NANOCATALYSIS

NANOCATALYSIS

Synthesis andApplications

Edited by

Vivek PolshettiwarNanocatalysis Laboratory

Department of Chemical SciencesTata Institute of Fundamental Research

Colaba, Mumbai, India

Tewodros AsefaDepartment of Chemistry and Chemical Biology

Department of Chemical and Biochemical EngineeringThe Rutgers Catalysis Research Center (RCRC)

Rutgers, The State University of New JerseyPiscataway, NJ, USA

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Library of Congress Cataloging-in-Publication Data:

Nanocatalysis : synthesis and applications / edited by Vivek Polshettiwar, Tewodros Asefa.pages cm

“Published simultaneously in Canada”–Title page verso.Includes bibliographical references and index.ISBN 978-1-118-14886-0 (cloth)

1. Nanostructured materials. 2. Catalysts. 3. Nanostructured materials–Industrial applications.4. Catalysts–Industrial applications. I. Polshettiwar, Vivek II. Asefa, Tewodros.

TA418.9.N35N2466 2013660′.2995–dc23

2012049879

Printed in the United States of America.

10 9 8 7 6 5 4 3 2 1

CONTENTS

Foreword viiGraham Hutchings

Preface ix

List of Contributors xiii

1 INTRODUCTION TO NANOCATALYSIS 1Vivek Polshettiwar and Tewodros Asefa

2 NANOCATALYSTS FOR THE HECK COUPLING REACTIONS 11T. Asefa, A. V. Biradar, S. Das, K. K. Sharma, and R. Silva

3 NANOCATALYSTS FOR THE SUZUKI COUPLING REACTIONS 51Liane M. Rossi, Natalia J. S. Costa, Jones Limberger,and Adriano L. Monteiro

4 SONOGASHIRA REACTIONS USING NANOCATALYSTS 89Rafael Chinchilla and Carmen Najera

5 NANOCATALYSTS FOR HIYAMA, STILLE, KUMADA, ANDNEGISHI C–C COUPLING REACTIONS 133Abhinandan Banerjee and Robert W. J. Scott

6 ARYL CARBON–HETEROATOM COUPLING REACTIONS USINGNANOMETAL CATALYST 189Brindaban C. Ranu, Debasree Saha, Debasish Kundu,and Nirmalya Mukherjee

7 NANOSTRUCTURED CATALYSTS FOR THE ALDOL,KNOEVENAGEL, AND HENRY REACTIONS 221T. Asefa, A. V. Biradar, S. Das, and R. Silva

8 NANOCATALYSTS FOR REARRANGEMENT REACTIONS 251Joaquın Garcıa-Alvarez, Sergio E. Garcıa-Garrido, and Victorio Cadierno

9 OXIDATION OF ALCOHOLS USING NANOCATALYSTS 287Takato Mitsudome and Kiyotomi Kaneda

10 TUNING THE MORPHOLOGY OF METAL OXIDES FORCATALYTIC APPLICATIONS 333Yong Li and Wenjie Shen

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vi CONTENTS

11 NANOCATALYSTS FOR HYDROGENATION REACTIONS 405Radha Narayanan

12 HYDROGENOLYSIS REACTIONS USING NANOCATALYSTS 443Aziz Fihri and Vivek Polshettiwar

13 NANOMATERIAL-BASED PHOTOCATALYSTS 469Biswajit Mishra and Deepa Khushalani

14 NANOCATALYSTS FOR WATER SPLITTING 495Xu Zong, Gaoqing Lu, and Lianzhou Wang

15 PROPERTIES OF NANOCATALYTIC MATERIALS FOR HYDROGENPRODUCTION FROM RENEWABLE RESOURCES 561Zhong He and Xianqin Wang

16 NANOCATALYSTS FOR BIOFUELS 595Vitaliy Budarin, Peter S. Shuttleworth, Brigid Lanigan,and James H. Clark

17 NANOMATERIAL-BASED BIOCATALYST 615Jin Hyung Lee, Soo Youn Lee, Zhi-Kang Xu, and Jeong Ho Chang

18 ROLE OF NANOCATALYSIS IN CHEMICAL INDUSTRY 643Anirban Ghosh, K. S. Nagabhushana, Debabrata Rautaray,and Rajiv Kumar

19 NANOCATALYSIS: ACTIVATION OF SMALL MOLECULESAND CONVERSION INTO USEFUL FEEDSTOCK 679Suresh Babu Kalidindi and Balaji R. Jagirdar

Index 713

FOREWORD

This book, entitled Nanocatalysis: Synthesis and Applications, edited by Vivek Polshet-tiwar and Tewodros Asefa, who are both active researchers in this exciting field, com-prises a broad range of authorative sections that are authored by world-class researchers.The book is an important addition to the rapidly growing area of nanocatalysis. Thebook gives comprehensive perspectives on a wide array or research topics related tonanocatalysis, by highlighting the importance of nanocatalysis in areas ranging fromthe efficient production of commodity and value-added chemical products to renew-able energy and environmental remediation—topics that are of contemporary interestworldwide from government and industry to academia as well as to society as a whole.The book comprises several different topics related to nanocatalysis with topical areasdistributed throughout the text, including fundamental aspects of nanocatalysis, sur-face science, and mechanistic and theoretical studies on how nanocatalysts function.In addition, the range of applications of nanocatalysis in several areas is also cov-ered, including energy and environment. Therefore, researchers in both industry andacademia alike, as well as new students and seasoned researchers, will appreciate readingthe book.

