Epoxidation of Alkenes Catalyzed by Phenyl Group‐Modified, Periodic Mesoporous Organosilica‐Entrapped, Dimeric Manganese–Salen Complexes

Abstract

A series of reusable, recoverable, diamine-bridged dimeric manganese-salen complexes were prepared by the encapsulation of homogeneous dimeric Mn(salen) complexes into nanocages of a 3D periodic mesoporous organosilica (PMO) support followed by silylation of the support with organosilane. The composition, structure, morphology, and textural properties of the prepared PMO-entrapped dimeric Mn(salen) complexes were characterized, and their catalytic performances were tested in the epoxidation of alkenes (styrene, cyclohexene, and 1-phenylcyclohexene), with NaClO as an oxygen source and 4-phenylpyridine-N-oxide as an axial ligand. Furthermore, the influences of the textural and morphological properties of the entrapped dimeric Mn(salen) complexes and the key reaction parameters on the catalytic activity and selectivity are discussed. Finally, the reusability of the supported dimeric Mn(salen) complexes was evaluated over three catalytic runs.

Aminopropyl group-modified SBA-15 covalent attachment Mn(salen) complexes as catalysts for styrene epoxidation

“…It shows that PPNO applied in current catalytic system can obviously enhance the catalytic activity of both of the homogeneous and heterogeneous Mn(salen) complexes [3] . Under the same conditions, increased PPNO amount from 0 to 0.3 mmol, the yield of styrene epoxide increased from 2.8% to 88.9% (entries 3-6 in Table S 1 Supplemental Materials).…”

“…A pair of weak absorption peaks at 2985 cm -1 and 2937 cm -1 was ascribed to the symmetric and asymmetric of the saturation of C-H, manifesting that the modified aminopropyl groups successfully into silicon matrix surface (NH 2 /SBA-15) [3] . From [17,18] ,demonstrating that the Mn(salen) complex was immobilized on the support.…”

“…Epoxides are a significant class of industrial chemicals that have been widely used as chemical intermediates in several fields, such as agriculture, industry and medical science, and catalytic epoxidation of olefins is of great importance for the formation of epoxides [1][2][3] . Metal(salen) complexes have been reported as active catalysts for the epoxidation of olefins [4][5][6] .…”

Efficient and convenient epoxidation of alkenes to epoxides with H2O2 catalyzed by Co(OAc)2 in ionic liquid [C12py][PF6]

“…[3][4][5], and suffer from considerable drawbacks such as low yield, harsh or delicate reaction condition, and a large amount of waste byproducts. Oxidation with NaClO [6,7], PAA [8], TBHP [9,10], PhIO [11,12], NaIO 4 [13,14], CHP [15], oxone [16][17][18], peracetic acid [19,20], TADOOH [21], PPO [22], and other reagents [23][24][25][26][27][28] have also been developed for this conversion. However, these protocols are generally associated with one or more disadvantages, such as complex handling procedures, problematic side reactions, the use of expensive, toxic and moisture-sensitive reagents, long reaction times, low yields, and environmental concerns associated with the use of poorly manageable catalysts.…”

A novel Schiff base of Mn(III) complex supported on magnetic cobalt nanoparticles as a highly efficient retrievable heterogeneous catalyst in oxidation of alcohols and sulfides compounds

“…Various solid supports include organosilica materials [18,19], carbon materials [20,21], silica materials [22][23][24], zeolites [25] and layered compounds [26,27]. The immobilization occurs through covalent, dative, electrostatic, encapsulation or adsorption binding onto/in the solid supports [28][29][30][31][32][33].…”