Bioinspired Complex-Nanoparticle Hybrid Catalyst System for Aqueous Perchlorate Reduction: Rhenium Speciation and Its Influence on Catalyst Activity

ACS Catalysis ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 511-522 ◽  
Author(s):  
Jinyong Liu ◽  
Jong Kwon Choe ◽  
Yin Wang ◽  
John R. Shapley ◽  
Charles J. Werth ◽  
...  
Keyword(s):  
Catalyst Activity ◽  
Catalyst System ◽  
Hybrid Catalyst ◽  
Perchlorate Reduction

scholarly journals Optimal Catalyst and Cocatalyst Precontacting in Industrial Ethylene Copolymerization Processes

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Paul Aigner ◽  
Christian Paulik ◽  
Apostolos Krallis ◽  
Vasileios Kanellopoulos
Keyword(s):  
Mass Transfer ◽  
Catalyst Activity ◽  
Plug Flow ◽  
Mass Transfer Process ◽  
Catalyst System ◽  
Transfer Model ◽  
Catalyst Activation ◽  
Before And After ◽  
Natta Catalyst ◽  
Experimental Findings

In industrial-scale catalytic olefin copolymerization processes, catalyst and cocatalyst precontacting before being introduced in the polymerization reactor is of profound significance in terms of catalyst kinetics and morphology control. The precontacting process takes place under either well-mixing (e.g., static mixers) or plug-flow (e.g., pipes) conditions. The scope of this work is to study the influence of mixing on catalyst/cocatalyst precontacting for a heterogeneous Ziegler-Natta catalyst system under different polymerization conditions. Slurry ethylene homopolymerization and ethylene copolymerization experiments with 1-butene are performed in a 0.5 L reactor. In addition, the effect of several key parameters (e.g., precontacting time, and ethylene/hydrogen concentration) on catalyst activity is analyzed. Moreover, a comprehensive mass transfer model is employed to provide insight on the mass transfer process and support the experimental findings. The model is capable of assessing the external and internal mass transfer limitations during catalyst/cocatalyst precontacting process. It is shown that catalyst/cocatalyst precontacting is very important for the catalyst activation as well as for the overall catalyst kinetic behavior. The study reveals that there is an optimum precontacting time before and after which the catalyst activity decreases, while this optimum time depends on the precontacting mixing conditions.

Selective Synthesis of Ethylene from Synthesis Gas over Hybrid Catalyst System

1986 ◽  
Vol 15 (8) ◽  
pp. 1341-1342 ◽  
Author(s):  
Hironori Arakawa ◽  
Yoshimichi Kiyozumi ◽  
Kunio Suzuki ◽  
Kazuhiko Takeuchi ◽  
Takehiko Matsuzaki ◽  
...  
Keyword(s):  
Synthesis Gas ◽  
Catalyst System ◽  
Selective Synthesis ◽  
Hybrid Catalyst

Acceptorless Dehydrogenation of Hydrocarbons by Noble-Metal-Free Hybrid Catalyst System

2018 ◽  
Vol 20 (7) ◽  
pp. 2042-2045 ◽  
Author(s):  
Hiromu Fuse ◽  
Masahiro Kojima ◽  
Harunobu Mitsunuma ◽  
Motomu Kanai
Keyword(s):  
Noble Metal ◽  
Catalyst System ◽  
Hybrid Catalyst ◽  
Metal Free

scholarly journals Photocatalytic redox-neutral hydroxyalkylation of N-heteroaromatics with aldehydes

2020 ◽  
Vol 11 (44) ◽  
pp. 12206-12211 ◽  
Author(s):  
Hiromu Fuse ◽  
Hiroyasu Nakao ◽  
Yutaka Saga ◽  
Arisa Fukatsu ◽  
Mio Kondo ◽  
...  
Keyword(s):  
Catalyst System ◽  
Hybrid Catalyst ◽  
Thiophosphoric Acid

Hydroxyalkylation of N-heteroaromatics with aldehydes was achieved using a binary hybrid catalyst system comprising an acridinium photoredox catalyst and a thiophosphoric acid organocatalyst.