The timing of this book could not be any better—as can be witnessed by thelarge number of research publications being reported in the journals concerned withnanoscience and nanotechnology in general, which relate to nanocatalysis in particu-lar. The field of nanocatalysis has attracted intense interest over the last two decades,although, of course, the use of nano-sized materials as catalysts has been a research topicfor many decades. The strength of this book is that it brings together the key areas in thisbroad subject in an easily accessible way. Readers will readily be able to obtain quickinformation on a variety of topics from synthesis and characterization of nanocatalystsas well as their applications. So, we should thank the two editors for embarking on thisproject and bringing together this key collection of studies on nanocatalysis. As an activeresearcher in the field of nanocatalysis, I strongly feel that this book will also stimulatenew cutting-edge research activities in the area. However, at the same time, this bookgives a wealth of fundamental information that is highly relevant for newcomers tothe field as well as providing basic information to graduate and undergraduate studentsalike. I also consider that the text will be a valuable resource to lecturers with interestsin teaching the principles of nanocatalysis. Moreover, I expect the book to inspire moreresearchers to work on a variety of new research aspects related to nanocatalysis andthe development of novel and improved nanocatalysts, especially directed to many of

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viii FOREWORD

the contemporary grand challenges of our generation that the world faces today in areassuch as renewable energy, production of value-added chemical products, and synthesisof materials in a “greener” or sustainable way, as well as environmental remediation.The book is, therefore, a very valuable resource.

Professor Graham J. Hutchings FRSDirector of the Cardiff Catalysis Institute

The Cardiff School of ChemistryCardiff University, UK

PREFACE

Catalysis lies at the heart of chemical processes that lead to a variety of chemicalproducts and synthetic materials. This can be highlighted by the fact that about morethan 80–85% of synthetic materials and commercial chemical products see at least one,if not more, catalyst at some point of their synthesis. This means, the synthesis of manyuseful household products, such as medicines, detergents, polymeric fibers, perfumes,fuels, paints, lubricants, and a myriad of other value-added chemical products essentialto humans, would have been neither possible nor feasible in the absence of catalysts.

Catalysts are chemical substances that enable the (“smooth”) transformation of finechemicals into value-added chemical products or synthetic materials. Catalysts playmajor roles in such conversions of many different chemical species into important finalproducts by enabling the chemical transformations to take place effectively, that is, in aneconomical manner, with less by-products, with less energy consumption, or by givingthe desired products in larger amount in relatively shorter reaction times.

Besides many conventional chemical processes where catalysts have already beenused, the emergence of the grand challenges in areas such as renewable energy and envi-ronmental problems that our world faces has made the development of catalysts capableof contributing to the production of renewable energy and environmental remediationamong the “holly-grail” research areas worldwide currently. Furthermore, in the face ofdwindling fossil fuel sources, the development of catalysts that allow the transformationof CO2 into fuels and the conversion of water into H2 in a viable manner has becomevery vital and contemporary research area today.

Catalysts are traditionally divided into two major groups based on the type of phaseof the catalyst is in relative to the catalytic reaction mixtures, that is, homogeneous orheterogeneous catalysts. Homogeneous catalysts are those that exist in the same phase asthe reactants. They are generally soluble organic or organometallic complexes and oftengive chemo-, regio-, and stereoselective products. However, they are relatively difficult toseparate from reaction mixtures for reuse at the end of reactions. On the other hand, thereare solid or insoluble catalysts, also called heterogeneous catalysts. In many instances,the solid catalysts contain homogeneous catalysts supported on neutral or catalytic-activesolid support materials such as porous silica or alumina. These types of catalysts areeasily separable and reusable at the end of reactions; however, they often give relativelypoor reaction yields, compared with many of their homogeneous counterparts.

The fields of nanoscience and nanotechnology have been unquestionably thrivingover the last two or so decades. The positive societal impacts of nanoscience and nan-otechnology have also now become clear to scientists and engineers alike, and even tothe public, although much work still remains in understanding the potential biologicaland health effects of many nanomaterials. One of the first examples where the applica-tions of nanoscience and nanotechnology were successfully demonstrated has been in

ix

x PREFACE

the area of catalysis; that is, nanoscience and nanotechnology has made it possible for aclass of nanomaterials with potential applications in catalysis (or nanocatalysts) to comealight. Many nanomaterials with different interesting catalytic properties have actuallybeen documented, and some of them have also been commercially used. In fact, evenbefore systematic research on nanocatalyst development began or unbeknownst to many,several materials with nanoscale sizes have been successfully used as catalysts in manyreactions. Nanocatalysts are interesting from a point of view of being in between homo-geneous and heterogeneous catalysts, although this classification is not quite strict. Inother words, nanocatalysts exhibit quasihomogeneous or quasiheterogeneous catalyticproperties, and thus allow for rapid and selective chemical transformations, with excel-lent product yield and ease of catalyst separation and recovery. Nanocatalysis can thusbe simply defined as the use of nanoscale materials in catalysis, often with effective cat-alytic properties, that is, efficient catalytic activities as well as ease of catalyst separation,recovery, and reuse.

The objective of the book is to review the development and progress of nanocatalystsand nanocatalysis over the past two decades and to provide readers with well-compiledinformation about the status of the field on the synthesis and applications of variousnanocatalysts for the production of industrially and pharmaceutically important com-pounds and synthetic materials. The book is also prepared to give quick and highlycompiled information on various topics related to nanocatalysts and nanocatalysis tostudents, faculty, and industrial personnel, who are working in catalysis research. This,in turn, is expected to promote further advances in the field.

The information in the book has been compiled in 19 chapters. The first chapterprovides some introduction on nanocatalysts and nanocatalysis. The next six chaptersare devoted to nanocatalysts or nanocatalysis for carbon–carbon and carbon–heteroatomcoupling reactions. The next two chapters are devoted to nanocatalysts and nanocatal-ysis for fine chemical synthesis. The subsequent four chapters are devoted to the useof nanocatalysts for oxidation–hydrogenation-type reactions. The four next chapters arealso devoted to the topic of nanomaterial-based photocatalysis and the use of nanocatal-ysis to produce nonconventional sources of energy. The last two chapters focus on theuse of nanocatalysts in the chemical industry.

Many of the chapters are written in such a way that they dwell on the synthesisand characterization of nanocatalysts and their properties and applications in synthesis.Each chapter has been contributed by different groups of researchers worldwide, whohave expertise in various aspects of nanocatalysts and/or nanocatalysis. Each teamhas used recent literature in its respective areas of expertise. Thus, we hope that thebook will give a broad perspective on the design and synthetic methods to varioustypes of nanocatalysts and their applications. In addition, the various types of advancedcharacterization methods described in most of the chapters will highlight the currentstate-of-the-art of various spectroscopic and microscopy tools used for elucidation ofnanocatalysts and nanocatalysis. Moreover, methods used for probing the activities ofcatalysts and the strategies utilized to improve the catalytic activities and selectivities ofnanocatalysts should give further information for the researchers working in the area.

