Epoxidation of olefins with molecular oxygen as the oxidant using gold catalysts supported on polyoxometalates

Activation of atomically precise silver clusters on carbon supports for styrene oxidation reactions

“…Others have shown that TBHP works as a radical initiator, when present in sub-stoichiometric quantities, which then allows the reaction to proceed with oxygen as the main oxidant. 67,68 Using the Ag 25 /carbon@250 C catalyst, we performed reactions with substoichiometric amounts of TBHP and for longer reaction times, and the results are presented in Table 3. The reduction in amount of TBHP from 24 mmol (i.e.…”

Biomass Derived Chemicals: Furfural Oxidative Esterification to Methyl-2-furoate over Gold Catalysts

“…The catalyst could be reused four times without significant loss of activity. Moreover, the catalysts with decreased activity after repeated use were restored by heating at 170˝C for 4 h. Gold nanoparticles supported on salts of polyoxometalates are highly active (>90% conversion) selective to epoxide formation for norbornene and cyclooctene oxidation and recyclable catalysts for the epoxidation of olefins using molecular oxygen as oxidant and t-butyl hydroperoxide as initiator [100]. Such catalyst showed little deactivation with prolonged reaction time and was easily recovered by filtration and was reused with almost no loss in activity and selectivity.…”

Green epoxidation of cyclooctene with molecular oxygen over an ecofriendly heterogeneous polyoxometalate-gold catalyst Au/BW11/Al2O3

“…Hence, the optimal calcination temperature was 500 °C. According to a recent study (Tebandeke et al, 2014), the gold in the sample calcinated at low temperature is mainly present in an oxidized state, while the clusters in the sample calcinated at high temperature are reduced to the metallic state which might be the reason for altered activity.…”