Download or read book Mechanistic Understanding of Catalytic Upgrading Reactions of Biomass derived C2 Oxygenates written by Tu Nguyet Pham and published by . This book was released on 2014 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Kinetics of Catalytic Upgrading Reactions of Biomass derived and Model Oxygenates written by Benginur Demir and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lignocellulosic biomass, as a renewable carbon-neutral resource, can be utilized to sustainably produce versatile chemicals and fuels while eliminating the environmental issues caused by unrestrained use of fossil fuels. Fundamental understanding of reaction mechanisms and kinetics for many catalytic transformations of biomass-derived compounds is required to synthesize a variety of chemical intermediates in the fine chemical, polymer and pharmaceutical industries. This dissertation focuses on the kinetics of catalytic upgrading reactions of biomass-derived and model oxygenates using a combined approach including experimental, characterization and computational methods to design rational solvent systems, novel catalysts and efficient reactors for biorefineries. Chapter 3 and Chapter 4 discuss the fundamentals of catalytic upgrading of biomass-derived carbohydrates, which have high content of oxygenated functional groups. In Chapter 3, we show that the use of polar aprotic solvents in acid-catalyzed biomass conversion reactions such as fructose dehydration to hydroxymethylfurfural leads to improved reaction rates and product selectivities. In Chapter 4, we illustrate that further increases in catalyst performance in polar aprotic solvents can be achieved through the addition of inorganic salts, specifically chlorides, which was explained by the initial and transition state contributions to solvation effects. In Chapter 5 and Chapter 6, we discuss metal-catalyzed hydrogenation of biomass-derived chemicals employing kinetic studies with a model oxygenate. Chapter 5 reports that platinum displays a self-adjusting surface that is active for the hydrogenation of acetone over a wide range of reaction conditions investigated by reaction kinetics measurements under steady-state and transient conditions, electronic structure calculations employing density-functional theory, and microkinetic modeling with Bragg-Williams and Langmuir approximations. Chapter 6 outlines the promotional effects of water addition on the rates of acetone hydrogenation over oxophilic metal catalysts. Chapter 7 and Chapter 8 present the sustainable valorization of lignin streams to propose a depolymerization technique of lignin that can be combined with a current polysaccharide-centric biorefinery process. Chapter 7 focuses on the kinetics and mechanistic studies on lignin hydrogenolysis on Pd/C to continuously manufacture near-theoretical yields of phenolic platform monomers in a flow-through system. Chapter 8 expands upon the process development on continuous lignin hydrogenolysis and provides insights on the reactivity and selectivity of bimetallic catalysts consisting of an easily-reducible metal (i.e., Pt and Pd) and an oxophilic promoter (i.e., Co and Ag) using [beta]-ether lignin model compounds. Finally, this dissertation is concluded with suggestions for future directions.
Download or read book Reaction Pathways and Mechanisms in Thermocatalytic Biomass Conversion II written by Marcel Schlaf and published by Springer. This book was released on 2015-10-30 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume II presents the latest advances in catalytic hydrodeoxygenation and other transformations of some cellulosic platform chemicals to high value-added products. It presents the theoretical evaluation of the energetics and catalytic species involved in potential pathways of catalyzed carbohydrate conversion, pathways leading to the formation of humin-based by-products, and thermal pathways in deriving chemicals from lignin pyrolysis and hydrodeoxygenation. Catalytic gasification of biomass under extreme thermal conditions as an extension of pyrolysis is also discussed. Marcel Schlaf, PhD, is a Professor at the Department of Chemistry, University of Guelph, Canada. Z. Conrad Zhang, PhD, is a Professor at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, China.
Download or read book Bifunctional Catalysts for Upgrading of Biomass derived Oxygenates written by and published by . This book was released on 2016 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deoxygenation is an important reaction in the conversion of biomass-derived oxygenates to fuels and chemicals. A key route for biomass refining involves the production of pyrolysis oil through rapid heating of the raw biomass feedstock. Pyrolysis oil as produced is highly oxygenated, so the feasibility of this approach depends in large part on the ability to selectively deoxygenate pyrolysis oil components to create a stream of high-value finished products. Identification of catalytic materials that are active and selective for deoxygenation of pyrolysis oil components has therefore represented a major research area. One catalyst is rarely capable of performing the different types of elementary reaction steps required to deoxygenate biomass-derived compounds. For this reason, considerable attention has been placed on bifunctional catalysts, where two different active materials are used to provide catalytic sites for diverse reaction steps. Here, we review recent trends in the development of catalysts, with a focus on catalysts for which a bifunctional effect has been proposed. We summarize recent studies of hydrodeoxygenation (HDO) of pyrolysis oil and model compounds for a range of materials, including supported metal and bimetallic catalysts as well as transition-metal oxides, sulfides, carbides, nitrides, and phosphides. Particular emphasis is placed on how catalyst structure can be related to performance via molecular-level mechanisms. Finally, these studies demonstrate the importance of catalyst bifunctionality, with each class of materials requiring hydrogenation and C-O scission sites to perform HDO at reasonable rates.
