Recoverable and Recyclable Catalysts

Recoverable and Recyclable Catalysts

There is continued pressure on chemical and pharmaceutical industries to reduce chemical waste and improve the selectivity and efficiency of synthetic processes. The need to implement green chemistry principles is a driving force towards the development of recoverable and recyclable catalysts.

The design and synthesis of recoverable catalysts is a highly challenging interdisciplinary field combining chemistry, materials science engineering with economic and environmental objectives. Drawing on international research and highlighting recent developments, this book serves as a practical guide for both experts and newcomers to the field.

Topics covered include:

• An introduction to the principles of catalyst recovery and recycling
• Catalysts on insoluble and soluble support materials
• Thermomorphic catalysts, self-supported catalysts and perfluorous catalytic systems
• The development of reusable organic catalysts
• Continuous flow and membrane reactors

Each chapter combines principles with practical information on the synthesis of catalysts and strategies for catalyst recovery. The book concludes with a comparison of different catalytic systems, using case studies to illustrate the key features of each approach.

Recoverable and Recyclable Catalysts is a valuable reference source for academic researchers and professionals from a range of pharmaceutical and chemical industries, particularly those working in catalysis, organic synthesis and sustainable chemistry.

Preface xiii

Acknowledgements xv

Contributors xvii

1 The Experimental Assay of Catalyst Recovery: General Concepts 1
John A. Gladysz

1.1 Introduction 1

1.2 Catalyst Precursor vs Catalyst 2

1.3 Catalyst vs Catalyst Resting State 3

1.4 Catalyst Inventory: Loss Mechanisms 5

1.4.1 Catalyst Decomposition 5

1.4.2 Catalyst Leaching 7

1.5 Evaluation of Catalyst Recovery 8

1.5.1 Product Yield, Conversion, or TON as a Function of Cycle: Poor and Potentially Deceptive Criteria 8

1.5.2 Reaction Rate or TOF as a Function of Cycle 9

1.5.3 Gravimetric and Other Assays of Recovered Catalyst 12

1.5.4 Special Caveats when ‘Residues’ are Recycled 13

1.6 Prospective 13

References 14

2 Surface-functionalized Nanoporous Catalysts for Renewable Chemistry 15
Brian G. Trewyn, Hung-Ting Chen and Victor S.-Y. Lin

