Question

Mechanism of ziegler natta polymerisation with active hydrogen containing compound

Answer 1

Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, is a catalyst used in the synthesis of polymers of 1-alkenes (alpha-olefins). Two broad classes of Ziegler–Natta catalysts are employed, distinguished by their solubility:

Heterogeneous supported catalysts based on titanium compounds are used in polymerization reactions in combination with cocatalysts, organoaluminumcompounds such as triethylaluminium, Al(C2H5)3. This class of catalyst dominates the industry.[1]

Homogeneous catalysts usually based on complexes of Ti, Zr or Hf. They are usually used in combination with a different organoaluminum cocatalyst, methylaluminoxane (or methylalumoxane, MAO). These catalysts traditionally contains metallocenes but also feature multidentate oxygen- and nitrogen-based ligands.[2]

Ziegler–Natta catalysts are used to polymerize terminal alkenes (ethylene and alkenes with the vinyl double bond):

n CH2=CHR → −[CH2−CHR]n−;