Reaction

Highly Fluorinated Poly(arylene ether ketone) Prepared by a CaH₂‐Mediated Polycondensation Reaction