Refernces
10.1021/cs5004454
The research presents a novel synthesis strategy for preparing 2-5 nm metallic silver nanoparticles (AgNPs) supported on tungsten oxide (WO3) nanorods for the selective oxidation of propylene to propylene oxide (PO) using molecular oxygen. The catalyst, prepared in the presence of cetyltrimethylammonium bromide (CTAB), polyvinylpyrrolidone (PVP), and hydrazine, exhibits a PO production rate of 6.1 × 10-2 mol gcat -1 h-1, comparable to industrial ethylene-to-ethylene oxide production rates. The Ag/WO3 catalyst shows 15.5% propylene conversion with 83% PO selectivity at 250 °C and 2 MPa pressure. The study highlights that the synergistic effect between AgNPs and WO3 nanorods is crucial for PO formation, with the rod-like morphology of WO3 facilitating the dispersion of AgNPs and the activation of molecular oxygen. The catalyst's performance is attributed to the formation of Ag2O species during the reaction, which selectively converts propylene to PO.
10.1021/ja063717g
The study focuses on the development and analysis of hafnocene catalysts for the selective oligomerization of propylene to produce 4-methyl-1-pentene, a branched olefin used in the production of polymers with desirable properties. A series of hafnocene complexes with varying substituents were tested as catalyst precursors. Upon activation with methylaluminoxane (MAO) or [Ph3C][B(C6F5)4]/AliBu3, these complexes catalyzed the dimerization of propylene, with selectivities for 4-methyl-1-pentene ranging from 23.9 to 61.6 wt%. The selectivity was found to depend on the nature of the substituents R1 and R2, with the highest selectivity observed for the complex (η5-C5Me4iBu)2HfCl2 (12). The study also investigated the influence of steric effects on the selectivity and the mechanism of propylene oligomerization, including the rate constants for propagation, β-hydride elimination, and β-methyl elimination. The purpose of these chemicals was to evaluate their catalytic performance in producing 4-methyl-1-pentene and to understand the underlying reaction mechanisms that govern the selectivity and activity of the catalysts.
10.1039/b607286k
The study explores the platinum(II)-catalyzed intermolecular hydroarylation of unactivated alkenes with indoles. The researchers discovered that ethylene, α-olefins, and vinyl arenes can undergo hydroarylation with substituted indoles in moderate to good yields using platinum(II) complexes as catalysts. The key chemicals involved include 1,2-dimethylindole, which reacts with ethylene under the catalysis of [PtCl2(H2CLCH2)]2 to produce 3-ethyl-1,2-dimethylindole. The study also examines the hydroarylation of α-olefins like propene and 1-butene, as well as vinyl arenes such as p-chlorostyrene, with indoles. The platinum(II) catalysts enable these reactions to proceed efficiently, even with various substituents on the indole ring, demonstrating good functional group compatibility and selectivity. The study highlights the potential for further development of more active and selective hydroarylation catalysts, contributing to the field of organic synthesis.
F+
F++:极易燃物质;
