Slow Reactant-Water Exchange and High Catalytic Performance of Water-Tolerant Lewis Acids

2014 ◽  
Vol 20 (26) ◽  
pp. 8068-8075 ◽  
Author(s):  
Yusuke Koito ◽  
Kiyotaka Nakajima ◽  
Hisayoshi Kobayashi ◽  
Ryota Hasegawa ◽  
Masaaki Kitano ◽  
...  
Keyword(s):  
Lewis Acids ◽  
Water Exchange ◽  
Catalytic Performance

Establishing the correlation between catalytic performance and N→Sb donor–acceptor interaction: systematic assessment of azastibocine halide derivatives as water tolerant Lewis acids

2019 ◽  
Vol 48 (23) ◽  
pp. 8478-8487 ◽  
Author(s):  
Jian Lei ◽  
Lingteng Peng ◽  
Renhua Qiu ◽  
Yongping Liu ◽  
Yi Chen ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Lewis Acids ◽  
Catalytic Performance ◽  
Acid Catalysts ◽  
Lewis Acid Catalysts ◽  
Acceptor Interaction ◽  
Systematic Assessment ◽  
Donor Acceptor ◽  
Halide Complexes

A series of organoantimony(iii) halide complexes with a tetrahydrodibenzo[c,f][1,5]azastibocine framework were synthesized and employed as water tolerant Lewis acid catalysts.

The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

2019 ◽  
Vol 9 (3) ◽  
pp. 811-821 ◽  
Author(s):  
Zhao-Meng Wang ◽  
Li-Juan Liu ◽  
Bo Xiang ◽  
Yue Wang ◽  
Ya-Jing Lyu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Aerobic Oxidation ◽  
Catalytic Performance ◽  
Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

Optimizing electron density of nickel sulfide electrocatalysts through sulfur vacancy engineering for alkaline hydrogen evolution

2020 ◽  
Vol 8 (35) ◽  
pp. 18207-18214
Author(s):  
Dongbo Jia ◽  
Lili Han ◽  
Ying Li ◽  
Wenjun He ◽  
Caichi Liu ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Electron Density ◽  
Rational Design ◽  
Nickel Sulfide ◽  
Catalytic Performance ◽  
Sulfide Catalysts ◽  
Sulfur Vacancy

A novel, rational design for porous S-vacancy nickel sulfide catalysts with remarkable catalytic performance for alkaline HER.

The main principles and results of pollution monitoring of sediments in the river basin

2020 ◽  
pp. 14-20
Author(s):  
B. Korzhenevsky ◽  
Gleb Tolkachev ◽  
Nikolay Kolomiycev
Keyword(s):  
Heavy Metals ◽  
River Basin ◽  
Water Exchange ◽  
Pollution Monitoring ◽  
Small Rivers ◽  
Volga River ◽  
Natural Landscape ◽  
Volga River Basin ◽  
Ivankovo Reservoir ◽  
Selection Of

The problems of modern geological ecology associated with the study of pollution of sediments of water bodies by heavy metals are considered. The Volga River basin is quite heterogeneous, both in geomorphological and hydrological terms, and in thechnogenical development and usage. A fourrank taxonomy is presented for the selection of sites for monitoring, based on a combination of natural, landscape, climatic and thechnogenical factors. To the largest – the highest taxon – sites of the Ist category – bowls of reservoirs with the slopes and the urban zones, industrial and agricultural structures located within them are carried. Within these areas are allocated to smaller taxa, areas category IInd are the industrial and urban zones, areas category IIIrd are the small rivers without significant contamination and areas category IVth to conduct special observations. The examples of special observations in the study of the annual migration of heavy metals in the system «bottom sediments – water column» on the Ivankovo reservoir are highlighted. The investigations were carried out under the conditions of the standard flow rate for this reservoir and in the conditions of slow water exchange.

Density-driven water exchange controls seasonal declines in jellyfish (Aurelia aurita) abundance in a shallow fjord system

2018 ◽  
Vol 597 ◽  
pp. 137-145 ◽  
Author(s):  
J Goldstein ◽  
C Jürgensen ◽  
UK Steiner ◽  
HU Riisgård
Keyword(s):  
Water Exchange ◽  
Aurelia Aurita ◽  
Fjord System

Catalytic Resonance Theory: Parallel Reaction Pathway Control

2019 ◽  
Author(s):  
M. Alexander Ardagh ◽  
Manish Shetty ◽  
Anatoliy Kuznetsov ◽  
Qi Zhang ◽  
Phillip Christopher ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Active Site ◽  
Active Sites ◽  
Reaction Pathway ◽  
Control Strategies ◽  
Oscillation Amplitude ◽  
Catalytic Performance ◽  
Parallel Reaction ◽  
Resonance Theory ◽  
Static Conditions

Catalytic enhancement of chemical reactions via heterogeneous materials occurs through stabilization of transition states at designed active sites, but dramatically greater rate acceleration on that same active site is achieved when the surface intermediates oscillate in binding energy. The applied oscillation amplitude and frequency can accelerate reactions orders of magnitude above the catalytic rates of static systems, provided the active site dynamics are tuned to the natural frequencies of the surface chemistry. In this work, differences in the characteristics of parallel reactions are exploited via selective application of active site dynamics (0 < ΔU < 1.0 eV amplitude, 10<sup>-6</sup> < f < 10<sup>4</sup> Hz frequency) to control the extent of competing reactions occurring on the shared catalytic surface. Simulation of multiple parallel reaction systems with broad range of variation in chemical parameters revealed that parallel chemistries are highly tunable in selectivity between either pure product, even when specific products are not selectively produced under static conditions. Two mechanisms leading to dynamic selectivity control were identified: (i) surface thermodynamic control of one product species under strong binding conditions, or (ii) catalytic resonance of the kinetics of one reaction over the other. These dynamic parallel pathway control strategies applied to a host of chemical conditions indicate significant potential for improving the catalytic performance of many important industrial chemical reactions beyond their existing static performance.

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