Toward an Efficient Process for the Cu(0)-Mediated Synthesis and Chain Extension of Poly(methyl acrylate) Macroinitiator Using PMDETA as Ligand

Me6TREN (tris[2-(dimethylamino)ethyl]amine) is commonly used in Cu(0)-mediated polymerization of acrylates due to its ability to promote high reaction rates while maintaining excellent control of chain growth. However, its cost presents a significant barrier to commercialization. Thus, the use of PMDETA (N,N,NMODIFIER LETTER PRIME,NMODIFIER LETTER PRIMEMODIFIER LETTER PRIME,NMODIFIER LETTER PRIMEMODIFIER LETTER PRIME-pentamethyldiethylenetriamine), a ligand that is significantly less expensive than Me6TREN but is known to reduce the polymerization rate as well as control, is explored. The continuous production of low molecular weight (MW) poly(methyl acrylate) using PMDETA ligand in a copper tubular reactor is demonstrated, with conversions >70% achieved with a residence time of 32 min at 70 degrees C. The resulting macroinitiator solution can be stored and chain extended with methyl acrylate (MA) to high conversion in a semibatch reactor using either PMDETA or Me6TREN as additional ligand, increasing the versatility of a newly developed process to efficiently produce block copolymers using either ligand, or a combination of the two. First results suggest that the two-step process can also be used to chain extend the macroinitiator with methacrylates, thus extending the range of materials that can be produced.