We edited this book because we realize that there are several missing areas of inter-est in the field of nanocatalysis today, especially in light of the rapid progress being made

PREFACE xi

in the field and the enormous number of papers being published in the area. In addi-tion, although there are few other books written on topics related to nanocatalysis, thisbook focuses on nanocatalysts and contains a comprehensive review and a fair distribu-tion of synthesis and characterization of nanocatalysts and application of nanocatalystsand nanocatalysis in areas ranging from pharmaceutical products to renewable energymaterials and biotransformations.

The book is possible only because of the involvement of many outstandingresearchers worldwide, who devoted a significant amount of their time to make contri-butions to the different sections of the chapters in the book. They are the real craftsmenof this very comprehensive book. We are, therefore, indebted to all of them, who havecontributed enormously to make this book possible. We also acknowledge the support wehave received from our coworkers, friends, and family members throughout the processof putting the book together.

Vivek Polshettiwar and Tewodros Asefa

LIST OF CONTRIBUTORS

Editors

Vivek Polshettiwar, Nanocatalysis Laboratory, Department of Chemical Sciences, TataInstitute of Fundamental Research, Mumbai, India

Tewodros Asefa, Department of Chemistry and Chemical Biology and Department ofChemical and Biochemical Engineering, The Rutgers Catalysis Research Center(RCRC), Rutgers, The State University of New Jersey, Piscataway, NJ, USA

Authors

Abhinandan Banerjee, Department of Chemistry, University of Saskatchewan, Saska-toon, SK, Canada

A. V. Biradar, Department of Chemistry and Chemical Biology and Department ofChemical and Biochemical Engineering, Rutgers, The State University of NewJersey, Piscataway, NJ, USA

Vitaliy Budarin, Department of Chemistry, Green Chemistry Centre of Excellence,University of York, Heslington, York, UK

Victorio Cadierno, Departamento de Quımica Organica e Inorganica, Facultad deQuımica, Universidad de Oviedo, Oviedo, Spain

Jeong Ho Chang, Korea Institute of Ceramic Engineering and Technology, Seoul,South Korea

Rafael Chinchilla, Department of Organic Chemistry and Institute of Organic Synthe-sis, University of Alicante, Alicante, Spain

James H. Clark, Department of Chemistry, Green Chemistry Centre of Excellence,University of York, Heslington, York, UK

Natalia J. S. Costa, Laboratory of Nanomaterials and Catalysis, Institute of Chemistry,USP, Sao Paulo, Brazil

S. Das, Department of Chemistry and Chemical Biology, Rutgers, The State Universityof New Jersey, Piscataway, NJ, USA

Aziz Fihri, Nano-Catalysis Laboratory, KAUST Catalysis Centre, King Abdullah Uni-versity of Science and Technology, Thuwal, KSA

Joaquın Garcıa-Alvarez, Departamento de Quımica Organica e Inorganica, Facultadde Quımica, Universidad de Oviedo, Oviedo, Spain

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xiv LIST OF CONTRIBUTORS

Sergio E. Garcıa-Garrido, Departamento de Quımica Organica e Inorganica, Facultadde Quımica, Universidad de Oviedo, Oviedo, Spain

Anirban Ghosh, Tata Chemicals Ltd, Innovation Center, Pune, India

Zhong He, Department of Chemical, Biological and Pharmaceutical Engineering, NewJersey Institute of Technology, Newark, NJ, USA

Balaji R. Jagirdar, Department of Inorganic and Physical Chemistry, Indian Instituteof Science, Bangalore, India

Suresh Babu Kalidindi, Department of Inorganic and Physical Chemistry, IndianInstitute of Science, Bangalore, India; Anorganische Chemie II, Ruhr UniversitatBochum, Bochum, Germany

Kiyotomi Kaneda, Department of Materials Engineering Science, Graduate School ofEngineering Science, Osaka University, Toyonaka, Osaka, Japan

Deepa Khushalani, Materials Chemistry Group, Tata Institute of FundamentalResearch, Mumbai, India

Rajiv Kumar, Tata Chemicals Ltd, Innovation Center, Pune, India

Debasish Kundu, Department of Organic Chemistry, Indian Association for the Culti-vation of Science, Jadavpur, Kolkata, India

Brigid Lanigan, Department of Chemistry, Green Chemistry Centre of Excellence,University of York, Heslington, York, UK

Jin Hyung Lee, Korea Institute of Ceramic Engineering and Technology, Seoul, SouthKorea

Soo Youn Lee, Korea Institute of Ceramic Engineering and Technology, Seoul, SouthKorea

Yong Li, State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics,Chinese Academy of Sciences, Dalian, China

Jones Limberger, Laboratory of Molecular Catalysis, Institute of Chemistry, UFRGS,Porto Alegre, Brazil

Gaoqing Lu, ARC Centre of Excellence for Functional Nanomaterials, School ofChemical Engineering and AIBN, The University of Queensland, Qld, Australia

Biswajit Mishra, Materials Chemistry Group, Tata Institute of Fundamental Research,Mumbai, India

Takato Mitsudome, Department of Materials Engineering Science, Graduate Schoolof Engineering Science, Osaka University, Toyonaka, Osaka, Japan

Adriano L. Monteiro, Laboratory of Molecular Catalysis, Institute of Chemistry,UFRGS, Porto Alegre, Brazil

Nirmalya Mukherjee, Department of Organic Chemistry, Indian Association for theCultivation of Science, Jadavpur, Kolkata, India

K. S. Nagabhushana, Tata Chemicals Ltd, Innovation Center, Pune, India

Carmen Najera, Department of Organic Chemistry and Institute of Organic Synthesis,University of Alicante, Alicante, Spain

LIST OF CONTRIBUTORS xv

Radha Narayanan, Department of Chemistry, University of Rhode Island, Kingston,RI, USA