2.1 Introduction 15

2.1.1 Homogeneous Catalysis vs Heterogeneous Catalysis 16

2.1.2 Multi-Site vs Single-Site Heterogeneous Catalysis 16

2.2 Immobilization Strategies of Heterogeneous Catalysts 17

2.2.1 Supported Materials 17

2.2.2 Conventional Methods to Functionalize Silica Surfaces 18

2.2.3 Alternative Synthesis of Immobilized Complex Catalysts on a Solid Support 25

2.2.4 Techniques for Characterization of Heterogeneous Catalysts 26

2.3 Efficient Heterogeneous Catalysts with Enhanced Reactivity and Selectivity with Functionality 26

2.3.1 Surface Interaction of Silica and Immobilized Homogeneous Catalysts 26

2.3.2 Introduction of Functionalities and Control of Silica Support Morphology 29

2.3.3 Selective Surface Functionalization of Solid Support for Utilization of Nanospace Inside the Porous Structure 31

2.3.4 Cooperative Catalysis by Multifunctionalized Heterogeneous Catalyst Systems 35

2.3.5 Mesoporous Mixed Metal Oxides for Heterogeneous Catalysts 43

2.4 Other Heterogeneous Catalyst Systems on Nonsilica Supports 44

2.5 Conclusion 45

References 45

3 Insoluble Resin-supported Catalysts 49
Gang Zhao and Zhuo Chai

3.1 Introduction 49

3.2 Transition Metal catalyzed c c Bond Formation Reactions 50

3.2.1 Pd-catalyzed Reactions 50

3.2.2 Asymmetric Additions of Organozinc Reagents to Aldehydes 53

3.2.3 Rh-catalyzed Asymmetric Intermolecular c H Activation 54

3.2.4 Cu-catalyzed Asymmetric Cyclopropanation 55

3.3 Oxidation 56

3.3.1 Oxidation of Sulfides to Sulfoxide 56

3.3.2 Oxidation of Alkanes, Alkenes and Alcohols 57

3.3.3 Epoxidation of Alkenes 58

3.3.4 Asymmetric Hydroformylation of Olefins 59

3.3.5 Asymmetric Dihydroxylation of Alkenes 60

3.4 Reduction 61

3.4.1 Asymmetric Reduction of Ketones 61

3.4.2 Reduction of Carboxamides to Amines 62

3.5 Organocatalyzed Reactions 62

3.5.1 Asymmetric Aldol Reaction and Aminoxylation 63

3.5.2 Asymmetric Tandem Reaction 64

3.5.3 Allylation of Aldehydes 65

3.5.4 Nucleophilic Substitution Reactions 66

3.6 Annulation Reactions 66

3.6.1 Cycloaddition 66

3.6.2 Intramolecular Hydroamination 68

3.7 Miscellaneous 70

3.8 Conclusion 72

References 72

4 Catalysts Bound to Soluble Polymers 77
Tamilselvi Chinnusamy, Petra Hilgers and Oliver Reiser

4.1 Introduction 77

4.2 Soluble Supports – General Considerations 78

4.3 Recent Developments of Soluble Polymer-supported Catalysts 79

4.3.1 Attachment of Catalysts to Polymer Supports 79

4.3.2 Polymer-bound Metal Catalysts – General Considerations 81

4.3.3 Polymer-bound Organocatalysts – General Considerations 81

4.4 Recent Examples for Reactions Promoted by Catalysts Bound to Soluble Polymers 81

4.4.1 Achiral Catalysts 81

4.4.2 Chiral Catalysts 88

4.5 Conclusion 98

List of Abbreviations 98

References 98

5 Polymeric, Recoverable Catalytic Systems 101
Qiao-Sheng Hu

5.1 Introduction 101

5.2 Polymeric Catalyst Systems 102

5.2.1 1,1 0 -Bi-2-naphthol (BINOL)-based Polymeric Catalytic Systems 102

5.2.2 Bisphosphine-containing Polymeric Catalyst Systems 103

5.2.3 Salen-containing Polymeric Catalytic Systems 108

5.2.4 BINOL–BINAP-based Bifunctional Polymeric Catalytic Systems 108

5.2.5 Dendrimer Catalyst Systems 110

5.2.6 Dendronized Polymeric Catalytic Systems 111

5.3 Summary 114

Acknowledgements 115

References 115

6 Thermomorphic Catalysts 117
David E. Bergbreiter

6.1 Introduction 117

6.2 Thermomorphic Catalyst Separation Strategies 118

6.3 Hydrogenation Reactions Under Thermomorphic Conditions 122

6.4 Hydroformylation Reactions Under Thermomorphic Conditions 126

6.5 Hydroaminations Under Thermomorphic Conditions 129

6.6 Pd-catalyzed Reactions Under Thermomorphic Conditions 130

6.6.1 Pd-catalyzed Allylic Substitution Under Thermomorphic Conditions 130

6.6.2 Pd-catalyzed Cross-coupling Reactions Under Thermomorphic Conditions 131

6.7 Polymerization Reactions Under Thermomorphic Conditions 138

6.8 Organocatalysis Under Thermomorphic Conditions 142

6.9 Cu(I)-catalyzed 1,3-Dipolar Cycloadditions Under Thermomorphic Conditions 144

6.10 Thermomorphic Hydrosilylation Catalysts 144

6.11 Thermomorphic Catalytic Oxidations 145

6.12 Conclusions 147

References 147

7 Self-supported Asymmetric Catalysts 155
Wenbin Lin and David J. Mihalcik

7.1 Introduction 155

7.2 Self-supported Asymmetric Catalysts Formed by Linking Catalytically Active Subunits via Metal–Ligand Coordination 156

