نتایج جستجو برای: heterogeneous catalyst

تعداد نتایج: 166602  

2013
Emrah Ozensoy Evgeny I. Vovk

Elucidation of complex heterogeneous catalytic mechanisms at the molecular level is a challenging task due to the complex electronic structure and the topology of catalyst surfaces. Heterogeneous catalyst surfaces are often quite dynamic and readily undergo significant alterations under working conditions. Thus, monitoring the surface chemistry of heterogeneous catalysts under industrially rele...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
Seong H Kim Gabor A Somorjai

This article reviews the surface science of the heterogeneous olefin polymerization catalysts. The specific focus is on how to prepare and characterize stereochemically specific heterogeneous model catalysts for the Ziegler-Natta polymerization. Under clean, ultra-high vacuum conditions, low-energy electron irradiation during the chemical vapor deposition of model Ziegler-Natta catalysts can be...

2005
K. Barbusiński

A novel modified Fenton process using heterogeneous catalyst (swarf) was developed to catalyze the oxidation reaction of azo dye Acid Red 18. It was found that swarf could be used to replace iron salts as a catalyst for the Fenton reaction. The examined continuous Fenton process proved to be very efficient for decolorization of simulated wastewater containing 100 mg/dm3 Acid Red 18. Performance...

Journal: :Chemical communications 2016
Xu Tian Fanzhi Yang Dace Rasina Michaela Bauer Svenja Warratz Francesco Ferlin Luigi Vaccaro Lutz Ackermann

C-H arylations were accomplished with a user-friendly heterogeneous palladium catalyst in the biomass-derived γ-valerolactone (GVL) as an environmentally-benign reaction medium. The user-friendly protocol was characterized by ample substrate scope and high functional group tolerance in the C-H arylation of 1,2,3-triazoles, and the palladium catalyst could be recycled and reused in the C-H activ...

Journal: :Chemical communications 2014
Chen Chen Lingyu Kong Tanyu Cheng Ronghua Jin Guohua Liu

A facile method to construct chiral organoiridium-functionalized periodic mesoporous organosilica is developed. The heterogeneous catalyst displays excellent catalytic efficiency in the enantioselective reduction of α-cyanoacetophenones and α-nitroacetophenones in aqueous medium because of the hydrophobic nature and uniformly distributed active iridium species. The catalyst could be convenientl...

Journal: :Organic & biomolecular chemistry 2010
Subhash Banerjee Vagulejan Balasanthiran Ranjit T Koodali Grigoriy A Sereda

A novel, heterogeneous Pd-MCM-48 catalyst has been developed by encapsulating palladium nanoparticles into the cubic phase of mesoporous MCM-48 matrix at room temperature. The catalyst demonstrated excellent chemo- and regioselectivity for the hydrogenation of olefins at room temperature within 30-80 min. The turnover frequency for the hydrogenation is very high (4400 h(-1)). Interestingly, sel...

2016
Dyah Retno Sawitri Arief Budiman

Kinetic study of free fatty acids (FFAs) esterification for biodiesel production from palm fatty acid distillate (PFAD) using sulfated zirconia (S-ZrO2) prepared by solvent-free method calcined at low temperature as the heterogeneous catalyst was studied. The reaction was performed in a batch-stirred reactor at the different temperature to obtain the kinetic data. The effect of reaction conditi...

Journal: :Journal of the American Chemical Society 2010
Wenyu Huang Jack Hung-Chang Liu Pinar Alayoglu Yimin Li Cole A Witham Chia-Kuang Tsung F Dean Toste Gabor A Somorjai

A highly active heterogeneous Pd-nanoparticle catalyst for the intramolecular addition of phenols to alkynes was developed and employed in a continuous flow reaction system. Running the reaction in flow mode revealed reaction kinetics, such as the activation energy and catalyst deactivation, and provides many potential practical advantages.

2016

Biodiesel is an environmental friendly liquid fuel similar to conventional diesel in combustion properties. It has received international attention in recent times, as that biodiesel is renewable, non-toxic and safe to store. In this study, high grade biodiesel was produced from microalgae (Nannochloropsis oculata) derived lipids via transesterification reaction with methanol in the presence of...

2014
S. Mohammad Sajadi

An efficient method for the preparation of 5-substituted 1H-tetrazole derivatives is reported using MoO3-SiO2 as an efficient heterogeneous catalyst. This method has the advantages of high yields, simple methodology and easy work-up. This catalyst could be recycled very easily, which makes this methodology environmentally benign.

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