Deep Eutectic Solvents: Synthesis, Properties, and Applications

A useful guide to the fundamentals and applications of deep eutectic solvents Deep Eutectic Solvents contains a comprehensive review of the use of deep eutectic solvents (DESs) as an environmentally benign alternative reaction media for chemical transformations and processes. The contributors cover a range of topics including synthesis, structure, properties, toxicity and biodegradability of DESs. The book also explores myriad applications in various disciplines, such as organic synthesis and (bio)catalysis, electrochemistry, extraction, analytical chemistry, polymerizations, (nano)materials preparation, biomass processing, and gas adsorption. The book is aimed at organic chemists, catalytic chemists, pharmaceutical chemists, biochemists, electrochemists, and others involved in the design of eco-friendly reactions and processes. This important book: -Explores the promise of DESs as an environmentally benign alternative to hazardous organic solvents -Covers the synthesis, structure, properties (incl. toxicity) as well as a wide range of applications -Offers a springboard for stimulating critical discussion and encouraging further advances in the field Deep Eutectic Solvents is an interdisciplinary resource for researchers in academia and industry interested in the many uses of DESs as an environmentally benign alternative reaction media.

Table of Contents:
Preface xiii 1 Synthesis and Properties 1 Karine De Oliveira Vigier and Francois Jerome 1.1 Introduction 1 1.2 Synthesis 2 1.3 Properties 4 1.3.1 Freezing Point (Tf) 4 1.3.2 Density 5 1.3.3 Viscosity 11 1.3.4 Ionic Conductivity 16 1.3.5 Polarity 19 1.3.6 Surface Tension 19 1.4 Summary and Conclusions 21 References 21 2 Structure and Implications 25 Oliver S. Hammond and Karen J. Edler 2.1 Introduction 25 2.2 Nanostructure of DES 26 2.2.1 Complex Ion Model 26 2.2.2 An Extended Hydrogen Bond Network Model: “Alphabet Soup” 27 2.2.3 Non‐cholinium DES 36 2.3 Conclusions and Implications 38 Abbreviations 40 References 40 3 Toxicity and Biodegradability of Deep Eutectic Solvents and Natural Deep Eutectic Solvents 43 Zhen Yang 3.1 Introduction 43 3.2 Toxicity to Microorganisms 44 3.2.1 Toxicity to Bacteria 44 3.2.2 Toxicity to Other Microorganisms 47 3.3 Toxicity to Animals 48 3.3.1 In Vitro Toxicity Tests on Vertebrates and Invertebrates 48 3.3.2 Cytotoxicity 49 3.3.3 In Vivo Acute Toxicity Tests and Pharmacokinetics 53 3.4 Toxicity to Plants 55 3.5 Biodegradability 56 3.6 Summary and Conclusions 57 Abbreviations 58 References 59 4 Natural Deep Eutectic Solvents: From Their Discovery to Their Applications 61 Henni Vanda, Robert Verpoorte, Peter G. L. Klinkhamer, and Young H. Choi 4.1 Introduction 61 4.2 Natural Deep Eutectic Solvents is a Concept Based on How Physicochemical Features Could Be Used for Biological Functions 63 4.3 Extraction and Solubilization of Non‐water‐Soluble Metabolites 66 4.4 Solvents for Macromolecules 69 4.4.1 Application of ILs and DES to Macromolecules 69 4.4.2 Recent NADES Application for DNA, RNA, and Proteins 70 4.5 Application to Enzyme Reactions 75 4.6 Pharmaceutical Applications 76 4.7 Perspective of NADES 76 Abbreviations 79 References 79 5 Hydrophobic Deep Eutectic Solvents 83 Samah E.E. Warrag and Maaike C. Kroon 5.1 Introduction 83 5.2 Physiochemical Properties of Hydrophobic DESs 84 5.2.1 Density 85 5.2.2 Viscosity 86 5.3 Thermal Stability Window 86 5.4 Applications of Hydrophobic DESs 87 5.4.1 The Extraction of Fatty Acids and Biomolecules from Water 87 5.4.2 The Removal of Transition Metal Ions from Water 89 5.4.3 Impregnation in Membranes 90 5.4.4 The Removal of Pesticides from Water 90 5.4.5 CO2 Capture 90 5.5 Prediction of the Hydrophobic DESs Phase Behavior 91 5.5.1 The Use of PC‐SAFT 91 5.6 Outlook and Recommendations 92 Abbreviations 92 References 93 6 Deep Eutectic Solvents: Exploring Their Role in Nature 95 Rita Craveiro, Francisca Mano, Alexandre Paiva, and Ana Rita C. Duarte 6.1 (Introduction) DES in Nature 95 6.2 Honey 97 6.2.1 Behind Beehive: How Honey is Really Produced? 