7.3 Self-supported Asymmetric Catalysts Formed by Post-synthetic Modifications of Coordination Polymers 163

7.4 Self-supported Asymmetric Catalysts Formed by Linking Multitopic Chiral Ligands with Catalytic Metal Centers 168

7.5 Conclusions and Outlook 172

Acknowledgments 174

References 174

8 Fluorous Chiral Catalyst Immobilization 179
Tibor Soos

8.1 Introduction 179

8.2 Fluorous Chemistry and its Basic Recovery Concepts 180

8.3 Application of Fluorous Chiral Catalysts 181

8.3.1 Fluorous Nitrogen Ligands 182

8.3.2 Fluorous Oxygen Ligands 192

8.3.3 Phosphorous Ligands 194

8.4 Summary 196

References 197

9 Biphasic Catalysis: Catalysis in Supercritical CO2 and in Water 199
Simon L. Desset and David J. Cole-Hamilton

9.1 Introduction 199

9.2 Biphasic Catalysis 200

9.3 Aqueous Biphasic Catalysis 202

9.3.1 Introduction 202

9.3.2 Aqueous Biphasic Catalysis: Beyond Mass Transfer 203

9.3.3 Additives 203

9.3.4 Surface-active Ligands 212

9.3.5 Homogeneous Reaction with Biphasic Separation 214

9.3.6 Supported Aqueous Phase Catalysis (SAPC) 220

9.3.7 New Reactor Design 227

9.3.8 Conclusion 228

9.4 Supercritical Carbon Dioxide 229

9.4.1 Introduction 229

9.4.2 Supercritical Carbon Dioxide for Catalyst Recycling 230

9.5 Conclusion 246

References 247

10 Asymmetric Catalysis in Ionic Liquids 259
Lijin Xu and Jianliang Xiao

10.1 Introduction 259

10.2 Metal-catalyzed Asymmetric Reactions in ILs 261

10.2.1 Asymmetric Hydrogenation 261

10.2.2 Asymmetric Transfer Hydrogenation 270

10.2.3 Asymmetric Oxidation 271

10.2.4 Asymmetric c c Bond Formation 275

10.2.5 Miscellaneous Reactions 283

10.3 Asymmetric Organocatalytic Reactions in ILs 287

10.3.1 Asymmetric Aldol Reactions 287

10.3.2 Asymmetric Michael Addition 290

10.3.3 Asymmetric Diels–Alder Reaction 292

10.3.4 Asymmetric Mannich Reaction 292

10.3.5 Asymmetric Baylis–Hillman Reaction 293

10.4 Concluding Remarks 294

References 295

11 Recoverable Organic Catalysts 301
Maurizio Benaglia

11.1 Introduction 301

11.2 Achiral Organic Catalysts 304

11.2.1 Oxidation Catalysts 304

11.2.2 Phase Transfer Catalysts 307

11.2.3 Miscellaneous Catalysts 309

11.3 Chiral Organic Catalysts 311

11.3.1 Phase Transfer Catalysts 311

11.3.2 Lewis Base Catalysts 313

11.3.3 Miscellaneous Catalysts 319

11.4 Catalysts Derived from Amino Acids 319

11.4.1 Proline Derivatives 320

11.4.2 Amino Acid-derived Imidazolinones 328

11.4.3 Other Amino Acids 331

11.5 General Considerations on Recyclable Organocatalysts 334

11.6 Outlook and Perspectives 336

References 337

12 Organic Polymer-microencapsulated Metal Catalysts 341
Jun Ou and Patrick H. Toy

12.1 Introduction 341

12.2 Non-cross-linked Polymer-microencapsulated Catalysts 342

12.2.1 Non-cross-linked Polystyrene 342

12.2.2 Non-cross-linked Polystyrene Derivatives 350

12.2.3 Polysulfone 353

12.2.4 Poly(xylylviologen dibromide) 354

12.3 Cross-linked Polymer-microencapsulated Catalysts 355

12.3.1 Divinyl Benzene Cross-linked Polystyrene 355

12.3.2 Oligo(ethylene glycol) Cross-linked Polystyrene 357

12.3.3 Urea Group Cross-linked Polyphenylene 367

12.4 Summary Table 374

12.5 Conclusions 375

References 375

13 Organic Synthesis with Mini Flow Reactors Using Immobilised Catalysts 379
Sascha Ceylan and Andreas Kirschning

13.1 Introduction 379

13.1.1 General Remarks 379

13.1.2 Batch versus Flow Processes 380

13.1.3 Micro versus Mini Flow Reactors 381

13.2 Catalysis in Mini Flow Reactors with Immobilised Catalysts 382

13.2.1 Solid Supports Based on Silica 382

13.2.2 Solid Supports Based on Polymers 387

13.2.3 Monolithic Supports 392

13.2.4 Immobilisation on Membranes 401

