Sonochemical syntheses of nano-sized dioxomolybdenum complexes: An efficient, selective and reusable heterogeneous nanocatalyst for oxidation of alkenes

Authors:   Saeed Rayati, Payam Abdolalian

Abstract:
Two Schiff base ligands derived from 2-hydroxy-4-methoxyacetophenone and 2,2' - dimethylpropylenediamine (H₂L¹) or 1,2-cyclohexanediamine (H₂L²) have been synthesized and characterized by physico-chemical and spectroscopic methods. Then dioxomolybdenum complexes have been prepared by reaction of Schiff base ligands and MoO₂(acac)₂ under ultrasonic irradiation to give nanoparticles of MoL¹ and MoL². FT-IR, UV–vis, ¹H NMR and ¹³C NMR spectroscopy, elemental analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), were used to characterize and investigate the nanocatalysts. A practical catalytic method for efficient and highly selective oxidation of wide range of olefins with anhydrous tert-butyl hydroperoxide over the prepared molybdenum nanocatalysts was investigated. Under mild reaction conditions, oxidation of cyclooctene led to the formation of corresponding epoxide with a yield of more than 90%. The catalysts were reused five consecutive times without detectable catalyst leaching or significant loss of activity.

Keywords:
Epoxidation
Ultrasonic irradiation
Olefins Heterogeneous nanocatalyst
Molybdenum
Schiff base complexes

Published in: Applied catalysis A: General  (Volume 456, Pages 1-248, 10 April 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Sonochemical syntheses of nano-sized dioxomolybdenum complexes: An efficient, selective and reusable heterogeneous nanocatalyst for oxidation of alkenes

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