Aromatic polymers obtained by precipitation polycondensation: 4. Synthesis of poly(ether ketone ketone)s

Zolotukhin, Mikhail G.; Rueda, Daniel R.; Calleja, F. J. Baltà; Cagiao, M. E.; Bruix, Marta; Sedova, E. A.; Gileva, N. G.

doi:10.1016/s0032-3861(97)89719-4

Cited by 70 publications

(62 citation statements)

References 7 publications

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“…They can be prepared by the so-called nucleophilic route [1,[3][4][5][6] or the electrophilic route [7][8][9][10][11][12][13][14] involving a (FC) [15,16] polyacylation [17][18][19][20]. In Fig.…”

Section: Introductionmentioning

confidence: 99%

“…If these carbonyl groups are positioned ortho-to an ether group in PAEKs synthesized through the electrophilic route due to the nucleophilicity of both the o-and p-position of DPE, an intramolecular electrophilic attack yields a cyclization into a structure containing a xanthydrol motif (Fig. 1c) [13,14,23]. To the authors' best knowledge, no computational studies have been carried out that aim to explain the formation of such structures.…”

Section: Introductionmentioning

confidence: 99%

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A DFT study of the formation of xanthydrol motifs during electrophilic poly(aryl ether ketone) synthesis

et al. 2015

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The reaction pathway of the cyclization of 2-phenoxybenzophenone into 9-phenyl-9H-xanthen-9-ol in the presence of acid and an excess of AlCl33 was studied using density functional theory. This type of reaction is known to occur during the Friedel-Crafts polycondensation of poly(aryl ether ketones) following the undesired benzoylation of nucleophilic positions ortho- to the growing polymer's ether groups. The formed defect acts as an undesired terminator of the polymer chain, causing severe problems in the polymer's melt state. A branched, multistep mechanism reminiscent of the Friedel-Crafts acylation reaction is discovered; the reaction starts with the protonation of the carbonyl oxygen, followed by intramolecular electrophilic attack on the carbonyl carbon that determines the turnover frequency of the catalytic cycle and ends by deprotonation of the Wheland intermediate.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A DFT study of the formation of xanthydrol motifs during electrophilic poly(aryl ether ketone) synthesis

et al. 2015

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“…Preparations of PEKs are classified into two methods; the aromatic nucleophilic substitution and the aromatic electrophilic substitution, so-called Friedel-Crafts acylation catalyzed by aluminum trichloride (AlCl 3 ) [1]. In the latter case, the reaction gives a precipitate of the complex of oligomer and catalyst in the course of polymerization [2][3][4][5][6]. It has been revealed that even though the oligomer is precipitated, the molecular weight of PEK increases with reaction time in the precipitates formed in 1,2-dichloroethane (DCE) [3,5,7].…”

Section: Introductionmentioning

confidence: 99%

Consideration of Solvent Effect on Precipitation Polymerization of Poly(ether-ketone)s via Friedel-Craft Acylation

et al. 2006

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Precipitation polymerization of diphenyl ether and isophthaloyl chloride catalyzed by AlCl 3 via Friedel-Crafts acylation was examined in various solvents to clarify the polymerization behavior. Polymerizations were carried out in three categorized solvents based on the solubility to both catalyst and polymer, which were cyclohexane (CH), 1,2-dichloroethane (DCE) and DCE containing 2 wt% nitrobenzene (2%-NB). In DCE which was widely used, the oligomers were precipitated as a form of the complex with AlCl 3 at the early stage of polymerization. The precipitates of the oligomers were swollen by the solvent, in which any short-range regular structure did not exist. The further polymerization proceeded even in the precipitates with eliminating by-produced HCl, and high molecular weight poly(ether-ketone)s (PEK) were finally formed. Nevertheless the reaction in 2%-NB yielded the well-swollen precipitates, the high molecular weight PEK was not synthesized in the precipitates because the reaction was terminated by not only the inefficient elimination of HCl due to the higher solubility of HCl but also the deactivation of catalyst by coordination of NB to AlCl 3 . Although the precipitation occurred more readily in CH due to the lower solubility of oligomers, the polymer was not synthesized in the precipitates. The resulting precipitates comprised of the dimers were not swollen in this case, and thereby it was very difficult to react between dimers and eliminate HCl from the precipitates. The solvents having high miscibility to catalyst and the polymers, low solubility of HCl gas, and no basicity are necessary for making high molecular weight polymers via the precipitation polymerization.

