Patent ID: 7119154
Filing Date: 2006-10-10
Classification: C07F,C08F

Abstract:
1. A method of preparing syndiotactic polypropylene having M w ranging from 10,000 to 500,000 and defects of the type rmr and [rrrr] pentad content greater than 0.50 comprising polymerizing propylene dissolved in an aprotic solvent in the presence of a catalytically effective amount of a complex having the structure: where R is selected from group consisting of halogen atoms, C 1 –C 10 branched or straight chain alkyl groups, C 1 –C 6 branched or straight chain alkoxide groups, and C 1 –C 6 branched or straight chain amido groups, R 1 is phenyl optionally substituted with one to five C 1 –C 6 branched or straight chain alkyl groups or one to five electron withdrawing atoms or groups, is cyclohexyl substituted with one to five C 1 –C 6 branched or straight chain alkyl groups or one to five electron withdrawing atoms or groups or is C 1 –C 10 branched, cyclic or straight chain alkyl group, and R 2 and R 3 are the same or different and are selected from the group consisting of H or C 1 –C 6 branched or straight chain alkyl groups; where when R 2 is t-butyl, R 3 is t-butyl; and an activating effective amount of compound that converts titanium of the complex to cationic form.