Design and Preparation of Heterogeneous Catalysts by Controlled Chemical Reactions with Oxygen and Hydrogen

1994 ◽  
Vol 368 ◽  
Author(s):  
David L. Cocke ◽  
Donald G. Naugle ◽  
Thomas R. Hess
Keyword(s):  
Chemical Reactions ◽  
Heterogeneous Catalysts ◽  
Formation Processes ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Reduction Processes ◽  
Alloy Oxidation ◽  
Reaction Models ◽  
Catalyst Systems ◽  
Insight Into

ABSTRACTChemical reactions of metals and strongly interacting alloys such as Cu-Mn, Ni-Ti, Ni-Hf and Ni-Zr with oxygen and hydrogen play important roles in the preparation, activation, and regeneration of many important heterogeneous catalytic systems involving supported and unsupported metals and alloys. Recent advances in the understanding of metal and alloy oxidation is bringing new insight into the reactive design and activation of bi- and multi-metallic catalysts. By surface studies of oxidation, thermal annealing and reduction of selected alloys and their thin films and reaction layers and products we have been able to delineate the factors which are most important to the oxide formation processes and the oxide reduction processes. Reaction models developed from these results are permitting the design of new catalyst systems and providing long sought understanding to explain specific aspects of well established metallic catalysts.

Some Aspects of Particuology in Heterogeneous Catalysts

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Rasidah Razali ◽  
Ho Chin Siong ◽  
Lai Sin Yuan ◽  
Sheela Chandren ◽  
Hadi Nur
Keyword(s):  
Heterogeneous Catalysts ◽  
Sol Gel ◽  
Bifunctional Catalyst ◽  
Catalytic Systems ◽  
Particulate Materials ◽  
Design And Synthesis ◽  
Heterogeneous Catalytic ◽  
Catalyst Systems ◽  
First Time ◽  
High Length

The design and synthesis of particulate materials for new catalyst systems with novel properties remain a big challenge today. Here an attempt has been made to synthesize particulate materials for several heterogeneous catalytic systems, which contain examples from our recent research projects in this area. The particulate catalysts have been designed for single centre catalyst, phase-boundary catalyst, bifunctional catalyst, photocatalyst and chiral catalyst. In our current research, the synthesis of well-aligned titanium dioxide catalyst with very high length to the diameter ratio has also been demonstrated for the first time by sol-gel method under magnetic field with surfactant as the structure aligning agent. 

scholarly journals Recent Progresses in the Multicomponent Synthesis of Dihydropyridines by Applying Sustainable Catalysts Under Green Conditions

2021 ◽  
Vol 9 ◽  
Author(s):  
Immandhi Sai Sonali Anantha ◽  
Nagaraju Kerru ◽  
Suresh Maddila ◽  
Sreekantha B. Jonnalagadda
Keyword(s):  
Heterogeneous Catalysts ◽  
Reaction Times ◽  
Cost Effective ◽  
Multicomponent Synthesis ◽  
One Pot ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Significant Efficacy ◽  
Magnetic Silica ◽  
Active Methylene

The synthesis of dihydropyridines, valuable molecules with diverse therapeutic properties, using eco-friendly heterogeneous catalysts as a green alternative received significant consideration. By selecting appropriate precursors, these compounds can be readily modified to induce the desired properties in the target product. This review focused on synthesising diverse dihydropyridine derivatives in single-pot reactions using magnetic, silica, and zirconium-based heterogeneous catalytic systems. The monograph describes preparation techniques for various catalyst materials in detail. It covers facile and benign magnetic, silica, zirconium-based, and ionic liquid catalysts, exhibiting significant efficacy and consistently facilitating excellent yields in short reaction times and in a cost-effective way. Most of the designated protocols employ Hantzsch reactions involving substituted aldehydes, active methylene compounds, and ammonium acetate. These reactions presumably follow Knoevenagel condensation followed by Michael addition and intra-molecular cyclisation. The multicomponent one-pot protocols using green catalysts and solvents have admirably increased the product selectivity and yields while minimising the reaction time. These sustainable catalyst materials retain their viability for several cycles reducing the expenditure are eco-friendly.

