QUANTUM CHEMICAL CALCULATION OF INITIATION MECHANISM OF CATIONIC POLYMERISATION OF PROPYLENE WITH CHLORIDE-ALUMINIUM AQUACOMPLEX.

The first quantum-chemical study of the initiation mechanism of propylene in the presence of a complex chloride aluminium catalyst by the ab initio HF/6-311G** method was carried out with optimisation of the geometry in all parameters by a standard gradient method for attacks of the initiating particle on a-carbon monomer atoms. We showed that this reaction is barrier-like and exothermic. The mechanism of initiation is a coordinated process of SN 2-nucleophilic substitution. The energy barrier in the attack of the initiating particle on the a-carbon atom of propylene is 124 kJ/mol, the thermal effect of the reaction equals -49 kJ/mol. [ABSTRACT FROM AUTHOR]