Microwaves in Catalysis

Satoshi Horikoshi received his PhD degree in 1999 from Meisei University, and was subsequently a postdoctoral researcher at the Frontier Research Center for the Global Environment Science (Ministry of Education, Culture, Sports, Science and Technology) until 2006. He joined Sophia University as Assistant Professor in 2006, and then moved to Tokyo University of Science as Associate Professor in 2008, after which he returned to Sophia University as Associate Professor in 2011. Currently he is Vice-President of the Japan Society of Electromagnetic Wave Energy Applications (JEMEA), and is on the Editorial Advisory Board of the Journal of Microwave Power and Electromagnetic Energy and other international journals. His research interests involve new material synthesis, molecular biology, formation of sustainable energy, environmental protection and CO2-fixation using microwave- and/or photo-energy. He has co-authored over 150 scientific publications and has contributed to and edited or co-edited 20 books. Nick Serpone obtained his Ph.D. in Physical-Inorganic Chemistry at Cornell University (1964-1968; Ithaca, NY). He joined Concordia University (Montreal) in 1968 as Assistant Professor, was made Associate Professor in 1973, Professor in 1980, University Research Professor (1998-2004), and Professor Emeritus in 2000. He was Program Director at the U.S. National Science Foundation (Washington, DC, 1998-2001) and has been a Visiting Professor at the University of Pavia, Italy, since 2002 and at the Tokyo University of Science, Noda Campus (July- August 2008). His major research interests are in the photophysics and photochemistry of semiconductor metal oxides, heterogeneous photocatalysis, environmental photochemistry, photochemistry of sunscreen active agents, and application of microwaves to nanomaterials and to environmental remediation. He has co-authored over 430 articles and has co-authored, translated or co-edited 9 monographs. In July 2010, he was elected Fellow of the European Academy of Sciences (EurASc), and is currently Head of the Materials Sciences Division of EurASc.

• List of Contributors XVIIPreface XXI1 General Introduction to Microwave Chemistry 1Satoshi Horikoshi and Nick Serpone1.1 ElectromagneticWaves and Dielectric Materials 11.2 Microwave Heating 21.3 The Various Types of Microwave Heating Phenomena 41.3.1 Conduction Loss Heating (Eddy Current Loss and Joule Loss) 51.3.2 Dielectric Heating 51.3.3 Magnetic Loss Heating (Eddy Current Loss and Hysteresis Loss Heating) 61.3.4 Penetration Depth of Microwaves 61.4 Fields of Applications with Microwave Heating 91.5 Microwaves in Solid Material Processing 111.6 Microwaves in Organic Syntheses 121.7 Microwave Chemical Equipment 121.8 Chemical Reactions Using the Characteristics of Microwave Heating 171.9 Microwave Frequency Effect in Chemical Syntheses 211.10 Summary 25References 25Part I Fundamentals 292 Loss Mechanisms and Microwave-Specific Effects in Heterogeneous Catalysis 31A.E. Stiegman2.1 Introduction 312.2 Heterogeneous Catalyst Systems 332.3 Physics of Microwave Absorption 332.4 Microwave Loss Processes in Solids 352.4.1 Dielectric Loss 352.4.2 Charge Carrier Processes 362.4.2.1 Conduction Loss 362.4.2.2 Space–Charge Recombination 372.4.2.3 Dipolar Loss 382.4.3 Magnetic Loss Processes 402.5 Loss Processes and Microwave-Specific Catalysis: Lessons from Gas–Carbon Reactions 412.5.1 Thermochemical Considerations 422.6 Final Comments on Microwave-Specific Effects in Heterogeneous Catalysis 45Acknowledgments 45References 463 Transport Phenomena and Thermal Property under Microwave Irradiation 49Yusuke Asakuma3.1 Introduction 493.2 Bubble Formation 503.3 Convection 533.4 Surface Tension 563.5 Discussion of Nonthermal Effect for Nanobubble Formation 58References 594 Managing Microwave-Induced Hot Spots in Heterogeneous Catalytic Systems 61Satoshi Horikoshi and Nick Serpone4.1 What Are Hot Spots? 