Download or read book Biomass Derived Oxygenates Upgrading Over Mixed Oxide Catalysts written by Senthil Subramaniam and published by . This book was released on 2019 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ethanol can be used as a platform molecule for synthesizing valuable chemicals and fuel precursors. Synthesis of C5+ ketones from ethanol in single step was achieved over a stable Pd-promoted ZnO-ZrO2 catalyst. A sequence of reaction steps is involved in the C5+ ketone formation from ethanol and the key reaction step was found to be the in situ generation of acetone intermediate and the cross aldol condensation between the reaction intermediates acetaldehyde and acetone. The formation of Pd-Zn alloy in situ at the reaction condition was identified to be key factor in maintaining high yield to the C5+ ketones and the stability of the catalyst. The yield of >70% to C5+ ketones was achieved over a 0.1%Pd-ZnO-ZrO2 mixed oxide catalyst and the catalyst was demonstrated to be stable beyond 2000 hour time on stream without any catalyst deactivation.Other oxygenates selectivity to higher ketones, olefins had been identified and the mechanisms had been reported.
Download or read book Reaction Pathways and Mechanisms in Thermocatalytic Biomass Conversion I written by Marcel Schlaf and published by Springer. This book was released on 2015-09-25 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume I mainly focuses on the current understanding of the reaction pathways and mechanisms involved in several important catalytic conversions of cellulose and carbohydrates. It starts with nanoscale illustrations of biomass structures and describes various reactions including cellulose depolymerization to sugars, catalytic aldose-ketose isomerization and dehydration, selective oxidation, hydrogenolysis of cellulose and sugars, and the conversion of short carbohydrates. The specificity and function of different catalysts and reaction media in relation to the catalytic performances for these reactions are discussed with significant mechanistic details. Marcel Schlaf, PhD, is a Professor at the Department of Chemistry, University of Guelph, Canada. Z. Conrad Zhang, PhD, is a Professor at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, China.
Download or read book New and Future Developments in Catalysis written by Qingfeng Ge and published by Elsevier Inc. Chapters. This book was released on 2013-07-11 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalysis for Green Energy and Technology written by Samira Bagheri and published by Springer. This book was released on 2017-06-28 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the importance of catalysis for the sustainable production of biofuels and biochemicals, focusing primarily on the state-of-the-art catalysts and catalytic processes expected to play a decisive role in the "green" production of fuels and chemicals from biomass. The book also includes general sections exploring the entire chain of biomass production, conversion, environment, economy, and life-cycle assessment.
Download or read book Catalytic Upgrading of Biomass Derived Carboxylic Acids to Fuels and Chemicals written by Jher Hau Yeap and published by . This book was released on 2019 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mots-clés de l'auteur: carboxylic acids ; olefins ; aviation fuel ; heterogeneous catalysis ; lignocellulosic biomass ; carboxylate platform ; fundamental catalyst-substrate interactions ; copper.
Download or read book Catalytic Conversion of Biomass derived Oxygenates to alpha omega Diols written by Kevin Barnett and published by . This book was released on 2018 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New catalytic technology for conversion of biomass derived oxygenates into bio fuels and imines written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Conversion of Oxygenates from Biomass derived Compounds Over Supported Metal Catalysts written by Surapas Sitthisa and published by . This book was released on 2012 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Catalytic Technology for Conversion of Biomass derived Oxygenates Into Bio fuels and Imines amines written by Raju Poreddy and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book SDG11 Sustainable Cities and Communities written by Shyama V. Ramani and published by Taylor & Francis. This book was released on 2022-06-16 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores Sustainable Development Goal (SDG) 11, providing insights into viable pathways and policy designs for a transition towards sustainable, inclusive and resilient cities. The volume discusses existing scientific literature on SDG 11 and provides conceptual frameworks relating to systemic transitions, sectoral transitions and behavioural transitions for overcoming challenges related to governance and implementation. Through detailed case studies from cities and settlements, in Europe, Middle East and Asia, it showcases the dynamic processes involved in urban transformations. Drawing from these comparative analyses, the book provides robust frameworks and tools for better solutions and viable pathways to achieve SDG targets in diverse urban settings. Rich in empirical data, this book will be useful for scholars and researchers of development studies, environment studies, urban studies, urban sociology, political economy, political studies, public policy and sociology. It will also be useful for policy makers, professionals, non-governmental organisations (NGOs) and think tanks working in the area of sustainable development and urban planning.
