Preface ...................................................... XIII
1. Introduction ................................................. 1
1.1. Green Chemistry and Sustainable Development ............. 1
1.1.1. What is "Green Chemistry"? ....................... 2
1.1.2. Quantifying Environmental Impact: Efficiency,
E-factors, Atom Economy .......................... 4
1.1.3. Just How "Green" is this Process? ................ 6
1.1.4. Product and Process Life-Cycle Assessment
(LCA) ............................................ 9
1.2. What is Catalysis and Why is it Important? ............. 10
1.2.1. Homogeneous Catalysis, Heterogeneous
Catalysis, and Biocatalysis ..................... 12
1.2.2. Replacing Stoichiometric Reactions with
Catalytic Cycles ................................ 19
1.2.3. Industrial Example: The BHC Ibuprofen Process ... 22
1.3. Tools in Catalysis Research ............................ 23
1.3.1. Catalyst Synthesis and Testing Tools ............ 24
1.3.2. Catalyst Characterization Tools ................. 26
1.3.3. Tools for Modeling/Mechanistic Studies .......... 28
1.4. Further Reading ........................................ 29
1.5. Exercises .............................................. 31
References ............................................. 35
2. The Basics of Catalysis ..................................... 39
2.1. Catalysis is a Kinetic Phenomenon ...................... 39
2.1.1. Reaction Rates, Reaction Orders, Rate
Equations, and Rate-Determining Steps ........... 40
2.1.1.1. The Reaction Order ..................... 42
2.1.1.2. The Rate-Determining Step .............. 43
2.1.2. The Reaction Profile and the Reaction
Coordinate ...................................... 44
2.1.3. Zero-Order, First-Order, and Second-Order
Kinetics ........................................ 46
2.1.3.1. Zero-Order Rate Equations .............. 46
2.1.3.2. First-Order Rate Equations ............. 47
2.1.3.3. Second-Order Rate Equations ............ 48
2.1.4. Langmuir-Hinshelwood Kinetics ................... 49
2.1.5. The Steady-State Approximation .................. 52
2.1.6. Michaelis-Menten Kinetics ....................... 54
2.1.7. Consecutive and Parallel First-Order
Reactions ....................................... 56
2.1.8. Pre-Equilibrium, "Catalyst Reservoirs,"
and Catalyst Precursors ......................... 58
2.2. Practical Approaches in Kinetic Studies ................ 60
2.2.1. Initial Reaction Rates and Concentration
Effects ......................................... 61
2.2.1.1. Concentration Effects .................. 62
2.2.2. Creating Pseudo Order Conditions ................ 62
2.2.3. What You See versus What You Get ................ 63
2.2.4. Learning from Stoichiometric Experiments ........ 64
2.3. An Overview of Some Basic Concepts in Catalysis ........ 64
2.3.1. Catalyst/Substrate Interactions and
Sabatier's Principle ............................ 65
2.3.2. Catalyst Deactivation, Sintering, and Thermal
Degradation ..................................... 66
2.3.2.1. Catalyst Deactivation .................. 66
2.3.2.2. Catalyst Sintering and Thermal
Degradation ............................ 66
2.3.3. Catalyst Inhibition ............................. 68
2.3.3.1. Catalyst Poisoning ..................... 69
2.4. Exercises .............................................. 69
References ............................................. 73
3. Homogeneous Catalysis ....................................... 77
3.1. Metal Complex Catalysis in the Liquid Phase ............ 77
3.1.1. Elementary Steps in Homogeneous Catalysis ....... 78
3.1.1.1. Ligand Exchange: Dissociation and
Coordination ........................... 79
3.1.1.2. Oxidative Addition ..................... 81
3.1.1.3. Reductive Elimination .................. 83
3.1.1.4. Insertion and Migration ................ 84
3.1.1.5. De-insertion and P-Elimination ......... 85
3.1.1.6. Nucleophilic Attack on a Coordinated
Substrate .............................. 85
3.1.1.7. Other Reaction Types ................... 86
3.1.2. Structure/Activity Relationships in
Homogeneous Catalysis ........................... 88
3.1.2.1. Steric Effects: Ligand Size,
Flexibility, and Symmetry .............. 88
3.1.2.2. Electronic Effects of Ligands,
Substrates, and Solvents ............... 92
3.1.3. Asymmetric Homogeneous Catalysis ................ 93
3.1.4. Industrial Examples ............................. 96
3.1.4.1. The Shell Higher Olefins Process
(SHOP) ................................. 97
3.1.4.2. The Wacker Oxidation Process ........... 99
3.1.4.3. The Du Pont Synthesis of
Adiponitrile .......................... 100
3.1.4.4. The Ciba-Geigy Metolachlor Process .... 102
3.2. Homogeneous Catalysis without Metals .................. 104
3.2.1. Classic Acid/Base Catalysis .................... 104
3.2.2. Organocatalysis ................................ 105
3.3. Scaling up Homogeneous Reactions: Pros and Cons ....... 108
3.3.1. Catalyst Recovery and Recycling ................ 108
3.3.2. Hybrid Catalysts: Bridging the
Homogeneous/Heterogeneous Gap .................. 110
3.4. "Click Chemistry" and Homogeneous Catalysis ........... 111
3.5. Exercises ............................................. 113
References ............................................ 117
4. Heterogeneous Catalysis .................................... 127
4.1. Classic Gas/Solid Systems ............................. 129
4.1.1. The Concept of the Active Site ................. 131
4.1.2. Model Catalyst Systems ......................... 132
4.1.3. Real Catalysts: Promoters, Modifiers, and
Poisons ........................................ 134
4.1.4. Preparation of Solid Catalysts: Black Magic
Revealed ....................................... 135
4.1.4.1. High-Temperature Fusion and Alloy