Photocatalytic H2 production on hybrid catalyst system composed of inorganic semiconductor and cobaloximes catalysts

2011 ◽  
Vol 281 (2) ◽  
pp. 318-324 ◽  
Author(s):  
Fuyu Wen ◽  
Jinhui Yang ◽  
Xu Zong ◽  
Baojun Ma ◽  
Donge Wang ◽  
...  
Keyword(s):  
Catalyst System ◽  
H2 Production ◽  
Hybrid Catalyst ◽  
Inorganic Semiconductor

Binary molybdenum-based catalyst for coordination polymerization of styrene

2016 ◽  
Vol 49 (5) ◽  
pp. 408-421 ◽  
Author(s):  
Jieting Geng ◽  
Youguo Shao ◽  
Feng Song ◽  
Feng Li ◽  
Jing Hua
Keyword(s):  
Molecular Weight ◽  
Catalyst Activity ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Catalyst System ◽  
Bulk Polymerization ◽  
Molar Ratio ◽  
Scanning Calorimetry ◽  
Coordination Polymerization ◽  
Co Catalyst

Coordination polymerization of styrene (St) using molybdenum pentachloride supported by phosphite ligand in the presence of metal organic compound was studied for the first time. The types of phosphite and co-catalysts significantly affected the catalytic activity of the molybdenum (V) (Mo(V)) active center and the number-average molecular weight ( Mn) of the resultant polymer. Among the examined catalysts, tri(nonylphenyl)phosphite (TNPP) ligand and AlOPhCH3( i-Bu)2 as co-catalyst provided the polymer with highest yield (up to 87.1%), metallocene as co-catalyst provided the polymer with highest Mn (up to 5.32 × 105). The effect of [P]/[Mo] molar ratio on catalyst activity of the polymerization was discussed and the structures of Mo·TNPP complexes were preliminarily studied by infrared (IR) and ultraviolet spectroscopies. Besides, the polystyrene (PS) samples synthesized through bulk polymerization and solution polymerization were characterized by gel permeation chromatography, IR, carbon 13 nuclear magnetic resonance, and differential scanning calorimetry, respectively, and the results indicated both of the PS had high molecular weight (approximately 105) and atactic structure. All these results demonstrated that Mo(V) catalyst system was very effective for St polymerization.

scholarly journals A Bond-Weakening Borinate Catalyst that Improves the Scope of the Photoredox α-C–H Alkylation of Alcohols

Synthesis ◽  
2020 ◽  
Vol 52 (15) ◽  
pp. 2171-2189
Author(s):  
Kounosuke Oisaki ◽  
Motomu Kanai ◽  
Kentaro Sakai
Keyword(s):  
Hydrogen Atom ◽  
Visible Light ◽  
Organic Synthesis ◽  
Hydroxy Group ◽  
Functional Group ◽  
Chemical Yield ◽  
Catalyst System ◽  
Hydrogen Atom Transfer ◽  
Hybrid Catalyst ◽  
Site Selective

The development of catalyst-controlled, site-selective C(sp3)–H functionalization reactions is currently a major challenge in organic synthesis. In this paper, a novel bond-weakening catalyst that recognizes the hydroxy group of alcohols through formation of a borate is described. An electron-deficient borinic acid–ethanolamine complex enhances the chemical yield of the α-C–H alkylation of alcohols when used in conjunction with a photoredox catalyst and a hydrogen atom transfer catalyst under irradiation with visible light. This ternary hybrid catalyst system can, for example, be applied to functional-group-enriched­ peptides.

A novel hybrid catalyst system and its effects on the curing, thermal, and dielectric properties of cyanate ester

2011 ◽  
Vol 51 (11) ◽  
pp. 2236-2244 ◽  
Author(s):  
Shankai Dai ◽  
Dongxian Zhuo ◽  
Aijuan Gu ◽  
Guozheng Liang ◽  
Li Yuan
Keyword(s):  
Dielectric Properties ◽  
Catalyst System ◽  
Cyanate Ester ◽  
Hybrid Catalyst
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