Kinetics and mechanism of o-aminophenol oxidation by the supported mesoporous silica (HISiO2) in the binary system with Amberlite resin

S. A. El-Safty, J. Evans, M. Y. El-Sheikh, A. B. Zaki

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

HISiO2 (hexagonal mesoporous silica) was synthesized with a high concentration of a non-ionic template. The synthesized HISiO2 materials have a well defined porous architecture with surface area (760 m2 g-1), and pore size=35 Å. Cu(II)-aquo complex was anchored onto silica (S-CuII) through the coordination with amino-functionalized HISiO2 (S-NH2) without impregnation on the surface. The oxidation of o-aminophenol (o-AP) with (S-CuII), Cu(II)-oxalate complex supported on Amberlite resin (R-CuII), (R-CuII)/S-NH2 (0.05 g), and a mixture (1:1) of (R-CuII)/(S-CuII), has been studied at different temperatures (25-40°C) ±0.1. The oxidation product has been monitored kinetically and spectrophotometrically. All redox reactions were characterized by first-order kinetics. The rate constant of the oxidation reaction of o-AP decreases in the following order; (S-CuII)>(R-CuII)/(S-CuII)>(R-Cu II)/(S-NH2)>(R-CuII). This sequence reflects the role of the effective surface area of HISiO2 on the redox reaction. The activation parameters for the amine oxidation have been estimated. Besides, a mechanism of the oxidation process of o-AP has been proposed.

Original languageEnglish
Pages (from-to)217-228
Number of pages12
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Volume203
Issue number1-3
DOIs
Publication statusPublished - 2002 Apr 25
Externally publishedYes

Keywords

  • Amberlite anion-exchanger
  • Copper-complexes
  • Hexagonal mesoporous silica
  • Kinetics
  • O-Aminophenol
  • Oxidation
  • Synthesis

ASJC Scopus subject areas

  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry

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