Brindaban C. Ranu, Department of Organic Chemistry, Indian Association for theCultivation of Science, Jadavpur, Kolkata, India

Debabrata Rautaray, Tata Chemicals Ltd, Innovation Center, Pune, India

Liane M. Rossi, Laboratory of Nanomaterials and Catalysis, Institute of Chemistry,USP, Sao Paulo, Brazil

Debasree Saha, Department of Organic Chemistry, Indian Association for the Cultiva-tion of Science, Jadavpur, Kolkata, India

Robert W. J. Scott, Department of Chemistry, University of Saskatchewan, Saskatoon,SK, Canada

K. K. Sharma, Department of Chemistry and Chemical Biology, Rutgers, The StateUniversity of New Jersey, Piscataway, NJ, USA

Wenjie Shen, State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics,Chinese Academy of Sciences, Dalian, China

Peter S. Shuttleworth, Departamento de Fısica de Polımeros, Elastomeros y Aplica-ciones Energeticas, Instituto de Ciencia y Tecnologıa de Polımeros, CSIC, Madrid,Spain

R. Silva, Department of Chemistry and Chemical Biology, Rutgers, The State Univer-sity of New Jersey, Piscataway, NJ, USA

Lianzhou Wang, ARC Centre of Excellence for Functional Nanomaterials, School ofChemical Engineering and AIBN, The University of Queensland, Qld, Australia

Xianqin Wang, Department of Chemical, Biological and Pharmaceutical Engineering,New Jersey Institute of Technology, Newark, NJ, USA

Zhi-Kang Xu, Department of Polymer Science and Engineering, Zhejiang University,Hangzhou, China

Xu Zong, ARC Centre of Excellence for Functional Nanomaterials, School of ChemicalEngineering and AIBN, The University of Queensland, Qld, Australia

1

INTRODUCTION TONANOCATALYSIS

Vivek Polshettiwar and Tewodros Asefa

Catalysis provides sustainable and cost-effective methods to transform raw materialsinto valuable chemicals. Thus, catalytic processes have long become essential to solv-ing the energy and environmental challenges that we currently face around the globe.Catalysis can be broadly divided into homogeneous and heterogeneous catalysis. Homo-geneous catalysis involves catalysts and reactants in the same phase.1 As homogeneouscatalysts are generally soluble molecular or ionic compounds, they have more easilyaccessible active catalytic sites, and thus often exhibit good catalytic activity. Moreover,their structures and functional groups can easily be changed to result in chemo-, regio-,and enantioselectivity. However, despite their many advantages and being widely usedin industry, homogeneous catalysts do have some disadvantages, which is mainly todo with the fact that they are difficult to separate from the final products or reactionmixtures. Furthermore, even with the use of numerous techniques, such as chromatogra-phy, distillation, or extraction, the removal of trace amounts of residual catalytic speciesfrom the reaction mixture is always challenging in the case of homogeneous catalysis.This is an important issue that requires attention, given the fact that the presence oftrace amounts of catalytic moieties, especially metallic ones, is strictly regulated in thecommodity chemicals and pharmaceutical products, which are often produced usingcatalysts. All of these issues together, therefore, pose major hurdles for homogeneouscatalysts, making many of them to have only limited applications.

Nanocatalysis: Synthesis and Applications, First Edition. Edited by Vivek Polshettiwar and Tewodros Asefa.© 2013 John Wiley & Sons, Inc. Published 2013 by John Wiley & Sons, Inc.

1

2 INTRODUCTION TO NANOCATALYSIS

Some of these drawbacks of homogeneous catalysts can be overcome by support-ing the homogeneous catalytic species on solid support materials and producing theircorresponding solid catalysts, known as heterogeneous catalysts.2 The general approachbehind the synthesis of heterogeneous catalysts involves either the entrapment (immo-bilization) or the attachment of an active catalytic moiety on the solid support material.The former can be accomplished by letting the catalytic species to adsorb on the solidsupport materials, whereas the latter can be realized by tethering the catalytic groupson the support materials with covalent bonds, preferably with strong covalent bondsthat can tolerate severe reaction conditions. Because of the physical attachment of thecatalytic groups onto the solid support materials, heterogeneous catalysts often possessnumerous advantages, such as their ease of handling, efficient recovery, enhanced sta-bility and shelf-life, and reusability. However, because the reactants and the catalystsin heterogeneous catalysis must necessarily be in two different phases, the interactionbetween the reactant and the catalyst is reduced. This, in turn, can result in reducedoverall catalytic activity in heterogeneous catalysts compared with their homogeneouscounterparts. Possible leaching of active catalytic sites from the solid support materials,either from the cleavage of the covalent bonds between the catalytic groups and thesolid support material or from the possible desorption of the catalytic groups off thesolid support material, can also be an issue for some heterogeneous catalytic systems.Although the concentration of trace metals can often be much smaller in heterogeneouscatalytic systems compared with that in the corresponding homogeneous catalytic sys-tems, such possible leached trace metals in heterogeneous catalytic systems might stillrequire separation from final products.

To overcome some of the limitations associated with both homogeneous and hetero-geneous catalysts, new catalytic systems were needed that could have the advantages ofboth homogeneous and heterogeneous catalytic systems, allow all catalytic active sitesto be accessible and effective (i.e., give good catalytic activity, selectivity, and yield), andmake catalyst separation easily possible (i.e., stable catalyst, catalyst recovery, and cat-alyst reuse). Nanocatalysts and nanocatalysis could meet the need of such new catalystsystems (Figure 1.1).

WHAT IS NANOCATALYSIS?

