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Despite decades of extensive studies, the atomic-scale structure active sites in heterogeneous Ziegler–Natta (ZN) catalysts, one most important processes chemical industry, remains elusive and a matter debate. In present work, ZN catalysts absence ethylene, referred to as dormant sites, is elucidated from magnetic resonance experiments carried out on samples reacted with increasing amounts BCl3...

The effect of gold presence on carbon monoxide oxidation and ethanol steam reforming catalytic behavior of two Ce-Zr-Co mixed oxides catalysts with a constant Co charge and different Ce/Zr ratios was investigated. The Ce-Zr-Co mixed oxides were obtained by the pseudo sol-gel like method, based on metallic propionates polymerization and thermal decomposition, whereas the gold-supported Ce-Zr-Co ...

We have been engaged in a search for coordination catalysts for the copolymerization of polar monomers (such as vinyl chloride and vinyl acetate) with ethylene. We have been investigating complexes of late transition metals with heterocyclic ligands. In this report we describe the synthesis of a symmetrical bis-thiadiazole. We have characterized one of the intermediates using single crystal X-r...

In heterogeneous Ziegler-Natta catalysts for olefin polymerization, isolation of a single type of active sites is a kind of ambition, which would solve long-standing questions on the relationship between active site and polymer structures. In this paper, polypropylene produced by TiCl3/MgCl2 model catalysts with minimum Ti heterogeneity was analyzed by combined solvent fractionation and the two...

Of all polymerization methods, catalytic polymerization offers the broadest scope of microstructure control. Stereoregularity, comonomer incorporation and sequences, molecular weights, and molecular weight distributions can be controlled by the catalyst structure. Polyolefins are produced on a vast scale of nearly 100 million tons annually, predominantly by catalytic polymerization. High-densit...