Controlling Reactivity in the Conversion of Biomass-derived Levoglucosenone to Renewable Chemicals Over Metal and Acid Catalysts

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (112 download)

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Book Synopsis Controlling Reactivity in the Conversion of Biomass-derived Levoglucosenone to Renewable Chemicals Over Metal and Acid Catalysts by : Siddarth Hari Krishna

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.

Aqueous-phase Catalytic Conversions of Renewable Feedstocks for Sustainable Biorefineries

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Publisher : Frontiers Media SA
ISBN 13 : 2832553745
Total Pages : 196 pages
Book Rating : 4.8/5 (325 download)

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Book Synopsis Aqueous-phase Catalytic Conversions of Renewable Feedstocks for Sustainable Biorefineries by : Georgios Papadogianakis

Download or read book Aqueous-phase Catalytic Conversions of Renewable Feedstocks for Sustainable Biorefineries written by Georgios Papadogianakis and published by Frontiers Media SA. This book was released on 2024-08-23 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today, there is growing interest in aqueous-phase catalytic conversions for the valorization of renewable biomass-based feedstocks for biorefineries to produce, in a sustainable way, biofuels, chemicals, power, energy, materials, pharmaceuticals and food. This is because of the highly polar nature of water which makes it an ideal medium to convert polar biomass-based lignocellulose (cellulose, hemicellulose, lignin), with high oxygen content, and their upgraded products such as hydrophilic carbohydrates, platform chemicals and their derivatives. Another reason which makes water the solvent of choice is that water itself is involved either as a reagent or as a byproduct even in large amounts in typical conversions for the valorization of biomass. The obtained intermediates further react in the aqueous medium, often without any separation and purification, to manufacture more valuable products. This results in substantial energy savings, lower emissions and economic benefits. Furthermore, water could act as a catalyst in conversions of biomass-based feedstocks such as in liquefaction reactions under subcritical conditions. Moreover, novel types of catalytic reactivity have been observed in the aqueous solvent, not only with water-soluble transition metal catalytic complexes, but also with conventional heterogeneous catalysts and catalytic nanoparticles in a broad spectrum of different reactions such as, inter alia, aldol condensations and hydrogenation reactions. For example, in the aqueous-phase hydrogenation of the biomass-based key platform chemical levulinic acid into γ-valerolactone and beyond, employing heterogeneous catalysts and nanoparticles the presence of water has a beneficial effect and accelerates the reaction rates, whereas in organic solvents much lower activities were observed. This promotional effect of water in the hydrogenation of levulinic acid was proved by many experimental and theoretical studies using a broad spectrum of different types of catalytic systems.

Engineering Mixed Solvent Environments for Acid-catalyzed Biomass Conversion Reactions

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ISBN 13 :
Total Pages : 237 pages
Book Rating : 4.:/5 (113 download)

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Book Synopsis Engineering Mixed Solvent Environments for Acid-catalyzed Biomass Conversion Reactions by : Theodore W. Walker

