Manganese Schiff Base Immobilized on Graphene Oxide Complex and Its Catalysis for Epoxidation of Styrene

Immobilization of metal complexes on solid supports is an efficient approach to circumvent the drawbacks of homogeneous catalysis. In this paper, using graphene oxide as carrier, manganese Schiff base supported on graphene oxide (Salen Mn-GO) was prepared through aminosilane covalent modification as well as salicylaldehyde condensation and coordination reaction. The structures and properties of the composite were examined by FT-IR, XRD, XPS, TEM, TG techniques, and the catalytic performance of Salen Mn-GO in styrene epoxidation was explored. The effects of catalyst and styrene amount as well as that of reaction time on the performance of the catalyst were investigated. The results showed that Salen Mn-GO has excellent catalytic activity and reusability for epoxidation of styrene in the presence of hydrogen peroxide. Finally, the mechanism of styrene epoxidation catalyzed by Salen Mn-GO has been preliminarily discussed.

Manganese Schiff Base Immobilized on Graphene Oxide Complex and Its Catalysis for Epoxidation of Styrene

Immobilization of metal complexes on solid supports is an efficient approach to circumvent the drawbacks of homogeneous catalysis. In this paper, using graphene oxide as carrier, manganese Schiff base supported on graphene oxide (Salen Mn-GO) was prepared through aminosilane covalent modification as well as salicylaldehyde condensation and coordination reaction. The structures and properties of the composite were examined by FT-IR, XRD, XPS, TEM, TG techniques, and the catalytic performance of Salen Mn-GO in styrene epoxidation was explored. The effects of catalyst and styrene amount as well as that of reaction time on the performance of the catalyst were investigated. The results showed that Salen Mn-GO has excellent catalytic activity and reusability for epoxidation of styrene in the presence of hydrogen peroxide. Finally, the mechanism of styrene epoxidation catalyzed by Salen Mn-GO has been preliminarily discussed.

Manganese Schiff Base Immobilized on Graphene Oxide Complex and Its Catalysis for Epoxidation of Styrene

Immobilization of metal complexes on solid supports is an efficient approach to circumvent the drawbacks of homogeneous catalysis. In this paper, using graphene oxide as carrier, manganese Schiff base supported on graphene oxide (Salen Mn-GO) was prepared through aminosilane covalent modification as well as salicylaldehyde condensation and coordination reaction. The structures and properties of the composite were examined by FT-IR, XRD, XPS, TEM, TG techniques, and the catalytic performance of Salen Mn-GO in styrene epoxidation was explored. The effects of catalyst and styrene amount as well as that of reaction time on the performance of the catalyst were investigated. The results showed that Salen Mn-GO has excellent catalytic activity and reusability for epoxidation of styrene in the presence of hydrogen peroxide. Finally, the mechanism of styrene epoxidation catalyzed by Salen Mn-GO has been preliminarily discussed.

An Alginate-Confined Peroxygenase-CLEA for Styrene Epoxidation

Oxyfunctionalisation reactions in neat substrate still pose a challenge for biocatalysis. Here, we report an alginate-confined peroxygenase-CLEA to catalyse the enantioselective epoxidation of cis-β-methylstyrene in a solvent-free reaction system achieving...

Manganese Schiff Base Immobilized on Graphene Oxide Complex and Its Catalysis for Epoxidation of Styrene

Immobilization of metal complexes on solid supports is an efficient approach to circumvent the drawbacks of homogeneous catalysis. In this paper, using graphene oxide as carrier, manganese Schiff base supported on graphene oxide (Salen Mn-GO) was prepared through aminosilane covalent modification as well as salicylaldehyde condensation and coordination reaction. The structures and properties of the composite were examined by FT-IR, XRD, XPS, TEM, TG techniques, and the catalytic performance of Salen Mn-GO in styrene epoxidation was explored. The effects of catalyst and styrene amount as well as that of reaction time on the performance of the catalyst were investigated. The results showed that Salen Mn-GO has excellent catalytic activity and reusability for epoxidation of styrene in the presence of hydrogen peroxide. Finally, the mechanism of styrene epoxidation catalyzed by Salen Mn-GO has been preliminarily discussed.

Enabling Highly (R)-Enantioselective Epoxidation of Styrene by Engineering Unique Non-Natural P450 Peroxygenases

Unlike the excellent (<i>S</i>)-enantioselective epoxidation of styrene performed by natural styrene monooxygenase (<i>ee</i> >99%), the (<i>R</i>)-enantioselective epoxidation of styrene has not yet achieved a comparable efficiency using natural or engineered oxidative enzymes. This report describes the H₂O₂-dependent (<i>R</i>)-enantioselective epoxidation of unfunctionalized styrene and its derivatives by site-mutated variants of a unique non-natural P450BM3 peroxygenase, working in tandem with a dual-functional small molecule (DFSM). The observed (<i>R</i>)-enantiomeric excess of styrene epoxidation is up to ~99%, which is unprecedented relative to natural or engineered oxidative enzymes. The catalytic turnover number is up to ~4500 (with ~98% <i>ee</i>), representing the best activity of a P450 peroxygenase towards styrene epoxidation, to date. This study indicates that the synergistic use of protein engineering and an exogenous DFSM constitutes an efficient strategy to control enantioselectivity of styrene epoxidation, thus substantially expanding the chemical scope of P450 enzyme functions as useful bio-oxidative catalysts.