A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles

Abstract

A new heterogeneous catalytic system consisting of cobalt nanoparticles (CoNPs) supported on MgO and tert-butyl hydroperoxide (TBHP) as oxidant is presented. This CoNPs@MgO/t-BuOOH catalytic combination allowed the epoxidation of a variety of olefins with good to excellent yield and high selectivity. The catalyst preparation is simple and straightforward from commercially available starting materials and it could be recovered and reused maintaining its unaltered high activity.

Copper-complexed dipyridyl-pyridazine functionalized periodic mesoporous organosilica as a heterogeneous catalyst for styrene epoxidation

“…The presence of both organic moieties, i.e. bridging ethylene groups in the silica framework and vinyl groups in the channel pores, on the parent material and the resulting surface Diels-Alder adducts on dppz-vPMO have been confirmed by DRIFT and solid-state 13 C CP/MAS NMR measurements (Fig. 4).…”

“…After the Diels-Alder reaction, dppz-vPMO showed additional vibrational signals associated with the CvN stretching (1560 cm −1 ) and skeletal vibrations (1360-1600 cm −1 ) of the dipyridyl-pyridazine units. 43 The solid-state 13 C CP/MAS NMR spectrum of vPMO (Fig. 4b) showed an intense signal at 5 ppm and signals at 130 and 137 ppm corresponding to the Csp 3 and Csp 2 of the ethane and vinyl groups, respectively.…”

“…Although these systems lead to high yields in the epoxidation reactions, their immobilization on solid supports has gained much more attention from an environmental and economic perspective due to their potential applications in industry. [9][10][11][12][13][14] Nowadays, the development of efficient heterogenized catalytic systems for the epoxidation of olefins remains a challenge. 4,[15][16][17] Different types of porous materials, such as zeolites, 18 polymers, 19 mesoporous silicas, 14 activated carbons 20 or MOFs, 21 have been employed as supports of transition metal complexes for liquid phase epoxidation of olefins.…”

Silver Cyanide Powder‐Catalyzed Selective Epoxidation of Cyclohexene and Styrene with its Surface Activation by H2O2(aq) and Assisted by CH3CN as a Non‐Innocent Solvent

“…The use of highly active hydroperoxyl species such as H 2 O 2(aq) , m ‐chloroperoxybenzoic acid ( m ‐CPBA), and t ‐butyl hydroperoxide (TBHP) for the activation of olefins in a liquid phase are common approaches for selective epoxidation [2] . In most cases, metal catalysts are required, and CH 3 CN often serves as a popular solvent for the corresponding conversions [2a–c,i–l] …”

Oxidative Cleavage and Fluoromethylthiolation of C═C Bonds: A General Route toward Mono-, Di-, and Trifluoromethylthioesters from Alkenes

“…However, there are still two potential impediments that might make this transformation difficult to realize. First, considering the common features of oxidation cleavage of CC bonds into carbonyls, there are some competing side reactions, such as dihydroxylation, epoxidation, Wacker-type oxidation, and overoxidation to carboxylic acids, which might prevent our design. Second, acyl radical intermediate from the scission of CC bonds might react with the unreacted part of alkenes existing in the reaction mixture to compete with the desired fluoromethylthiolation .…”