scholarly journals HOMOGENEOUS VINYLATION OF 2-HYDROXY-2 PHENYLETHANICAL ACID

2018 ◽  
Vol 6 (11) ◽  
pp. 350-354
Author(s):  
Parmanov A.B. ◽  
Nurmanov S.E. ◽  
Tomash Maniecki ◽  
Ziyadullayev O.E. ◽  
Abdullayev J.U.
Keyword(s):  
Carboxylic Acids ◽  
Vinyl Ester ◽  
Mandelic Acid ◽  
Heterogeneous Catalysts ◽  
Raw Materials ◽  
Zinc Salt ◽  
Vinyl Esters ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Ethylene Series

Homogeneous-catalytical vinylation of 2-hydroxy-2-phenylethanical acid was carried out. Influence of catalylists nature, temperature and duration reaction on yield of synthesized vinyl ester has been investigated. basis of natural raw materials. Based on vinyl esters of carboxylic acids, their polymers and copolymers with unsaturated compounds of the ethylene series, emulsifiers for emulsion paints have been obtained; compounds that improve the viscosity of lubricating oils and are used as crosslinking agents in the rubber industry. Synthesis of vinyl esters based on monobasic aliphatic acids has been studied by the example of acetic acid by many researchers. In this respect, the aromatic carboxylic acids remain unexplored. Goal: Synthesis of vinyl ester of mandelic acid by it’s reaction with acetylene in the presence of heterogeneous catalysts, investigation of the influence of the nature of catalysts and the reaction temperature on the yield of obtained product. Methodology: Catalytic systems based on AlCl3∙6H2O or zinc salt of mandelic acid with dimethylsulfoxide were prepared and heterogeneous catalytic vinylation of mandelic acid with acetylene was carried out and it’s vinyl ether was obtained. Scientific Novelty. The synthesis of vinyl ester of mandelic acid with it’s reactions with acetylene using the catalytic systems AlCl3∙6H2O-DMSO and (C6H5CH(OH)COO)2Zn-DMSO was carried out. Obtained Data: The vinyl ester of mandelic acid was synthesized by it’s vinylation in stationary heterogeneous conditions. The influence of the nature of the catalyst (AlCl3∙6H2O, (C6H5CH(OH)COO)2Zn), temperature and duration of the reaction on the yield of the product was investigated. Features: vinylation of hydroxy carboxylic acid was investigated; the catalytic systems AlCl3∙6H2O-DMSO and (C6H5CH(OH)COO)2Zn-DMSO are used; factors influencing the yield of vinyl ester of mindalic acid and optimal conditions of it’s synthesis were found.

scholarly journals Development of Covalent Triazine Frameworks as Heterogeneous Catalytic Supports

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1326 ◽  
Author(s):  
Norini Tahir ◽  
Chidharth Krishnaraj ◽  
Karen Leus ◽  
Pascal Van Der Voort
Keyword(s):  
Heterogeneous Catalysis ◽  
Surface Area ◽  
Chemical Reactions ◽  
Chemical Stability ◽  
Structural Design ◽  
Heterogeneous Catalysts ◽  
Molecular Complexes ◽  
Heterogeneous Catalytic ◽  
Catalytic Supports ◽  
Thermal And Chemical Stability

Covalent triazine frameworks (CTFs) are established as an emerging class of porous organic polymers with remarkable features such as large surface area and permanent porosity, high thermal and chemical stability, and convenient functionalization that promotes great potential in heterogeneous catalysis. In this article, we systematically present the structural design of CTFs as a versatile scaffold to develop heterogeneous catalysts for a variety of chemical reactions. We mainly focus on the functionalization of CTFs, including their use for incorporating and stabilization of nanoparticles and immobilization of molecular complexes onto the frameworks.