614.2 Microwaves in Heterogeneous Catalysis 614.3 Microwave-Induced Formation of Hot Spots in Heterogeneous Catalysis 634.3.1 Hot Spot Phenomenon 634.3.2 Mechanism(s) of Formation of Hot Spots 684.3.3 Particle Aggregation by Polarization of Activated Carbon Particulates 694.3.4 Control of the Occurrence of Hot Spots 73References 75Part II Applications – Preparation of Heterogeneous Catalysts 775 Preparation of Heterogeneous Catalysts by a Microwave Selective Heating Method 79Satoshi Horikoshi and Nick Serpone5.1 Introduction 795.2 Synthesis of Metal Catalysts on Carbonaceous Material Supports 795.3 Photocatalysts 815.3.1 Preparation of TiO2/AC Particles 835.3.2 Proposed Mechanism of Formation of TiO2/AC Particles 865.3.3 Photoactivity ofMW-Prepared TiO2/AC Composite Particles in the Degradation of Isopropanol 875.4 Microwave-Assisted Syntheses of Catalytic Materials for Fuel Cell Applications 885.4.1 Microwave-Assisted Synthesis of Pt/C Catalyst Particulates for a H2 Fuel Cell 895.4.2 Preparation of Nanocatalysts for a Methanol Fuel Cell 915.4.3 Effects of pH on Pt Particle Size and Electrocatalytic Activity of Pt/CNTs for Methanol Electro-oxidation 935.5 Other Catalysts Prepared by Microwave-Related Procedures 945.6 Concluding Remarks 103References 103Part III Applications – Microwave Flow Systems and Microwave Methods Coupled to Other Techniques 1096 Microwaves in Cu-Catalyzed Organic Synthesis in Batch and Flow Mode 111Faysal Benaskar, Narendra Patil, Volker Rebrov, Jaap Schouten, and Volker Hessel6.1 Introduction 1116.2 Microwave-Assisted Copper Catalysis for Organic Syntheses in Batch Processes 1126.2.1 Bulk and Nano-structured Metals in a Microwave Field 1126.2.1.1 Interaction of Bulk Metal with Microwaves 1126.2.1.2 Metallic Catalyst Particle Size and Shape Effect on Microwave Heating 1136.2.1.3 Polymetallic Systems in Microwave Chemistry 1156.2.2 Microwave-Assisted Copper Catalysis for Chemical Synthesis 1166.2.2.1 Bulk Copper Particles for Catalysis and Microwave Interaction 1166.2.2.2 Microwave-Assisted Copper-Catalyzed Bond Formation Reactions 1176.2.3 Supported Cu-Based Catalyst for Sustainable Catalysis in Microwave Field 1206.2.3.1 Microwave Activation and Synthesis of Cu-Based Heterogeneous Catalysts 1206.2.3.2 Cu-Supported Catalyst Systems for C–O, C–C, C–S, and C–N Coupling Reactions 1216.3 Microwave-Assisted Copper Catalysis for Organic Syntheses in Flow Processes 1226.3.1 Microwave-Assisted Catalyzed Organic Synthesis in Flow Processes 1226.3.1.1 Microwave Heating in Homogeneously Catalyzed Processes 1226.3.1.2 Microwave Energy Efficiency and Uniformity in Catalyzed Flow Processes 1246.3.2 Structured Catalyst in Microwave-Assisted Flow Processing for Organic Reactions 1306.3.2.1 Thin-Film Flow Reactors for Organic Syntheses 1306.3.2.2 Structured Fixed-Bed Reactors for Flow Synthesis 1316.3.2.3 Scale-Up of Microwave-Assisted Flow Processes 1336.4 Concluding Remarks 136References 1367 Pilot Plant for Continuous Flow Microwave-Assisted Chemical Reactions 141Mitsuhiro Matsuzawa and Shigenori Togashi7.1 Introduction 1417.2 Continuous Flow Microwave-Assisted Chemical Reactor 1427.2.1 Basic Structure 1427.3 Pilot Plant 1457.3.1 Design ofWaveguide 1457.3.2 Configuration of Pilot Plant 1477.3.3 Water Heating Test 1487.3.4 Sonogashira Coupling Reaction 1517.4 Conclusions 153Acknowledgment 154References 1548 Efficient Catalysis by Combining Microwaves with Other Enabling Technologies 155Giancarlo Cravotto, Laura Rinaldi, and Diego Carnaroglio8.1 