Leaching .............................. 137
4.1.4.2. Slurry Precipitation and
Co-precipitation ...................... 138
4.1.4.3. Impregnation of Porous Supports ....... 139
4.1.4.4. Hydrothermal Synthesis ................ 139
4.1.4.5. Drying, Calcination, Activation,
and Forming ........................... 141
4.1.5. Selecting the Right Support .................... 143
4.1.6. Catalyst Characterization ...................... 146
4.1.6.1. Traditional Surface Characterization
Methods ............................... 146
4.1.6.2. Temperature-Programmed Techniques ..... 149
4.1.6.3. Spectroscopy and Microscopy ........... 149
4.1.7. The Catalytic Converter: an Example from
Everyday Life .................................. 154
4.1.8. Surface Organometallic Chemistry ............... 156
4.2. Liquid/ Solid and Liquid/ Liquid Catalytic Systems .... 158
4.2.1. Aqueous Biphasic Catalysis ..................... 159
4.2.2. Fluorous Biphasic Catalysis .................... 161
4.2.3. Biphasic Catalysis Using Ionic Liquids ......... 163
4.2.4. Phase-Transfer Catalysis ....................... 164
4.3. Advanced Process Solutions Using Heterogeneous
Catalysis ............................................. 165
4.3.1. The BP AVADA Ethyl Acetate Process ............. 166
4.3.2. The ABB Lummus/Albemarle AlkyClean Process ..... 168
4.3.3. The IFP and Yellowdiesel Processes for
Biodiesel Production ........................... 168
4.3.4. The ABB Lummus/UOP SMART Process ............... 172
4.4. Exercises ............................................. 173
References ............................................ 177
5. Biocatalysis ............................................... 189
5.1. The Basics of Enzymatic Catalysis ..................... 190
5.1.1. Terms and Definitions - The Bio Dialect ........ 191
5.1.2. Active Sites and Substrate Binding Models ...... 194
5.1.3. Intramolecular Reactions and Proximity
Effects ........................................ 195
5.1.4. Common Mechanisms in Enzymatic Catalysis ....... 197
5.2. Applications of Enzyme Catalysis ...................... 199
5.2.1. Whole-Cell Systems versus Isolated Enzymes ..... 200
5.2.2. Immobilized Enzymes: Bona Fide Heterogeneous
Catalysis ...................................... 202
5.2.2.1. Binding Enzymes to Solid Supports...... 202
5.2.2.2. Trapping Enzymes in Polymers or
Sol/Gel Matrices ...................... 203
5.2.2.3. Cross-Linking of Enzymes .............. 204
5.2.3. Replacing "Conventional Routes" with
Biocatalysis ................................... 205
5.2.4. Combining "Bio" and "Conventional" Catalysis ... 207
5.3. Developing New Biocatalysts: Better than
Nature's Best ......................................... 210
5.3.1. Prospecting Natural Diversity .................. 210
5.3.2. Rational Design ................................ 211
5.3.3. Directed Evolution ............................. 211
5.4. Nonenzymatic Biocatalysts ............................. 213
5.4.1. Catalytic Antibodies (Abzymes) ................. 213
5.4.2. Catalytic RNA (Ribozymes) ...................... 214
5.5. Industrial Examples ................................... 215
5.5.1. High-Fructose Corn Syrup: 11 Million Tons
per Year ....................................... 215
5.5.2. The Mitsubishi Rayon Acrylamide Process ........ 217
5.5.3. The BMS Paclitaxel Process ..................... 218
5.5.4. The Tosoh/DSM Aspartame Process ................ 220
5.6. Exercises ............................................. 221
References ............................................ 224
6. Computer Applications in Catalysis Research ................ 231
6.1. Computers as Research Tools in Catalysis .............. 231
6.2. Modeling of Catalysts and Catalytic Cycles ............ 233
6.2.1. A Short Overview of Modeling Methods ........... 233
6.2.2. Simplified Model Systems versus Real
Reactions ...................................... 236
6.2.3. Modeling Large Catalyst Systems Using
Classical Mechanics ............................ 236
6.2.4. In-Depth Reaction Modeling Using Quantum
Mechanics ...................................... 238
6.3. Predictive Modeling and Rational Catalyst Design ...... 240
6.3.1. Catalysts, Descriptors, and Figures of Merit ... 241
6.3.2. Three-Dimensional (3D) Descriptors ............. 242
6.3.2.1. Comparative Molecular Field Analysis
(CoMFA) ............................... 243
6.3.2.2. The Ligand Repulsive Energy Method .... 244
6.3.3. Two-Dimensional (2D) Descriptors ............... 245
6.3.4. Generating Virtual Catalyst Libraries in
Space A ........................................ 248
6.3.5. Understanding Catalyst Diversity ............... 250
6.3.6. Virtual Catalyst Screening: Connecting
Spaces A, B, and С ............................. 253
6.3.7. Predictive Modeling in Heterogeneous
Catalysis ...................................... 255
6.3.8. Predictive Modeling in Biocatalysis ............ 256
6.4. An Overview of Data-Mining Methods in Catalysis ....... 257
6.4.1. Principal Components Analysis (PCA) ............ 259
6.4.2. Partial Least-Squares (PLS) Regression ......... 260
6.4.3. Artificial Neural Networks (ANNs) .............. 262
6.4.4. Classification Trees ........................... 264
6.4.5. Model Validation: Separating Knowledge from
Garbage ........................................ 264
6.4.5.1. Cross-Validation and Bootstrapping .... 265
6.4.5.2. Mixing the Dependent Variables
(γ-Randomizing) ....................... 266
6.4.5.3. Defining the Model Domain ............. 266
6.5. Exercises ............................................. 266
References ............................................ 268
Index ......................................................... 275
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