Diffusion Processes Affecting the Performance of Heterogeneous Catalysts: Part 1

2011 ◽  
Vol 319-320 ◽  
pp. 107-115
Author(s):  
Mohammad Ebrahim Zeynali ◽  
S. Hakim
Keyword(s):  
Diffusion Coefficient ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Heterogeneous Catalysts ◽  
Molecular Diffusion ◽  
Diffusion Processes ◽  
Knudsen Diffusion ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic

The diffusion processes taking place in heterogeneous catalytic systems have been discussed. Various diffusion mechanisms such as Knudsen diffusion, molecular diffusion, configurational diffusion and surface diffusion sensitivity in catalytic systems were investigated. The concentration gradients inside the catalyst pellet were obtained for various Thiele modulus. The Knudsen number was calculated and discussed for large and small pores. The transitional diffusion coefficient was determined for diethylbenzene. The experimental pore size distribution carves for an industrial and synthesized catalyst was obtained and the effect of pore size distribution on diffusion coefficient was discussed.

Hydrogen peroxide decomposition on a two-component CuO-Cr2O3 catalyst

1988 ◽  
Vol 53 (8) ◽  
pp. 1636-1646 ◽  
Author(s):  
Viliam Múčka ◽  
Kamil Lang
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Extreme Values ◽  
Catalytic Properties ◽  
Active Components ◽  
Catalytic Systems ◽  
Heterogeneous Catalytic ◽  
Peroxide Decomposition ◽  
Two Component ◽  
Catalytically Active

Some physical and catalytic properties of the two-component copper(II)oxide-chromium(III)oxide catalyst with different content of both components were studied using the decomposition of the aqueous solution of hydrogen peroxide as a testing reaction. It has been found that along to both basic components, the system under study contains also the spinel structure CuCr2O4, chromate washable by water and hexavalent ions of chromium unwashable by water. The soluble chromate is catalytically active. During the first period of the reaction the equilibrium is being established in both homogeneous and heterogeneous catalytic systems. The catalytic activity as well as the specific surface area of the washed solid is a non-monotonous function of its composition. It seems highly probable that the extreme values of both these quantities are not connected with the detected admixtures in the catalytic system. The system under study is very insensitive with regard to the applied doses of gamma radiation. Its catalytic properties are changed rather significantly after the thermal treatment and particularly after the partial reduction to low degree by hydrogen. The observed changes of the catalytic activity of the system under study are very probably in connection with the changes of the valence state of the catalytically active components of the catalyst.

Insight into SEI Growth in Li-Ion Batteries using Molecular Dynamics and Accelerated Chemical Reactions

2021 ◽  
Vol 125 (34) ◽  
pp. 18588-18596
Author(s):  
Lorena Alzate-Vargas ◽  
Samuel M. Blau ◽  
Evan Walter Clark Spotte-Smith ◽  
Srikanth Allu ◽  
Kristin A. Persson ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Chemical Reactions ◽  
Li Ion Batteries ◽  
Li Ion ◽  
Insight Into

scholarly journals Selective Styrene Oxidation to Benzaldehyde over Recently Developed Heterogeneous Catalysts

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1680
Author(s):  
Marta A. Andrade ◽  
Luísa M. D. R. S. Martins
Keyword(s):  
Heterogeneous Catalysts ◽  
Carbon Materials ◽  
Oxygen Species ◽  
Styrene Oxidation ◽  
Reaction Conditions ◽  
Reactive Metal ◽  
Catalytic Systems ◽  
Tert Butyl Hydroperoxide ◽  
Metal Organic ◽  
Important Intermediate

The selective oxidation of styrene under heterogeneous catalyzed conditions delivers environmentally friendly paths for the production of benzaldehyde, an important intermediate for the synthesis of several products. The present review explores heterogeneous catalysts for styrene oxidation using a variety of metal catalysts over the last decade. The use of several classes of supports is discussed, including metal–organic frameworks, zeolites, carbon materials and silicas, among others. The studied catalytic systems propose as most used oxidants tert-butyl hydroperoxide, and hydrogen peroxide and mild reaction conditions. The reaction mechanism proceeds through the generation of an intermediate reactive metal–oxygen species by catalyst-oxidant interactions. Overall, most of the studies highlight the synergetic effects among the metal and support for the activity and selectivity enhancement.

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