Download or read book Engineering Mixed Solvent Environments for Acid-catalyzed Biomass Conversion Reactions written by Theodore W. Walker and published by . This book was released on 2019 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has been shown that mixtures of water with polar aprotic cosolvents (mixed solvent environments) can be used to control the rates and selectivities of acid-catalyzed biomass conversion reactions. A quantitative understanding of these solvent effects would therefore enable a powerful measure of control over biomass conversion processes, but this framework is currently lacking. This dissertation combines reaction kinetics studies, spectroscopic methods and molecular dynamics investigations to explore the fundamental aspects underlying the reactivity of biomass-derived oxygenates in mixed solvent environments, and the solvent-mediated decomposition of real biomasses over acid catalysts. Chapters 3 and 4 focus on the production of levoglucosenone (LGO) from cellulose in mixed solvent environments containing dilute sulfuric acid. In Chapter 3, we show that water mediates the interconversion of LGO and its isomer, 5-hydroxymethylfurfural (HMF). Following this insight, we demonstrate in Chapter 4 how the composition water/tetrahydrofuran mixtures can be modulated to control the selectivity of LGO and HMF as coproducts from cellulose conversion. Chapters 5, 6 and 7 combine reaction kinetics studies and molecular dynamics (MD) investigations to probe the fundamental bases whereby mixed solvent environments control the rates and selectivities of acid-catalyzed biomass conversion reactions. In Chapter 5, we show that the rates of acid-catalyzed reactions of biomass-derived oxygenates generalize with the MD-observable properties of water-enriched local solvent domains that nucleate in the immediate vicinity of solvated reactant molecules. In Chapter 6, we demonstrate how the selectivity of acid-catalyzed biomass conversion reactions can be partially understood in terms of the thermodynamic relationships between solvated reactant and product molecules in mixed solvent environments. In Chapter 7, we distill these insights into a model-predictive framework that allows for the rational design of mixed solvent environments for biomass conversion processes using computationally efficient screening methods and minimal experimentation. In Chapter 8, we use solid-state nuclear magnetic resonance (NMR) spectroscopy to explore how mixed solvents containing acid catalysts alter the properties cellulosic structures in real biomass. We show that these NMR-observable properties predict the extent to which hydrolytic enzymes are able to depolymerize the residual cellulose into glucose. This dissertation is concluded with a discussion of future directions.

Kinetics of Catalytic Upgrading Reactions of Biomass-derived and Model Oxygenates

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)

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Book Synopsis Kinetics of Catalytic Upgrading Reactions of Biomass-derived and Model Oxygenates by : Benginur Demir

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.

Catalytic Biomass to Renewable Biofuels and Biomaterials

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Publisher : MDPI
ISBN 13 : 3039363123
Total Pages : 208 pages
Book Rating : 4.0/5 (393 download)

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Book Synopsis Catalytic Biomass to Renewable Biofuels and Biomaterials by : Yi-Tong Wang

Download or read book Catalytic Biomass to Renewable Biofuels and Biomaterials written by Yi-Tong Wang and published by MDPI. This book was released on 2020-11-13 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomass is the only renewable carbon source that can be converted into high value-added carbon products. This book presents a collection of studies on the conversion of catalytic biomass to renewable biofuels and biomaterials by chemical conversion, co-combustion technology, and biological conversion technology. The fundamentals and mechanisms of catalytic materials design, process optimization, product development, and by-product utilization are outlined. All articles were contributed by experts in catalysis and bioenergy fields to provide readers with a broad range of perspectives on cutting-edge applications. This book is an ideal reference guide for academic researchers and engineering technicians in the fields of catalytic material synthesis, biomass energy conversion, enzyme catalysis, pyrolysis, combustion, vaporization, and fermentation. It can also be used as a comprehensive reference source for university students in renewable energy science and engineering, agricultural engineering, thermal engineering, chemical engineering, material science, and environmental engineering. This book contains 12 articles: (1) “Catalytic Biomass to Renewable Biofuels and Biomaterials”; (2) “Experimental Design to Improve Cell Growth and Ethanol Production in Syngas Fermentation by Clostridium carboxidivorans”; (3) “Glycerol Acetylation Mediated by Thermally Hydrolysed Biosolids-Based Material”; (4) “Influence of Base-Catalyzed Organosolv Fractionation of Larch Wood Sawdust on Fraction Yields and Lignin Properties”; (5) “Ca-based Catalysts for the Production of High-Quality Bio-Oils from the Catalytic Co-Pyrolysis of Grape Seeds and Waste Tyres”; (6) “Synthesis of Diesel and Jet Fuel Range Cycloalkanes with Cyclopentanone and Furfural”; (7) “Gel-Type and Macroporous Cross-Linked Copolymers Functionalized with Acid Groups for the Hydrolysis of Wheat Straw Pretreated with an Ionic Liquid”; (8) “Role of Humic Acid Chemical Structure Derived from Different Biomass Feedstocks on Fe(III) Bioreduction Activity: Implication for Sustainable Use of Bioresources”; (9) “Selective Production of Terephthalonitrile and Benzonitrile via Pyrolysis of Polyethylene Terephthalate (PET) with Ammonia over Ca(OH)2/Al2O3 Catalysts”; (10) “Experimental Studies on Co-Combustion of Sludge and Wheat Straw”; (11) “Carbonate-Catalyzed Room-Temperature Selective Reduction of Biomass-Derived 5-Hydroxymethylfurfural into 2,5-Bis(hydroxymethyl)furan”; (12) “Clostridium sp. as Bio-Catalyst for Fuels and Chemicals Production in a Biorefinery Context”.

