Green Chemistry of Poly(l-lactides)
W. Swope1, R. Waymouth2, J. Hedrick1, and C. Wade1
As part of a series of studies on the green chemistry of poly(l-lactides), we have performed a theoretical study of the mechanism of ring-opening polymerization. We have investigated two alternative mechanisms for the ring-opening polymerization of l-lactide using a guanidine-based catalyst, the first involving acetyl transfer to the catalyst, and the second involving only hydrogen bonding to the catalyst. Using computational chemistry methods, we show that the hydrogen bonding pathway shown above is preferred over the acetyl transfer pathway and that this is consistent with experimental information.
1: IBM Almaden Research Center, 2: Stanford University