In-Situ Nitroxide-Mediated Radical Polymerization (NMP) Processes:  Their Understanding and Optimization

Abstract

Introduction 1104 2. Common Radical Synthesis of Alkoxyamines Active in NMP 1106 3. Nitrones: Precursors of Nitroxides for the Synthesis of Alkoxyamines and in-Situ NMP 1107 3.1. Nitrones as Precursors of Nitroxides 1107 3.2. Contributions of Nitrones to the in-Situ NMP 1107 3.3. Cyclic Oxazolidine as Initiator and Regulator for the Radical Polymerization of Vinyl Monomers 1111 3.4. Advantages and Drawbacks of the Nitrone Systems 1112 4. Nitroso Compounds 1112 4.1. Reaction of C-Nitroso Compounds with Free Radicals 1112 4.2. Use of C-Nitroso Compounds in Controlled Radical Polymerization 1113 4.3. Limitations of C-Nitroso Compounds 1116 5. Sodium Nitrite and NO/NO 2 Mixtures for the in-Situ NMP 1116 5.1. Preliminary Results and Mechanistic Considerations 1116 5.2. Controlled Radical Polymerization of Alkyl Methacrylates in the Presence of the in-Situ-Formed R-Nitro-ω-nitroso Adducts 1117 5.3. NO/NO 2 Mixtures: An Alternative Way to the Nitroso Compounds as Precursors of Nitroxides 1118 5.4. Advantages and Limitations of the Sodium Nitrite and NO/NO 2 Systems 1118 6. Hindered Secondary Amines and the in-Situ NMP 1118 6.1. Oxidation of Secondary Amines into Nitroxides 1118 6.2. One-Pot Processes for the Preparation of Alkoxyamines Active in NMP 1118 6.3. In-Situ NMP Using Hindered Secondary Amines and Oligomeric Secondary Amines 1120 6.4. Advantages and Limitations 1120 7. Hydroxylamines and the in-Situ NMP 1120 7.1. Oxidation of Hydroxylamines into Nitroxides 1120 7.2. Hydroxylamines and the in-Situ NMP 1120 7.3. High Molecular Weight Hydroxylamines for the Polymerization of Vinyl Monomers and Synthesis of Block Copolymers 1122 7.4. Advantages and Limitations 1122 8. Conclusions 1122 9. Acknowledgments 1123 10. References 1123

Living Radical Polymerization by the RAFT Process – A Third Update

“…The transfer agent-derived radical (R ) is also partitioned between adding to monomer and reacting with the macro-RAFT agent (3). We therefore define a rate coefficient associated with this reaction (k Àtr ) as shown in Eqn 2.…”

“…The initial RAFT agents (1) and the polymer RAFT agent (3) should have a reactive C¼S double bond (high k add ). The intermediate radicals (2) and (4) should fragment rapidly (high k b , weak S-R bond in intermediate) and give no side reactions.…”

“…New materials with the potential of revolutionizing a large part of the polymer industry continue to appear. The polymerization techniques that are receiving greatest attention are nitroxidemediated polymerization (NMP), [3][4][5][6] atom transfer radical polymerization (ATRP), [7][8][9][10][11] and reversible additionfragmentation chain transfer (RAFT).…”

In situ bidentate to tetradentate ligand exchange reaction in cobalt-mediated radical polymerization

“…Controlled radical polymerization CRP has become an important tool for the preparation of well-defined polymer materials [1][2][3][4][5][6][7][8][9]. The use of organometallic complexes was a significant step towards the development of CRP of various vinylic monomers [1,[9][10][11][12].…”

Recent developments in metal-catalyzed living radical polymerization

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Besides these metal catalytic systems, there have also been substantial developments in various living radical polymerizations, such as nitroxide-mediated polymerizations, reversible addition fragmentation chain-transfer polymerizations and others, and in all of these, there are characteristic features of the mechanisms and components. [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] The metal-catalyzed living radical polymerization was originally discovered via evolution of the metal-catalyzed Kharasch or atom transfer radical addition reaction 35 to the chain-growth polymerization of vinyl monomers ( Figure 1). 1 The initiating system generally consists of a transition metal complex in a lower oxidation state and an organic halide, in which the carbon-halogen bond of the halogen compound is activated by the metal catalyst to generate the carbon radical species upon a one-electron oxidation of the metal complex associated with the abstraction of the halogen by the metal species.…”