Catalytic Conversion of Biomass-derived Molecules Into Mono- and Dicarboxylic Acids and Esters

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ISBN 13 :
Total Pages : 114 pages
Book Rating : 4.:/5 (958 download)

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Book Synopsis Catalytic Conversion of Biomass-derived Molecules Into Mono- and Dicarboxylic Acids and Esters by : Yuran Wang

Download or read book Catalytic Conversion of Biomass-derived Molecules Into Mono- and Dicarboxylic Acids and Esters written by Yuran Wang and published by . This book was released on 2016 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomass can serve as a renewable alternative to the inevitably depleting fossil fuel resources and provide feedstocks for the production of fuels and chemicals. Mono- and dicarboxylic acids and esters are key intermediates to chemical products, especially for biodegradable polymers. This thesis has addressed the challenges in chemocatalytic synthesis of mono- and dicarboxylic acids and esters, including gluconic acid, succinic acid, itaconic acid and their esters, from biomass-derived molecules. Gold (Au) catalysts have been rarely investigated for the oxidation of glucose in the absence of a base. These conditions are critical, however, to enable the sequential one-pot combination of cellulose hydrolysis and glucose oxidation. The study provides insights into the deactivation of the catalysts caused by leaching and hydrothermal sintering of Au nanoparticles, as well as by adsorption of reaction species. We found that lowering the surface density of Au on metal oxides decreases the sintering rate of the Au nanoparticles and hence enhances the stability and activity of the catalyst. Levulinate derivatives are an attractive platform for the production of renewable chemicals. We report on the oxidation of methyl levulinate into dimethyl succinate with peroxides under mild conditions using Bronsted and Lewis acid catalysts and focuses on the reaction selectivity control. While the molecular structure (i.e., carbon chain length and branching around the C=O group) and the oxidant type affect the product distribution, solvent choice has the strongest impact on changing the location of oxygen insertion into the carbon backbone. In contrast to Brønsted acids, for water-tolerant Lewis acidic triflate salts, the reaction selectivity is affected by the size of the metal cation. We have developed a novel approach to synthesize unsaturated dicarboxylic acid esters via aldol condensation of keto esters catalyzed by Lewis acidic zeolites. Hafnium-containing BEA (Hf- BEA) zeolites are highly active, selective and stable for the condensation of ethyl pyruvate into itaconic acid ester analogues. Analysis of the dynamic behavior of Hf-BEA under flow conditions and studies with Na-exchanged zeolites suggest that Hf(IV) open sites possess dual functionality for Lewis and Bronsted acid catalysis.

Fundamental Reaction Kinetics Studies of Acid-catalyzed Biomass Conversion Reactions Into Chemicals and Fuels

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ISBN 13 :
Total Pages : 169 pages
Book Rating : 4.:/5 (98 download)

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Book Synopsis Fundamental Reaction Kinetics Studies of Acid-catalyzed Biomass Conversion Reactions Into Chemicals and Fuels by : Max A. Mellmer

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 169 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.

