scholarly journals Hydrogenation and Hydrogenolysis with Ruthenium Catalysts and Application to Biomass Conversion

2021 ◽  
Author(s):  
Thomas Ernst Müller
Keyword(s):  
Rational Design ◽  
Biomass Conversion ◽  
Dissociative Adsorption ◽  
Ruthenium Catalysts ◽  
Chemical Transformations ◽  
Detailed Understanding ◽  
Catalytic Function ◽  
Ruthenium Catalysis ◽  
Selective Chemical ◽  
Characteristic Features

With the rising emphasis on efficient and highly selective chemical transformations, the field of ruthenium-catalysed hydrogenation and hydrogenolysis reactions has grown tremendously over recent years. The advances are triggered by the detailed understanding of the catalytic pathways that have enabled researchers to improve known transformations and realise new transformations in biomass conversion. Starting with the properties of ruthenium, this chapter introduces the concept of the catalytic function as a basis for rational design of ruthenium catalysts. Emphasis is placed on discussing the principles of dissociative adsorption of hydrogen. The principles are then applied to the conversion of typical biomolecules such as cellulose, hemicellulose and lignin. Characteristic features make ruthenium catalysis one of the most outstanding tools for implementing sustainable chemical transformations.

Computational predictions of metal-macrocycle stability constants require accurate treatments of local solvent and pH effects

2021 ◽  
Author(s):  
Brian Gentry ◽  
Tae Hoon Choi ◽  
William S. Belfield ◽  
John A. Keith
Keyword(s):  
Quantum Chemistry ◽  
Rational Design ◽  
Chelating Agents ◽  
Ph Effects ◽  
Detailed Understanding ◽  
Metal Interactions ◽  
Solvent Phase ◽  
Computational Quantum Chemistry ◽  
Computational Predictions ◽  
Computational Quantum

Rational design of molecular chelating agents requires a detailed understanding of physicochemical ligand-metal interactions in solvent phase. Computational quantum chemistry methods should be able to provide this, but computational reports...

scholarly journals Enamine/Transition Metal Combined Catalysis: Catalytic Transformations Involving Organometallic Electrophilic Intermediates

2019 ◽  
Vol 377 (6) ◽  
Author(s):  
Samson Afewerki ◽  
Armando Córdova
Keyword(s):  
Transition Metal ◽  
Metal Complex ◽  
Carbonyl Compounds ◽  
Transition Metal Catalysis ◽  
Chemical Transformations ◽  
Considerable Effort ◽  
Metal Catalysis ◽  
First Report ◽  
Wide Range ◽  
Selective Chemical

AbstractThe concept of merging enamine activation catalysis with transition metal catalysis is an important strategy, which allows for selective chemical transformations not accessible without this combination. The amine catalyst activates the carbonyl compounds through the formation of a reactive nucleophilic enamine intermediate and, in parallel, the transition metal activates a wide range of functionalities such as allylic substrates through the formation of reactive electrophilic π-allyl-metal complex. Since the first report of this strategy in 2006, considerable effort has been devoted to the successful advancement of this technology. In this chapter, these findings are highlighted and discussed.

scholarly journals Catalytic Hydrogenation and Hydrodeoxygenation of Furfural over Pt(111): A Model System for the Rational Design and Operation of Practical Biomass Conversion Catalysts

2017 ◽  
Vol 121 (15) ◽  
pp. 8490-8497 ◽  
Author(s):  
Martin J. Taylor ◽  
Li Jiang ◽  
Joachim Reichert ◽  
Anthoula C. Papageorgiou ◽  
Simon K. Beaumont ◽  
...  
Keyword(s):  
Catalytic Hydrogenation ◽  
Rational Design ◽  
Biomass Conversion ◽  
Model System

scholarly journals Genetically Engineered Proteins to Improve Biomass Conversion: New Advances and Challenges for Tailoring Biocatalysts

