Synthesis of Branched Polyethylene by Tandem Catalysis

Recent Advances in Olefin Polymerization Using Binary Catalyst Systems

“…[12] The choice of these catalyst precursors was based on the capability of 9 to generate 1-alkenes and of 10 to copolymerize ethylene with 1-alkenes.…”

Tandem catalytic system: Rac‐Et(ind)2ZrCl2/AlEt2Cl/MAO toward the synthesis of branched polyethylene

“…We find that the homopolymer achieved at fixed pressure (1 atm) possesses T m of 130. 5 C and v c of 68.3%, a parallel result was also gained (T m ¼ 130. 7 C and v c ¼ 65.3%, Run 1) at varied pressure reaction condition under rac-Et(Ind) 2 ZrCl 2 /MAO system.…”

“…After that, a wide variety of promising tandem catalytic systems have been developed to prepare LLDPE in situ involving two different Ziegler-Natta catalysts, Ziegler-Natta catalyst/ homogeneous catalyst, two or three different homogeneous catalysts. [3][4][5][6][7][8][9][10] Surveying these works, [11][12][13][14][15][16] it is found that tandem catalysis is consisted of two kinds of catalysts and one activator, in which one catalyst oligomerizes the ethylene to a-olefins, and the other is responsible for polymerizing the ethylene and incorporating the a-olefins into the growing polymer chain under the same activator. In other words, the essential of tandem catalysis exists a dual functional catalyst active species: oligomerization/copolymerization active species in the same reaction system.…”

Turning a Cr-based heterogeneous ethylene polymerisation catalyst into a selective ethylene trimerisation catalyst

“…Currently, they are industrially obtained using a two-step process: production of 1-hexene by ethylene oligomerisation and subsequent use of 1-hexene in the production of LLDPE. A single-step process involves either the use of a bi-functional catalyst active in both processes or the use of a tandem catalytic system [5][6][7][8]. So far, no homogeneous catalysts are reported to be simultaneously active in both processes and, therefore, more attention is paid to heterogeneous systems, which present the advantage that different active sites can be created on a support surface.…”