The seemingly magical properties of nanoparticles have been unknowingly taken advan-tage of and used for various applications for centuries. Early uses of nanostructuredmaterials include the third-century Lycurgus Cup,1 made of a dichroic glass of gold andsilver nanoparticles, which made the cup look opaque green when lit from the outside andglowing red when lit from the inside. Similar shiny and sparkling ceramic glazes, whichwere used between the ninth and seventeenth centuries,2 also contained various metallicnanoparticles. The qualities of “Damascus” saber blades, used from 300 BCE to 1700CE, including their excellent strength, toughness, and resistance to shattering, as wellas their ability to remain extremely sharp, all came from their construction from carbonnanotubes and cementite nanowires.3 Even in the century-old Haber–Bosch process forammonia synthesis,4 iron nanoparticles were present.5 It was also in the beginning of

NANOCATALYSIS: TRUTH OR HYPE? 3

Nanocatalysis

Heterogeneouscatalysis

Reduced contacts betweencatalyst and substrates

Inferior catalytic performance(homogeneous counterparts)

Leaching of active species

Homogeneouscatalysis

Cumbersome productpurification

Difficulty in recovery andrecycling of the expensive

catalyst

Deactivation via the aggregation ofmetal nonoparticles

Figure 1.1. Nanocatalysis can bridge the gap between homogeneous and heterogeneous

catalysis, bring together the advantages of both homogeneous and heterogeneous catalysts,

and overcome some of the issues associated with both homogeneous and heterogeneous

catalytic systems.

the twentieth century that Ostwald performed simple experimental demonstration thatindicated the considerable increase of surface area from dividing cubes and its conse-quences for surface-dependent catalysis. In fact, we now use, perhaps still unknowinglytoo, huge varieties of nanomaterials in our daily lives6 as well as in industrial processessuch as catalysis. As is often said, “nature makes and chemistry reshapes.”

Nanocatalysis has long become an important part of nanoscience.7 Nanoparticlescan substitute conventional materials and serve as active and stable heterogeneous cat-alysts6 or as support materials for various catalytic groups.7 Due to their small sizes,catalytic-active nanoparticles have higher surface area and increased exposed activesites, and thereby improved contact areas with reactants, akin to those of homogeneouscatalytic systems. At the same time, nanostructured catalysts can behave as heteroge-neous catalysts; thus, they can also be easily separated from the reaction mixtures. Inaddition to their tunable catalytic activity and selectivity, often with activities close tohomogeneous catalytic systems, the stability of nanocatalysts can be improved by tai-loring the chemical and physical properties of the nanomaterials by various syntheticmethods. For example, nanocatalysts with better activity, stability, and selectivity canbe designed and synthesized merely by controlling the sizes, shapes, and morphologiesof nanomaterials.7–9

NANOCATALYSIS: TRUTH OR HYPE?

There has been much discussion about the originality of the concept “nanocatalysis.”The question whether nanocatalysis is novel science or merely a fancy version of alreadyknown catalysis has often been posed. Several researchers have said, “Catalysis is alwaysnano”. But, is this true? If it is true, then why is gold not active in its bulk state whenit exhibits extraordinary catalytic activity when reduced to the nanoscale? Why does

4 INTRODUCTION TO NANOCATALYSIS

bulk cobalt oxide need high temperatures to oxidize CO to CO2, while cobalt oxide cancatalyze the same reaction at very low temperatures at nanoscale size? There are a hugenumber of such examples (with their numbers increasing every day) of materials thatshow unprecedented catalytic activities when reduced from the bulk into nanoscale sizes.

Thus, the statement that “catalysis is always nano” may not be correct. What we cansafely say, however, is that “catalytic interactions are always in the nanoscale.” Moreprecisely, nanocatalysis (catalysis using nanomaterials), with catalytic interactions obvi-ously in the nanoscale range, is at least a step beyond conventional catalysis (catalysisusing bulk materials).

Nanocatalysts are extremely structure-sensitive, and their catalytic activity andselectivity depend heavily on the size, shape, and composition of the nanoparticles aswell as their support materials. This can be exemplified by the largely unexpected resultsthat gold nanoparticles smaller than 5 nm are very active catalysts even at subambienttemperatures, while bulk and bigger size gold is inactive.8, 9 The benefit of the increasedsurface-to-volume ratio and the benefit of accessibility to specific sites (e.g., steps,edges, and corners) of nanoparticles to catalysis are now well-known.10, 11 Therefore,multiple and extremely varied approaches to develop efficient nanocatalysts have beenpursued. This includes the synthesis of metallic and metal oxide nanomaterials withdifferent unique structures and shapes and their applications either as catalysts or assupport materials for catalytic active species. Further research in this area or the devel-opment of nanocrystalline catalytic systems are also currently continuing. Furthermore,nanocatalytic reaction mechanisms are complex and not yet fully understood,12 makingnanocatalysis a very exciting science with lots of room for further investigation.

Nanocatalysis can be considered as part of “green” science as well, becausenanocatalysis often allows conducting chemical transformations in an environmentallyfriendly manner.13 This is possible, for example, by adopting magnetic nanocatalystrecovery,14 by mixing ionic liquids with metal nanoparticles,15 by creating electrodeswith nanocatalysts with improved redox properties for energy-relevant applications, byencapsulating nanoparticles in nanoporous cavities of zeolites and molecular organicframeworks, and by controlling the shapes of metal and metal oxide nanoparticles toenhance their catalytic activities.16

The purpose of this book is to give readers a broad perspective and current infor-mation about catalytic protocols developed over the past several years involving nano-materials as catalysts, (i.e., nanocatalysis). The 18 chapters in the book cover a hugerange of fields, where a variety of nanomaterials are successfully used as catalysts. Ineach chapter, some discussion is made about the synthesis, characterization, and appli-cation of nanocatalysts in different chemical reactions. In addition, some typical detailedexperimental procedures for the synthesis and characterization of nanocatalysts and howthese nanocatalysts are employed to catalyze various important chemical reactions arepresented.

The first six chapters are devoted to nanocatalysts or nanocatalysis for carbon–carbon (C C) and carbon–heteroatom coupling reactions. While there are many C Ccross-coupling reactions, the Heck, Sonogashira, Suzuki–Miyaura, Kumada–Corriu,Negishi, Stille, Hiyama, and Fukuyama coupling reactions remain among the mostbroadly used in industrial applications. These C C coupling reactions are essential

NANOCATALYSIS: TRUTH OR HYPE? 5

in wide ranges of synthetic chemistry. This can be evidenced by the Nobel Prize inChemistry awarded to Heck, Negishi, and Suzuki in 2010. In Chapter 2, Asefa andcoworkers have reviewed the Heck reaction catalyzed by transition metal (mainly Pd)nanoparticles. The authors have also included other metal nanoparticles, such as Ru,Ni, and trimetallic Au–Ag–Pd, which have been recently shown to catalyze the Heckreaction.