Catalytic Upgrading of Biologically-derived Chemicals Via Ring-opening Reactions

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ISBN 13 :
Total Pages : 154 pages
Book Rating : 4.:/5 (18 download)

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Book Synopsis Catalytic Upgrading of Biologically-derived Chemicals Via Ring-opening Reactions by : Zachary James Brentzel

Download or read book Catalytic Upgrading of Biologically-derived Chemicals Via Ring-opening Reactions written by Zachary James Brentzel and published by . This book was released on 2017 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research efforts on renewable and sustainable products from biologically-derived sources have shifted directions from the production of fuels to the production of chemicals. The motivation for switching the focus to renewable commodity or high value chemicals stems from the favorable process economics. Renewable and sustainable processes to synthesize chemicals are more economically feasible than those to produce fuels. This dissertation discusses strategies to synthesize biorenewable chemicals from both microbially-derived and lignocellulosic biomass-derived platform chemicals. A significant fraction of lignocellulosic biomass-derived platform chemicals and microbial metabolites are cyclic molecules with heteroatoms. A fraction of the resulting target products are linear, and the reactants need to be selectively ring-opened. We discuss routes, processes, and mechanisms for the upgrading and ring-opening of microbially-derived and lignocellulosic biomass-derived platform chemicals. Chapters 3 and 4 focus on a process for the production of chemicals from microbially-derived triacetic acid lactone (TAL). The first stage in the upgrading of TAL is hydrogenation of the C=C bonds in the ring. Prior work has demonstrated that residual amino acids and vitamins from fermentation media carried through to the hydrogenation are detrimental to catalyst stability. In Chapter 3, we document the degree to which representative amino acids and vitamins inhibit Pt, Pd, and Ni for a probe reaction, cyclohexene hydrogenation. Chapter 4 covers a new chemical pathway to upgrade lactones synthesized from TAL. This project characterizes the vapor phase selectivity for the ring-opening esterification of TAL-derived [delta]-hexalactone (DHL) and biomass-derived [gamma]-valerolactone (GVL) using oxide catalysts. Chapters 5 through 8 detail the process development, technoeconomics, reaction mechanism, and catalyst studies for the production of 1,5-pentanediol (1,5-PD) from biomass-derived furfural. Chapter 5 presents the overview of the process to synthesize 1,5-PD from tetrahydrofurfuryl alcohol (THFA) and includes initial technoeconomic analyses. This chapter also details the reaction network and describes the enhanced reactivity of the new intermediate, 2-hydroxytetrahydropyran (2-HY-THP). Chapter 6 expands upon the process development and provides more in-depth technoeconomic analyses that includes the initial furfural to THFA hydrogenation step. The processes considered in both Chapter 5 and 6 use a noble metal catalyst, Ru, for the hydrogenation of 2-HY-THP to 1,5-PD. In Chapters 7 and 8, we investigate the the feasibility of using an earth abundant metal, Ni, for the hydrogenation. Chapter 7 includes work focused on elucidating the role of oxophilic metals on their enhancement in the hydrogenation rates of carbonyl groups. After determining that Mo and Re provide the greatest degree of promotion, probe reactions studies, extensive catalyst characterization, and density functional theory calculations were performed on the NiMo system. Chapter 8 studies the role of support, oxophilic promoter, and organic functional group of the leaching rate and stability of Ni catalysts.

Acid-catalyzed Reactions for the Production of Platform Chemicals from Cellulosic Biomass in Liquid Phase Systems

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (882 download)

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Book Synopsis Acid-catalyzed Reactions for the Production of Platform Chemicals from Cellulosic Biomass in Liquid Phase Systems by :

