Unusual rate acceleration in brønsted acid catalyzed dehydration reactions: Local hydrophobic environment in aggregated N-(2,6-diphenylphenyl)-N- mesitylammonium pentafluorobenzenesulfonates

Akira Sakakura, Hitoshi Watanabe, Shoko Nakagawa, Kazuaki Ishihara

Research output: Contribution to journalArticle

24 Citations (Scopus)


Bulky diarylammonium pentafluorobenzenesulfonates effectively promote dehydration reactions, such as condensation reactions to give esters and the dehydrative cyclization of 1,3,5-triketones. In particular, N-(2,6- diphenylphenyl)-N-mesitylammonium pentafluorobenzenesulfonate shows much higher catalytic activity than C6F5SO3H under reaction conditions without the removal of generated water, even though the former is a weaker acid. Its crystallization gives an aggregated cyclic ion pair, which is composed of two diarylammonium cations, four pentafluorobenzenesulfonate anions, and two oxonium cations. This ion pair is strongly stabilized by four intermolecular and two intramolecular π-π attractive interactions and 10 hydrogen bonds. The extremely high catalytic activity of N-(2,6-diphenylphenyl)- N-mesitylammonium pentafluorobenzenesulfonate in the dehydration reactions may be ascribed to the local hydrophobic environment of the tightly aggregated ammonium salts.

Original languageEnglish
Pages (from-to)477-483
Number of pages7
JournalChemistry - An Asian Journal
Issue number4
Publication statusPublished - 2007
Externally publishedYes



  • Aggregation
  • Ammonium salts
  • Condensation
  • Dehydration
  • Homogeneous catalysis

ASJC Scopus subject areas

  • Chemistry(all)

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