scholarly journals Correction: Rapid kinetic evaluation of homogeneous single-site metallocene catalysts and cyclic diene: how do the catalytic activity, molecular weight, and diene incorporation rate of olefins affect each other?

RSC Advances ◽  
2021 ◽  
Vol 11 (53) ◽  
pp. 33301-33301
Author(s):  
Amjad Ali ◽  
Muhammad Nadeem ◽  
Jianwei Lu ◽  
Jamile Mohammadi Moradian ◽  
Tahir Rasheed ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Incorporation Rate ◽  
Single Site ◽  
Metallocene Catalysts ◽  
Kinetic Evaluation ◽  
Cyclic Diene

Correction for ‘Rapid kinetic evaluation of homogeneous single-site metallocene catalysts and cyclic diene: how do the catalytic activity, molecular weight, and diene incorporation rate of olefins affect each other?’ by Amjad Ali et al., RSC Adv., 2021, 11, 31817–31826, DOI: 10.1039/D1RA06243C.

scholarly journals Rapid kinetic evaluation of homogeneous single-site metallocene catalysts and cyclic diene: how do the catalytic activity, molecular weight, and diene incorporation rate of olefins affect each other?

RSC Advances ◽  
2021 ◽  
Vol 11 (50) ◽  
pp. 31817-31826
Author(s):  
Amjad Ali ◽  
Muhammad Nadeem ◽  
Jinwei Lu ◽  
Jamile Mohammadi Moradian ◽  
Tahir Rasheed ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Kinetics And Mechanism ◽  
Incorporation Rate ◽  
Single Site ◽  
Metallocene Catalysts ◽  
Kinetic Evaluation ◽  
Cyclic Diene

The kinetics and mechanism of ethylene and 5-ethylidene-2-norbornene copolymerization catalyzed by rac-Et(Ind)2ZrCl2 were investigated using 2-thiophenecarbonyl chloride.

Metathesis Polymerization of Phenylacetylene by Tungsten Aryloxo Complexes

1995 ◽  
Vol 60 (3) ◽  
pp. 489-497 ◽  
Author(s):  
Hynek Balcar ◽  
Jan Sedláček ◽  
Marta Pacovská ◽  
Vratislav Blechta
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Induction Period ◽  
Average Molecular Weight ◽  
Molar Fraction ◽  
Molar Ratio ◽  
Weight Average Molecular Weight ◽  
Polymer Yield ◽  
Positive Effect ◽  
Ligand Addition

Catalytic activity of the tungsten aryloxo complexes WCl5(OAr) and WOCl3(OAr), where Ar = 4-t-C4H9C6H4, 2,6-(t-C4H9)2C6H3, 2,6-Cl2C6H3, 2,4,6-Cl3C6H2, and 2,4,6-Br3C6H2 in polymerization of phenylacetylene (20 °C, monomer to catalyst molar ratio = 1 000) was studied. The activity of WCl5(OAr) as unicomponent catalysts increases with increasing electron withdrawing character of the -OAr ligand. Addition of two equivalents of organotin cocatalysts (Me4Sn, Bu4Sn, Ph4Sn, Bu3SnH) to WCl5(O-C6H2Cl3-2,4 ,6) has only slight positive effect (slightly higher polymer yield and/or molecular weight of poly(phenylacetylene)s was achieved). However, in the case of WOCl3(O-C6H3Cl2-2, 6) catalyst, it enhances the activity considerably by eliminating the induction period. Poly(phenylacetylene)s prepared with the catalysts studied have weight-average molecular weight ranging from 100 000 to 200 000. They are trans-prevailing and have relatively low molar fraction of monomer units comprised in cyclohexadiene sequences (about 6%).

The effect of reaction parameters on catalytic activity in the polymerization of ethylene using supported and unsupported metallocene catalysts

1998 ◽  
Vol 166 (1) ◽  
pp. 207-213 ◽  
Author(s):  
Raúl Quijada ◽  
René Rojas ◽  
Ana Narvaez ◽  
Luis Alzamora ◽  
Jaime Retuert ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Metallocene Catalysts ◽  
Reaction Parameters

scholarly journals Catalytic Degradation of Chitosan by Supported Heteropoly Acids in Heterogeneous Systems

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1078
Author(s):  
Hang Zhang ◽  
Zhipeng Ma ◽  
Yunpeng Min ◽  
Huiru Wang ◽  
Ru Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Catalytic Activity ◽  
Activated Carbon ◽  
Reaction Time ◽  
High Molecular Weight ◽  
Reaction Temperature ◽  
Water Soluble ◽  
High Catalytic Activity ◽  
High Molecular Weight Chitosan

Several kinds of composite materials with phosphotungstic acid (PTA) as the catalyst were prepared with activated carbon as support, and their structures were characterized. According to the Box–Behnken central combination principle, the mathematical model of the heterogeneous system is established. Based on the single-factor experiments, the reaction temperature, the reaction time, the amount of hydrogen peroxide and the loading capacity of PTA were selected as the influencing factors to study the catalyzed oxidation of hydrogen peroxide and degradation of high molecular weight chitosan. The results of IR showed that the catalyst had a Keggin structure. The results of the mercury intrusion test showed that the pore structure of the supported PTA catalyst did not change significantly, and with the increase of PTA loading, the porosity and pore volume decreased regularly, which indicated that PTA molecules had been absorbed and filled into the pore of activated carbon. The results of Response Surface Design (RSD) showed that the optimum reaction conditions of supported PTA catalysts for oxidative degradation of high molecular weight chitosan by hydrogen peroxide were as follows: reaction temperature was 70 ℃, reaction time was 3.0 h, the ratio of hydrogen peroxide to chitosan was 2.4 and the catalyst loading was 30%. Under these conditions, the yield and molecular weight of water-soluble chitosan were 62.8% and 1290 Da, respectively. The supported PTA catalyst maintained high catalytic activity after three reuses, which indicated that the supported PTA catalyst had excellent catalytic activity and stable performance compared with the PTA catalyst.

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