Download or read book Catalyst Characterization written by Boris Imelik and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: to the Fundamental and Applied Catalysis Series Catalysis is important academically and industrially. It plays an essential role in the manufacture of a wide range of products, from gasoline and plastics to fertilizers and herbicides, which would otherwise be unobtainable or prohibitive ly expensive. There are few chemical-or oil-based material items in modern society that do not depend in some way on a catalytic stage in their manufacture. Apart from manufacturing processes, catalysis is finding other important and over-increasing uses; for example, successful applications of catalysis in the control ofpollution and its use in environmental control are certain to in crease in the future. The commercial import an ce of catalysis and the diverse intellectual challenges of catalytic phenomena have stimulated study by a broad spectrum of scientists including chemists, physicists, chemical engineers, and material scientists. Increasing research activity over the years has brought deeper levels of understanding, and these have been associated with a continually growing amount of published material. As recentlyas sixty years ago, Rideal and Taylor could still treat the subject comprehensively in a single volume, but by the 19 50s Emmett required six volumes, and no conventional multivolume text could now cover the whole of catalysis in any depth.
Download or read book Controlling Reactivity in the Conversion of Biomass derived Levoglucosenone to Renewable Chemicals Over Metal and Acid Catalysts written by Siddarth Hari Krishna and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have investigated the catalytic conversion of biomass-derived intermediates to a variety of renewable chemicals over metal and acid catalysts, with an emphasis on the platform molecule levoglucosenone. Lignocellulosic biomass and sugars are sustainable sources of carbon which can be converted, through selective C-O cleavage and hydrogenation reactions, to precursors to high-value chemicals such as polymers and non-toxic solvents. Metal catalysts facilitate hydrogenation of C=C and C=O bonds; acid catalysts facilitate C-O cleavage reactions; and bifunctional metal-acid catalysts facilitate these reactions in tandem. As biomass-derived feedstocks are highly functionalized, controlling the selectivity to desired products is a critical component of economically viable conversion processes. Reaction pathways were elucidated using a combination of techniques including analysis of products formed over time, variation of reaction conditions, variation of active site properties, investigation of stereochemistry, and isotopic labeling. Reactions studied include the acid-catalyzed isomerization of levoglucosenone to 5-hydroxymethylfurfural; the metal-catalyzed hydrogenation to Cyrene and levoglucosanol; hydrogenolysis of levoglucosanol to tetrahydrofurandimethanol; hydrogenolysis of levoglucosanol to 1,2,5,6-hexanetetrol; and conversion of methyl glycosides to hexane-tetrols and hexane-triols. We demonstrated how a fundamental understanding of the catalytic chemistry leads to the ability to tune selectivity towards desired products, thereby providing directions for the rational design of processes to produce valuable chemicals from biomass.
Download or read book Fundamental Reaction Kinetics Studies of Acid catalyzed Biomass Conversion Reactions Into Chemicals and Fuels written by Max A. Mellmer and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transition to a sustainable source of chemicals and energy is being driven by political, economic, and environmental concerns associated with petroleum-derived feedstocks. In this context, the conversion of biomass into platform molecules and fuels has received increasing interest. Acid catalysis is pervasive in biomass conversion processes, and recently, it has been shown that organic solvents are beneficial in the chemical conversion of biomass. This dissertation discusses strategies in utilizing nonaqueous solvents for the efficient upgrading of biomass to platform molecules using both homogeneous and heterogeneous acid catalysts, and based on reaction kinetics studies, we outline fundamental principles in understanding solvation effects in acid-catalyzed reactions. Chapter 3, Chapter 4, and Chapter 5 focus on the upgrading of biomass-derived molecules to yield platform chemicals. In Chapter 3, we show that high yields of hydroxymethylfurfural from glucose can be achieved using biomass-derived solvents and a combination of solid Lewis and Brønsted acids. In Chapter 4, the production of furfural from xylose, arabinose, and ribose was studied using H-Beta zeolite in [gamma]-valerolactone. We show in Chapter 5 that furfuryl alcohol is hydrolyzed to levulinic acid in high yields using H-ZSM-5 zeolite as the catalyst in tetrahydrofuran-water solvent systems. In Chapter 6 and Chapter 7, we use polar aprotic solvents to upgrade constituent fractions of biomass. We show in Chapter 6 that cellulose and corn stover can be converted with high yield to levulinic acid using Amberlyst 70 and [gamma]-valerolactone. Chapter 7 outlines a processing strategy using [gamma]-valerolactone for the simultaneous conversion of hemicellulose and cellulose in a single reactor to produce furfural and levulinic acid. Chapter 8, Chapter 9, and Chapter 10 report reaction kinetics studies providing insights into solvation effects in acid-catalyzed reactions using polar aprotic solvents. In Chapter 8, we studied the reaction kinetics of the dehydration of xylose into furfural using nonaqueous solvents. We show in Chapter 9 that polar aprotic solvents also enhance the kinetics of biomass hydrolysis reactions. Finally, in Chapter 10, we dissect solvation effects into initial and transition state contributions using experimental and computational methodologies. This dissertation is concluded with a discussion of future directions.