Download or read book Acid-catalyzed Reactions for the Production of Platform Chemicals from Cellulosic Biomass in Liquid Phase Systems written by and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acid catalysts are used in many applications focused on biomass conversion. Liquid phase processing serves as one of the primary routes to produce platform chemicals from cellulosic biomass. The fundamental challenge with producing products by acid catalyzed reactions is that undesired carbonaceous species (i.e. humins) form by both parallel and series reactions, which limit the selectivity to desired products. The goal of this research is to study the fundamental acid-catalyzed chemistry to produce biomass-derived platform chemicals in liquid phase systems. We use an integrated approach that includes: (1) understanding the fundamental chemistry and reaction pathways through kinetic studies with homogeneous acid catalysts and (2) elucidating the relationship between the properties of solid acid catalysts and their correlation with activity and selectivity of acid catalyzed reactions. We have developed kinetic models for the aqueous phase production of furfural and hydroxymethylfurfural (HMF) from xylose and glucose respectively using homogeneous catalysts. The dehydration chemistry to form these furanic derivatives from carbohydrates is distinguished by a relatively high activation energy step (ca. 120-160 kJ/mol). Undesired humins also form, which typically have lower activation barriers (i.e. 50-70 kJ/mol). Product selectivity can be tuned by altering the Brønsted to Lewis acid site ratio of the acid catalysts. Lewis acid sites decrease furfural and HMF selectivity, as they mainly catalyze the formation of isomerization byproducts and humins. Brønsted acid sites catalyze the dehydration step to produce furfural and HMF. These findings are true for both heterogeneous and homogeneous catalysts. Accordingly, in our studies with solid acid metal(IV) phosphate catalysts, we show that zirconium phosphate with a P/Zr molar ratio of 2 is favorable for levulinic acid production from glucose due to its inherently high surface area and enhanced Brønsted acidity. We have also discovered that HMF can selectively be produced from cellulose under mild reaction conditions in polar aprotic solvents (i.e. tetrahydrofuran) without the presence of water. This pathway goes through a levoglucosan intermediate. The turnover frequency for cellulose conversion increases as the water content in the solvent decreases, with conversion rates in tetrahydrofuran being more than twenty times higher than those in water.

Organometallics and Renewables

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Publisher : Springer
ISBN 13 : 3642282881
Total Pages : 239 pages
Book Rating : 4.6/5 (422 download)

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Book Synopsis Organometallics and Renewables by : Michael A.R. Meier

Download or read book Organometallics and Renewables written by Michael A.R. Meier and published by Springer. This book was released on 2012-05-26 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lucas Montero de Espinosa and Michael A. R. Meier: Olefin Metathesis of Renewable Platform Chemicals.- Pieter C. A. Bruijnincx, Robin Jastrzebski, Peter J. C. Hausoul, Robertus J. M. Klein Gebbink, and Bert M. Weckhuysen: Pd-Catalysed Telomerisation of 1,3-Dienes with Multifunctional Renewable Substrates - Versatile Routes for the Valorisation of Biomass-Derived Platform Molecules.- A Behr, A. J. Vorholt: Hydroformylation and related reactions of renewable resources.- Ties J. Korstanje, Robertus J.M. Klein Gebbink: Catalytic oxidation and deoxygenation of renewables with rhenium complexes.- Antoine Buchard, Clare M. Bakewell, Jonathan Weiner and Charlotte K. Williams: Recent Developments In Catalytic Activation Of Renewable Resources For Polymer Synthesis.

Reaction Pathways and Mechanisms in Thermocatalytic Biomass Conversion II

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Publisher : Springer
ISBN 13 : 9789812877680
Total Pages : 0 pages
Book Rating : 4.8/5 (776 download)

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Book Synopsis Reaction Pathways and Mechanisms in Thermocatalytic Biomass Conversion II by : Marcel Schlaf

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 2015-11-06 with total page 0 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.