98 6.2.2 Honey and Its Properties 99 6.2.3 Honey as the First THEDES 99 6.3 Maple Syrup: How is Maple Syrup Produced? 100 6.3.1 Maple Syrup Nutraceutical Value 101 6.3.2 Maple Syrup and NADES 102 6.4 Sugar Beet 102 6.5 Resurrection Plants 106 6.6 Summary and Conclusions 107 Abbreviations 107 Acknowledgments 108 References 108 7 Organic Synthesis in DESs 111 Filippo M. Perna, Paola Vitale, and Vito Capriati 7.1 Introduction 111 7.2 DESs in Organocatalysis 112 7.3 DESs in the Synthesis of Heterocycles 116 7.3.1 Synthesis of Nitrogen‐ or Nitrogen‐ and Oxygen‐Containing Rings in DESs 117 7.3.2 Synthesis of Thiophenes in DESs 119 7.3.3 Synthesis of Benzo‐Condensed Rings in DESs 120 7.4 Multicomponent Reactions in DESs 123 7.4.1 Multicomponent Reactions in the Synthesis of Heterocycles 123 7.4.2 Synthesis of Betti Bases in DESs 128 7.4.3 Ugi and Passerini Reactions 128 7.5 Miscellaneous Transformations in DESs 129 7.6 Conclusion and Perspective 130 Abbreviations 131 References 132 8 DES as Catalyst 135 Mehran Shahiri‐Haghayegh and Najmedin Azizi 8.1 Introduction 135 8.2 DES Promoted Organic Transformations 136 8.2.1 Fischer Indole Synthesis 136 8.2.2 Carbon–Carbon Bond Formation 138 8.2.3 Synthesis of Pyrroles 141 8.2.4 Oxidation Reactions 141 8.2.5 “Green” Multicomponent Reactions 142 8.2.5.1 Isocyanide‐Based MCRs 143 8.2.5.2 Mannich‐Type Reactions 144 8.2.5.3 Biginelli Reaction 147 8.2.5.4 Synthesis of Chromene, Pyran, and Spiroxindole Derivatives 149 8.2.5.5 Multicomponent Synthesis of Pyrrole and Pyrazole 149 8.2.5.6 Synthesis of Quinazoline 153 8.2.5.7 A3‐Coupling Reaction 153 8.3 Desulfurization of Fuels 154 8.3.1 Olefin Alkylation of Thiophenic Sulfur 155 8.3.2 Oxidative Desulfurization of Fuels 156 8.4 Biodiesel Production 157 8.4.1 Transesterification of Triglycerides 158 8.4.2 Esterification of Free Fatty Acids 159 8.4.3 Hydrolysis/Dehydration of Carbohydrates 160 8.5 CO2 Chemical Fixation 161 8.6 Chemical Recycling of Polymers 163 8.7 Epoxy Resin Crosslinking 165 8.8 Supramolecular Macrocyclic Host Synthesis 166 8.9 Conclusion 166 References 167 9 Metal‐Promoted Organic Transformation in DES 171 Cristian Vidal and Joaquin Garcia‐Alvarez 9.1 Introduction 171 9.2 Design of New Synthetic Sustainable Organic Procedures Coupling Deep Eutectic Solvents and Highly‐Polarized Organometallic Reagents (RLi and RMgX) 173 9.3 Transition‐Metal‐Catalyzed Organic Reactions in Deep Eutectic Solvents 177 9.3.1 Palladium Catalyzed C–C Coupling Reactions in DESs 177 9.3.2 Ruthenium Catalyzed Isomerization of Allylic Alcohols and Design of One‐Pot Tandem Reactions in DESs 179 9.3.3 Gold Catalyzed Cycloisomerizations of Unsaturated Organic Substrates in DESs 180 9.4 Summary and Conclusions 181 Abbreviations 182 Acknowledgments 182 References 183 10 Polymerizations 187 Josue D. Mota‐Morales 10.1 Introduction 187 10.2 Deep Eutectic Solvents and Green Chemistry 188 10.3 The Role of Deep Eutectic Solvents in Polymerizations 189 10.3.1 Polymerizations Carried Out in Deep Eutectic Solvents 189 10.3.2 Polymerization of Monomers Containing Deep Eutectic Solvents: DES Monomers 191 10.3.3 DES as Cosolvents and Auxiliaries in Polymerizations 192 10.3.4 Cooperative Hydrogen Bonding Network of Water Added to DESs 194 10.4 Mechanisms of Polymerization Explored 194 10.4.1 Polycondensation 194 10.4.2 Free‐Radical Polymerization 197 10.4.3 Ring Opening Polymerization 207 10.4.4 Other Mechanisms of Polymerizations 209 10.5 Outlook and Future Directions 210 Abbreviations 212 References 212 11 Extraction of Bioactive Compounds 217 Mohamad H. Zainal‐Abidin, Maan Hayyan, Gek C. Ngoh, Won F. Wong, and Adeeb Hayyan 11.1 Introduction 217 11.2 The Main Features of DESs as an Extractive Agent 218 11.2.1 Effect of Water Addition on