Solid-State NMR Investigations of MgCl₂ Catalyst Support

Abstract

MgCl 2 is a vital component of Ziegler–Natta catalysts for olefin polymerization. Here we synthesized anhydrous MgCl 2 using different drying protocols and exploited 1 H NMR to quantify the proton content. We report on our study of neat and ball-milled MgCl 2 samples by means of 25 Mg and 35 Cl solid-state NMR. DFT calculations of the quadrupole tensor aid in analysis of the spectra. The results show that, due to the morphology of the neat particles, a preferred orientation is induced which manifests itself in unusual powder line shapes. Ball milling reduces particle size, which subsequently leads to a small distribution of quadrupole parameters for the bulk. Surface sites, highly relevant for catalysis, are not directly observed, due to their broad lines of low intensity.