Recent Developments in Heterogeneous Catalyzed Epoxidation of Styrene to Styrene Oxide

Abstract

Epoxidation of styrene under heterogeneous catalyzed conditions provides environmentally friendly routes to produce styrene oxide, an important synthetic intermediate for synthesis of perfumes, epoxy resins, plasticizers, drugs, sweeteners and fine chemicals. The present review explores epoxidation of styrene under heterogeneous catalysed conditions using a variety of catalysts such as metal nanoparticles, metal oxides (of group 12 and 13 metals, transition metals, rare earth metals), transition metals and complexes, polyoxometallates, microporous and mesoporous materials (zeolites, modified zeolites, organic/inorganic porous hybrid materials, porous metal oxides, SBA 15) and polymers using hydrogen peroxide (H2O2), tert‐butyl hydroperoxide (TBHP), air or oxygen as oxidants.The use of salen based transition metal complexes and of chiral porphyrins as catalysts in asymmetric epoxidation of styrene is also reviewed. The reaction mechanism studies of most of these reactions suggest an intermediate formation of a reactive metal‐oxygen species, by interactions between the catalyst and oxidant.

Isolated Single‐Atom Ruthenium Anchored on Beta Zeolite as an Efficient Heterogeneous Catalyst for Styrene Epoxidation

“…The epoxidation of styrene has attracted extensive interest owing to its application in fine chemicals and pharmaceuticals [1–3] . The precious‐metal‐group materials are generally efficient heterogeneous catalysts for styrene epoxidation [4–7] .…”

Selective Styrene Oxidation to Benzaldehyde over Recently Developed Heterogeneous Catalysts

“…Commonly used oxidants in these systems are tert -butyl hydroperoxide (TBHP) and also hydrogen peroxide, air or oxygen. Still, most of the reported studies are focused on the selective styrene oxidation to styrene oxide [ 10 ], and comparatively fewer studies are focused on benzaldehyde as the main reaction product. The mechanism for this reaction, as proposed by most of the authors, involves the formation of a reactive metal–oxygen species intermediate by interactions between the catalyst and oxidant.…”

Instant and quantitative epoxidation of styrene under ambient conditions over a nickel(ii)dibenzotetramethyltetraaza[14]annulene complex immobilized on amino-functionalized SBA-15

“…Transition metal-based catalysts, such as transition metal ions, transition metal-oxo and -peroxo complexes, organotransition metal complexes (OTMC), or transition-metal surfaces are the most investigated catalysts for the epoxidation of styrene. 7 In recent years, many efforts have been devoted to developing simple and efficient routes for the epoxidation of styrene by applying efficient and highly effective catalysts. OTMC have shown signicant efficiency towards the catalytic epoxidation of styrene.…”

“…Most of OTMC have been evaluated in epoxidation of styrene are Schiff base metal complexes and metallo-porphyrins, using various oxidants such as H 2 O 2 , O 2 , tert-butyl hydroperoxide t-BuOOH, iodosylbenzene PhIO and m-CPBA. [7][8][9][10] Dibenzotetraaza (14)annulene complexes derivatives have been used as catalysts in many reactions including the hydroxylation and epoxidation of alkenes. 11,12 They are interesting macrocycles for both practical and theoretical reasons.…”