The metal-catalyzed Suzuki cross-coupling reaction of aryl, vinyl, or alkyl halideor pseudohalides with organoboron reagents is among the most efficient synthetic meth-ods to construct C C bonds. The Suzuki reaction has, therefore, found widespreadapplications in organic syntheses. In Chapter 3, Rosi and coworkers have provided acritical review regarding the use of nanocatalysts for the Suzuki coupling reaction. Manyadvantages, such as catalyst recovery, catalyst reusability, and wide accessibility of thecatalytic groups supported on organic, inorganic, or organic–inorganic hybrid solids andliquids (biphasic catalysis), are also discussed in detail.

Another important C C coupling protocol is the Sonogashira reaction, which isoften catalyzed by palladium-based catalysts and is capable of coupling a terminal sp-hybridized carbon in an alkyne with an sp2 carbon of an aryl or vinyl halide (or triflate).In Chapter 4, Chinchilla and Najera have reviewed the development of nanocatalysts forthis reaction. The authors have discussed the many different methods used to synthesizePd nanocatalysts by immobilizing palladium nanoparticles on polymers, carbon nanos-tructures or inorganic materials for the Sonogashira reaction, and the applications of thematerials as catalysts for the reaction. They have also included a review on the synthesisand use of non-palladium nanoparticles composed of copper, iron, ruthenium, or goldas catalysts for this reaction.

In Chapter 5, Banerjee and Scott have provided a review of the use of nanocat-alysts for a variety of other types of C C coupling reactions, namely the Hiyamareaction (involving organosilicon reactants), the Negishi reaction (involving organozincreactants), the Stille reaction (involving organotin reactants), and the Kumada–Corriureaction (involving organomagnesium reactants). The authors have discussed the syn-thesis and use of stabilized nanoparticles as catalysts for these coupling reactions. Theyhave also discussed some newer synthetic strategies to nanocatalysts for these reactionsfrom recent literature. Furthermore, they have presented mechanistic aspects of thesecoupling reactions as catalyzed by nanocatalysts, which include in situ conversions ofprecatalysts to actual zerovalent catalytic metal clusters.

In Chapter 6, Ranu and coworkers have reviewed the research works on nanocata-lysts for carbon–heteroatom bond-forming reactions. The latter include carbon–sulfur,carbon–nitrogen, carbon–oxygen, and carbon–selenium reactions, which are used exten-sively in various chemical, material, and industrial processes. The authors have providedsome accounts of the developments in the field of nanocatalysis and also discussed boththe advantages and disadvantages of many nanocatalytic processes.

The next two chapters are devoted to nanocatalysis for fine chemical synthesis.In Chapter 7, Asefa and coworkers have reviewed nanocatalysis of three important andrelated reactions, namely the Henry, Aldol, and Knoevenagel reactions. The authors havealso included several different synthetic approaches or methods developed to variousnanocatalysts for these reactions.

6 INTRODUCTION TO NANOCATALYSIS

The concept of atom economy, that is, designing synthetic methods to maximize theincorporation of all atoms used in a reaction into final reaction products, has emerged as amajor goal for chemists in recent years. The skeletal rearrangements of organic molecules(e.g., isomerizations, cycloisomerizations, and pericyclic reactions) are typical notableexamples of atom economical reactions because such reactions generate no by-products.In Chapter 8, Garcıa-Alvarez and coworkers have provided an up-to-date overviewof published literature on the synthesis and applications of metal and metal oxidenanoparticles that can serve as catalysts for various rearrangement reactions of organiccompounds.

The subsequent four chapters are devoted to the use of nanocatalysts for oxidationand hydrogenation reactions. Oxidation of alcohols is widely recognized as a fundamen-tal and important transformation in both laboratory and industrial chemistry because thereaction results in carbonyl compounds that can serve as versatile solvents, polymerprecursors, fragrances, and intermediates for fine chemicals and pharmaceuticals. InChapter 9, Mitsudome and Kaneda have reviewed nanocatalysts based on inorganicmaterial- or polymer-supported active metals of Ru, Pd, and Au for alcohol oxida-tion reaction in the liquid phase. The chapter not only provides good understanding ofnanocatalysis for alcohol oxidation reactions but also highlights the issues related in thisarea that still need to be addressed in the future.

Besides their size, the shape of nanocatalysts plays an important role in determiningthe catalytic activity, selectivity, and stability of various nanocatalysts. In Chapter 10,Shen has summarized recent progress on morphologically controlled synthesis of Co3O4,Fe2O3, and CeO2 nanomaterials. Furthermore, the authors have described how tuning theshapes of these metal oxide nanocatalysts modulates their surface atomic configurations,and thereby catalytic properties for various reactions, including oxidation. In addition,the authors have discussed how morphology-dependent nanocatalysis has enabled ourfundamental understanding of the structure–reactivity relationship in heterogeneouscatalysis and provided some of their thoughts for some new direction for the developmentof highly efficient nanocatalysts.

Like oxidation, hydrogenation is an important reaction. In Chapter 11, Narayananhas reviewed the different types of nanocatalysts developed for hydrogenation reactionsof alkenes, alkynes, and aromatic compounds. The author has also presented a surveyof various nanocatalysts, including metal nanoparticles in colloidal solutions and metalnanoparticles adsorbed onto different supports, for hydrogenation and related reactions.

Along similar lines, Fihri and Polshettiwar have discussed nanocatalysts forhydrogenolysis reactions in Chapter 12. The authors have divided the chapter intotwo sections: the first one is on the nanocatalytic hydrogenolysis of glycerol, an impor-tant category of processes for glycerol conversion into commodity chemicals; and thesecond one is on the hydrogenolysis of alkanes, which potentially allows the conversionof natural gas into hydrocarbons with higher carbon numbers or liquid form. In bothsections, various nanocatalytic systems that use mono- and bimetallic nanomaterials aswell as metal nanoparticles modified by metal oxides are discussed.