Introduction 1558.2 Catalysis with Hyphenated and Tandem Techniques 1578.3 Microwave and Mechanochemical Activation 1598.4 Microwave and UV Irradiation 1628.5 Microwave and Ultrasound 1648.6 Conclusions 166References 166Part IV Applications – Organic Reactions 1719 Applications of Microwave Chemistry in Various Catalyzed Organic Reactions 173Rick Arneil Desabille Arancon, Antonio Angel Romero, and Rafael Luque9.1 Introduction 1739.1.1 Homogeneous Catalysis 1759.2 Microwave-Assisted Reactions in Organic Solvents 1759.3 Microwave-Assisted Reactions inWater-Coupling Reactions 1799.3.1 The Heck Reactions 1809.3.2 The Suzuki Reaction 1869.4 Conclusions and Prospects 190Acknowledgments 190References 19110 Microwave-Assisted Solid Acid Catalysis 193Hyejin Cho, Christian Schäfer, and Béla Török10.1 Introduction 19310.2 Microwave-Assisted Clay Catalysis 19310.3 Zeolites in Microwave Catalysis 19910.4 Microwave Application of Other Solid Acid Catalysts 20510.4.1 Heteropoly Acids 20510.4.2 Acidic Ion-Exchange Resins (Nafion-H, Amberlyst, Dowex) 20610.4.2.1 Nafion-H 20610.4.2.2 Amberlyst 20710.4.2.3 Dowex 20810.5 Conclusions and Outlook 209References 20911 Microwave-Assisted Enzymatic Reactions 213Takeo Yoshimura, ShigeruMineki, and Shokichi Ohuchi11.1 Introduction 21311.2 Synthewave (ProLabo) 21711.2.1 Lipase 21711.2.2 Glucosidase 22011.3 Discover Series (CEM) 22011.3.1 Lipase (Synthesis, Esterification) 22011.3.2 Enzymatic Resolution 22811.3.3 β-Glucosidase, β-Galactosidase 23211.3.4 Aldolase 23311.4 Mechanism of the Microwave-Assisted Enzymatic Reaction 233References 236Part V Applications – Hydrogenation and Fuel Formation 23912 Effects of Microwave Activation in Hydrogenation–Dehydrogenation Reactions 241Leonid M. Kustov12.1 Introduction 24112.2 Specific Features of Catalytic Reactions Involving Hydrogen 24212.3 Hydrogenation Processes under MWConditions 24612.4 Dehydrogenation 25012.5 Hydrogen Storage 25212.6 Hydrogenation of Coal 254Acknowledgment 254References 25413 Hydrogen Evolution from Organic Hydrides throughMicrowave Selective Heating in Heterogeneous Catalytic Systems 259Satoshi Horikoshi and Nick Serpone13.1 Situation of Hydrogen Energy and Feature of Stage Methods 25913.2 Selection of Organic Hydrides as the Hydrogen Carriers 26113.3 Dehydrogenation of Hydrocarbons with Microwaves in Heterogeneous Catalytic Media 26213.3.1 Selective Heating by the Microwave Method 26213.3.2 Dehydrogenation of Tetralin in a Pt/AC Heterogeneous Catalytic Dispersion Subjected to a Microwave Radiation Field 26313.3.3 Effects of the Tetralin: Pt/AC Ratio on Tetralin Dehydrogenation 26413.3.4 Dehydrogenation of an Organic Carrier in a Continuous Flow System 26613.3.5 Dehydrogenation of Methylcyclohexane in a Microwave Fixed-Bed Reactor 26913.3.6 Simulation Modeling for Microwave Heating of Pt/AC in the Methylcyclohexane Solution 27113.4 Dehydrogenation of Methane with Microwaves in a Heterogeneous Catalytic System 27213.5 Problems and Improvements of Microwave-Assisted Heterogeneous Catalysis 273Acknowledgments 277References 277Part VI Applications – Oil Refining 28114 Microwave-Stimulated Oil and Gas Processing 283Leonid M. Kustov14.1 Introduction 28314.2 Early Publications 28314.3 Use of Microwave Activation in Catalytic Processes of Gas and Oil Conversions 28514.3.1 Hydrogen Production 28514.3.2 CO2 Conversion 28614.3.3 Synthesis Gas (Syngas) Production 28614.3.4 Methane Decomposition 28714.3.5 Methane Steam Reforming 28814.3.6 Oxidative Coupling of Methane 28814.3.7 Partial Oxidation and Other Hydrocarbon Conversion Processes 29114.3.8 Oxidative Dehydrogenation 29414.3.9 Oil Processing 29514.4 Prospects for the Use of Microwave Radiation in Oil and Gas Processing 295Acknowledgment 