Mesoporous SBA-15 modified with manganese pyrazolylpyridine complexes for the catalytic epoxidation of terminal alkenes

Modulated synthesis of cesium phosphomolybdate encapsulated in hierarchical porous UiO-66 for catalysing alkene epoxidation

“…Meanwhile, t-BuOOH may also be activated to form a radical species, which can usually result in the formation of other oxidation products (route 2). 21,54,55 Further controlling experiments demonstrated that the oxidation of cyclooctene over the CsPM@HP-UiO-66 catalyst could be slightly inhibited when hydroquinone was introduced into the reaction system as a radical scavenger. In this case, the conversion of cyclooctene slightly decreases from 97% to 92% (Fig.…”

Recent Advancements in Graphene‐Based Supports of Metal Complexes/Oxides for Epoxidation of Alkenes

“…[50] Oxygent ransfer from ap rotonated tetranuclear peroxotungstate to aC =Cb ond of the olefin is the rate-determining step. [53] Styrene oxide was mainly produced through pathways ao rb(Scheme 3) with meta-chloroperoxybenzoica cid (m-CPBA) as the oxidizing agent for styrene epoxidation in the presence of CH 3 CN, whereas benzaldehyde was formed through radicalp athway cw ith tBuOOH as the oxidizing agent. [52] Ta ng et al reported the mechanism of the epoxidationo fa lkenes over am anganese catalyst with differento xidizing agents.…”

“…[53] Several groups reported that the ROOÀMn III adduct was initially generateda nd then aL ewis acid mechanism occurred in the presence of H 2 O 2 , tBuOOH, or m-CPBA for the epoxidation alkenes over manganese-containing catalysts. However,h eterolytic cleavage of the intermediate OÀOb ond mainly occurred with m-CPBA because the chlorophenylg roup of m-CPBA could withdrawe lectron density better from the peroxo unit on the alkyl chain of tBuOOH.…”

“…[52] Ta ng et al reported the mechanism of the epoxidationo fa lkenes over am anganese catalyst with differento xidizing agents. [53] Styrene oxide was mainly produced through pathways ao rb(Scheme 3) with meta-chloroperoxybenzoica cid (m-CPBA) as the oxidizing agent for styrene epoxidation in the presence of CH 3 CN, whereas benzaldehyde was formed through radicalp athway cw ith tBuOOH as the oxidizing agent. Homolytic cleavage of the OÀOb ond in the intermediate occurred easily to generate tBuOOÀMn II from tBuOOH.…”

“…However,h eterolytic cleavage of the intermediate OÀOb ond mainly occurred with m-CPBA because the chlorophenylg roup of m-CPBA could withdrawe lectron density better from the peroxo unit on the alkyl chain of tBuOOH. [53] Several groups reported that the ROOÀMn III adduct was initially generateda nd then aL ewis acid mechanism occurred in the presence of H 2 O 2 , tBuOOH, or m-CPBA for the epoxidation alkenes over manganese-containing catalysts. [54] In addition, O=Mn V or HOÀ Mn IV speciesf ormed through heteroor homolytic cleavage.…”