Highly active MgCl2-supported catalysts containing novel diether donors for propene polymerization

Abstract

The structural origin of thermal instability of cathode materials, a critical safety issue for lithium‐ion batteries, is studied systematically using a combination of various in situ synchrotron X‐ray techniques and transmission electron microscopy. As Lijun Wu, Xiao‐Qing Yang, and co‐workers report , an in‐depth understanding of the thermal‐decomposition behavior of overcharged cathode materials is obtained through this investigation.

Impact of three‐dimensional transesophageal echocardiography on prosthesis sizing for transcatheter aortic valve implantation

“…The novel generation Z–N catalyst (MgCl 2 /TiCl 4 /BMF) was synthesized similarly to a method described in the literature 15. The polymerization of PP alloy was operated in a two‐stage reaction process: the first stage was the liquid bulk polymerization of propylene without any external donor at 70°C for 1 h, in which spherical PP particles were produced, and the second stage was successive gas copolymerization at 60°C.…”

“…Most of the papers12–14 on preparing PP alloy have been mainly concerned with Ziegler–Natta (Z–N) catalyst, based on MgCl 2 /TiCl 4 or MgCI 2 /TiCl 4 /DIBP (DIBP is diisobutyl phthalate as an internal donor) catalyst, alkyl aluminum as a cocatalyst, and alkoxysilane as an external donor. Recently, a novel generation Z–N catalyst containing diether compound as an internal donor has high activity and satisfactory stereospecificity without any external donor for propylene polymerization 15. The novel generation catalyst, however, is used to prepare PP/EPR alloy, which has not been reported yet so far.…”

Effect of high polymerization temperature on the microstructure of isotactic polypropylene prepared using heterogeneous ticl4/mgcl2 catalysts

“…To determine the effect of polymerization temperature on activity and microstructure, we carried out polymerizations with a catalyst system prepared by the method described in Mao et al,3 ranging from 50 to 120°C. We used a novel catalyst containing the internal donors 9,9‐bis(methoxymethyl)fluorine (BMMF), which can obtain high activity and isospecificity without external donors 4. The investigation was simplified because we did not need to consider the reaction between internal and external donors at high temperature.…”

Propylene polymerization over MgCl2‐supported TiCl4 catalysts bearing different amounts of a diether internal electron donor: Extrapolation to the role of internal electron donor on active site

“…Moreover, there are fewer interactions between 1,3‐diether and MgCl 2 , which make it simple to study the influence of 1,3‐diether on active sites 30. Meanwhile, BMMF, as a typical 1,3‐diether, is proved to be able to prepare ZN catalyst with higher isotacticity 29, 31. Therefore, we chose BMMF as internal donor, and prepare a series of ZN catalysts containing different BMMF amount.…”