Esterolyses of p-nitrophenyl esters catalyzed by dialkylaminopyridines attached to polyorganosiloxane

Nobukatsu Nemoto, Masayuki Aizawa, Yukihiko Ueno, Koji Ikeda, Nobuo Takamiya

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The present study describes the preparation of polyorganosiloxanes containing dialkylaminopyridines in their side chains (POS-DAAPs) and the use of them as catalysts for esterolyses of p-nitrophenyl esters of CH3(CH2)nCOOH (n=0-5). The POS-DAAPs (4, 5) were prepared from poly[(3-chlorocarbonylpropyl)methylsiloxane] (PCCPMS, 1) and two pyridine derivatives, such as 4-[(2-hydroxyethyl)methylamino]pyridine (HEMAP, 2) and 4-[4-(2-hydroxyethyl)piperidino]pyridine (HEPP, 3). Pyridyl groups of POS-DAAPs 4 and 5 were partially quaternized with dimethylsulfate (6, 7) in order to carry out esterolysis in homogenious systems. The esterolyses were examined in methanol/tris(hydroxymethyl)-aminomethane-hydrochloric acid buffer solution (vol. ratio 2/1, pH of buffer solution: 7.5) and analyzed following Michaelis-Menten like kinetics. The second-order rate constants (k2/Km) of the esterolyses catalyzed by POSs 6 and 7 were 22-38 fold values of those catalyzed by the corresponding monomolecular catalysts 2 and 3. In addition, the effects of POSs were discussed from the kinetic, thermodynamic, and activation parameters.

Original languageEnglish
Pages (from-to)413-420
Number of pages8
JournalPolymer Bulletin
Volume27
Issue number4
DOIs
Publication statusPublished - 1992 Jan 1

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Polymers and Plastics
  • Materials Chemistry

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