Extraction Efficiency 219 11.3 DESs in the Bioactive Compound Extractions 221 11.3.1 Phenolic Compounds 222 11.3.1.1 Flavonoid Compounds 225 11.3.2 Polysaccharides 226 11.3.3 Proteins 227 11.3.4 Hydrophobic Compounds 228 11.4 Summary 230 Abbreviations 230 References 231 12 Processing of Biomass in Deep Eutectic Solvents 235 Miao Zuo, Xianhai Zeng, Yong Sun, Xing Tang, and Lu Lin 12.1 Introduction 235 12.2 Chemical Process of Products Extraction from Biomass in DESs 235 12.2.1 Extraction and Solubility of Lignocellulose in DESs 235 12.2.2 Value‐Added Products Extraction from Biomass in DESs 238 12.3 Modification of Cellulose in DESs 240 12.4 Catalytic Conversion of Carbohydrates in DESs 242 12.4.1 Catalytic Conversion of Carbohydrates in Neat DESs 242 12.4.2 HMF Production from Carbohydrates in Bio‐Based DESs 244 12.4.3 Carbohydrates Dehydration in Biphasic DES/Organic Solvent Systems 246 12.4.4 Carbohydrates Dehydration to Other Value‐Added Products in DESs 249 12.5 Conclusions and Prospects 251 Abbreviations 252 Acknowledgments 252 References 253 13 Enzyme Catalysis: In DES, with DES, and in the Presence of DES 257 Pablo Dominguez de Maria, Nadia Guajardo, and Selin Kara 13.1 DESs as “Non‐Conventional Media” and “Non‐Conventional Solutions” for Biocatalysis 257 13.2 Hydrolases and Deep Eutectic Solvents 259 13.3 Oxidoreductases and Deep Eutectic Solvents 264 13.4 Other Biocatalytic Concepts in Deep Eutectic Solvents 266 13.5 Conclusions 267 Abbreviations 268 References 268 14 Nanoscale and Functional Materials 273 Diego A. Alonso, Alejandro Baeza, Rafael Chinchilla, Cecilia Gomez, and Isidro M. Pastor 14.1 Introduction 273 14.2 Nanoparticulated Materials 274 14.3 Nanofilms and Nanolayers 282 14.4 Carbonaceous Materials 283 14.5 Porous Materials 287 14.6 DNA Manipulation 290 14.7 Summary and Conclusions 291 Abbreviations 292 References 292 15 Carbon Dioxide Capture 297 Yingying Zhang, Xiaohua Lu, and Xiaoyan Ji 15.1 Introduction 297 15.2 Properties of DESs 299 15.2.1 Thermophysical Properties 299 15.2.1.1 Gas Solubility 299 15.2.1.2 Viscosity 305 15.2.1.3 Molar Heat Capacity 309 15.2.2 Kinetic Property 312 15.3 Screening and Evaluation of DESs for CO2 Separation 313 15.3.1 Property‐Based Method 313 15.3.2 Thermodynamic Analysis‐Based Method 313 15.3.3 Process Simulation‐Based Method 314 15.4 Further Conversion with DESs 314 15.5 Conclusions 314 Abbreviations 315 References 316 16 DES‐Mediated Approaches Toward Green Analytical Chemistry 321 Federico J.V. Gomez, Magdalena Espino, Maria de los A. Fernandez, Joana Boiteux, and Maria F. Silva 16.1 Introduction 321 16.2 Extraction Techniques and Deep Eutectic Solvents 323 16.2.1 Ultrasound Assisted Extraction (UAE) 324 16.2.2 Microwave Assisted Extraction (MAE) 325 16.2.3 Liquid Phase Microextraction (LPME) 325 16.2.4 Solid Phase Microextraction (SPME) 326 16.3 Separation Techniques and DES 326 16.3.1 Gas Chromatography and DES 327 16.3.2 Liquid Chromatography and DES 327 16.3.3 Capillary Electrophoresis and DES 328 16.4 DES Detection Techniques Compatibility 328 16.5 Future Trends and Challenges for Green Solvents in Analytical Chemistry 330 Abbreviations 331 Acknowledgments 332 References 332 17 Electrochemistry 335 Zhimin Xue, Wancheng Zhao, and Tiancheng Mu 17.1 Introduction 335 17.2 Conductivity 336 17.3 Electrochemical Stability 347 17.4 Electrochemical Applications 350 17.4.1 Electrodeposition 350 17.4.2 Electropolishing 357 17.5 Summary and Conclusions 359 Abbreviations 359 Acknowledgments 360 References 360 Index 363

About the Author :
Diego J. Ram??n is full professor at the University of Alicante, Spain, since 2010. His current research interests lie in the eld of organometallic chemistry and asymmetric synthesis. Gabriela Guillena is full professor and Head of the Department of Organic Chemistry at the University of Alicante, Spain. Her research is focused on new methodologies and asymmetric organocatalysis.