Ethylene Polymerization by Thioether Bridged Dinuclear Titanocene Complex

2011 ◽  
Vol 213 ◽  
pp. 354-357 ◽  
Author(s):  
Yu Jing Nie ◽  
Ming Yang
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Ethylene Polymerization ◽  
Gel Permeation Chromatography ◽  
Molar Ratio ◽  
Polymerization Temperature ◽  
High Concentration ◽  
Highly Active ◽  
Cyclopentadienyl Ligand ◽  
Broad Molecular Weight Distribution

The thioether bridged metallocene complex [(C5H5)Cl2TiC5H4CH2CH2]2S has been synthesized by treating the dilithium salts of the thioether bridged cyclopentadienyl ligand with two equivalents of C5H5TiCl3 and characterized by 1HMNR and elemental analysis. After activation with methylaluminoxane (MAO), the complex was highly active catalysts for homogeneous ethylene polymerization in toluene. The influence of the molar ratio [MAO]/[Cat], the catalyst concentration, time and temperature have been studied systematically. The catalytic activity of 1 is 3.63×105 g PE/mol•Cat•h. Rising the polymerization temperature decreases the catalytic activity for 1. A high concentration of the catalysts drops the catalytic activity as well as the molecular weight of polyethylene for the complex. High temperature gel permeation chromatography (HT-GPC) proves the production of polyethylene with a broad molecular weight distribution (MWD).

Ethylene Polymerization by Thioether Bridged Dinuclear Zirconocene Complex

2011 ◽  
Vol 213 ◽  
pp. 374-377 ◽  
Author(s):  
Yu Jing Nie ◽  
Ming Yang
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Ethylene Polymerization ◽  
Gel Permeation Chromatography ◽  
Molar Ratio ◽  
High Concentration ◽  
Concentration Time ◽  
Cyclopentadienyl Ligand ◽  
Broad Molecular Weight Distribution ◽  
Higher Temperature

The thioether bridged Zirconocene complex [(C5H5)Cl2ZrC5H4CH2CH2]2S has been synthesized by treating the dilithium salts of the thioether bridged cyclopentadienyl ligand with two equivalents of C5H5ZrCl3(DME) and characterized by 1HMNR and elemental analysis. Homogenous ethylene polymerization by this complex has been conducted systematically in the presence of methylaluminoxane (MAO). The influence of the molar ratio [MAO]/[Cat], the catalyst concentration, time and temperature have been studied in detail. The catalytic activity of 1 is 6.46×105 g PE/mol•Cat•h. Higher temperature is favorable for increasing the catalytic activity for 1. A high concentration of the catalysts drops the catalytic activity as well as the molecular weight of polyethylene for the complex. High temperature gel permeation chromatography (HT-GPC) proves the production of polyethylene with a broad molecular weight distribution (MWD).

Ethylene Polymerization by Phenyl Sulfide Bridged Dinuclear Titanocene Complex/MAO

2011 ◽  
Vol 181-182 ◽  
pp. 804-808
Author(s):  
Yu Jing Nie ◽  
Ming Yang
Keyword(s):  
Catalytic Activity ◽  
Ethylene Polymerization ◽  
Gel Permeation Chromatography ◽  
Molar Ratio ◽  
Polymerization Temperature ◽  
Phenyl Sulfide ◽  
Highly Active ◽  
Concentration Time ◽  
Cyclopentadienyl Ligand ◽  
Broad Molecular Weight Distribution

The phenyl sulfide bridged metallocene complex [(C5H5)Cl2TiC5H4CH2(C6H4-p)]2S has been synthesized by treating the dilithium salts of the phenyl sulfide bridged cyclopentadienyl ligand with two equivalents of C5H5TiCl3 and characterized by 1HMNR and elemental analysis. After activation with methylaluminoxane (MAO), the complex was highly active catalysts for homogeneous ethylene polymerization in toluene. The influence of the molar ratio [MAO]/[Cat], the catalyst concentration, time and temperature have been studied systematically. The highest catalytic activity of 1 is up to 8.30×105 g PE/mol•Cat•h. Rising the polymerization temperature decreases the catalytic activity for 1. High temperature gel permeation chromatography (HT-GPC) proves the production of polyethylene with a broad molecular weight distribution (MWD), which is reached 10.11.

Ethylene Polymerization by Phenyl Sulfide Bridged Dinuclear Zirconocene Complex/MAO

2011 ◽  
Vol 181-182 ◽  
pp. 809-813
Author(s):  
Yu Jing Nie ◽  
Ming Yang
Keyword(s):  
Catalytic Activity ◽  
Ethylene Polymerization ◽  
Catalyst Concentration ◽  
Gel Permeation Chromatography ◽  
Molar Ratio ◽  
Phenyl Sulfide ◽  
Concentration Time ◽  
Cyclopentadienyl Ligand ◽  
Broad Molecular Weight Distribution ◽  
Higher Temperature

The phenyl sulfide bridged Zirconocene complex [(C5H5)Cl2ZrC5H4CH2(C6H4-p)]2S has been synthesized by treating the dilithium salts of the phenyl sulfide bridged cyclopentadienyl ligand with two equivalents of C5H5ZrCl3(DME) and characterized by 1HMNR and elemental analysis. Homogenous ethylene polymerization by this complex has been conducted systematically in the presence of methylaluminoxane (MAO). The influence of the molar ratio [MAO]/[Cat], the catalyst concentration, time and temperature have been studied in detail. The highest catalytic activity of 1 is up to 13.78×105 g PE/mol•Cat•h. Higher temperature is favorable for increasing the catalytic activity for 1. High temperature gel permeation chromatography (HT-GPC) proves the production of polyethylene with a broad molecular weight distribution (MWD), which is reached 6.02.

