High Catalytic Activity In Epoxidation Research Articles

Formation of β-Ga2O3 nanorings from metal–organic frameworks and their high catalytic activity for epoxidation of alkenes

β-Ga2O3 nanorings fabricated by structural transformation of concave Ga-MOF nanodisks exhibit high catalytic activity for epoxidation of alkenes.

Olefin epoxidation with ionic liquid catalysts formed by supramolecular interactions

This work demonstrated that the specific ionic liquids (ILs) have been designed via the supramolecular complexation between 18-crown-6 (CE) and ammonium peroxoniobate (NH4-Nb). The resultant ILs have been characterized by elemental analysis, FT-IR, Raman, NMR, DSC, conductivity measurement and MALDI-TOF, etc. The IL (CE-1) consisting of CE and ammonium peroxoniobate can be further coordinated with GLY to generate a new IL (CE-2), which showed both high catalytic activity in epoxidation with H2O2 and good recyclability. The characterization of 93Nb NMR spectra revealed that the peroxoniobate anions has demonstrated a structural evolution in the presence of hydrogen peroxide, in which NbO species can be easily oxidized into the catalytically active niobium−peroxo species. Especially, the supramolecular complexation can provide suitable hydrophobicity, which ensured that the hydrophobic olefins and allylic alcohols were easily accessible to the catalytically active anions, and thus facilitated the epoxidation reaction. Notably, the supramolecular IL catalysts in this work exhibited a huge advantage of the easy availability, as compared with the previously reported peroxoniobate-based ILs. As far as we know, this is the first example of the highly selective epoxidation of olefins and allylic alcohols by using supramolecular ILs as catalysts.

Sponge-structured titanosilicate zeolite with high catalytic activity in epoxidation of fatty acid methyl ester

Epoxidation of fatty acid methyl ester (FAME) is commercially adopting peracids process, which possesses low selectivity and serious pollution problems. Herein, spongy titanosilicate zeolite with high catalytic performance in epoxidation of fatty acid methyl ester (FAME) has been demonstrated. The zeolite is constructed by combining pore-extending and post-treatment processes, which features mesopores with a diameter of 3–5.5nm. Thus, in the epoxidation of FAME with tert-butyl hydroperoxide under 90°C, the spongy TS-1 zeolite exhibits >99% conversion within 3h, far higher than that of TS-1 (39%), with a high selectivity (>90%) of epoxy product as well.

Ruthenium bis(bipyridine) sulfoxide complexes: new catalysts for alkene epoxidation.

The ruthenium bis(bipyridine) sulfoxide complexes Ru-1 and Ru-2 exhibit high catalytic activity for epoxidation of unfunctionalized olefins in the presence of [bis(acetoxy)iodo]benzene; with the chiral catalyst, Ru-2, asymmetric induction up to 94% was observed for beta-methylstyrene.