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Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction
Published on: August 23, 2018
Highly selective olefin epoxidation with aqueous H2O2 over surface-modified TaSBA15 prepared via the TMP method
1Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, USA.
Chemical Communications (Cambridge, England)
|November 21, 2007
Summary
Trialkylsiloxy-modified tantalum(V) catalysts on mesoporous silica show high selectivity for cyclohexene epoxidation using hydrogen peroxide. These catalysts demonstrate enhanced stability and longevity, maintaining high epoxide yields over extended reaction times.
Area of Science:
- Catalysis
- Materials Science
- Green Chemistry
Background:
- Mesoporous silica supports are widely used in heterogeneous catalysis.
- Tantalum-based catalysts are effective for oxidation reactions.
- Improving catalyst stability and selectivity is crucial for industrial applications.
Purpose of the Study:
- To develop and characterize trialkylsiloxy-modified tantalum(V) centers on mesoporous silica.
- To evaluate the catalytic performance of these modified centers for cyclohexene epoxidation.
- To assess the stability and reusability of the novel catalysts.
Main Methods:
- Synthesis of trialkylsiloxy-modified tantalum(V) species anchored on mesoporous silica.
- Catalytic testing for cyclohexene oxidation using aqueous hydrogen peroxide.
- Analysis of reaction products using gas chromatography to determine selectivity and conversion.
- Long-term stability tests to evaluate catalyst lifetime.
Main Results:
- The modified catalysts achieved excellent selectivity for epoxide formation (>98% after 2 hours).
- High selectivity was maintained over extended reaction periods (>95% epoxide after 6 hours).
- The trialkylsiloxy modification enhanced catalyst stability and lifetime compared to unmodified counterparts.
Conclusions:
- Trialkylsiloxy-modified Ta(V) centers on mesoporous silica represent highly selective and stable catalysts for cyclohexene epoxidation.
- The use of aqueous hydrogen peroxide as an oxidant aligns with green chemistry principles.
- These findings offer a promising pathway for efficient and sustainable epoxide production.
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