Synthesis of MWNTs/SiO2 supported nickel and palladium complexes and their application as catalysts for cyclic olefins polymerization

He, Xiaohui; Guo, Yan; Chen, Xueqi; Wu, Bin; Zou, Jianhua; Wen, Yufei; Chen, Defu

doi:10.1016/j.jorganchem.2021.121953

Cited by 6 publications

(2 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The slightly higher (0 .7 eV) bind energy of COF@Zr should be attributed to the interaction between dMAO and Cp 2 ZrCl 2 , as a similar phenomenon has been found in other supported catalysts. [69][70][71] Besides, the peak at 74.5 eV belonging to (OÀ AlÀ CH 3 ) [72] could be observed in the Al 2p spectrum of COF@Zr (Figure S5c), which confirms the existence of dMAO.…”

Section: Resultsmentioning

confidence: 65%

Covalent Organic Framework‐Supported Metallocene for Ethylene Polymerization

Zhu

Liu

Luo

et al. 2023

Chemistry A European J

View full text Add to dashboard Cite

The loading of homogeneous catalysts with support can dramatically improve their performance in olefin polymerization. However, the challenge lies in the development of supported catalysts with well-defined pore structures and good compatibility to achieve high catalytic activity and product performance. Herein, we report the use of an emergent class of porous material-covalent organic framework material (COF) as a carrier to support metallocene catalyst-Cp 2 ZrCl 2 for ethylene polymerization. The COF-supported catalyst demonstrates a higher catalytic activity of 31.1 × 10 6 g mol À 1 h À 1 at 140 °C, compared with 11.2 × 10 6 g mol À 1 h À 1 for the homogenous one. The resulting polyethylene (PE) products possess higher weight-average molecular weight (M w ) and narrower molecular weight distribution (Ð) after COF supporting, that is, M w increases from 160 to 308 kDa and Ð drops from 3.3 to 2.2. The melting point (T m ) is also increased by up to 5.2 °C. Moreover, the PE product possesses a characteristic filamentous microstructure and demonstrates an increased tensile strength from 19.0 to 30.7 MPa and elongation at break from 350 to 1400 % after catalyst loading. We believe that the use of COF carriers will facilitate the future development of supported catalysts for highly efficient olefin polymerization and high-performance polyolefins.

show abstract

Section: Resultsmentioning

confidence: 65%

Covalent Organic Framework‐Supported Metallocene for Ethylene Polymerization

Zhu

Liu

Luo

et al. 2023

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…displays the Al 2p energy level spectrum of the covalently heterogeneous catalyst. The absorption of Al 2p occurs at about 75.03 eV and 74.45 eV, which have been attributed to O-Al-O and O-Al-CH3, respectively[39]. The analysis mentioned above illustrates that complex CatA has been successfully attached to SiO2 supports through the covalent bond.…”

mentioning

confidence: 87%

Synthesis of α-Diimine Complex Enabling Rapidly Covalent Attachment to Silica Supports and Application of Homo-/Heterogeneous Catalysts in Ethylene Polymerization

Zhao,

Hou,

et al. 2023

IJMS

View full text Add to dashboard Cite

For covalent attachment-supported α-diimine catalysts, on the basis of ensuring the thermal stability and activity of the catalysts, the important problem is that the active group on the catalyst can quickly react with the support, anchoring it firmly on the support, shortening the loading time, reducing the negative impact of the support on the active centers, and further improving the polymer morphology, which makes them suitable for use in industrial polymerization temperatures. Herein, we synthesized a α-diimine nickel(II) catalyst bearing four hydroxyl substituents. The hydroxyl substituents enable the catalyst to be immobilized firmly on silica support by covalent linkage in 5–10 min. Compared with the toluene solvent system, the homogeneous catalysts show high activity and thermal stability in hexane solvent at the same conditions. Compared with homogeneous catalysts, heterogeneous catalysis leads to improvements in catalyst lifetime, polymer morphology control, catalytic activity, and the molecular weight of polyethylene (up to 679 kg/mol). The silica-supported catalysts resulted in higher melting temperatures as well as lower branching densities in polyethylenes. Even at 70 °C, the polyethylene prepared by S-CatA-2 still exhibits dispersed particle morphology, and there is no phenomenon of reactor fouling, which is suitable for industrial polymerization processes.

show abstract