The subsequent two chapters are devoted to the topic of nanomaterial-basedphotocatalysis. Photocatalysts increase the rate of a reaction when specifically activatedby either ultraviolet (UV) or visible electromagnetic radiation. Using UV or visible

NANOCATALYSIS: TRUTH OR HYPE? 7

light as a source of energy, especially sunlight, to promote photocatalytic reactions is ofgreat importance to making catalytic protocols sustainable in terms of the environmentand the economy. In Chapter 13, Mishra and Khushalani have summarized differenttypes of nanomaterials used in photocatalysis, by paying particular attention to metaloxide-based photocatalytic materials and methods employed for their synthesis and theirapplication as photocatalyst for the degradation of organic pollutants using visible light.

Water splitting is a reaction that can provide hydrogen from water; thus, it can serveas a potential energy source and solution to energy and environmental problems ourworld faces. Photocatalytic water splitting using nanomaterials as catalysts is extensivelyreviewed by Zong, Lu, and Wang in Chapter 14. The authors have started with a briefintroduction of water-splitting reactions activated by nanocatalysts. They have also givenan overview of semiconductor nanocatalysts by classifying them according to the typeof light they can absorb or their absorption properties as well as elemental compositions.At the end of the chapter, they have discussed important criteria for the design anddevelopment of efficient and stable semiconductor nanocatalysts for water splitting andother related photochemical processes.

The next two chapters are devoted to the use of nanocatalysis to produce non-conventional sources of energy. Environmental concerns, process efficiency, and safetyremain to be important issues in the development of catalysts, and these issues arestimulating the development and innovation of catalysts for sustainable H2 production.Hydrogen can actually be produced from renewable sources. In Chapter 15, He andWang have reviewed the latest research advances related to H2 production from biomassand biomass-derived feedstock. They have also discussed the existing challenges behindconversion of both types of feedstock. They have included the use of synchrotron-basedX-ray absorption spectroscopy as the characterization method for determination of theproperties of nanocatalytic materials considered for renewable H2 production.

Along similar lines, in Chapter 16, Budarin, Shuttleworth, Lanigan, and Clark haveprovided a critical overview of biofuel production using nanocatalysts. The authors havediscussed that nanocatalysis has been increasingly used or considered in biofuel produc-tion, for greener processing of various chemical raw materials, and for affording higheryields of desired products of various chemical processes. This, in turn, results in moreeconomically favorable and cost-competitive processes compared with conventionalchemical processes.

Owing to their large surface area, physical robustness, high resistance to organicsolvents, and high thermal stability, nanomaterials are also attractive as support materialsfor immobilizing enzymes. Consequently, a variety of future applications are envisagedfor nanomaterial-based biocatalysts in the medical, industrial, pharmaceutical, and envi-ronmental areas, including biosensor development, bioremediation, and food production.In Chapter 17, Lee and coworkers discussed nanomaterial-based biocatalysts and bio-catalysis. The authors have also given an overview of the state-of-the-art technologies inpractice and discussed this rapidly developing field that focuses on nanomaterial-basedbiocatalyst systems. Because nanomaterial-based biocatalysts have greater stability andhigher shelf-lives, these materials enable traditional enzymes to find applications ascatalysts in conventional chemical synthesis, where relatively harsh reaction conditionsare often employed.

8 INTRODUCTION TO NANOCATALYSIS

The last two chapters focus on the use of nanocatalysts in the chemical industry.In Chapter 18, Ghosh and coworkers have critically reviewed the role of nanocatalysisin the chemical industry. Using several case studies, they have explained how nanocat-alysts have already been successfully used for several important chemical processes inindustry.

In the final chapter, Chapter 19, Kalidindi and Jagirdar have discussed nanocatalystsin the context of activation of small molecules and their conversion to useful chemi-cals. The authors have discussed three nanocatalytic processes, namely CO oxidation onAu/metal oxide catalysts, direct synthesis of H2O2 from H2 and O2, and methanol syn-thesis from CO and CO2. These three reactions have great industrial and environmentalimportance.

In its entirety, this book provides fundamental understanding of nanocatalysis and awealth of information on synthesis, characterization and applications of nanocatalysts.The book also provides an important and critical overview on how nanocatalysis canserve as a platform from which a virtually unlimited number of crucial chemical processissues can be resolved. The obvious applications of nanocatalysts will be in fine chemicalsynthesis, where refined nanocatalysts allow the production of desired products in higheryields. Another notable example where nanocatalysts have potential application is inenergy (hydrogen) production from water, or a renewable source of energy with sunlight.Nanocatalysis can also a play significant role in resolving the energy and environmentalchallenges that we as a global society now face. Thus, nanocatalysis can help us takegigantic steps forward for the betterment of humankind through the use of tiny nanoscaleparticles.17

REFERENCES

1. Tait H., editor. Five Thousand Years of Glass. London: The British Museum Press; 1991.

2. Carboni S. Glass from Islamic Lands. London: Thames & Hudson, Ltd; 2001, p 51.

3. Reibold M., Paufler P., Levin A. A., Kochmann W., Patzke N., Meyer D. C. Materials: Carbonnanotubes in an ancient damascus sabre. Nature 2006;444:286–286.

4. Smil V. Detonator of the population explosion. Nature 1999;400:415–416.

5. Rodriguez M. M., Bill W., Brennessel W. W., Holland P. L. N-2 reduction and hydrogenationto ammonia by a molecular iron-potassium complex. Science 2011;334:780–783.

6. Ozin G. A., Arsenault A. C., Cademartiri L., editors. Nanochemistry: A Chemical Approachto Nanomaterials, 2nd ed. Royal Society of Chemistry; 2008.

7. Astruc D., editor. Nanoparticles and Catalysis, Weinheim: Wiley-VCH Verlag GmbH; 2008.

8. Ishida T., Haruta M. Gold catalysts: Towards sustainable chemistry. Angew. Chem. Int. Ed.2007;46:7154–7156.

9. Hashmi A. S. K., Hutchings G. J. Gold catalysis. Angew. Chem. Int. Ed. 2006;47:7896–7936.

10. Somorjai G. A., Frei H., Park J. Y. Advancing the frontiers in nanocatalysis, biointerfaces,and renewable energy conversion by innovations of surface techniques. J. Am. Chem. Soc.2009;131:16589–16605.

