نتایج جستجو برای: homogeneous co oligomerization of olefins
تعداد نتایج: 21201291 فیلتر نتایج به سال:
Although Fe-based catalysts have made significant progress in Fischer–Tropsch synthesis, the effect of residual sodium on structural properties and catalytic performance has been controversial. Herein, we report positive role FeAlNa for olefins synthesis from syngas. Meanwhile, as-prepared were characterized by multiple characterization technique to reveal properties. The results revealed that ...
background: the ultrastructural analysis of cultured follicles could direct us to understand subcellular changes during in vitro culture. objective: this study was done to verify the ultrastructural characteristics of in vitro cultured mouse isolated preantral follicles in co-culture system in the presence and absence of leukemia inhibitory factor (lif) materials and methods: mechanically isola...
Unactivated acyclic internal aliphatic olefins are often found to be unreactive in conventional alkenylation reactions. To address this problem, a cobalt catalyzed allylic selective dehydrogenative Heck reaction with internal aliphatic olefins has been developed. The method is highly regioand stereoselective, the conditions are mild and a wide variety of functional groups can be tolerated. Rema...
This contribution presents an updated overview of the different copolymers containing stereoregular polystyrene blocks. Special emphasis is placed on syndiospecific and isospecific copolymerization of styrene with co-monomers (ethylene and α-olefins, conjugated and non-conjugated dienes, styrene derivatives, etc.). The catalytic systems involved are described and the polymerization mechanisms a...
Carbon-carbon bond-forming reactions are among the most important types of bond constructions in organic chemistry. Yet, the paucity of methods for the stereoselective incorporation of abundantly available carbon feedstocks such as CO, CO2, HCN, or simple olefins to prochiral substrates is one of the major limitations in this area.1 Ideally, from a manufacturing perspective, these reactions sho...
beside ziegler-natta and phillips catalysts the development of methylaluminoxane (mao) as cocatalyst incombination with metallocenes or other transition metal complexes for the polymerization of olefins haswidely increased the possibilities in controlling the polymer composition, polymer structure, tacticity and special properties with high precision. these catalysts allow the synthesis of isot...
The human cytidine deaminase APOBEC3G (A3G) is a potent inhibitor of retroviruses and transposable elements and is able to deaminate cytidines to uridines in single-stranded DNA replication intermediates. A3G contains two canonical cytidine deaminase domains (CDAs), of which only the C-terminal one is known to mediate cytidine deamination. By exploiting the crystal structure of the related tetr...
Medium-pore (diameter ~ 6A) zeolites such as ZSM-5 and silicalite impregnated with Group VIII metals provide selective catalytic pathways for the conversion of synthesis gas to gasoline or olefins. Mössbauer and magnetic studies on these catalysts containing iron or iron plus cobalt are reported. The zeolites were impregnated with metal nitrate solutions, reduced, and carbided to yield showed F...
Economic and powerful olefins separation is the most important technology for the energy optimisation and reduction of fossil fuel in petrochemical industry. On account of that the specific structures of olefins will make some influences on the separation, in this work, by means of density functional theory, we perform a theoretical estimation of the olefin-structure-induced effects on the reac...
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