Polymerization of propylene catalyzed over highly active and stereospecific catalysts synthesized with Mg(OEt)₂/benzoyl chloride/TiCl₄

Abstract

A series of monoester catalysts has been studied, each catalyst prepared by the reaction of magnesium diethoxide with benzoyl chloride [BzCOCl, to produce ethyl benzoate (EB) in situ] in the presence of excess titanium tetrachloride. Solid product and catalysts obtained by subsequent treatments with titanium tetrachloride were characterized by elemental analysis, IR spectroscopy, x‐ray diffraction, BET measurement, and thermal gravimetric analysis. The catalysts yielded very high activity (above 20 kg polymer/g Ti h atm) for the polymerization of propylene in slurry reactions. From the results of polymerization as well as catalyst characterization, the effects of internal and external Lewis bases on the isospecificity and stability of catalysts are discussed in detail. © 1992 John Wiley & Sons, Inc.

Propylene polymerization using supported Ziegler–Natta catalyst systems with mixed donors

“…(1) and (2) can occur simultaneously in the reaction mixture to yield a solid catalyst 21, 23–25. EB is generated in‐situ through reaction of added BzCl with partial chlorinated magnesium ethoxide and/or titanium chloroethoxide species in the reaction mixture 24 Two solid catalysts with only EB in one and DIBP in other were also prepared for comparison.…”

“…Mg (wt %) remains in the range of 17.9–18.8 indicating comparable yield for all the catalysts system. Impurities in the form of ethoxy remains below 1.0 (wt %) 21, 24. Surface area was also measured through nitrogen sorption for Cat‐A and Cat‐E.…”

“…Intensity of the peak at 417 nm (ε = 782.7 L −1 mol −1 cm −1 ) was used to quantify the titanium content. Solid samples were hydrolyzed in acidic solution for quantitative estimation of DIBP, EB, and ethoxy content as ethanol by gas chromatographic analysis 21, 23, 24. The morphology was examined by FEI Inspect scanning electron microscope before the measurements, the sample was fixed on the carbon tape under nitrogen atmosphere and quickly loaded in the chamber.…”

Formation of Highly Active Ziegler–Natta Catalysts Clarified by a Multifaceted Characterization Approach

“…42 Finally, Kim et al mostly focused on the mutual reactions between Mg(OEt) 2 , TiCl 4 , and the benzoyl chloride (BzCl) used as an electron donor or its precursor, demonstrating the high interchangeability of (OEt) − and Cl − anionic ligands. 41 Recently, we proposed a combination of cutting edge characterization techniques to clarify the identity of δ-MgCl 2 , which includes X-ray total scattering for defining the nanosized and disordered structure 30 and vibrational spectroscopies for determining the exposed surfaces and their relative extension. 43 In this study, the same approach has been adopted, but complemented by chemical analysis, polymerization tests, and UV−vis spectroscopy, in order to elucidate the chemical reactions and structural evolution taking place during the ZN catalyst preparation.…”

Poisoning effect of CO on ethylene polymerization with Ni(II)–diimine/MAO

“…Simultaneous kinetic and inhibition method was developed by Caunt, Tait and coworkers [6,7]. A small amount of suitable inhibitor was injected into polymerization run and decrease in the overall rate of polymerization were measured simultaneously as well as the amount of inhibitor adsorbed [8][9][10][11][12].…”