Over-All Kinetics of Polymerization Process

As already stated in the first chapter, several catalytic systems show a certain stereospecificity in the a-olefin polymerization. 

These systems may be differentiated either by the nature of the compound of the transition metal or by the type of the metallorganic compound used for their preparation. 

The behavior of the different catalytic systems (containing transition metal crystalline compounds) in the a-olefin polymerization, except for the different degree of stereospecificity, may be connected with a definite kinetic scheme. This was shown by experimental work performed at the Institute of Industrial Chemistry of the Milan Polytechnic. 

The nature of the olefin exerts a certain influence on the rate constant of the over-all polymerization. This is connected with factors of steric character and to the more-or-less enhanced electron-releasing character of the alkyl group bound to the vinyl group which may influence several steps of the over-all polymerization process. 

Although the catalysts containing beryllium alkyl are more stereospeciflc than those with alkylaluminum (5, 6), nevertheless the greater part of our kinetic measurements were performed using alkylaluminum compounds, since they represent a special practical interest due to the higher availability, and lower toxicity compared with the corresponding beryllium compounds. 

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