New synthetic method for aromatic polyketones from bis(arylsilane)s and aromatic dicarboxylic acid chlorides

Abstract

A new synthetic method for aromatic polyketones was developed through Friedel-Crafts polycondensation of bis(arylsilane) monomers with aromatic dicarboxylic acid chlorides. The solution polycondensation of these monomer pairs in the presence of aluminum chloride in 1,2-dichloroethane readily afforded aromatic polyketones having inherent viscosities up to 0.37 dL/g with the elimination of chlorotrimethylsilane. The polycondensation proceeded through aromatic electrophilic ipso substitution, the mechanism of which is very similar to that of normal Friedel-Crafts acylation.

New regioselective synthesis of metalinked aromatic polyketones from metasubstituted bis(arylsilane)s and aromatic dicarboxylic acid chlorides

“…The IR spectra of compounds 2a and 2b exhibited an absorption band at 3057–3058 cm −1 due to aromatic CH stretching and a characteristic carbonyl absorption at 1656–1657 cm −1 . The 13 C NMR spectrum of compound 2a showed 11 peaks and was quite different from that of bis(4‐benzoylphenyl) ether, which had 9 peaks 6. In addition, the 13 C NMR spectrum of compound 2b exhibited 12 peaks as expected.…”

“…The model reaction was then extended to the polycondensation of the bifunctional monomer pairs, metasubstituted bis(arylsilane)s ( 1a and 1b ) and aromatic dicarboxylic acid chlorides ( 3a – 3c ), under the Friedel–Crafts reaction conditions (Scheme ). The polymerization conditions were selected by reference to those for the aromatic polyketone synthesis with parasubstituted bis(arylsilane)s reported previously 6. Therefore, the polycondensation was carried out in the presence of 3 equiv of aluminum chloride (based on the diacid chloride) in 1,2‐dichloroethane at 20 °C for 24 h. The results of the polycondensation are summarized in Table 1.…”

“…Aromatic polyketones are usually prepared by the aromatic electrophilic substitution polymerization of electron‐rich aromatic compounds such as diphenyl ether with aromatic dicarboxylic acid chlorides in the presence of Lewis acid catalysts under Friedel–Crafts acylation conditions 1–5. In a previous study,6 we demonstrated a new synthetic method of aromatic polyketones that involved the Friedel–Crafts‐type polycondensation of bis(arylsilane) monomers, in which the silyl groups were in the paraposition to the ortho/paradirecting groups, with aromatic dicarboxylic acid chlorides, along with the elimination of chlorotrimethylsilane.…”

“…This article deals with a new successful regioselective synthesis of metaconnected aromatic polyketones through the aromatic electrophilic ipso‐substitution polymerization of metasubstituted bis(arylsilane) monomers with aromatic dicarboxylic acid chlorides under Friedel–Crafts acylation conditions (Scheme ). The properties of these new metalinked aromatic polyketones are also compared and discussed with those of known paracatenated aromatic polyketones 1, 4, 6…”

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

“…Since it is generally thought that precipitation terminates chain growth, the increase of molecular weight after precipitation is very interesting phenomenon. It has also been reported that the polymerization medium greatly affects the molecular weight of the resulting PEK, and DCE is a good solvent to prepare the high molecular weight PEK [8]. However, further details of the solvent effect on the precipitation polymerization have not been clarified so far, and few considerations were performed on the polymerization behavior of the precipitation polymerization from the view of the morphology and the structure of the precipitates to our knowledge.…”