نتایج جستجو برای: natta catalysts

تعداد نتایج: 33137  

2017
Wei Wang Caleb F Anderson Zongyuan Wang Wei Wu Honggang Cui Chang-Jun Liu

Noble metal catalysts have been widely used in many applications because of their high activity and selectivity. However, a controllable preparation of noble metal catalysts still remains as a significant challenge. To overcome this challenge, peptide templates can play a critical role in the controllable syntheses of catalysts owing to their flexible binding with specific metallic surfaces and...

Journal: :Chemical science 2017
Shuang Yang Wen Che Hui-Ling Wu Shou-Fei Zhu Qi-Lin Zhou

We developed neutral iridium catalysts with chiral spiro phosphine-carboxy ligands (SpiroCAP) for asymmetric hydrogenation of unsaturated carboxylic acids. Different from the cationic Crabtree-type catalysts, the iridium catalysts with chiral spiro phosphine-carboxy ligands are neutral and do not require the use of a tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF-) counterion, which is ne...

2015
Kyle M. Brunner Baiyu Huang Brian F. Woodfield William C. Hecker

A novel, solvent-deficient precipitation (SDP) method for catalyst preparation in general and for preparation of iron FT catalysts in particular is reported. Eight catalysts using a 23 factorial design of experiments to identify the key preparation variables were prepared. The catalysts were characterized by electron microprobe, N2 adsorption, TEM, XRD, and ICP. Results show that the morphology...

Journal: :journal of physical & theoretical chemistry 2007
m. vadi a. safavi a. jamshidi

the mono-metallic and bi-metallic catalysts have been prepared by impregnating with solutions containing a compound of h2ptcl6,wo3 and 1ml hcl (0.1 mol). it should be noted that the catalysts’ activity and selectivity have been determined under these conditions : 450-5000c ,and 15-25atm by h2. for converting n-heptane , the molar ratio h2/c7h16 is 5 , and lhsv is 1.5ml/h. it has been proved tha...

Journal: :Molecules 2014
Dong Wang Didier Astruc

Magnetically recyclable catalysts with magnetic nanoparticles (MNPs) are becoming a major trend towards sustainable catalysts. In this area, recyclable supported ruthenium complexes and ruthenium nanoparticles occupy a key place and present great advantages compared to classic catalysts. In this micro-review, attention is focused on the fabrication of MNP-supported ruthenium catalysts and their...

In this study, the nanoporous γ-alumina catalysts were prepared by the sol-gel method using hydrolysis of aluminum isopropoxide in the presence of TX-100 or gelatin/TX-100 mixture. Catalysts were characterized by XRD, FT-IR, TEM, BET-BJH and N2 adsorption-desorption isotherms. To investigate reactivity and selectivity of the synthesized catalysts, dehydration reaction of 2-octanol was carried o...

Journal: :Angewandte Chemie 2005
Thorsten Ressler Benjamin L Kniep Igor Kasatkin Robert Schlögl

Received: 15 December 2004; Revised: 26 January 2005 Abstract Copper zinc oxide catalysts prepared similar to industrially used catalysts were studied by high-resolution electron microscopy. The microstructure of the Cu/ZnO catalysts deviates considerably from that of bulk copper metal and idealized copper model systems. In order to reveal reliable structure-activity relationships for copper ca...

Copper-manganese oxide catalysts are prepared with an atomic ratio of Cu/Mn=2/1 using a coprecipitation procedure under air atmosphere. The time of aging, i.e., the time that precipitate remains in contact with the precipitating medium, has been varied from 0 (for unaged precursor) to 300 minutes and the effect of precipitate aging time in each atmosphere upon the structure and morphology of di...

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