1H‐Perfluorohexane—An efficient modifier for ethylene tri‐/tetramerization

Abstract

Silicon‐bridged/N, P (PNSiP) ligand/Cr (III) catalyst system based on different fluorinated hydrocarbons as modifiers have been explored for ethylene selective tri‐/tetramerization. Modifiers like 1H‐Perfluorohexane (1H‐PFH), Hexafluorobenzene (HFB), and Perfluorobiphenyl (PFB) have been proven to show a significant influence on ethylene oligomerization toward 1‐hexene and 1‐octene of the catalytic system. Among them, 1H‐PFH showed the most significant promotion effect in improving activity from 0.95 × 106 g·(mol Cr·h)−1 to as much as 5.66 × 106 g·(mol Cr·h)−1 at high temperature 90°C. Through the analysis of nuclear magnetic resonance (NMR) spectroscopy and ultraviolet visible diffuse reflectance spectroscopy (UV–vis DRS) results, we concluded that 1H‐PFH can react with an amount of trimethylaluminum (TMA) contained in the cocatalyst modified methylaluminoxane (MMAO) and the solubility of Cr (III) in solvent can be increased after adding 1H‐PFH. Furthermore, the possible reaction routes of 1H‐PFH with TMA and MMAO were proposed.