Peroxometalates Immobilized on Magnetically Recoverable Catalysts for Epoxidation

Molybdenum/Tungsten-Based Heteropoly Salts in Oxidations

Oxidation represents one of the most important and practical chemical transformations for both organic synthesis, material science and pharmaceutical area. Among the existing strategies, molybdenum/tungsten-based heteropoly salts involved oxidations with low-cost and environmentally benign terminal oxidant and thus have attracted considerable attention in recent years. In this review, we have summarized the recent development of heteropoly salts utilized in oxidations, mainly the peroxomolybdates and peroxotungstates. We wish to highlight the progress made in the past 20 years of this field. Three categories are classified according to the aggregation state of metal oxides. Special attention is paid to the catalytically active peroxometalate species generated during the oxidation process. It is helpful to shed light on the common features that enable highly efficient and selective oxidations. We aim to inspire fellow chemists to explore more functional metalates for catalytic oxidations, especially asymmetric versions. Meanwhile, we attempt to understand the design principles for the discovery of more efficient, selective and economical catalytic systems.

Magnetic Nanoparticle Supported Ionic Liquid Phase Catalyst for Oxidation of Alcohols

A new magnetic nanoparticle supported ionic liquid phase (SILP) catalyst containing perruthenate anions was prepared by a multistep procedure. The various analytical techniques such as FT-IR spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, thermogravimetric analysis, energy dispersive X-ray analysis, and vibrating sample magnetometer analysis ascertained the successful formation of catalyst. The performance of a magnetically retrievable SILP catalyst was evaluated in the selective oxidation of alcohols. The split test and leaching studies of the SILP catalyst confirmed its heterogeneous nature. In addition, the reusability potential of SILP catalyst was also investigated which revealed its robust activity up to six consecutive cycles.

Cellulose-Supported Ionic Liquid Phase Catalyst-Mediated Mannich Reaction

Cellulose-supported ionic liquid phase (SILP) catalyst containing a camphor sulfonate anion with a pendant ferrocenyl group was prepared and characterised with different analytical techniques such as Fourier-transform infrared, Fourier-transform Raman, and cross polarization–magic angle spinning (CP-MAS) 13C NMR spectroscopy, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The SILP catalyst displayed excellent catalytic activity in the synthesis of β-amino carbonyl compounds by Mannich reaction. Recycling studies revealed that SILP catalyst could be reused six times without significant decrease in catalytic activity.

An expedient synthesis of oxazolones using a cellulose supported ionic liquid phase catalyst

A novel cellulose supported ionic liquid phase catalyst has been synthesized and effectively employed as a heterogeneous catalyst in the synthesis of oxazolones.

Heterogenization of heteropoly compounds: a review of their structure and synthesis

The heterogenization of different types of heteropoly compoundsviasix popular methods from those published over the past recent 15 years is reviewed.

Immobilization of imidazolium ionic liquids on hydrotalcites using silane linkers: retardation of memory effect

We report a new covalent surface immobilization of silane-modified imidazolium ionic liquids on hydrotalcite-like materials (HTs) and provide detailed characterization of the resulting surface chemistry using PXRD, CP-MAS, TGA and FT-IR.

Acetalization of aldehydes and ketones over H4[SiW12O40] and H4[SiW12O40]/SiO2

A Keggin cluster of H₄[SiW₁₂O₄₀] (H-SiW₁₂) has been developed to catalyze the acetalization of aldehydes and ketones under solvent-free conditions, and could be recycled at least ten times without an obvious decrease in catalytic activity.