نتایج جستجو برای: cocatalyst

تعداد نتایج: 432  

Journal: :علوم و تکنولوژی پلیمر 0
رضا مهترانی حسن عربی محمدباقر تیموری سید صابر حسینی شیراز وحید اسلامی منش

copolymerization of ethylene and propylene was investigated using a 4th generation phthalate ziegler-natta catalyst in normal hexane in a buchi reactor. the effects of different mole fractions of [al]/[ti], [si]/[al] and various amounts of hydrogen on productivity and weight percent of ethylene on the product, were studied. in the copolymerization reactions, tri-isobutyl aluminum (tibal) was us...

Journal: :Journal of the American Chemical Society 2005
Jodie L Brice Jenna E Harang Vitaliy I Timokhin Natia R Anastasi Shannon S Stahl

The first examples of palladium-catalyzed oxidative amination of unactivated alkyl olefins have been identified. To be successful, these reactions must be conducted under cocatalyst-free conditions that involve direct dioxygen-coupled turnover of the palladium catalyst. The oxidative amination products of norbornene and other cyclic alkenes implicate a cis-aminopalladation mechanism.

Journal: :Journal of the American Chemical Society 2013
Marie-Gabrielle Braun Abigail G Doyle

The first catalytic allylic C-H fluorination reaction using a nucleophilic fluoride source is reported. Under the influence of a Pd/Cr cocatalyst system, simple olefin substrates undergo fluorination with Et3N·3HF in good yields with high branched:linear regioselectivity. The mild conditions and broad scope make this reaction a powerful alternative to established methods for the preparation of ...

Journal: :Advanced Functional Materials 2023

Cocatalyst engineering with non-noble metal nanomaterials can play a vital role in low-cost, sustainable, and large-scale photocatalytic hydrogen production. This research adopts slow carburization simultaneous hydrocarbon reduction to synthesize carbon-encapsulated Mo/Mo2C heterostructure nanoparticles, namely Mo/Mo2[email protected] cocatalyst. Experimental theoretical investigations indicate...

Journal: :Journal of the American Chemical Society 2008
Yuichi Kajita Takuya Kurahashi Seijiro Matsubara

An intermolecular nickel-catalyzed addition reaction has been developed where phthalic anhydrides react with alkynes to afford substituted isocoumarins. A mechanistic rationale is proposed, implying reductive elimination of Ni(0) promoted by ZnCl(2) cocatalyst as the key step of the catalytic cycle.

Journal: :Angewandte Chemie 2013
Juan delPozo Desirée Carrasco Mónica H Pérez-Temprano Max García-Melchor Rosana Álvarez Juan A Casares Pablo Espinet

Journal: :The Journal of organic chemistry 2007
Daniel H Paull Ethan Alden-Danforth Jamison Wolfer Cajetan Dogo-Isonagie Ciby J Abraham Thomas Lectka

A catalytic, asymmetric process for the synthesis of 1,4-benzoxazinones from o-benzoquinone imides and ketene enolates is reported. Addition of Lewis acids (Zn(OTf)2, In(OTf)3, and in particular Sc(OTf)3) creates a bifunctional catalytic system that dramatically increases the reaction rate and the yield of these non-natural amino acid precursors while preserving the remarkable enantioselectivit...

Journal: :Journal of the American Chemical Society 2015
Andrei V Iosub Shannon S Stahl

A palladium(II) catalyst system has been identified for aerobic dehydrogenation of substituted cyclohexenes to the corresponding arene derivatives. Use of sodium anthraquinone-2-sulfonate (AMS) as a cocatalyst enhances the product yields. A wide range of functional groups are tolerated in the reactions, and the scope and limitations of the method are described. The catalytic dehydrogenation of ...

2013
Kotohiro Nomura

This review summarizes recent results for ethylene/styrene copolymerization using half-titanocenes containing anionic donor ligands, Cp’TiX2(Y) (X = halogen, alkyl; Y = aryloxo, ketimide etc.)–cocatalyst systems. The product composition, the styrene incorporation and microstructures in the resultant copolymers are highly influenced by the anionic donor employed. A methodology for an exclusive s...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
Hongbo Li Tobin J Marks

A series of bimetallic organo-group 4 "constrained geometry" catalysts and binuclear bisborane and bisborate cocatalysts have been synthesized to probe catalyst center-catalyst center cooperativity effects on olefin enchainment in homogenous olefin polymerization and copolymerization processes. Significant nuclearity effects are found versus mononuclear controls, and the effect can be correlate...

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