Titanium complexes bearing carbamato ligands as catalytic precursors for propylene polymerization reactions

Abstract

This report describes propylene polymerization reactions with titanium complexes bearing carbamato ligands, Ti(O 2 CNMe 2 )Cl 2 (I) and Ti(O 2 CR 2 ) 4 [R 2 5 NMe 2 (II), NEt 2 (III) and (IV)]. Combinations of these complexes and MAO form catalysts for the synthesis of atactic polypropylene, as confirmed by FT-IR, DSC and 13 C NMR analysis. Effects of main reaction parameters on the catalyst activity were studied including the type of complex, solvent, temperature, and the [Al]/[Ti] molar ratio. The highest activity was observed when chlorobenzene was used as a solvent and AlMe 3depleted MAO was employed as a cocatalyst. V C 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4095-4102

Polymerization of alkenes with a post‐metallocene catalyst containing a titanium complex with an oxyquinolinyl ligand

“…Nevertheless, a weak trend is obvious: the T m value slightly increases with reaction temperature. This trend is too weak to be distinguished by C NMR.…”

“…C NMR data show that all the products have a strictly “head‐to‐tail” structure. Figure compares NMR spectra of heptane‐insoluble and heptane‐soluble fractions of PP prepared at 50 °C.…”

“…The spectrum of the soluble amorphous fraction [Fig. (B)] is typical for the spectra of amorphous fractions of PP prepared with different post‐metallocene catalysts; it contains numerous signals of pentads and heptads characterizing various types of steric sequences in PP chains . This amorphous fraction has a noticeable prevalence of isotactic sequences (the mmmm signal at −21.3 ppm); its mmmm content is about 30%; it would be merely ∼6% if the material were completely atactic.…”

“…C NMR spectra of poly(1‐hexene), poly(1‐octene), and poly(1‐decene) (10% solutions in a mixture of 1,2,4‐trichlorobenzene with deuterated chloroform) were recorded at 25 °C on a Bruker Avance‐400 spectrometer (10.613 MHz).…”

“…The content of 1‐octene in E/O copolymers ( ° p ° l , mol %) was calculated from C NMR and IR data (from A 1380 /A 1368 and A 1380 /A 722 absorbance ratios) using the calibration curve for ethylene/1‐hexene copolymers . Additionally, copolymer compositions were estimated from differences between copolymer yields and ethylene consumption in particular runs.…”