Polymerization of 2,5-diaminoterephthalic acid-type monomers for the synthesis of polyamides containing ladder unit

Akihiro Yokoyama, Jinya Kuramochi, Ryohei Kiyota, Kazuki Kishimoto, Kazuto Takaishi, Tsutomu Yokozawa

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Abstract

To synthesize ladder-type polyamides by construction of two amide bonds successively, 2,5-diaminoterephthalic acid derivatives bearing anthranilic acid ester and isatoic anhydride moieties were synthesized and their polymerization was investigated. Polymerization of the methyl ester monomer proceeded in the presence of lithium hexamethyldisilazide (LiHMDS) as a base in tetrahydrofuran (THF). However, mass spectroscopic analysis of the product suggested that not only the bis(trimethylsilyl)amide anion of LiHMDS but also the methoxide anion eliminated at the second amide-linkage formation reaction decomposed the isatoic anhydride unit of the growing oligomer by nucleophilic attack to disturb the polymerization. To reduce the nucleophilicity of the eliminated anion, methyl ester of the monomer was changed to phenyl ester and its polymerization was studied. The reaction conditions were optimized, and the best result was obtained when the polymerization was conducted in the presence of 1.0 equivalent of LiHMDS without additives in THF at 50 °C.

Original languageEnglish
JournalJournal of Polymer Science, Part A: Polymer Chemistry
DOIs
Publication statusAccepted/In press - 2017

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Keywords

  • Anthranilic acid
  • Isatoic anhydride
  • Ladder
  • NMR
  • Polyamides
  • Synthesis

ASJC Scopus subject areas

  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry

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