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2879 ◽  
Author(s):  
Lucas Ferreira Ribeiro ◽  
Vanesa Amarelle ◽  
Luana de Fátima Alves ◽  
Guilherme Marcelino Viana de Siqueira ◽  
Gabriel Lencioni Lovate ◽  
...  
Keyword(s):  
Protein Engineering ◽  
Rational Design ◽  
Biomass Conversion ◽  
Low Cost ◽  
Catalytic Performance ◽  
Genetically Engineered ◽  
Production Lines ◽  
Current Application ◽  
Powerful Approach

Protein engineering emerged as a powerful approach to generate more robust and efficient biocatalysts for bio-based economy applications, an alternative to ecologically toxic chemistries that rely on petroleum. On the quest for environmentally friendly technologies, sustainable and low-cost resources such as lignocellulosic plant-derived biomass are being used for the production of biofuels and fine chemicals. Since most of the enzymes used in the biorefinery industry act in suboptimal conditions, modification of their catalytic properties through protein rational design and in vitro evolution techniques allows the improvement of enzymatic parameters such as specificity, activity, efficiency, secretability, and stability, leading to better yields in the production lines. This review focuses on the current application of protein engineering techniques for improving the catalytic performance of enzymes used to break down lignocellulosic polymers. We discuss the use of both classical and modern methods reported in the literature in the last five years that allowed the boosting of biocatalysts for biomass degradation.

Towards Rational Design of Porcelain Tile Glazes

2014 ◽  
Vol 92 ◽  
pp. 138-147 ◽  
Author(s):  
José Luis Amorós
Keyword(s):  
Kinetic Model ◽  
Effective Viscosity ◽  
Rational Design ◽  
Mineralogical Composition ◽  
Chemical Transformations ◽  
Crystalline Phases ◽  
Complex Behaviour ◽  
Different Temperatures ◽  
The One ◽  
Porcelain Tile

The complexity of porcelain tile glaze compositions translates into equally complex behaviour during firing in which, concurrently or in partially overlapping form, very different processes develop, such as the dissolution of crystalline phases, the crystallisation of new phases, and sintering phenomena. This complexity, and the scarcity of studies relating to the subject, make it extremely difficult to formulate such glaze compositions scientifically and efficiently. The present study analysed the physico-chemical transformations that occurred during the firing of these glazes, focusing in particular on the sintering process and its kinetics. A kinetic model was developed, first, which describes the sintering of complex glaze compositions (containing more than five components) with significant frit contents (45–70%) that devitrify crystalline phases during firing. A second, more comprehensive kinetic model was then developed, involving a formal multi-step kinetic model that encompassed even more complex glaze compositions (up to nine components), to calculate the effective viscosity of the glaze melt. This property was compared, on the one hand, with the effective viscosity obtained experimentally by hot stage microscopy (HSM) and, on the other, with that estimated theoretically from the chemical and mineralogical composition of the material, at different temperatures. The results obtained by the two methods exhibited very good agreement. The concept of effective viscosity provides a better understanding of the role played by the different glaze constituents and the firing conditions in sintering, enabling more rational design of these materials.

Rational Design of MIL-101(Cr)-Based Catalysts for Asymmetric Synthesis and Biomass Conversion

2017 ◽  
Vol 23 (6) ◽  
pp. 5821-5823 ◽  
Author(s):  
Huixian Yu ◽  
Zhiwei Guo ◽  
Yindi Zang ◽  
Yan Jin ◽  
Tao Shi ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Rational Design ◽  
Biomass Conversion

Stereochemistry of Dehydrogenation by D-Galactose Oxidase

1971 ◽  
Vol 49 (21) ◽  
pp. 3429-3437 ◽  
Author(s):  
A. Maradufu ◽  
G. M. Cree ◽  
A. S. Perlin
Keyword(s):  
Hydrogen Atom ◽  
Isotope Effect ◽  
Galactose Oxidase ◽  
Relative Impact ◽  
Chemical Transformations ◽  
Product Analysis ◽  
Deuterium Isotope Effect ◽  
Oxidation Rates ◽  
Selective Chemical ◽  
Sugar Derivatives