Design of Supported Metal Catalysts for Aqueous-phase Conversion of Biomass-derived Oxygenates

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Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (934 download)

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Book Synopsis Design of Supported Metal Catalysts for Aqueous-phase Conversion of Biomass-derived Oxygenates by :

Download or read book Design of Supported Metal Catalysts for Aqueous-phase Conversion of Biomass-derived Oxygenates written by and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increases in the cost of fossil fuels along with growing concerns for greenhouse gas emissions are prompting the search for renewable sources of liquid fuel and chemicals. Biomass has been considered as the only realistic and sustainable source of renewable organic carbon for the foreseeable future. Heterogeneous catalysis has played an important role in the development of efficient chemical processes to convert biomass to fuels and chemicals. In this respect, the design of inexpensive active and stable heterogeneous catalysts is important to develop new and improved processes for the conversion of biomass. This dissertation focuses on aqueous-phase hydrodeoxygenation (APHDO) and aqueous-phase hydrogenation (APH) as model reactions to design improved supported metal catalysts for the conversion of biomass-derived feedstocks. Both APHDO and APH are crucial in converting biomass-derived compounds into liquid fuels and chemicals. In this dissertation, the activity of a number of monometallic and bimetallic catalysts is compared for APH of carbonyl compounds which is an important reaction in APHDO. Bimetallic Pd-Fe is the most active catalyst among the tested catalysts for APH of C=O and C=C bonds. APHDO of sorbitol was performed with the bimetallic Pd-Fe supported on zirconium phosphate (Zr-P). Zr-P was chosen as the support due to its high Brønsted to Lewis acid ratio and stability in the aqueous phase. The Pd1Fe3/Zr-P catalyst is up to 14 times more active than monometallic Pd/Zr-P and Pt/Zr-P catalysts. Moreover, the Pd1Fe3/Zr-P catalyst produces more C4-C6 products by promoting the conversion of sorbitan and isosorbide and more C1-C3 products by promoting C-C bond cleavage (dehydrogenation/retro-aldol condensation) of sorbitol. Another critical issue of designing heterogeneous catalysts for aqueous-phase reactions is stability of the catalysts. A method for stabilizing base-metal particles of a Co/TiO2 catalyst is developed using atomic layer deposition (ALD) of TiO2 film onto the surface of the Co/TiO2 catalyst. The ALD TiO2 coated Co/TiO2 catalyst was tested for APH reactions in a continuous flow reactor and characterized using chemisorption, surface area analysis, electron microscopy, X-ray diffraction, and small-angle X-ray scattering. Through these techniques, it is shown that the ALD TiO2 coating protects the cobalt particles against leaching and sintering under aqueous conditions. High-temperature treatments of a Co/TiO2 catalyst cause migration of partially reduced TiO2 onto cobalt particles caused by strong metal-support interaction (SMSI) between cobalt and TiO2. The SMSI effect in the Co/TiO2 catalyst is elucidated using in situ Raman spectroscopy and electron microscopy. By the SMSI effect, cobalt particles of the Co/TiO2 catalyst are decorated by TiOx (x 2) species. The TiOx decoration stabilizes the cobalt particles in a similar way to ALD TiO2 overcoating. The SMSI effect also creates a bifunctional catalytic site in the Co/TiO2 which facilitates a furanyl ring-opening reaction. The high-temperature treated Co/TiO2 catalyst had 95 % yield for APH of carbonyl compounds to their corresponding alcohols. The two methods for stabilizing cobalt catalysts introduced in this dissertation, ALD and SMSI, may enable the replacement of expensive novel-metal catalysts with inexpensive base-metal catalysts for aqueous-phase conversion of biomass-derived feedstocks.

A Study on Catalytic Conversion of Non-Food Biomass into Chemicals

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Publisher : Springer
ISBN 13 : 9811003327
Total Pages : 171 pages
Book Rating : 4.8/5 (11 download)

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Book Synopsis A Study on Catalytic Conversion of Non-Food Biomass into Chemicals by : Mizuho Yabushita

