Monomer: NIPAM; Initiator: BiBB; Catalyst: CuBr; Ligand: PMDETA
I added CuBr and the mixture was blue, after that, I purged with nitrogen for 30 minutes and the mixture turned green. The mixture is placed in an oil bath for 2 hours, 5 hours, and 24 hours, open to the air to stop polymerization. I passed the mixture through alumina and the mixture was still green. I purified the crude with cold diethyl ether and I got blue liquid.
What's wrong during the reaction process? The (i) initial mixture was supposed to be green (CuBr) and (ii) the mixture should change to brown after degassing and (iii) white precipitate should be collected after purification
Dear Chan Min Min, no mention about the solvent! Water (and mixtures of it with organic solvents) has special features on NIPAM polymerization. Most probably the problems you encountered are due either to the unsolubility of the shorts oligomeric chains, which is the case when solvents such as alcohols are used, or to the fast uncontrolled reaction progress. Addition of small amount of water solve the problem. My Regards
10.1021/jp808905s
10.1021/bk-2009-1023.ch009
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