Discovery and Optimization of New Chromium Catalysts for Ethylene Oligomerization and Polymerization Aided by High-Throughput Screening

• Published in: Journal of the American Chemical Society 2005-08, Vol.127 (31), p.11037-11046
• Main Authors: Jones, David J, Gibson, Vernon C, Green, Simon M, Maddox, Peter J, White, Andrew J. P, Williams, David J
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polymerization; Preparation, kinetics, thermodynamics, mechanism and catalysts
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja0518171

High throughput screening (HTS) of a 205 member Schiff base salicylaldimine ligand library derived from salicylaldehydes bearing bulky ortho-substituents, i.e., 9-anthracenyl, 1,4,5,8-tetramethylanthracenyl or triptycenyl, reacted in-situ with (p-tolyl)CrCl2(thf)3, identified two new classes of highly active chromium based systems for the oligomerization and polymerization of ethylene, respectively. The polymerization system comprises bidentate ortho-substituted anthracenyl Schiff bases bearing small primary or secondary alkyl imine substituents. The oligomerization catalysts are based upon tridentate ortho-triptycenyl-substituted Schiff bases with pyridylmethyl or quinolyl substituents. Validation tests confirmed polymerization productivities of up to 3000 g·mmol-1h-1bar-1 for the polymerization catalyst systems while the oligomerization catalysts gave productivities up to 10 000 g·mmol-1h-1bar-1. Key catalyst precursors have been characterized by X-ray crystallography.