Supported micelles in biphasic oxidation catalysis
The research is concerned with a novel way of heterogenising a simple water-soluble salt, ammonium molybdate for catalytic cyclohexene oxidation with tert-butyl hydroperoxide (TBHP) in bulk dichoromethane. Surface tethered surfactant molecules created were presumed to form supported micellar assembl...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
Elsevier
2000
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| Summary: | The research is concerned with a novel way of heterogenising a simple water-soluble salt, ammonium molybdate for catalytic cyclohexene oxidation with tert-butyl hydroperoxide (TBHP) in bulk dichoromethane. Surface tethered surfactant molecules created were presumed to form supported micellar assemblies. These assemblies carried microscopic water droplets in turn containing the ammonium molybdate catalyst for use in a biphasic oxidation reaction. Thus heterogenisation of the water-soluble molybdate was accomplished through water droplet immobilization but without anchoring the catalytic component directly. Our results clearly showed that a faster oxidation rate was obtained using the silica supported with surfactant molecules than with the corresponding supported aqueous catalyst on unmodified silica. This implied that the oxidation catalysis occurred within the small surface supported surfactant assemblies as `nano-reactors', whose controlled hydrophobic and hydrophilic affinities in this microenvironment significantly improved the mass transfer efficiency of reaction components. |
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