1. Group Transfer Polymerization (GTP) Sujoy Saha (20101095) Nikhil Y. L. K. (2009004)

2. Brief Overview Introduction Discovery of Method Synthetic Routes Mechanisms: Then and Now Applications Pros and Cons Paper (2) Conclusion

3. Introduction conjugate addition of silyl ketene acetals to ,unsaturated carbonyl compounds Organic Chemistry, Clayden, p-755 Applied to alkylated methacrylate monomers and the initiator is a silyl ketene acetal. New monomer adds to the initiator and to the active growing chain in a Michael rxn. Discovered over 30 years ago at Anionic living polymerization- but active chain end is covalent

4. Discovery- A Story Webster et al at DuPonts Central R&D Methacrylate block polymers useful in automobile finishes. at -80C by sequential polymerization of different methacrylate monomers under living anionic conditions. maintaining reactors at -80C !!!

5. living anionic polymerization of methyl methacrylate with a 1,1- diphenylhexyl anion containing a silyl protected OH. trimethylsilyl ketene acetal could react with MMA to give polymer by a repetitive Mukiayama reaction.. few unsuccessful reactions with Lewis acids such as BF3 etherate First production of PMMA by group transfer polymerization with ZnBr2 catalyst Name suggested by Trost Discovery- A Story

6. Synthetic Routes Always start with conjugate addition of silyl ketene acetal initiators Monomer: Methacrylates, Acrylates, Ketones, Nitriles, Carboxamides -Nucleophilic Anions KHF2 TASHF2 Bu4NF TASCN Et4NCN TASN3 -Lewis Acids ZnBr2 ZnI2 ZnCl2 (i-Bu2Al)2O i-Bu2AlCl Et2AlCl Webster et al., J. Am. Chem. Soc. 1983, 105, 5706-5708 Sogah et al., Macromolecules, Vol. 20, No. 7, 1987 Catalysts: Two choices

7. Mechanisms

8. Pros and Cons Advantages 1. Good for making blocks of acrylates and methacrylates 2. Can be done at RT and elevated T 3. Excellent architectural control (stars, blocks, etc.) 4. Low PDIs (can get down to 1.03!) 5. No metallic or halide impurities left over 6. No bad odors! Disadvantages 1. Cannot be done in presence of water 2. Initiator still costly 3. Cannot use monomers with acidic or active hydrogen functional groups

9. Spinelli, H.J. Prog. Org. Coat. 1996, 27, 255-260 Applications Pigment Dispersant Emulsion Stabilizers AB block co-polymer A = Hydrophilic Block B = Hydrophobic Block H2O H2O H2O H2O

10. Spinelli, H.J. Prog. Org. Coat. 1996, 27, 255-260 Applications Pigment Dispersant Emulsion Stabilizers AB block co-polymer A = Hydrophilic Block B = Hydrophobic Block H2O H2O H2O H2O

11. Group Transfer Polymerization of Acrylates and Methacrylates using N-hetereocyclic Carbene Catalysts - Scholten et al., Polymer Preprints 2007, 48(2),167 N-heterocyclic carbenes (NHCs) as potent catalysts for GTP of methyl methacrylate and tert-butyl acrylate

12. Conc: NHCs demonstrate equivalent activity and superior control in comparison to bifluoride-catalyzed systems. Results

13. Group transfer polymerization of biobased unsaturated esters -E. Kassi et al./ European Polymer Journal 49 (2013) 761767 (As the fossil resources dwindle) concerned with organic synthetic building blocks.

14. Group transfer polymerization of biobased unsaturated esters -E. Kassi et al./European Polymer Journal 49 (2013) 761767 (As the fossil resources dwindle) concerned with organic synthetic building blocks.

15. Polymerization of Itaconic Acid esters can be obtained from distillation of citric acid. Attempted random block copolymerization of the pairs di(n-butyl)itaconate (DBI) with methyl methacrylate (DBI-MMA) and 2-(dimethylamino)ethyl methacrylate (DBI-MAEMA) Products were just DBI oligomers, whereas MMA and DMAEMA were not consumed. This indicated the greater reactivity of DBI compared to the methacrylates.

16. attachment of 12 DBI units to the second short block of DMAEMA DMAEMA-DBI combination corresponds to amphiphilic block copolymers capable of forming micelles in water Conc: nature designed unsaturated compounds are not inert Polymerization of Itaconic Acid esters

17. Conclusion Relatively new quasi- living oxyanionic polymerization technique, capable of the rapid, room-temperature polymerization of ,-unsaturated carbonyl compounds. Full of potential, still room for improvement Best method around for block polymers of methacrylate derivatives