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%).

scholarly journals Highly Dispersed Pd Species Supported on CeO2 Catalyst for Lean Methane Combustion: The Effect of the Occurrence State of Surface Pd Species on the Catalytic Activity

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 772
Author(s):  
Yanxiong Liu ◽  
Changhua Hu ◽  
Longchun Bian
Keyword(s):  
Catalytic Activity ◽  
Oxygen Vacancies ◽  
Methane Combustion ◽  
Pd Nanoparticles ◽  
High Concentration ◽  
Ch4 Combustion ◽  
Highly Active ◽  
Δ Phase ◽  
Occurrence State ◽  
Comprehensive Characterization

The correlation between the occurrence state of surface Pd species of Pd/CeO2 for lean CH4 combustion is investigated. Herein, by using a reduction-deposition method, we have synthesized a highly active 0.5% PdO/CeO2-RE catalyst, in which the Pd nanoparticles are evenly dispersed on the CeO2 nanorods CeO2-R. Based on comprehensive characterization, we have revealed that the uniformly dispersed Pd nanoparticles with a particle size distribution of 2.3 ± 0.6 nm are responsible for the generation of PdO and PdxCe1−xO2−δ phase with –Pd2+–O2−–Ce4+– linkage, which can easily provide oxygen vacancies and facilitate the transfer of reactive oxygen species between the CeO2-R and Pd species. As a consequence, the remarkable catalytic activity of 0.5% Pd/CeO2-RE is related to the high concentration of PdO species on the surface of the catalyst and the synergistic interaction between the Pd species and the CeO2 nanorod.

Chromium complexes supported by the bidentate PN ligands: synthesis, characterization and application for ethylene polymerization

2018 ◽  
Vol 47 (38) ◽  
pp. 13459-13465 ◽  
Author(s):  
Quande Zheng ◽  
Dejuan Zheng ◽  
Binghao Han ◽  
Shaofeng Liu ◽  
Zhibo Li
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Ethylene Polymerization ◽  
Chromium Complexes ◽  
Highly Active ◽  
Imine Ligands

Chromium complexes bearing phosphine–imine ligands are highly active for ethylene polymerization and produce HDPE with a high molecular weight.

Polymerization of n-butyl methylacrylate using bis(β- ketoamino)nickel(II)/MAO catalytic systems

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaohui He ◽  
Yiwang Chen ◽  
Yongming Liu ◽  
Muqing Chen ◽  
Shuxian Yu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Monomer Concentration ◽  
Polymerization Temperature ◽  
Moderate Activity ◽  
Polymerization Time ◽  
Catalytic Systems ◽  
Molecular Weights ◽  
Molar Ratios ◽  
Broad Molecular Weight Distribution ◽  
C Nmr

AbstractThe polymerizations of n-butyl methylacrylate (nBMA) were carried out using bis(β-ketoamino)nickel(II) complexes (Ni[CH3C(O)CHC(NR)CH3]2: R = phenyl, 1; R = naphthyl, 2) in combination with methylaluminoxane (MAO) in toluene. The effect of parameters such as polymerization temperature, Al/Ni molar ratios, polymerization time, and monomer concentration, on catalytic polymerization activity and polymer molecular weights, were examined in detail. Both of the nickel(II) catalytic systems exhibited moderate activity, and produced P(nBMA) with high molecular weight and relatively broad molecular weight distribution (Mw/Mn=2.0~3.0. The obtained polymer has been characterized by means of FTIR, 1H NMR, 13C NMR, DSC, and WAXD technique and was confirmed to be syndio-rich stereospecific P(nBMA).

scholarly journals Methylene-Bridged Tridentate Salicylaldiminato Binuclear Titanium Complexes as Copolymerization Catalysts for the Preparation of LLDPE through [Fe]/[Ti] Tandem Catalysis

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1114 ◽  
Author(s):  
Yani Luo ◽  
Jian Li ◽  
Derong Luo ◽  
Qingliang You ◽  
Zifeng Yang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Temperature ◽  
Gel Permeation Chromatography ◽  
13C Nmr Spectroscopy ◽  
Molar Ratio ◽  
Tandem Catalysis ◽  
Titanium Complexes ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Branching Degree

A novel tandem catalysis system consisted of salicylaldiminato binuclear/mononuclear titanium and 2,6-bis(imino)pyridyl iron complexes was developed to catalyze ethylene in-situ copolymerization. Linear low-density polyethylene (LLDPE) with varying molecular weight and branching degree was successfully prepared with ethylene as the sole monomer feed. The polymerization conditions, including the reaction temperature, the Fi/Ti molar ratio, and the structures of bi- or mononuclear Ti complexes were found to greatly influence the catalytic performances and the properties of obtained polymers. The polymers were characterized by differential scanning calorimetry (DSC), high temperature gel permeation chromatography (GPC) and high temperature 13C NMR spectroscopy, and found to contain ethyl, butyl, as well as some longer branches. The binuclear titanium complexes demonstrated excellent catalytic activity (up to 8.95 × 106 g/molTi·h·atm) and showed a strong positive comonomer effect when combined with the bisiminopyridyl Fe complex. The branching degree can be tuned from 2.53 to 22.89/1000C by changing the reaction conditions or using different copolymerization pre-catalysts. The melting points, crystallinity and molecular weights of the products can also be modified accordingly. The binuclear complex Ti2L1 with methylthio sidearm showed higher capability for comonomer incorporation and produced polymers with higher branching degree and much higher molecular weight compared with the mononuclear analogue.

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