Effects of titanium dispersion state on distribution and reactivity of active centers in propylene polymerization with MgCl 2 ‐supported Ziegler‐Natta catalysts: A kinetic study based on active center counting

ChemCatChem ◽  
2020 ◽  
Vol 12 (20) ◽  
pp. 5140-5148
Author(s):  
Baiyu Jiang ◽  
Biao Zhang ◽  
Yintian Guo ◽  
Amjad Ali ◽  
Wenqi Guo ◽  
...  
Keyword(s):  
Kinetic Study ◽  
Active Center ◽  
Propylene Polymerization ◽  
Active Centers ◽  
Dispersion State ◽  
Ziegler Natta Catalysts

Microstructure of polypropylene and active center in Ziegler–Natta catalyst: effect of novel salicylate internal donor

RSC Advances ◽  
2016 ◽  
Vol 6 (79) ◽  
pp. 75023-75031 ◽  
Author(s):  
Qian Zhou ◽  
Ailian Wang ◽  
Huayi Li ◽  
Zhi Luo ◽  
Tao Zheng ◽  
...  
Keyword(s):  
Active Center ◽  
Propylene Polymerization ◽  
Active Centers ◽  
Internal Donor ◽  
Important Impact ◽  
Natta Catalyst ◽  
Catalyst Effect ◽  
Ziegler Natta Catalyst

The volume of ecofriendly salicylate internal donors for propylene polymerization has an important impact on the catalyst active centers and microstructure of polypropylene.

Ziegler-Natta catalysts for propylene polymerization: Chemistry of reactions leading to the formation of active centers

2008 ◽  
Vol 287 (1-2) ◽  
pp. 45-52 ◽  
Author(s):  
Yury V. Kissin ◽  
Xinsheng Liu ◽  
David J. Pollick ◽  
Nancy L. Brungard ◽  
Main Chang
Keyword(s):  
Propylene Polymerization ◽  
Active Centers ◽  
Ziegler Natta Catalysts

Kinetic Study of the Effect of Heparin on the Amidase Activity of Trypsin, Plasmin and Urokinase

1983 ◽  
Vol 49 (03) ◽  
pp. 199-203 ◽  
Author(s):  
V M Yomtova ◽  
N A Stambolieva ◽  
B M Blagoev
Keyword(s):  
Kinetic Study ◽  
Active Center ◽  
Simultaneous Presence ◽  
Amidase Activity ◽  
Competitive Inhibitors ◽  
Uncompetitive Inhibitor

SummaryIt was found that the effect of heparin on the amidase activity of urokinase (E C 3.4.21.31), plasmin (E C 3.4.21.7) and trypsin (E C 3.4.21.4) depended on the substrate used. No effect of heparin on the amidase activity of urokinase and trypsin was observed when Pyro Glu-Gly-Arg-p-nitroanilide (S-2444) and α-N-acetyl-L-lysine-p-nitroanilide (ALNA) were used as substrates. Heparin acted as a uncompetitive inhibitor of trypsin (Ki = 1.2×10-6 M), plasmin (Ki = 4.9×10-6 M) and urokinase (Ki = l.0×10-7 M) when Bz-Phe-Val-Arg-p-nitroanilide (S-2160), H-D-Val-Leu-Lys-p-nitroanilide (S-2251) and plasminogen, respectively, were used as substrates. These results, as well as the data obtained by studying the effect of the simultaneous presence of heparin and competitive inhibitors suggest that although heparin is not bound at the active center of these enzymes, it may influence the effectivity of catalysis.

The Kinetic Study of Ethylene Polymerization over Titanium–Magnesium Catalysts in the Presence of Hydrogen: The Number and Reactivity of Active Centers

2020 ◽  
Vol 62 (1) ◽  
pp. 14-21 ◽  
Author(s):  
V. V. Sukulova ◽  
A. A. Barabanov ◽  
T. B. Mikenas ◽  
M. A. Matsko ◽  
V. A. Zakharov
Keyword(s):  
Kinetic Study ◽  
Ethylene Polymerization ◽  
Active Centers
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