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A Magnetic Particle‐Supported Sulfonic Acid Catalyst: Tuning Catalytic Activity between Homogeneous and Heterogeneous Catalysis
Author(s) -
Koukabi Nadiya,
Kolvari Eskandar,
Zolfigol Mohammad Ali,
Khazaei Ardeshir,
Shaghasemi Behzad Shirmardi,
Fasahati Behzad
Publication year - 2012
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201100352
Subject(s) - catalysis , sulfonic acid , chemistry , thermogravimetric analysis , x ray photoelectron spectroscopy , dynamic light scattering , heterogeneous catalysis , titration , magnetic nanoparticles , chemical engineering , magnetic separation , fourier transform infrared spectroscopy , homogeneous catalysis , inorganic chemistry , organic chemistry , materials science , nanoparticle , engineering , metallurgy
Surface functionalization of magnetic particles is an elegant way to bridge the gap between heterogeneous and homogeneous catalysis. The introduction of magnetic particles (MPs) in a variety of solid matrices allows the combination of well‐known procedures for catalyst heterogenization with techniques for magnetic separation. We have conveniently loaded sulfonic acid groups on magnetic particles supports in which chlorosulfonic acid is used as sulfonating agent. The main targets are room temperature, solvent‐free conditions, rapid (immediately) and easy immobilization technique, and low cost precursors for the preparation of highly active and stable MPs with high densities of functional groups. The inorganic, magnetic, solid acid catalyst was characterized via Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), thermal gravimetric analysis (TGA), X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), dynamic light scattering (DLS), vibrating sample magnetometer (VSM) and titration. The catalyst is active for the Hantzsch reaction and the products are isolated in high to excellent yields (90–98%). Supporting this acid catalyst on magnetic particles offers a simple and non‐energy‐intensive method for recovery and reuse of the catalyst by applying an external magnet. Isolated catalysts were reused for new rounds of reactions without significant loss of their catalytic activity.