11. Burda C., Chen X., Narayanan R., El-Sayed M. A. Chemistry and properties of nanocrystalsof different shapes. Chem. Rev. 2005;105:1025–1102.

REFERENCES 9

12. de Smit E., Swart I., Creemer J. F., Karunakaran C., Bertwistle D., Zandbergen H. W., deGroot F. M. F., Weckhuysen B. M. Nanoscale chemical imaging of a working catalyst byscanning transmission X-ray microscopy. Angew. Chem. Int. Ed. 2009;48:3632–3636.

13. Polshettiwar V., Varma R. S. Green chemistry by nan-catalysis. Green Chem. 2010;12:743–754.

14. Polshettiwar V., Luque R., Fihri A., Zhu H., Bouhrara M., Basset J. M. Magnetically recov-erable nano-catalysts. Chem. Rev. 2011;111:3036–3075.

15. Fihri A., Bouhrara M., Nekoueishahraki B., Basset J. M., Polshettiwar V. Nano-catalysis forSuzuki coupling reaction. Invited for nobel issue. Chem. Soc. Rev. 2011;40:5181–5203.

16. Xie X., Li Y., Liu Z.-Q., Haruta M., Shen W. Low temperature oxidation of CO by Co3O4,Nanorods. Nature 2008;458:746–749.

17. Rothenberg G., editor. Catalysis—Concepts and Green Applications. Weinheim: Wiley-VCHVerlag GmbH; 2008.

2

NANOCATALYSTS FOR THEHECK COUPLING REACTIONS

T. Asefa, A. V. Biradar, S. Das, K. K. Sharma, and R. Silva

INTRODUCTION

The fields of homogeneous and heterogeneous catalysis have made considerable progressin the past few decades, enabling the synthesis of a diverse range of useful and uniqueorganic compounds.1 In particular, the catalytic Heck coupling reaction (sometimesalso called the Mizoroki–Heck reaction), which was named after the pioneering andindependent works of Tsutomu Mizoroki2 and Richard F. Heck,3 has become among themost indispensable catalytic reactions today because it allows the synthesis of new C Cbonds between various aryl or vinyl halides and activated alkenes. Since its inception inthe early 1970s, the Heck reaction has made great strides and has now unarguably becomeamong the most powerful synthetic tools available for organic and inorganic chemistsalike as well as for many commercial processes today. The Nobel Prize awarded toRichard Heck in 2010 is also clearly a good testament of the importance of the reaction.

The classical Heck reaction involves C C bond formation between two sp2

hybridized carbon centers, one of which is an �-olefin and the second is an organiccompound containing a leaving group composed of bromo-, iodo-, or pseudohalide moi-ety(e.g., tosylate, mesitylate, triflate, and diazonium saltsdiazonium salt). Furthermore,in conjunction with other organic reactions such as carbonylation, esterification, andother types cross-coupling and intermolecular reactions, the Heck reaction can serveas the key step in the synthesis of various types of pharmaceuticals, agrochemicals,

Nanocatalysis: Synthesis and Applications, First Edition. Edited by Vivek Polshettiwar and Tewodros Asefa.© 2013 John Wiley & Sons, Inc. Published 2013 by John Wiley & Sons, Inc.

11

12 NANOCATALYSTS FOR THE HECK COUPLING REACTIONS

R – X + R′Pd0

Base- HX

RR′

Scheme 2.1. General schematic depiction of the Heck reaction between an unsaturated

halide or triflate and an alkene that contains at least one hydrogen atom and is electron

deficient (R = aryl, benzyl, or vinyl; and R′ = aryl, acrylate ester, etc).

and natural products.4 In addition, the Heck reaction enables the functionalization ofvarious molecules with different substituents, which otherwise take multiple steps toproduce. Thus, an impressive list of synthetically useful transformations is possible viathe Heck reaction, allowing the reaction to get a place in the repertoire of syntheticorganic chemists. Nevertheless, intensive research efforts have been continuing becausesimpler, “greener,” and more efficient catalytic systems beyond the traditionally usedorganopalladium-based catalysts and phosphine ligands are needed for many existingand other possible new Heck reactions.5

Transition metals, particularly organopalladium complexes, still remain at the fore-front of catalysts used for the Heck reaction (Scheme 2.1). The Pd(II) derivatives are oftenused in the presence of PPh3 and excess base to catalyze the reaction as shown in Scheme2.1.6 It is noteworthy that the same catalytic systems are now known to catalyze othertypes of C C bond-forming reactions such as acylation, methylation, and carboxyalky-lation,7 the Sonogashira reaction,8 the Suzuki reaction,9, 10 and the Stille reaction aswell.11, 12 Not surprisingly, these C C bond forming reactions are also widely utilizedas key steps for the syntheses of many organic chemicals, natural products, and a varietyof industrial products,13–16 as can be seen in the other chapters of this book.

It is worth noting that phosphines are generally used as electron-donating ligands toeffectively drive the Heck reaction. However, phosphines are toxic, moisture-sensitive,and costly; hence, they make large-scale industrial production of various coupling prod-ucts through the Heck reaction relatively expensive or less viable. Thus, research inphosphine-free catalytic systems for the Heck reaction has received greater attentionand is one of the research areas that has been widely pursued in recent years as well.17

HETEROGENEOUS CATALYSTS FOR THE HECK REACTION

Generally, the Heck reaction can be catalyzed by two different types of catalytic systems,namely homogeneous catalysts or heterogeneous catalysts, which include nanocatalysts.As the interest for “greener” chemical process with minimum potential effects in theenvironment is growing, research efforts toward the development of heterogeneouscatalysts for various reactions, including the Heck reaction, have surged. The latter, inturn, has led to, among other things, a greater effort in the development of new syntheticstrategies for stabilizing Pd-based homogeneous catalysts on solid support materials(also known as “heterogenization of homogeneous catalysts”) to produce heterogeneouscatalysts that are effective, easily recyclable, and help in reducing the costs associatedwith catalysts/catalysis.