Catalyst granule production in a spouted bed: Opportunities for creative catalyst design

1998 ◽  
pp. 451-457 ◽  
Author(s):  
A.J. Kamphuis ◽  
J.R. Walls
Keyword(s):  
Catalyst Design ◽  
Spouted Bed ◽  
Catalyst Granule

Iterative Supervised Principal Component Analysis-Driven Ligand Design for Regioselective Ti-Catalyzed Pyrrole Synthesis

2020 ◽  
Author(s):  
Xin Yi See ◽  
Benjamin Reiner ◽  
Xuelan Wen ◽  
T. Alexander Wheeler ◽  
Channing Klein ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
De Novo ◽  
Principal Component ◽  
Component Analysis ◽  
Catalyst Design ◽  
Data Driven ◽  
Initial Reaction ◽  
Training Set ◽  
Reaction Conditions ◽  
Component Loadings

<div> <div> <div> <p>Herein, we describe the use of iterative supervised principal component analysis (ISPCA) in de novo catalyst design. The regioselective synthesis of 2,5-dimethyl-1,3,4-triphenyl-1H- pyrrole (C) via Ti- catalyzed formal [2+2+1] cycloaddition of phenyl propyne and azobenzene was targeted as a proof of principle. The initial reaction conditions led to an unselective mixture of all possible pyrrole regioisomers. ISPCA was conducted on a training set of catalysts, and their performance was regressed against the scores from the top three principal components. Component loadings from this PCA space along with k-means clustering were used to inform the design of new test catalysts. The selectivity of a prospective test set was predicted in silico using the ISPCA model, and only optimal candidates were synthesized and tested experimentally. This data-driven predictive-modeling workflow was iterated, and after only three generations the catalytic selectivity was improved from 0.5 (statistical mixture of products) to over 11 (> 90% C) by incorporating 2,6-dimethyl- 4-(pyrrolidin-1-yl)pyridine as a ligand. The successful development of a highly selective catalyst without resorting to long, stochastic screening processes demonstrates the inherent power of ISPCA in de novo catalyst design and should motivate the general use of ISPCA in reaction development. </p> </div> </div> </div>

Towards a Design of Active Oxygen Evolution Catalysts: Insights from Automated Density Functional Theory Calculations and Machine Learning

2019 ◽  
Author(s):  
Seoin Back ◽  
Kevin Tran ◽  
Zachary Ulissi
Keyword(s):  
Machine Learning ◽  
Oxygen Evolution ◽  
Active Sites ◽  
Density Functional ◽  
Chemical Space ◽  
Density Functional Theory Calculations ◽  
Catalyst Design ◽  
Transition Metal Catalysts ◽  
Oxide Materials ◽  
Design Strategies

<div> <div> <div> <div><p>Developing active and stable oxygen evolution catalysts is a key to enabling various future energy technologies and the state-of-the-art catalyst is Ir-containing oxide materials. Understanding oxygen chemistry on oxide materials is significantly more complicated than studying transition metal catalysts for two reasons: the most stable surface coverage under reaction conditions is extremely important but difficult to understand without many detailed calculations, and there are many possible active sites and configurations on O* or OH* covered surfaces. We have developed an automated and high-throughput approach to solve this problem and predict OER overpotentials for arbitrary oxide surfaces. We demonstrate this for a number of previously-unstudied IrO2 and IrO3 polymorphs and their facets. We discovered that low index surfaces of IrO2 other than rutile (110) are more active than the most stable rutile (110), and we identified promising active sites of IrO2 and IrO3 that outperform rutile (110) by 0.2 V in theoretical overpotential. Based on findings from DFT calculations, we pro- vide catalyst design strategies to improve catalytic activity of Ir based catalysts and demonstrate a machine learning model capable of predicting surface coverages and site activity. This work highlights the importance of investigating unexplored chemical space to design promising catalysts.<br></p></div></div></div></div><div><div><div> </div> </div> </div>

Validating the MFiX-DEM Model for Flow Regime Prediction in a 3D Spouted Bed

2018 ◽  
Author(s):  
Subhodeep Banerjee ◽  
Chris Guenther ◽  
William A. Rogers
Keyword(s):  
Flow Regime ◽  
Spouted Bed ◽  
Dem Model

Pd Catalyzed N1/N4 Arylation of Piperazine for Synthesis of Drugs, Biological and Pharmaceutical Targets: An Overview of Buchwald Hartwig Amination Reaction of Piperazine in Drug Synthesis

2018 ◽  
Vol 15 (2) ◽  
pp. 208-220 ◽  
Author(s):  
Vaibhav Mishra ◽  
Tejpal Singh Chundawat
Keyword(s):  
Bond Formation ◽  
Catalyst Design ◽  
Biologically Active ◽  
Reaction Conditions ◽  
Biological Targets ◽  
Amination Reaction ◽  
Drug Synthesis ◽  
Substituted Piperazine ◽  
Approved Drugs ◽  
Fda Approved Drugs