Download or read book A Study on Catalytic Conversion of Non-Food Biomass into Chemicals written by Mizuho Yabushita and published by Springer. This book was released on 2016-01-13 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: The topic of this thesis is catalytic conversion of non-food, abundant, and renewable biomass such as cellulose and chitin to chemicals. In biorefinery, chemical transformation of polymers to valuable compounds has attracted worldwide interest for building sustainable societies. First, the current situation of this hot research area has been summarized well in the general introduction of the thesis, which helps readers to become familiar with this topic. Next, the author explains high-yielding production of glucose from cellulose by using an alkali-activated carbon as a catalyst, resulting in a yield of glucose as high as 88%, which is one of the highest yields ever reported. The characterization of carbon materials has indicated that weak acid sites on the catalyst promote the reaction, which is markedly different from reported catalytic systems that require strong acids. In addition, the first catalytic transformation of chitin with retention of N-acetyl groups has been developed. The combination of mechanocatalytic hydrolysis and thermal solvolysis enables the production of N-acetylated monomers in good yields of up to 70%. The catalytic systems demonstrated in this thesis are unique in the fields of both chemistry and chemical engineering, and their high efficiencies can contribute to green and sustainable chemistry in the future. Meanwhile, mechanistic studies based on characterization, thermodynamics, kinetics, and model reactions have also been performed to reveal the roles of catalysts during the reactions. The results will be helpful for readers to design and develop new catalysts and reaction systems.

Reaction Pathways and Mechanisms in Thermocatalytic Biomass Conversion I

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Publisher : Springer
ISBN 13 : 9789811013164
Total Pages : 260 pages
Book Rating : 4.0/5 (131 download)

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Book Synopsis Reaction Pathways and Mechanisms in Thermocatalytic Biomass Conversion I by : Marcel Schlaf

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 2016-08-23 with total page 260 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.

Deoxygenation and Hydrogenation of Biomass-derived Molecules Over Multifunctional Catalysts

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (862 download)

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Book Synopsis Deoxygenation and Hydrogenation of Biomass-derived Molecules Over Multifunctional Catalysts by : Mshari Alotaibi

Download or read book Deoxygenation and Hydrogenation of Biomass-derived Molecules Over Multifunctional Catalysts written by Mshari Alotaibi and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this work was to investigate heterogeneous catalysis of the deoxygenation of renewable feedstocks for value-added chemicals and fuels using heteropoly acids. The main focus was on H3PW12O40 (HPW) and its Cs acidic salt Cs2.5H0.5PW12O40 (CsPW), which have sufficiently high thermal stability, with decomposition temperatures of 450 and > 500 °C, respectively. These compounds have very strong Brønsted acidity and are well documented as acid catalysts. They were used for the deoxygenation and hydrogenation of propionic acid, methyl isobutyl ketone (MIBK) and diisobutyl ketone (DIBK) in the gas phase. For comparison, zeolite catalysts doped with Pt were examined for the deoxygenation of MIBK. CsPW was doped with Pd, Pt, Cu and Ru metals using the impregnation method, while Pt was doped on zeolites by ion exchange. The catalysts under study were characterised using various physical and chemical techniques. CsPW and CsPW-supported Pd, Pt and Cu catalysts were found to be stable in the deoxygenation of propionic acid. They retained the Keggin structure of their polyanion (primary structure), as well as the CsPW crystal structure (secondary structure), after reaction at 400 °C in H2, whereas HPW decomposed above 350 °C in N2. The reaction was found to involve several pathways including ketonisation, decarbonylation, decarboxylation and hydrogenation, leading to the partial or total deoxygenation of propionic acid. HPW/SiO2 and CsPW, both in H2 and in N2, exhibited ketonisation activity between 250 and 300 °C to yield 3-pentanone, CsPW being more selective than HPW. At 400 °C, HPW and CsPW were active for the decarbonylation and decarboxylation of propionic acid to yield ethene and ethane respectively. Loading Pd or Pt onto CsPW greatly enhanced decarbonylation in flowing H2, but had little effect in N2. Similar performance was exhibited by Pd and Pt on SiO2, giving almost 100% selectivity to ethene in H2. These results are consistent with the hydrodeoxygenation of propionic acid on Pd and Pt, suggesting that hydrogenolysis of the C-C bond plays an essential role. Cu catalysts were active in the hydrogenation of the C=O bond to yield propanal and 1-propanol. Turnover rates of propionic acid conversion on metal catalysts followed the order Pd > Pt > Cu. Pt/CsPW was found to be a very efficient catalyst for the selective one-step hydrodeoxygenation of biomass-derived aliphatic ketones MIBK and DIBK to yield 2-methylpentane (MP) and 2,6-dimethylheptane (DMH) under mild conditions at 100 °C and 1 bar pressure without isomerisation of the carbon backbone via a metal-acid bifunctional mechanism. For MIBK hydrogenation, the mechanism involves MIBK hydrogenation to MP-ol on metal sites followed by MP-ol dehydration on acid sites to form olefin and finally olefin hydrogenation to 2MP on metal sites. Pt/ZSM-5 matched the catalytic performance of Pt/CsPW at 200 °C, but considerable isomerisation of MP took place at this temperature. This shows that the strong acidity of CsPW is essential for the high efficiency of the Pt/CsPW catalyst.