13.3 Miscellaneous Enabling Techniques for Mini Flow Systems 404

13.3.1 Ionic Liquids as Media for Immobilisation 404

13.3.2 Inductive Heating – a New Technique for Mini Flow Processes 404

13.4 Perspectives and Outlook 406

References 407

14 Homogeneous Catalysis Using Microreactor Technology 411
Johan C. Brandt and Thomas Wirth

14.1 Introduction 411

14.2 Acid-catalysed Reactions 411

14.3 Liquid–liquid Biphasic Systems 413

14.4 Photocatalysis 418

14.5 Asymmetric Catalytic Reactions 421

14.6 Unusual Reaction Conditions 421

References 423

15 Catalyst Immobilization Strategy: Some General Considerations and a Comparison of the Main Features of Different Supports 427
Franco Cozzi

15.1 Introduction 427

15.2 General Considerations on Catalyst Immobilization 428

15.2.1 Prerequisite Conditions for Immobilization 428

15.2.2 Reasons Justifying Immobilization 433

15.2.3 A General Discussion on the Practical Aspects of Immobilization 437

15.3 Comparison of Different Supports Employed for the Immobilization of Proline 442

15.3.1 Organic Supports 442

15.3.2 Inorganic Supports 450

15.4 Comparison of Different Supports Employed for the Immobilization of Bis(oxazolines) 452

15.4.1 Noncovalent Immobilization 452

15.4.2 Covalent Immobilization 453

15.5 Conclusions 458

References 458

Index 463

"This book is most appropriate for researchers or graduate students who are familiar with the area of asymmetric catalysis and seek to become more involved in this important area of research." (The Quarterly Review of Biology, 1 March 2011)

"A substantial resource for those who do process development and scale-up work." (Organic Chemistry Portal, March 2010)

Maurizio Benaglia is Associate Professor at the Department of Organic and Industrial Chemistry, University of Milan, Italy. He is author of over ninety publications in international scientific journals, including five review articles. His current research focuses on stereoselective reactions, synthesis of chiral supramolecular systems, synthesis of supported organometallic and metal-free catalysts, and design and synthesis of new chiral catalysts, and environmentally pure catalysts. Recoverable and Recyclable Catalysts

There is continued pressure on chemical and pharmaceutical industries to reduce chemical waste and improve the selectivity and efficiency of synthetic processes. The need to implement green chemistry principles is a driving force towards the development of recoverable and recyclable catalysts.

The design and synthesis of recoverable catalysts is a highly challenging interdisciplinary field combining chemistry, materials science engineering with economic and environmental objectives. Drawing on international research and highlighting recent developments, this book serves as a practical guide for both experts and newcomers to the field.

Topics covered include:

• An introduction to the principles of catalyst recovery and recycling
• Catalysts on insoluble and soluble support materials
• Thermomorphic catalysts, self-supported catalysts and perfluorous catalytic systems
• The development of reusable organic catalysts
• Continuous flow and membrane reactors

Each chapter combines principles with practical information on the synthesis of catalysts and strategies for catalyst recovery. The book concludes with a comparison of different catalytic systems, using case studies to illustrate the key features of each approach.

Recoverable and Recyclable Catalysts is a valuable reference source for academic researchers and professionals from a range of pharmaceutical and chemical industries, particularly those working in catalysis, organic synthesis and sustainable chemistry.