297References 297Part VII Applications – Biomass andWastes 30115 Algal Biomass Conversion under Microwave Irradiation 303Shuntaro Tsubaki, Tadaharu Ueda, and Ayumu Onda15.1 Introduction 30315.2 Microwave Effect on Hydrothermal Conversion – Analysis Using Biomass Model Compounds 30415.2.1 Degradation Kinetics of Neutral Sugars under Microwave Heating 30415.2.2 Effects of Ionic Conduction on Hydrolysis of Disaccharides under Hydrothermal Condition 30815.3 Hydrolysis of Biomass Using Ionic Conduction of Catalysts 30915.3.1 Hydrolysis of Starch and Crystalline Cellulose Using Microwave Irradiation and Polyoxometalate Cluster 30915.3.2 Hydrolysis Fast-Growing Green Macroalgae Using Microwave Irradiation and Polyoxometalate Cluster 31115.4 Dielectric Property of Algal Hydrocolloids inWater 31315.4.1 Comparison of Dielectric Property of Aqueous Solution of Hydrocolloids Obtained from Algae and Land Plants 31315.4.2 The Effects of the Degree of Substitution of Acidic Functional Groups on Dielectric Property of Aqueous Solution of Algal Hydrocolloids 31515.4.3 The Correlation of Loss Tangent at 2.45 GHz and Other Physical Properties of Sodium Alginates and Carrageenans inWater 31615.5 Summary and Conclusions 319Acknowledgments 319References 31916 Microwave-Assisted Lignocellulosic Biomass Conversion 323TomohikoMitani and TakashiWatanabe16.1 Introduction 32316.2 Lignocellulosic Biomass Conversion 32416.3 Multi-mode Continuous Flow Microwave Reactor 32516.4 Direct-Irradiation Continuous Flow Microwave Reactor 32716.4.1 Concept of Reactor 32716.4.2 Designing of Microwave Irradiation Section 32716.4.3 Prototypes of Reactors 32916.5 Pilot-Plant-Scale Continuous Flow Microwave Reactor 33116.5.1 Concept of Reactor 33116.5.2 Designing of Microwave Irradiation Section 33116.5.3 Demonstration Experiments of Microwave Pretreatment 33316.6 Summary and Conclusions 335References 33517 Biomass andWaste Valorization under Microwave Activation 337Leonid M. Kustov17.1 Introduction 33717.2 Vegetable Oil and Glycerol Conversion 33817.3 Conversion of Carbohydrates 33917.4 Cellulose Conversion 34017.5 Lignin Processing 34217.6 Waste and Renewable Raw Material Processing 34317.7 Carbon Gasification 34717.8 Prospects for the Use of Microwave Irradiation in the Conversion of Biomass and Renewables 348Acknowledgment 350References 350Part VIII Applications – Environmental Catalysis 35518 Oxidative and Reductive Catalysts for Environmental Purification Using Microwaves 357Takenori Hirano18.1 Introduction 35718.2 Microwave Heating of Catalyst Oxides Used for Environmental Purification 35818.3 Microwave-Assisted Catalytic Oxidation of VOCs, Odorants, and Soot 36118.4 Microwave-Assisted Reduction of NOx and SO2 36418.5 Conclusions 367References 36719 Microwave-/Photo-Driven Photocatalytic Treatment of Wastewaters 369Satoshi Horikoshi and Nick Serpone19.1 Situation ofWastewater Treatment by Photocatalytic Classical Methods 36919.2 Experimental Setup of an Integrated Microwave/Photoreactor System 37019.3 Microwave-/Photo-Driven PhotocatalyticWastewater Treatment 37119.3.1 Degradation of Rhodamine B Dye 37119.3.2 Change of TiO2 Surface Condition under a Microwave Field 37619.3.3 Specific Nonthermal Microwave Effect(s) in TiO2 Photoassisted Reactions 37719.3.4 Microwave Frequency Effects on the Photoactivity of TiO2 37919.3.5 Increase in Radical Species on TiO2 under Microwave Irradiation 38019.3.6 Microwave Nonthermal Effect(s) as a Key Factor in TiO2 Photoassisted Reactions 38219.4 Microwave Discharge Electrodeless Lamps (MDELs) 38619.4.1 The Need for More Efficient UV Light Sources 38619.4.2 Purification ofWater Using TiO2-Coated MDEL Systems in Natural Disasters 38719.5 Summary Remarks 389References 389Index 393