Background: Substituted piperazine heterocycles are among the most significant structural components of pharmaceuticals. N1/N4 substituted piperazine containing drugs and biological targets are ranked 3rd in the top most frequent nitrogen heterocycles in U.S. FDA approved drugs. The high demand of N1/N4 substituted piperazine containing biologically active compounds and U.S. FDA approved drugs, has prompted the development of Pd catalyzed C-N bond formation reactions for their synthesis. Buchwald-Hartwig reaction is the key tool for the synthesis of these compounds. Objective: This review provides strategies for Pd catalyzed C-N bond formation at N1/N4 of piperazine in the synthesis of drugs and biological targets with diverse use of catalyst-ligand system and reaction parameters. Conclusion: It is clear from the review that a vast amount of work has been done in the synthesis of N1/N4 substituted piperazine containing targets under the Pd catalyzed Buchwald-Hartwig amination of aryl halides by using different catalyst-ligand systems. These methods have become increasingly versatile as a result of innovation in catalyst design and improvements in reaction conditions. This review gives an overview of recent utilization of Buchwald-Hartwig amination reaction in drug/target synthesis.

Bisurea and Bisthiourea H-Bonding Organocatalysts for Ring-Opening Polymerization: Cues for the Catalyst Design

2019 ◽  
Vol 52 (23) ◽  
pp. 9232-9237 ◽  
Author(s):  
Rukshika S. Hewawasam ◽  
U. L. D. Inush Kalana ◽  
Nayanthara U. Dharmaratne ◽  
Thomas J. Wright ◽  
Timothy J. Bannin ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Catalyst Design

scholarly journals Cover Feature: Impurity Control in Catalyst Design: The Role of Sodium in Promoting and Stabilizing Co and Co 2 C for Syngas Conversion (ChemCatChem 4/2021)

ChemCatChem ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1036-1036
Author(s):  
Arun S. Asundi ◽  
Adam S. Hoffman ◽  
Sindhu S. Nathan ◽  
Alexey Boubnov ◽  
Simon R. Bare ◽  
...  
Keyword(s):  
Catalyst Design ◽  
Syngas Conversion ◽  
Impurity Control

Insights into oxygen activation on metal clusters for catalyst design

2021 ◽  
Author(s):  
LiXin Chen ◽  
Zi Wen ◽  
Zhi Wen Chen ◽  
Qing Jiang ◽  
Chandra Veer Singh
Keyword(s):  
Metal Clusters ◽  
Aerobic Oxidation ◽  
Oxygen Activation ◽  
Vital Role ◽  
Catalyst Design ◽  
Activation Mechanism ◽  
Oxidation Reactions

The activation mechanism of O2 molecules plays a vital role in the development of catalysts for aerobic oxidation reactions. To gain insights into the activation mechanism of O2, the square...

scholarly journals Status and prospects of the decentralised valorisation of natural gas into energy and energy carriers

2021 ◽  
Author(s):  
Guido Zichittella ◽  
Javier Pérez-Ramírez
Keyword(s):  
Natural Gas ◽  
Catalyst Design ◽  
Liquefied Natural Gas ◽  
Energy Carriers ◽  
Recent Advances ◽  
Fuels And Chemicals

We critically review the recent advances in process, reactor, and catalyst design that enable process miniaturisation for decentralised natural gas upgrading into electricity, liquefied natural gas, fuels and chemicals.

Stereoretentive Olefin Metathesis: A New Avenue for the Synthesis of All-cis Poly(p-phenylene vinylene)s and Stereo­defined Polyalkenamers

Synlett ◽  
2021 ◽  
Author(s):  
Quentin Michaudel ◽  
Samuel J. Kempel ◽  
Ting-Wei Hsu
Keyword(s):  
Olefin Metathesis ◽  
Ring Opening ◽  
Diblock Copolymers ◽  
Catalyst Design ◽  
Phenylene Vinylene ◽  
Grand Challenge ◽  
Ru Catalyst ◽  
Unique Reaction ◽  
Photochemical Isomerization ◽  
Optimized Conditions

AbstractOlefin metathesis has tremendously impacted all fields of synthetic chemistry. However, the control of the olefin stereochemistry during this process remains a grand challenge. Recent innovations in catalyst design have permitted control of the stereochemistry of the olefin product. Here, we discuss the development of stereoretentive olefin metathesis, with an emphasis on the synthesis of stereodefined polyalkenamers through ring-opening metathesis polymerization (ROMP). We then present our application of this unique reaction manifold to the preparation of all-cis poly(p-phenylene vinylene)s (PPVs). A dithiolate Ru catalyst was found to deliver perfect cis selectivity for the polymerization of a paracyclophane diene monomer. By using optimized conditions, all-cis PPVs with narrow dispersities and predictable molar masses were obtained by varying the ratio of monomer to catalyst. The high chain fidelity of the stereoretentive ROMP with a paracyclophane diene monomer enabled the preparation of well-defined diblock copolymers with a norbornene co-monomer. Photochemical isomerization of all-cis to all-trans PPVs was effected with both homopolymers and diblock copolymers. This process was shown to be selective for the PPV block, and resulted in changes in optical properties, polymer size, and solubility. Stereoretentive ROMP provides a promising platform for synthesizing polymers with unique properties, including photoresponsive all-cis PPVs with living characteristics.1 Introduction2 Synthetic Applications of Stereoretentive Olefin Metathesis3 Stereocontrol of Polyalkenamers through Stereoretentive ROMP4 Stereoretentive ROMP To Access All-cis Poly(p-phenylene vinylene)s5 Conclusion

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