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“…Moreover, influence of monomer stoichiometric ratio on the molecular weight of resultant polymer is another characteristic phenomenon; it was reported that the polymerization with excess of DPE gave relatively higher molecular weight polymer than that with excess of IPC did. 14 As described above, the polymerization of PEK by Friedel-Crafts acylation has several characteristics different from general polycondensation reactions. Therefore, understanding of the polymerization mechanism of PEK with phase separation, especially the reaction mechanism in the precipitate, is very important and may lead us to control the polymerization process and the morphology of resultant polymers.…”

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confidence: 99%

“…Therefore, understanding of the polymerization mechanism of PEK with phase separation, especially the reaction mechanism in the precipitate, is very important and may lead us to control the polymerization process and the morphology of resultant polymers. Change in the inherent viscosity of polymer in the precipitate and oligomer in the solution with reaction time was chased in the past, 13,14 however, further investigation has not yet been investigated. In this study, the polymerization of PEK by Friedel-Crafts acylation was characterized mainly by using NMR method.…”

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confidence: 99%

Polymerization Behavior of Poly(ether ketone) via Friedel–Crafts Acylation Studied by End-Group Analysis with 1H NMR

Sakaguchi

Kimura

Omori

et al. 2002

Polym J

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ABSTRACT:Polymerization process of poly(ether ketone) made of diphenyl ether (DPE) and isophthaloyl chloride (IPC) catalyzed by aluminum chloride in dichloroethane was characterized by 1 H NMR. The polymerization gave a precipitate of polymer/catalyst complex during the reaction. End-group analyses for polymer appeared as precipitate and oligomers stayed in the solution were carried out respectively after decomposition of the complex by treatment with methanol. Time dependence of the content of end groups showed that the oligomer of which molecular weight exceeded a critical value precipitated out independent of the functionality of the end groups, and further reaction proceeded in the precipitate as well as in the solution. Another approach to understand the reaction was carried out by direct 1 H NMR observation of the polymerization in an NMR sample tube. This experiment detected the molecular weight change of soluble oligomer in the reaction system at real time, and the results were consistent with those of isolated oligomers described above.KEY WORDS Poly(ether ketone) / Friedel-Crafts Acylation / End-Group Analysis / 1 H NMR / Polymer-Catalyst Complex / Precipitate / Poly(arylene ether ketone)s (PEKs) are well known as high performance semicrystalline polymers having excellent thermal stability, mechanical properties and solvent resistance.Preparations of PEKs are classified into two methods. [1][2][3] One is the aromatic nucleophilic substitution reaction between activated aromatic halides and alkali metal phenoxides in which ether linkages are formed. This method is used for the production of not only poly(ether ether ketone) (PEEK), most popular representative of PEKs, but also commercial polysulfones and poly(ether sulfone)s. The other method is the aromatic electrophilic substitution reaction between electron-rich aromatic hydrocarbons and aromatic acid chlorides in which ketone linkages are formed. This polymerization is carried out either in an organic solvent with aluminum chloride as a catalyst, 4, 5 FriedelCrafts acylation, or in hydrogen fluoride/boron trifluoride as a catalyst and solvent. 6, 7 The polymerization also includes dehydrative acylation reaction in polyphosphoric acid, 8,9 in trifluoromethanesulfonic acid 10 and in a methanesulfonic acid/phosphorus pentoxide medium. 11 Preparation of poly(ether ketone)s with FriedelCrafts acylation catalyzed by aluminum chloride in dichloroethane as a solvent can be carried out under moderate conditions, and is considered as a convenient method to obtain poly(ether ketone)s on a laboratory scale. Furthermore, various combinations of monomers afford a number of structures of polymers.The polymerization by Friedel-Crafts acylation gives a precipitate of the complex of polymer and catalyst in the course of polymerization. 12 It has been revealed that the molecular weight of PEK increases in the precipitate with reaction time. 13 Since it is generally thought that precipitation during polymerization terminates the chain growth, the increase in molecular ...

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Aromatic polymers obtained by precipitation polycondensation: 4. Synthesis of poly(ether ketone ketone)s

Cited by 70 publications

References 7 publications

A DFT study of the formation of xanthydrol motifs during electrophilic poly(aryl ether ketone) synthesis

A DFT study of the formation of xanthydrol motifs during electrophilic poly(aryl ether ketone) synthesis

Consideration of Solvent Effect on Precipitation Polymerization of Poly(ether-ketone)s via Friedel-Craft Acylation

Polymerization Behavior of Poly(ether ketone) via Friedel–Crafts Acylation Studied by End-Group Analysis with 1H NMR

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