Peroxo and alkylperoxo metal complexes are presumed intermediates in the homogeneous and heterogeneous catalytic epoxidations of olefins. Both solid and soluble versions containing high valent, d° transition metal ions activate peroxides heterolytically, thereby facilitating oxygen atom transfer to electron-rich substrates (1). However, mechanistic studies have been undertaken largely with the ...

Since they were first synthesized in 1992, the ruthenium catalyst named after Nobel Laureate R. H. Grubbs have become a useful tool in organic synthesis. Compared to conventional heterogeneous metathesis catalysts, Grubbs catalysts are more reactive, faster to initiate and better for reaction control. Grubbs catalysts have been employed in good effort both in academia and industry, the later in...

The design and synthesis of metal-free heterogeneous catalysts for efficient hydrogenation remains a great challenge. Here we report a novel approach to create conjugated nanoporous polymers with efficient hydrogenation activities toward unsaturated ketones by leveraging the innate steric encumbrance. The steric bulk of the framework as well as the local sterics of the Lewis basic sites within ...

2014 The importance of Mössbauer Spectroscopy in heterogeneous catalysis research is increasing, since more and more catalysts are complex finely dispersed solids, sufficient characterization cannot be achieved easily with more conventional methods. After summarizing the special features of Mössbauer Spectroscopy of solid catalysts, we show and discuss some examples of its use in identifying ca...

Microwave-assisted organic synthesis (MAOS) provides a novel and efficient means of achieving heat organic reactions. Nevertheless, the potential arcing phenomena via microwave (MW) interaction with solid metal catalysts has limited its use by organic chemists. As arcing phenomena are now better understood, new applications of Pd/C-catalyzed reactions under MW dielectric heating are now possibl...

Heterogeneous single-site catalysts consist of isolated, well-defined, active sites that are spatially separated in a given solid and, ideally, structurally identical. In this review, the potential of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) as platforms for the development of heterogeneous single-site catalysts is reviewed thoroughly. In the first part of this art...

Current heterogeneous catalysts lack the fine steric and electronic tuning required for catalyzing the selective dimerization of ethylene to 1-butene, which remains one of the largest industrial processes still catalyzed by homogeneous catalysts. Here, we report that a metal-organic framework catalyzes ethylene dimerization with a combination of activity and selectivity for 1-butene that is pre...

The massive consumption of fossil fuels and associated environmental issues are leading to an increased interest in alternative resources such as biofuels. The renewable biofuels can be upgraded from bio-oils that are derived from biomass pyrolysis. Catalytic cracking and hydrodeoxygenation (HDO) are two of the most promising bio-oil upgrading processes for biofuel production. Heterogeneous cat...

The literature of olefin metathesis by heterogeneous supported catalysts, both industrial-type supported metal oxides (ReOx/Al2O3, ReOx/(SiO2−Al2O3), MoOx/SiO2, MoOx/Al2O3, MoOx/(SiO2−Al2O3), WOx/SiO2, and WOx/ (SiO2−Al2O3)) and supported organometallic complexes, is comprehensively reviewed. The focus of this Review is supported metal oxide catalysts, but the well-defined supported organometal...

heterogeneous ziegler-natta and homogeneous metallocene catalysts exhibit greatly different active sitenature in olefin polymerization. in our previous study, it was reported that mgcl2-supported titanocenecatalysts can generate both ziegler-natta-type and metallocene-type active sites according to the type of activators.the dual active site nature of the supported titanocene catalysts was furt...