Ethene/Norbornene Copolymerization with (Isodicyclopentadienyl)titanium Complex-MAO Catalyst

2007 ◽  
Vol 72 (5-6) ◽  
pp. 697-702 ◽  
Author(s):  
Sébastien Gentil ◽  
Nadine Pirio ◽  
Philippe Meunier ◽  
Fabrice Gallou ◽  
Leo A. Paquette
Keyword(s):  
Catalytic System ◽  
Catalyst System ◽  
Titanium Complex ◽  
Titanium Dichloride

Norbornene (NB) homopolymerization and ethene/NB copolymerizations with a silylene-bridged (isodicyclopentadienyl)(tert-butylamido)titanium dichloride-methylalumoxane (MAO) catalyst system were investigated. This catalytic system shows no efficiency towards NB homopolymerization but produces poly(ethene-co-norbornene)s. An increase in the initial NB feed content leads to a loss of copolymerization activity as well as NB copolymer incorporation. The structure of the isodicyclopentadienyl fragment (IsodiCp) has a strong limiting effect on comonomer incorporation possibilities.

Metathetical Degradation and Depolymerization of Unsaturated Polymers

1997 ◽  
Vol 70 (3) ◽  
pp. 519-529 ◽  
Author(s):  
J. C. Marmo ◽  
K. B. Wagener
Keyword(s):  
Molecular Weight ◽  
Transition Metal ◽  
Catalytic System ◽  
Lewis Acid ◽  
Catalyst System ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Side Reactions

Abstract The employment of transition metal catalysts has been a viable route in the degradation and depolymerization of unsaturated polymers. Initially, unsaturated polymers were degraded with a catalytic system containing a transition metal and a Lewis acid cocatalyst (WCl6/SnBu4). Degradation chemistry was effective in reducing the molecular weight of the polymer, however, the classical catalyst system induces side reactions which generates ill-defined products. These side reactions were obviated by using a preformed alkylidene without a Lewis acid cocatalyst, and perfectly difunctional telechelics were synthesized.

scholarly journals Effects of Various Mixed Metal Chlorides- AlCl3 in TiCl4/MgCl2/THF Catalytic System on Ethylene Polymerization

2015 ◽  
Vol 14 (2) ◽  
pp. 12
Author(s):  
Nittaya Sudsong ◽  
Wanna Phiwkliang ◽  
Bunjerd Jongsomjit ◽  
Piyasan Praserthdam
Keyword(s):  
Catalytic System ◽  
Ethylene Polymerization ◽  
Catalyst System ◽  
Polymerization Reaction ◽  
Molar Ratio ◽  
Metal Chlorides ◽  
Mixed Metal ◽  
Icp Analysis ◽  
Co Addition

In this research, the modification of TiCl4/MgCl2/THF catalyst system with various metal chlorides was investigated on ethylene polymerization. Experimentally, metal chlorides (CaCl2, FeCl2 and ZnCl2) were simultaneously introduced different with TiCl4/MgCl2/THF catalyst. ICP analysis was used to determine the total amount of each metal in the catalyst. For polymerization reaction, TEA was used as cocatalyst and hexane was used as a medium solvent. The Al/Ti molar ratio was 140. The activity result of Ca-Al, Zn-Al and Fe-Al was 979, 1009 and 1476 kgPE/molTi.h, respectively. The coaddition of AlCl3 and FeCl2 in TiCl4/MgCl2/THF catalyst system exhibited the highest activity. It suggested that the co-addition of AlCl3 and FeCl2 has higher electronegativity (EN) and the radius of Fe2+ is closer to Mg2+ resulting in an increased efficiency of the THF removal. This result led to improve the catalyst performance.

Modeling of the Kinetic Experiment of Dicyclopentadiene Olygomerization

2014 ◽  
Vol 880 ◽  
pp. 205-211 ◽  
Author(s):  
Alexey Lyapkov ◽  
Vladimir Bondaletov ◽  
Elena Melnik ◽  
Georgy Borisov
Keyword(s):  
Experimental Data ◽  
Catalytic System ◽  
Ion Pairs ◽  
Effective Rate Constant ◽  
Catalyst System ◽  
Effective Rate ◽  
Probable Mechanism ◽  
Raw Material ◽  
Kinetic Experiment ◽  
System Components

Regularities of the dicyclopentadiene cationic oligomerization under influence of the catalytic system AlEt2Cl: TiCl4 in toluene solution were studied. The most probable mechanism of polymerization in this system is the propagation chain on the contact or solvate-separated ion pairs. The effective rate constant of solvation of the catalyst and chain propagation were calculated. The thermal oligomerization effect and heat of the catalyst system components solvation are determined by heat of oligomerization raw material containing dicyclopentadiene. When taking into account the data of both material and thermal balance the experimental data were described adequately.

scholarly journals The impact of a binary catalyst system «tereftal + ascorbic acid» on the central nervous system

2017 ◽  
Vol 16 (2) ◽  
pp. 42-49
Author(s):  
N. P. Ermakova ◽  
S. S. Trofimov ◽  
N. Y. Kulbachevskaya ◽  
O. I. Konyaeva ◽  
V. M. Bukhman ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Ascorbic Acid ◽  
Nervous System ◽  
Body Temperature ◽  
Open Field ◽  
Catalytic System ◽  
Catalyst System ◽  
Emotional Status ◽  
The Central Nervous System ◽  
Binary Catalyst