The stereochemistry of dehydrogenation of the primary carbinol group of D-galactose by D-galactose oxidase has been determined. Using D-galactose-6-d and methyl β-D-galactopyranoside-6-d, it has been established that the reaction involves removal of the pro-S 6-hydrogen atom. This conclusion is based on product analysis, and on the relative impact of the deuterium isotope effect on oxidation rates of substrates having different R:S deuteration patterns. The absolute configurations at C-6 of these substrates have been determined by selective chemical transformations to products of known configuration. The rotational conformation of the 6-carbinol group of D-galactose and its possible relationship to the specificity of the enzyme are discussed, as well as the stereochemistry of reductive deuteration of aldehydo sugar derivatives.

Biosynthetically-inspired oxidations of capillobenzopyranol

2017 ◽  
Vol 15 (22) ◽  
pp. 4811-4815 ◽  
Author(s):  
Henry P. Pepper ◽  
Hiu C. Lam ◽  
Jonathan H. George
Keyword(s):  
Marine Sponge ◽  
Chemical Transformations ◽  
Selective Chemical

The marine sponge meroterpenoid capillobenzopyranol has been converted into the co-isolated verrubenzospirolactone using simple and selective chemical transformations.

Directed Evolution of Protein Catalysts

2018 ◽  
Vol 87 (1) ◽  
pp. 131-157 ◽  
Author(s):  
Cathleen Zeymer ◽  
Donald Hilvert
Keyword(s):  
Directed Evolution ◽  
Rational Design ◽  
Chemical Transformations ◽  
Catalytic Promiscuity ◽  
Catalytic Activities ◽  
Effective Strategies ◽  
Wide Range ◽  
Protein Properties ◽  
New Protein ◽  
Modify Protein

Directed evolution is a powerful technique for generating tailor-made enzymes for a wide range of biocatalytic applications. Following the principles of natural evolution, iterative cycles of mutagenesis and screening or selection are applied to modify protein properties, enhance catalytic activities, or develop completely new protein catalysts for non-natural chemical transformations. This review briefly surveys the experimental methods used to generate genetic diversity and screen or select for improved enzyme variants. Emphasis is placed on a key challenge, namely how to generate novel catalytic activities that expand the scope of natural reactions. Two particularly effective strategies, exploiting catalytic promiscuity and rational design, are illustrated by representative examples of successfully evolved enzymes. Opportunities for extending these approaches to more complex biocatalytic systems are also considered.

scholarly journals Exploration of new reaction tools for late-stage functionalization of complex chemicals

2019 ◽  
Vol 97 (2) ◽  
pp. 67-85 ◽  
Author(s):  
Alejandra Dominguez-Huerta ◽  
Xi-Jie Dai ◽  
Feng Zhou ◽  
Pierre Querard ◽  
Zihang Qiu ◽  
...  
Keyword(s):  
Environmental Impact ◽  
Late Stage ◽  
Chemical Transformations ◽  
Synthetic Route ◽  
Atom Economy ◽  
Complex Molecules ◽  
Mild Conditions ◽  
The Past ◽  
Renewable Feedstocks ◽  
Selective Chemical

Chemistry has always had as a target the conversion of molecules into valuable materials. Nevertheless, the aim of past synthesis has primarily focused on achieving a given transformation, regardless of the environmental impact of the synthetic route. Given the current global situation, the demand for sustainable alternatives has substantially increased. Our group focuses on developing selective chemical transformations that benefit from mild conditions, improved atom economy, and that can make use of renewable feedstocks as starting materials. This account summarizes our work over the past two decades specifically regarding the selective removal, conversion, and addition of functional groups that can, later on, be applied at a late stage for the modification of complex molecules.

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