Green Processes, Volume 8: Green Nanoscience

Green Chemistry is a vitally important subject area in a world where being as green and environmentally sound as possible is no longer a luxury but a necessity. Its applications include the design of chemical products and processes that help to reduce or eliminate the use of generation of hazardous substances. The Handbook of Green Chemistry comprises 12 volumes, split into subject–specific sets as follows: Set I:        Green Catalysis Set II:      Green Solvents Set III:     Green Processes Volume 7: Green Synthesis Volume 8: Green Nanoscience Volume 9: Designing Safer Chemicals Set IV:     Green Products Production of materials on a nanoscale can be considered to be environmentally friendly as fewer raw materials are required. These processes are being streamlined in order to reduce/recycle the types of chemicals used in order to create them. The aim of this book is to describe the existing synthetic tools, explain their characteristics and to provide a basis for the design of new multiphasic catalytic systems. In particular, the advantages of spontaneous phase separation to recover products, catalyst, and byproducts make for ease of operation and of separation are discussed.

About the Editors XI List of Contributors XV 1 Formation of Nanoparticles Assisted by Ionic Liquids 1 Jackson D. Scholten, Martin H.G. Prechtl, and Jairton Dupont 1.1 Metal Nanoparticles in Ionic Liquids: Synthesis 1 1.1.1 Reduction of Organometallic Precursors 2 1.1.2 Decomposition of Organometallic Precursors 7 1.1.3 Transfer from an Aqueous/Organic Phase to the Ionic Liquid Phase 9 1.1.4 Bombardment of Bulk Materials 10 1.2 Metal Nanoparticles in Ionic Liquids: Stabilization 11 1.3 Metal Nanoparticles in Ionic Liquids: Recyclable Multiphase Catalyst–Systems 13 1.3.1 Hydrogenation of Multiple Bonds with Metal Nanoparticles in Ionic Liquids 14 1.3.2 Carbon–Carbon Cross–Coupling Reactions Catalyzed by Palladium Nanoparticles in Ionic Liquids 17 1.3.3 Functionalization and Defunctionalization Reactions Using Metal Nanoparticles in Ionic Liquids 19 1.3.4 Isotope Exchange Catalyzed by Metal Nanoparticles in Ionic Liquids 22 1.3.5 Application of Metal Nanoparticle Catalysts in Ionic Liquids for Energy– and Environment–Related Systems 24 1.4 General Remarks 26 References 26 2 CO2–Expanded Liquids for Nanoparticle Processing 33 Steven R. Saunders, Christopher B. Roberts, Kendall M. Hurst, Christopher L. Kitchens, Gregory Von White II, and D. Brad Akers 2.1 Introduction 33 2.1.1 Gas–Expanded Liquids 34 2.2 Controlling Nanoparticle Dispersibility and Precipitation 34 2.3 Size–Selective Fractionation of Nanoparticles 38 2.3.1 Small–Scale Size–Selective Fractionation 40 2.3.2 Large–Scale Size–Selective Fractionation 41 2.4 Tuning the Precipitation Range 45 2.4.1 Effect of Temperature 45 2.4.2 Effect of Solvent 45 2.4.3 Effect of Stabilizing Ligand 47 2.5 Modeling Nanoparticle Dispersibility in CXLs 47 2.6 Thin–Film Deposition 50 2.6.1 Nanoparticle Thin–Film Deposition on MEMS Devices 52 2.7 Formation and Synthesis of Nanoparticles in CXLs 53 2.8 Nanoparticle Phase Transfer Using CXLs 55 2.9 Conclusion 55 References 56 3 Green Synthesis and Applications of Magnetic Nanoparticles 61 Liane M. Rossi, Alexandre L. Parize, and Joel C. Rubim 3.1 Introduction 61 3.2 Green Synthesis of Magnetic Nanoparticles 62 3.2.1 Background 62 3.2.2 Thermal Decomposition Methods 62 3.2.3 Microemulsion Methods 67 