نتایج جستجو برای: homogeneous catalyst

تعداد نتایج: 113196  

Journal: :Journal of the American Chemical Society 2013
Pavel A Donets Nicolai Cramer

Chiral trivalent phosphorus species are the dominant class of ligands and the key controlling element in asymmetric homogeneous transition-metal catalysis. Here, novel chiral diaminophosphine oxide ligands are described. The arising catalyst system with nickel(0) and trimethylaluminum efficiently activates formamide C-H bonds under mild conditions providing pyrrolidones via intramolecular hydro...

2009
D. Fernández S. Riaño L. Fadini

The obtaining of aldehydes or ketones through oxidative cleavage of vicinal diols requires the use of a catalyst. In this work we present the positive effects of ionic liquids in the homogeneous oxidative cleavage of ethylenglycol, pinacol, benzopinacol and hydrobenzoin, catalyzed by Mn(salen) complexes. The catalyst dissolved in ionic liquids allows high efficiency (yield up to 99% with air as...

Journal: :journal of sciences, islamic republic of iran 2013
h. khabazzadeh i. sheikhshoaie n. sotudeh

1, 8-dioxo-octahydroxanthene derivatives have efficiently been synthesized from dimedone and aromatic aldehydes using [fe(iii)(salen)cl] complex as an efficient and homogeneous catalyst in molten tetrabutyl ammonium bromide. this methodology offers several advantages, such as good yields, short reaction times, simple procedure, and mild conditions.

Journal: :Langmuir : the ACS journal of surfaces and colloids 2007
Troy R Hendricks Erin E Dams Steven T Wensing Ilsoon Lee

We studied the effects of catalyst introduction methods using poly(amidoamine) (PAMAM) dendrimers on the nickel patterning of polyelectrolyte multilayer (PEM)-coated substrates. Three different approaches to palladium catalyst introduction using microcontact printing as the patterning technique were utilized and compared. The catalyst introduction methods are (1) direct catalyst stamping, (2) d...

Journal: :Analytical chemistry 2008
Cornelius T Martha Niels Elders Johannes G Krabbe Jeroen Kool Wilfried M A Niessen Romano V A Orru Hubertus Irth

An integrated online screening system was developed to rapidly screen homogeneous catalysts for activity toward a selected synthesis. The continuous-flow system comprises standard HPLC pumps for the delivery of substrates, an HPLC autosampler for the injection of homogeneous catalysts, a thermostated reactor to mediate synthesis, and a single-stage quadrupole mass spectrometer (MS) equipped wit...

Journal: :Angewandte Chemie 2007
Hengquan Yang Lei Zhang Lin Zhong Qihua Yang Can Li

The solid catalyst with high catalytic activity and enantioselectivity in the hydrolytic kinetic resolution (HKR) of epoxides was prepared by confining Co(Salen) in the nanocage of SBA-16 through reducing the pore entrance size using a silylation method. It was found that the activity of the solid catalysts increased with the number of [Co(Salen)] molecules per nanocage increasing, and the soli...

Journal: :Chemical communications 2012
Kosei Sugahara Toshihiro Kimura Keigo Kamata Kazuya Yamaguchi Noritaka Mizuno

A tetra-n-butylammonium (TBA) salt of a γ-Keggin -6-charged germanodecatungstate, [γ-H(2)GeW(10)O(36)](6-) (I), could act as an efficient homogeneous catalyst for Knoevenagel condensation of active methylene compounds with carbonyl compounds.

Journal: :Chemical communications 2010
Byoung Se Lee Mihye Yi So Young Chu Ja Young Lee Hye Rim Kwon Kyu Reon Lee Donghyeon Kang Wan Seop Kim Heung Bin Lim Jouhahn Lee Hyung-Joong Youn Dae Yoon Chi Nam Hwi Hur

Copper nitride nanoparticles supported on a mesoporous superparamagnetic silica microsphere exhibit superior activity toward the Huisgen cycloaddition of azides and alkynes. The nitride catalyst offers significant advantages over homogeneous Cu catalysts.

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