Abstract
Background: The design of a highly active catalyst is a key point in olefins epoxidation. Recently, polyoxometalates have received an increasing interest in selective oxidation of organic compounds. Their scope as nanoparticle carriers is of immense importance as the high anionic charge associated with them prevents sintering of the nanoparticles which is a major issue related to nanoparticle based catalysts thus increasing the stability of the catalyst.
Objective: We have immobilized Na9PMo11O39 (PMo11) and gold nanoparticles on chloropropyltriethoxysilane functionalized SBA-15 mesoporous material. We investigated the molecular oxygen activation ability and stability of this heterogeneous hybrid catalytic system for green epoxidation of cyclohexene under mild reaction conditions.
Method: PMo11 was prepared according to the literature, while PMo11/CPTES-SBA-15, Au/CPTES-SBA-15 and Au/PMo11/CPTES-SBA-15 were prepared by wet deposition method. The catalytic performance was evaluated in a PTFE lined autoclave and analysis was done by gas chromatography.
Results: Cyclohexene epoxidation was carried out on different heterogeneous catalytic systems which included polyoxometalate and CPTES-SBA-15 support, nano gold and CPTES-SBA-15 support and the hybrid material Au/PMo11/CPTES-SBA-15 with varying amounts of doped nanogold. All the samples showed good conversion of cyclohexene and significant selectivity for oxidized products with molecular oxygen as an oxidant under mild conditions. 1 % Au/PMo11/CPTES-SBA-15 delivered 48.1 % conversion and 35.9 % selectivity to epoxide.
Conclusion: The CPTES-SBA-15 supported Au/PMo11 hybrid catalytic system demonstrated relatively high catalytic activity and selectivity for the green epoxidation of cyclohexene with molecular oxygen as an oxidant under mild reaction conditions. The hybrid catalyst was regenerated and reused for three cycles without compromising the catalytic performance.
Keywords: Gold nanoparticles, polyoxometalates, SBA-15, hybrid mesoporous materials, nanomaterials, cyclohexene epoxidation, molecular oxygen.
Graphical Abstract
Call for Papers in Thematic Issues
Advances of Heterocyclic Chemistry with Pesticide Activity
Global food safety and security will continue to be a global concern for the next 50 years and beyond. Plant diseases have had a significant impact on food safety and security throughout the entire food chain, from primary production to consumption. While conventional chemical pesticides have been traditionally used for ...read more
Calculation design of covalent/metal organic framework based catalysts
This research area combines theoretical computation and screening with machine learning for the design of covalent/metal organic framework-based catalysts, bridging the disciplines of organic chemistry, physical chemistry, computational chemistry, materials science, and machine learning. It covers several critical aspects: designing and synthesizing organic catalysts for improved performance, applying computational methods ...read more
Carbohydrates conversion in biofuels and bioproducts
Biomass pretreatment, hydrolysis, and saccharification of carbohydrates, and sugars bioconversion in biofuels and bioproducts within a biorefinery framework. Carbohydrates derived from woody biomass, agricultural wastes, algae, sewage sludge, or any other lignocellulosic feedstock are included in this issue. Simulation, techno-economic analysis, and life cycle analysis of a biorefinery process are ...read more
Catalytic C-H bond activation as a tool for functionalization of heterocycles
The major topic is the functionalization of heterocycles through catalyzed C-H bond activation. The strategies based on C-H activation not only provide straightforward formation of C-C or C-X bonds but, more importantly, allow for the avoidance of pre-functionalization of one or two of the cross-coupling partners. The beneficial impact of ...read more
Related Books
Advances in Organic Synthesis
The Synthetic Methods, Structures, and Properties of the Ca-C σ Bond Organocalcium Containing Compounds
Advances in Organic Synthesis
Chemistry of Bipyrazoles: Synthesis and Applications
Advances in Organic Synthesis
Advanced Nanocatalysis for Organic Synthesis and Electroanalysis
Advances in Organic Synthesis
Advances in Organic Synthesis
45
4
1
1