Epoxidation of styrene with cobalt-hydroxyapatite and oxygen in dimethylformamide: A green technology?

Aerobic Epoxidation of Olefins Catalyzed by the Cobalt‐Based Metal–Organic Framework STA‐12(Co)

“…Opre et al [23] have suggested that epoxidation might occur via a DMF-derived peroxide that would need to be formed prior to product formation. Although DMF oxidation is the cause of the pronounced solvent effect, a link between its conversion and the formed peroxides could not be established in this case.…”

“…The catalytic epoxidation of stilbene with the MOF featured an induction period, which was, interestingly, considerably reduced by styrene/stilbene coepoxidation. This could be traced backthe olefin transformation is accompanied by significant DMF oxidation [23] to N-formyl-N-methylformamide (FMF), which might provide an alternative explanation of the epoxidation on the basis of a solvent co-oxidation mechanism. Based on experiments with radical scavengers, the mechanism was suggested to be of radical nature.…”

Synthesis of thermally stable metal substituted hydroxy apatites for the selective oxidation of light paraffins

“…Several mechanisms have been proposed for the replacement of calcium in HAp by other metal ions, namely, ion exchange, ion adsorption, dissolution of HAp followed by deposition of a new phase or a combination of these methods [3,4,19,20]. Cobalt-exchanged hydroxyapatite was used by Opre et al [21] in the epoxidation of styrene. Analysis of the liquid phase removed from the reactor revealed formation of styrene oxide and benzaldehyde as the main products along with minors such as phenyl glycol, benzoic acid and phenylacetaldehyde.…”

Co2+-exchanged SAPO-5 and SAPO-34 as efficient heterogeneous catalysts for aerobic epoxidation of alkenes

“…However, whether DMF is a reductant or not has been considered as a controversial topic [17,30,33]. Actually, DMF could not be recognized as a real reductant in our catalytic system, different from the case reported in the literature [33].…”