The Selective Production of Biomass Derived Chemicals Using Heterogeneous Catalysts

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (969 download)

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Book Synopsis The Selective Production of Biomass Derived Chemicals Using Heterogeneous Catalysts by :

Download or read book The Selective Production of Biomass Derived Chemicals Using Heterogeneous Catalysts written by and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of heterogeneous catalytic technologies for the selective conversion of lignocellulosic biomass to platform molecules such as 5-hydroxymethylfurfural (HMF) and 2,5-dihydroxymethylfurfural (DHMTHF) has been studied. Supported metal catalysts were used for the selective hydrogenation of HMF to DHMTHF. Small trace amounts of acid in the aqueous solution with HMF feed was found to play an important role in determining the selectivity for the hydrogenation of HMF to DHMTHF. DHMTHF, tetrahydrofuran (THF), gamma valerolactone (GVL), and other aprotic miscible organic solvents were mixed with water to form a monophasic co-solvent. These co solvents systems were found to be separation friendly solvents compared to dimethyl sulfoxide (DMSO) and other higher boiling organic solvents that are selective for HMF production. The monophasic co-solvents investigated were also selective for the production of HMF from fructose using Brønsted acid catalysts; additionally, an increase in the rate of reaction, compared to water, was observed. Fructose tautomerization favors the furanose form in the mixed solvent, relative to water alone, explaining at least part of the rate enhancement. The use of co-solvents and acid-functionalized ordered mesoporous silica catalysts show high selectivity for HMF from fructose. The synthesis to intercalate PVP on the catalyst surface was developed to achieve high selectivities previously achieved only with ionic liquids. The high concentration of pyrrolidone in the confined space of the pores favors the furanose tautomers which can be easily dehydrated to HMF. Thus, the reaction environment within the catalyst has been designed to favor the desired product. Solvent reactivity studies for homogenous base, homogenous Lewis acid, solid bases, and solid Lewis acids for glucose isomerization to fructose were conducted. The small addition of miscible organic solvent led to a drop of reactivity compared to that of pure water. However, with increasing GVL concentration, the reactivity increased as well. Benzene-bridged PMOs doped with Lewis acidic Sn sites were readily and rapidly synthesized. These thermally robust, hydrophobic materials catalyze the selective isomerization of glucose to fructose in co-solvent systems. Brønsted acid sites were incorporated and a bifunctional PMO was synthesized for tandem conversion of glucose to fructose and its dehydration to HMF.

Conversion of Oxygenates from Biomass-derived Compounds Over Supported Metal Catalysts

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ISBN 13 :
Total Pages : 558 pages
Book Rating : 4.:/5 (87 download)

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Book Synopsis Conversion of Oxygenates from Biomass-derived Compounds Over Supported Metal Catalysts by : Surapas Sitthisa

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: