Prepare of Novel Zirconium Complex and Catalytic Performance for Ethylene Polymerization

2011 ◽  
Vol 179-180 ◽  
pp. 1091-1095 ◽  
Author(s):  
Zheng Zai Cheng ◽  
Yu Jing Nie ◽  
Xiao Chao Yan ◽  
Rui Lei ◽  
Su Su Lin
Keyword(s):  
Molecular Weight ◽  
Reaction Temperature ◽  
Ethylene Polymerization ◽  
Average Molecular Weight ◽  
Catalytic Performance ◽  
Zirconium Complex ◽  
Melting Points ◽  
Ligand Complex ◽  
Dichloromethane Solution ◽  
Very High

Novel zirconium complex 2 has been prepared by treatment of the ligand complex 1 with ZrCl4•2THF in dichloromethane solution. The complex 1 and 2 were characterized by 1H-NMR and IR. Activated by MAO, Complex 2 displays very high activity for ethylene polymerization under the reaction temperature of 40～80 °C and the viscosity-average molecular weight of polyethylene is more than 3.0×104 when reaction temperature is no more than 60°C.The molecular-weight distribution measured by gel permeation reached 2.50.High melting points measured by DSC indicates that the polyethylene produced by complex 2 is high linearity and high crystallinity.

Ethylene Polymerization by a New Zirconium Complex

2011 ◽  
Vol 214 ◽  
pp. 699-703
Author(s):  
Zheng Zai Cheng ◽  
Yu Jing Nie ◽  
Xiao Chao Yan ◽  
Rui Lei ◽  
Su Su Lin
Keyword(s):  
Molecular Weight ◽  
Reaction Temperature ◽  
Ethylene Polymerization ◽  
Average Molecular Weight ◽  
Zirconium Complex ◽  
Melting Points ◽  
Ligand Complex ◽  
Dichloromethane Solution ◽  
Gel Permeation ◽  
Very High

Novel zirconium complex C2 has been prepared by treatment of the ligand complex C1 with ZrCl4•2THF in dichloromethane solution. The complex C1 and C2 were characterized by 1H-NMR and IR. Activated by MAO, Complex C2 displays very high activity for ethylene polymerization under the reaction temperature of 30～80°C and the viscosity-average molecular weight of polyethylene is more than 3.50×104 when reaction temperature is no more than 60°C.The molecular-weight distribution measured by gel permeation reached 2.3.High melting points measured by DSC indicates that the polyethylene produced by complex C2 is high linearity and high crystallinity.

Polymerization of Methyl Methacrylate with a Novel Titanium Complex

2011 ◽  
Vol 179-180 ◽  
pp. 1203-1207
Author(s):  
Zheng Zai Cheng ◽  
Yu Jing Nie ◽  
Xiao Chao Yan ◽  
Rui Lei ◽  
Su Su Lin
Keyword(s):  
Molecular Weight ◽  
Methyl Methacrylate ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Ligand Complex ◽  
Dichloromethane Solution ◽  
Titanium Complex ◽  
Methyl Methacrylate Polymerization ◽  
Gel Permeation ◽  
Very High

Novel titanium complex [2-O-(5- NO2)C6H3CH=N[(C6H4) –2-O ]]2TiCl2 (1) has been prepared by treatment of the ligand complex 1a with TiCl4•2THF in dichloromethane solution. The complex 1a and 1 were characterized by 1H-NMR . Activated by MAO, Complex 1 displayed very high activity for methyl methacrylate polymerization and the viscosity-average molecular weight of PMMA is more than 35×104 at 60°C.The molecular-weight distribution of PMMA measured by gel permeation chromatography (GPC) is narrow.

Novel Iron(II) Complex as Single-Site Catalysts for Ethylene Polymerization

2011 ◽  
Vol 239-242 ◽  
pp. 3314-3318
Author(s):  
Zheng Zai Cheng ◽  
Ye Cong ◽  
Xiao Chao Yan ◽  
Yu Jing Nie ◽  
Su Su Lin ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Activity ◽  
Weight Distribution ◽  
Ethylene Polymerization ◽  
High Melting ◽  
Melting Points ◽  
H Nmr ◽  
Gel Permeation ◽  
Single Site Catalysts ◽  
Very High

Novel iron (II) complex C2has been prepared by treatment of the ligand C1with FeCl2in THF solution. The complex C1was characterized by MSand1H-NMR and complex C2was characterized by MSand element analyze. Activated by MAO, complex 2 exhibites very high activity and produces high molecular weight polyethylene. The molecular weight distribution measured by gel permeation reached 2.1 to 2.4. the GPC profile of PE obtained and High melting points measured by DSC indicates indicates that the polyethylene produced by complex C2is high linearity and high crystallinity.

Alternating poly(ester amide)s from glutaric anhydride and α,ω-aminoalcohols: synthesis and thermal properties

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Thomas Fey ◽  
Helmut Keul ◽  
Hartwig Höcker
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Homologous Series ◽  
Average Molecular Weight ◽  
Number Average Molecular Weight ◽  
Melting Points ◽  
Glutaric Anhydride ◽  
H Nmr ◽  
Activating Agent ◽  
Dimethylformamide Solution

Abstract Alternating poly(ester amide)s 6a - e were prepared by polycondensation of α-carboxyl-ω-hydroxyamides 3a - e which were obtained by aminolysis of glutaric anhydride (1) and α,ω-aminoalcohols, H2N-(CH2)x-OH (x = 2 - 6) 2a - e. The polycondensation was performed in dimethylformamide solution using a carbodiimide as activating agent, or in bulk with Bu2Sn(OMe)2, Ti(OBu)4 and Sn(octoate)2 as a catalyst. For the polycondensation in bulk, the influence of catalyst and of temperature on the number-average molecular weight was studied. 1H NMR analyses of the poly(ester amide)s clearly show the alternating microstructure. The poly(ester amide)s from glutaric anhydride and the homologous series of α,ω-aminoalcohols are semicrystalline materials; their melting points show the odd/even effect observed for other poly(ester amide)s.

scholarly journals Enhanced Fenton-like oxidation of hydroxypropyl guar gum catalyzed by EDTA-metal complexes in a wide pH range

2019 ◽  
Vol 79 (9) ◽  
pp. 1667-1674 ◽  
Author(s):  
Ying Tang ◽  
Huan Liu ◽  
Ling Zhou ◽  
Haomiao Ren ◽  
Hong Li ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Metal Complexes ◽  
Guar Gum ◽  
Average Molecular Weight ◽  
Oxygen Demand ◽  
Catalytic Performance ◽  
Hydroxypropyl Guar ◽  
Wide Ph Range ◽  
Ph Range ◽  
Hydroxypropyl Guar Gum

Abstract A series of EDTA-metal complexes was prepared for the Fenton oxidation catalysts and Fe(II)L exhibits high catalytic performance for degradation of hydroxypropyl guar gum in a wide pH range 7.0–13.0. The viscosity of hydroxypropyl guar gum can be reduced with the 10.0% H2O2 and 5.0% Fe(II)L. The viscosity average molecular weight of hydroxypropyl guar gum was decreased from almost 2 million to 3,199. Most important of all, the chemical oxygen demand (COD) value can be decreased to 104 mg/L from 8,080 mg/L with enough H2O2, and Fe(II)L also shows great catalytic ability in the degradation of various polymers by H2O2. The proposed mechanism of the activation of H2O2 by the complex was studied.

Bis-cycloheptyl-fused bis(imino)pyridine-cobalt catalysts for PE wax formation: positive effects of fluoride substitution on catalytic performance and thermal stability

2020 ◽  
Vol 49 (27) ◽  
pp. 9425-9437 ◽  
Author(s):  
Qiuyue Zhang ◽  
Ningning Wu ◽  
Junfeng Xiang ◽  
Gregory A. Solan ◽  
Hongyi Suo ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Ethylene Polymerization ◽  
Catalytic Performance ◽  
Cobalt Catalysts ◽  
Low Molecular Weight ◽  
Polymerization Catalysts ◽  
Positive Effects

The depicted ethylene polymerization catalysts exhibited optimal activities at 60 °C forming low molecular weight PE waxes; ortho-F substitution proved beneficial.

Synthesis of Polycarboxylate: Its Characterization and Application as a Superplasticizer in Concrete

2012 ◽  
Vol 204-208 ◽  
pp. 4181-4186
Author(s):  
Xiang Yin Mo ◽  
Xian San Feng ◽  
Chen Jie Yu ◽  
Ying Jie Jing
Keyword(s):  
Molecular Weight ◽  
Reaction Time ◽  
Cement Paste ◽  
Reaction Temperature ◽  
Methyl Acrylate ◽  
Average Molecular Weight ◽  
Monomethyl Ether ◽  
Noticeable Effect ◽  
Flow Test ◽  
Weight Effect

Polycarboxylate was synthesized by using polyethylene glycol monomethyl ether methyl-acrylate (PEG16), methylacrylamide sodium (MAS), methacrylic acid (MAA), methyl acrylate (MA), acryl amide (AM), and sodium persulfate (SPS) and evaluated as a superplasticizer for cement particles. The formulation of the superplasticizer: n (PEG16): n (MAS): n (MAA): n (MA): n (AM) =10:18:20:37:20, and the content of the SPS was 1.2wt% of all the monomers and optimized reaction conditions (80°C, 6h) were obtained via orthogonal test and single factor experiments. The water reducing effect of the synthesized copolymers was studied in terms of reaction temperature, reaction time and PEG side chain length. In this study, flow test of cement paste measurements were performed to compare the molecular weight effect on fluidity of the copolymers. It was observed that the reaction temperature had a noticeable effect on the molecular weight of the PEG-grafted samples thus causing a significant effect on fluidity. The polycarboxylate synthesized at about 80°C has given the highest fluidity result. In addition, the reaction time 6~7 hrs was identified for the best. Furthermore, copolymers with mPEG side chains with a degree of 16 gave the highest fluidity and viscosity average molecular weight value. The initial fluidity of the cement paste containing the prepared superplasticizer (1wt%, w(water)/w(cement)=(0.29)) was 316 mm.

scholarly journals Bis(η5-cyclopentadienyl)bistriphenylsilanolatozirconium( IV): a new precursor for ethylene polymerization catalysis

e-Polymers ◽  
2001 ◽  
Vol 1 (1) ◽  
Author(s):  
Angelina Altomare ◽  
Roberta Candian ◽  
Marco Michelotti ◽  
Guido Pampaloni ◽  
Francesco Ciardelli
Keyword(s):  
Molecular Weight ◽  
Ethylene Polymerization ◽  
Catalytic Performance ◽  
Ligand Substitution ◽  
Polymerization Catalysis ◽  
Comparable Activity

AbstractTrialkylsilanols were reported to modify and also to improve the catalytic performance in ethylene polymerization when added to zirconocene/methylaluminoxane (MAO) systems. In order to obtain more information about the chemistry involved, a new stable catalytic precursor was investigated in this work. The precursor bis(h5-cyclopentadienyl)bistriphenylsilanolatozirconium(IV) [ZrCp2(OSiPh3)2] was compared to ZrCp2(CH3)2 and ZrCp4, which can generate ZrCp2(OSiPh3)2 in situ on triphenylsilanol addition. In ethylene polymerization, ZrCp2(OSiPh3)2 exibits a comparable activity and a larger stability than dicyclopentadienylzirconium complexes. On addition of triphenylsilanol to zirconocenes, the productivity increased and the molecular weight sharply decreased, thus suggesting the occurrence of ligand substitution in solution. The reported results are discussed with reference to the proposed mechanism of ethylene polymerization with the conventional ZrCp2Cl2/MAO system.

scholarly journals Reduced Polymerization of Willebrand Factor in a Family of Pigs with a Variant of von Willebrand’s Disease

1977 ◽  
Author(s):  
D. N. Fass ◽  
E. J. W. Bowie
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Sodium Dodecyl ◽  
Factor Activity ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Severe Reduction ◽  
Genetically Determined ◽  
Willebrand Factor ◽  
Very High

Sodium dodecyl sulfate electrophoresis on 2% agarose allows the separation of porcine Willebrand factor into multiple macromolecular complexes from 1.5 million to 21 million, molecular weight. In non-denaturing buffers these forms are resistant to alteration by 10-4M mercaptoethanol, reduced glutathione, or cysteine. At sulfhydryl concentrations of 10-4M both dithiothreitol (DTT) and dithioerythritol (DTE) seem to catalyze disulfide interchange evidence by the appearance of very high molecular weight polymers. Both DTT and DTE in the absence of detergent or other denaturants lowered the average complex size at sulfhydryl concentration of 10-3M. Concomitant with the reduction in average polymer size there was a loss of ristocetin-Willebrand factor activity. A severe reduction of average molecular weight was found to be a characteristic of the Willebrand factor found in a genetically determined variant of the porcine model of von Willebrand’s disease. These observations provide a molecular basis for a qualitative version of the porcine disease in contrast to all previously described affected pigs which suffer a quantitative defieiency of Willebrand factor activity and antigen.

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