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)

Abstract

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
Volume2
Issue number4
DOIs
Publication statusPublished - 2007
Externally publishedYes

Fingerprint

Dehydration
Cations
Catalyst activity
Ions
Acids
Condensation reactions
Cyclization
Crystallization
Ammonium Compounds
Anions
Hydrogen
Hydrogen bonds
Esters
Salts
Water
hydronium ion

Keywords

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

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

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title = "Unusual rate acceleration in br{\o}nsted acid catalyzed dehydration reactions: Local hydrophobic environment in aggregated N-(2,6-diphenylphenyl)-N- mesitylammonium pentafluorobenzenesulfonates",
abstract = "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.",
keywords = "Aggregation, Ammonium salts, Condensation, Dehydration, Homogeneous catalysis",
author = "Akira Sakakura and Hitoshi Watanabe and Shoko Nakagawa and Kazuaki Ishihara",
year = "2007",
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T1 - Unusual rate acceleration in brønsted acid catalyzed dehydration reactions

T2 - Local hydrophobic environment in aggregated N-(2,6-diphenylphenyl)-N- mesitylammonium pentafluorobenzenesulfonates

AU - Sakakura, Akira

AU - Watanabe, Hitoshi

AU - Nakagawa, Shoko

AU - Ishihara, Kazuaki

PY - 2007

Y1 - 2007

N2 - 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.

AB - 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.

KW - Aggregation

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KW - Condensation

KW - Dehydration

KW - Homogeneous catalysis

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