Introduction. Neurotoxicity is one of the specific systemic complications of anticancer chemotherapy. Detection in experimental animals complications of psychotropic or neurotropic action of the new drug is one of the most difficult challenges of preclinical toxicology. Preclinical toxicological study of the effect of a binary catalyst system «tereftal + ascorbic acid» on the central nervous system (CNS). Objective. The prediction of toxic effects of binary catalytic system in clinical application in patients. Materials and methods. The study was conducted on 300 male mice hybrids (CBA х C57 Bl/6J) F1. Have terephtal - russian drug. A binary catalyst system was injected intravenously once at close to the maximum tolerated dose - 50 mg/kg tereftal + 110 mg/kg ascorbic acid and in therapeutic dose - 20 mg/kg tereftal + 44 mg/kg ascorbic acid. The obtained data were compared with a control animal treated with saline solution and with the data of animals treated with one tereftal and one ascorbic acid in equivalent doses. To assess neurotoxicity tests used standard neuropharmacological screening. An assessment of emotional status, muscle tone were undertaken. Behavior was evaluated in the tests «open field» and «aggression». We evaluated the response to pain stimulation, the change in rectal body temperature. Higher integrative brain functions were investigated on the model of the conditioned reflex of passive avoidance. Estimated effect on convulsive readiness of the CNS. Results. The catalytic system changed the general condition of the animals. This was manifested, on the one hand, in the suppression of their overall activity (sluggishness, inactivity until weakness, muscle relaxation, the lowering side, the slowing of breathing), the other - to increase their excitability (when in group, some animals adopted a characteristic aggressive stands, in some cases seizures). These animals were observed exophthalmos, the appearance of the position «frog», posture «praying mouse», the desire to hide. The inhibitory effect of the catalytic system was dose-dependent. Observed inhibition of various forms of behavior, emotional status, decrease in body temperature and pain sensitivity, in the test for aggression - reducing the number of fights, in open field test - locomotor activity suppression. Spontaneous seizures in the provocation corazol binary catalytic system was not strengthened. Conclusion. The obtained data allow to predict toxic effects from the CNS during clinical use of binary catalytic system «tereftal + ascorbic acid»: total confusion, lethargy, physical inactivity, decrease in body temperature, increased anxiety and aggression and, in very rare cases, the occurrence of seizures.

scholarly journals Kinetic Insights into Cyanosilylation of Aldehydes Catalyzed by a Covalently Bridged Dinuclear (Salen)titanium Complex

2020 ◽  
Author(s):  
Zhipeng Zhang ◽  
Zheng Wang ◽  
Kuiling Ding
Keyword(s):  
Asymmetric Catalysis ◽  
Catalytic System ◽  
Catalytic Mechanism ◽  
Organic Reactions ◽  
Kinetic Investigation ◽  
Chiral Catalysts ◽  
Titanium Complex ◽  
Trimethylsilyl Cyanide ◽  
First Order ◽  
Dual Activation

Enantioselective addition of trimethylsilyl cyanide (TMSCN) to aldehydes is one of the most extensively studied organic reactions in asymmetric catalysis. Herein, we report our intensive kinetic investigation on the asymmetric addition of TMSCN to benzaldehyde, catalyzed by a covalently bridged dinuclear (salen)titanium complex <b>2</b>, which has been one of the most efficient artificial chiral catalysts reported so far for this reaction. It was found that the method of initial rates for kinetic investigation is not appropriate in this case because of the presence of a significant <a></a><a>incubation </a>period in the catalysis, while the method of progress rates proved to be more reliable and efficient for judging the kinetic orders of this catalytic system. The kinetic results revealed that <a>the reaction follows first order with respect to the catalyst</a> and is nearly independent of concentrations of both benzaldehyde and TMSCN<a>. A detailed catalytic mechanism for cyanosilylation of benzaldehyde in the presence of <b>2</b> was proposed, wherein the key active dinuclear species works in a cooperative manner for dual activation of both reactants.</a>

Bimetallic titanium complex catalyzed enantioselective oxidation of thioethers using aqueous H2O2 as a terminal oxidant

RSC Advances ◽  
2015 ◽  
Vol 5 (59) ◽  
pp. 47732-47739 ◽  
Author(s):  
Prasanta Kumar Bera ◽  
Naveen Gupta ◽  
Sayed H. R. Abdi ◽  
Noor-ul H. Khan ◽  
Rukhsana I. Kureshy ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic System ◽  
Sulfide Oxidation ◽  
Environmentally Benign ◽  
Aqueous Hydrogen Peroxide ◽  
Titanium Complex ◽  
Enantioselective Oxidation ◽  
Highly Efficient

This study represents a highly efficient sulfide oxidation catalytic system using a non-toxic Ti-catalyst and environmentally benign aqueous hydrogen peroxide.

One-pot copolymerization of epoxides/carbon dioxide and lactide using a ternary catalyst system

2018 ◽  
Vol 8 (24) ◽  
pp. 6452-6457 ◽  
Author(s):  
Xiang Li ◽  
Chenyang Hu ◽  
Xuan Pang ◽  
Ranlong Duan ◽  
Xuesi Chen
Keyword(s):  
Carbon Dioxide ◽  
Catalytic System ◽  
Chain Transfer ◽  
Catalyst System ◽  
Transfer Mechanism ◽  
One Pot ◽  
Multiblock Copolymer ◽  
System P ◽  
Ternary Catalyst

A PLA/PPC multiblock copolymer was prepared using a novel ternary catalytic system that proceeds via an intermolecular chain transfer mechanism.

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