Ethylene homo and co‐polymerization catalyzed by extensively bulky nickel catalysts with shielding wings of chlorine atoms

Abstract

Designing the catalysts to get high molecular weight polyethylene is an art. The catalysts bearing imine functionality derived from 8‐arylnaphthyl amines are more impressive and attractive in this regard. In this work, we synthesize 2,4‐dibenzhydryl‐8‐(3,5‐dichlorophenyl)naphthalen‐1‐amine to condense with picolinaldehyde, pyridine‐N‐oxide‐2‐carbaldehyde and 3,4‐dibutanone and then subsequently the treatment of resulting ligands with nickel precursors to get the corresponding catalysts. It was hypothesized that 3,5‐dichlorophenyl having extended wings of chlorine atoms along with bulky dibenzhydryl groups can provide good shielding on both apical positions of metal in response to slow down the chain transfer. More interestingly, the polymerization was done in industrially claimed n‐heptane solvent. All the catalysts showed activity in an order of 106, whereas a value of 1.04 × 107 g mol−1 h−1 has been recorded from keto‐imine based Ni‐3 catalyst. All catalysts generates polymer with high molecular weight with maximum value was recorded by Ni‐2 up to 37.4 × 104 g mol−1. Ni‐3 can also incorporate methyl 10‐undecenoate up to 2.6% in polyethylene backbone.