ANIONIC-POLYMERIZATION OF BUTADIENE - A MNDO STUDY OF THE POTENTIAL-ENERGY SURFACE OF THE PROPAGATION REACTION IN POLAR AND NONPOLAR MEDIA

The anionic polymerization of butadiene, to both the 1,2- and 1,4- addition products, is an important industrial process. It is known that the reaction can be steered to either the 1,2- or 1,4-product by the addition, or absence, of a complexing solvent such as ether. The goals of the current study were to map the MNDO potential Energy Surfaces (PES) of the propagation reactions both in the presence and absence of dimethyl ether to gain insight into the factors influencing the reaction's selectivity. Single point ab initio calculations at the DZP level were run on all reactants, products and transition states as a cross check on the MNDO results.