3.2.4 Preparation of Magnetic NPs Using Renewable Resources 68 3.2.5 Synthesis of Magnetic NPs in Ionic Liquids 68 3.2.6 Other Methods 69 3.3 Magnetic Separation as a Green Separation Tool 69 3.3.1 Background 69 3.3.2 Oil Spill Containment and Recovery 71 3.3.3 Heavy Metal Recovery 72 3.3.4 Catalyst Recovery and Recycling 73 3.3.4.1 Metal Complex Catalysts 73 3.3.4.2 Metal Nanoparticle Catalysts 74 3.3.4.3 Organocatalysts 76 3.4 Conclusion 77 References 78 4 Photocatalysis by Nanostructured TiO2–based Semiconductors 89 Matteo Cargnello and Paolo Fornasiero 4.1 Introduction 89 4.2 Structure and Photocatalytic Properties 93 4.2.1 Elements Affecting Bandgap and Photocatalytic Activity 93 4.2.2 Influence of the Structure on the Bandgap and the Photocatalytic Activity 97 4.2.3 Nanocomposites for Photocatalytic Applications 99 4.3 Nanostructures, Nanoarchitectures, and Nanocomposites for Pollution Remediation 100 4.3.1 Photocatalytic Applications in Wastewater Treatment 100 4.3.2 Photocatalytic Applications in Gas–Phase Decontamination 104 4.3.3 Photocatalytic Applications to Disinfection 106 4.4 Nanostructures, Nanoarchitectures, and Nanocomposites for Energy Applications 107 4.4.1 Photocatalytic Applications for Hydrogen Production 108 4.4.2 Photoelectrochemical Devices 113 4.4.3 Photocatalytic Applications in Artificial Photosynthesis 115 4.5 Nanostructures, Nanoarchitectures, and Nanocomposites for Green Synthesis 117 4.5.1 Oxidation Reactions 117 4.5.2 Reductions 118 4.5.3 Other Reactions 119 4.6 Materials Stability and Toxicology – Safety Issues 120 4.7 Conclusion 121 References 122 5 Nanoencapsulation for Process Intensification 137 Aaron J. Yap, Anthony F. Masters, and Thomas Maschmeyer 5.1 Introduction and Scope 137 5.2 Cascade Reactions for Process Intensification 138 5.2.1 Background 138 5.2.2 Cascade Reactions with Incompatible Catalysts and Nanoencapsulation 140 5.2.3 Summary of Reactions and Systems 147 5.3 Other Cascade Reactions with Incompatible Catalysts – Polydimethylsiloxane (PDMS) Thimbles for Generic Site Isolation 148 5.4 Potential Methods of Nanoencapsulation 149 5.4.1 Layer–by–Layer (LbL) Methods 149 5.4.2 Sol–Gel–Based Methods 151 5.4.3 Inorganic Methods 153 5.4.3.1 Layered Inorganic Solids 153 5.4.3.2 Inorganic Spheres 154 5.4.4 Polymer–Based Methods 155 5.4.4.1 Micelle/Emulsion Encapsulation 156 5.4.4.2 Vesicle–Based Encapsulation 157 5.4.5 Cage Protein Encapsulation 158 5.4.6 Combinatorial Approaches 158 5.5 Conclusion and Future Directions 159 References 160 6 Formation of Nanoemulsions by Low–Energy Methods and Their Use as Templates for the Preparation of Polymeric Nanoparticles 165 Gabriela Calderó and Conxita Solans 6.1 Introduction 165 6.2 Use of Nano–Emulsions as Templates for the Preparation of Polymeric Nanoparticles 167 References 170 7 Toxicity of Carbon Nanotubes 175 Dania Movia and Silvia Giordani 7.1 Introduction – Nanotoxicology: Should We Worry? 175 7.2 Toxicity of Carbon Nanotubes 177 7.2.1 Challenges in the Assessment of CNT Toxicity 177 7.2.1.1 Interaction with Dispersing Medium 178 7.2.1.2 Interaction with Cytotoxicity Assays 178 7.2.1.3 Effect of Impurities 180 7.2.1.4 Effect of Dispersion 180 7.3 Dermal Exposure to CNTs 180 7.3.1 Dermal Cytotoxicity 181 7.3.2 In Vivo Dermal Toxicity 182 7.4 Pulmonary Response to CNTs 183 7.4.1 Pulmonary Cytotoxicity 183 7.4.2 In Vivo Pulmonary Toxicity 184 7.5 Toxic Response to CNTs in the Intra–Abdominal Cavity 187 7.5.1 CNT Cytotoxicity in the Intra–Abdominal Cavity 187 7.5.2 In Vivo CNT Toxicity in the Intra–Abdominal Cavity 188 7.6 CNTs and Immunity 189 7.6.1 Recognition of CNTs by Macrophages 189 7.6.2 In Vitro Responses of Macrophages Exposed to CNTs 190 7.6.3 CNTs and Immunity In Vivo 191 7.6.3.1 Local Immune Responses 191 7.6.3.2 Allergic Immune Responses 192 7.6.3.3 Systemic Immune Alterations 192 7.7 CNT Interactions with the Cardiovascular Homeostasis 193 7.7.1 In Vitro Interactions 193 7.7.2 In Vivo CNT Toxicity to Cardiovascular Homeostasis 193 7.8 Genotoxicity and Mutagenicity of CNTs 194 7.8.1 In Vitro Studies 194 7.8.2 In Vivo Studies 194 7.9 Biodistribution and Pharmacokinetics of CNTs 195 7.9.1 Internalization of CNTs into Mammalian Cells 196 7.10 Biodegradation of CNTs 198 7.11 Biocompatibility of CNT–Based Biomaterials 198 7.12 Conclusions – Are CNTs safe? 198 References 209 8 A Review of Green Synthesis of Nanophase Inorganic Materials for Green Chemistry Applications 217 Homer Genuino, Hui Huang, Eric Njagi, Lisa Stafford, and Steven L. Suib 8.1 Introduction 217 8.2 Green Synthesis of Nanophase Inorganic Materials 217 8.2.1 Metal Oxide Nanoparticles 217 8.2.1.1 Hydrothermal Synthesis 218 8.2.1.2 Reflux Synthesis 221 8.2.1.3 Microwave–Assisted Synthesis 222 8.3 Green Synthesis of Metallic Nanoparticles 223 8.4 Green Chemistry Applications of Inorganic Nanomaterials 225 8.4.1 Manganese Oxides 226 8.4.2 Titanium Dioxide 227 8.5 Environmental Applications of Nanomaterials 231 8.5.1 Background 231 8.5.2 Titanium Dioxide Nanomaterials 231 8.5.3 Zinc Oxide Nanomaterials 232 8.5.4 Iron–Based Nanomaterials 232 8.6 Conclusion and Future Perspectives 233 References 234 9 Use of Extracted Anthocyanin Derivatives in Nanostructures for Solar Energy Conversion 245 Gabriele Giancane, Vito Sgobba, and Ludovico Valli References 257 10 Nanomaterials from Biobased Amphiphiles: the Functional Role of Unsaturations 261 Vijai Shankar Balachandran, Swapnil Rohidas Jadhav, and George John 10.1 Introduction 261 10.1.1 Plant/Crop–Based Resources for Practicing Sustainable Chemistry 263 10.1.2 Self–Assembly and Noncovalent Strategy for the Synthesis of Soft–Materials 264 10.2 Cashew Nut Shell Liquid (CNSL) 265 10.2.1 Extraction of CNSL and Its Components 265 10.2.2 Lipid Nanotubes and Helical Fibers from Cardanyl Glycolipids 266 10.2.3 Self–Assembled Gels from Cardanyl Glycosides 268 10.2.4 Antibacterial Nanocomposite Films for Coatings 273 10.2.5 Stimuli–Responsive Nature of Unsaturations 275 10.3 Conclusion 276 References 277 Index 281

Paul T. Anastas joined Yale University as Professor and iserves as the Director of the Center for Green Chemistry and Green Engineering at Yale. From 2004–2006, Paul Anastas has been the Director of the Green Chemistry Institute in Washington, D.C. Until June of 2004 he served as Assistant Director for Environment at e White House Office of Science and Technology Policy where his responsibilities included a wide range of environmental science issues including furthering international public–private cooperation in areas of Science for Sustainability such as Green Chemistry. In 1991, he established the industry–government–university partnership Green Chemistry Program, which was expanded to include basic research, and the Presidential Green Chemistry Challenge Awards. He has published and edited several books in the field of Green Chemistry and developed the 12 principles of Green Chemistry.