A Novel Single-Site Catalyst for Olefin Polymerization

2010 ◽  
Vol 657 ◽  
pp. 83-87
Author(s):  
Sriram Venkataramani ◽  
Tharanikkarasu Kannan
Keyword(s):  
Ethylene Polymerization ◽  
Titanium Tetrachloride ◽  
Olefin Polymerization ◽  
Single Site ◽  
Turnover Frequency ◽  
Reaction Conditions ◽  
Co Catalyst ◽  
Infra Red ◽  
Turn Over Frequency ◽  
Turn Over

A novel single-site catalyst was prepared from N-pheneyldiethanolamine and titanium tetrachloride and characterized using spectroscopic methods such as Nuclear Magnetic Resonance (NMR) spectroscopy and Infra Red (IR) spectroscopy. It was prepared insitu and used to polymerize ethylene along with methylaluminoxane (MAO) as co-catalyst. The turnover frequency for ethylene polymerization was found to be 350 g and 550g polymer/mol catalyst/h for 1 bar and at 2 bar respectively. As the turn over frequency at the studied reaction conditions is good, the present N-pheneyldiethanolamine-based catalyst is a good single-site catalyst for olefin polymerization

scholarly journals Synthesis and Characterization of Novel Phyto-Mediated Catalyst, and Its Application for a Selective Oxidation of (VAL) into Vanillin under Visible Light

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 839 ◽  
Author(s):  
Afnan Al-Hunaiti ◽  
Qassem Mohaidat ◽  
Ibrahim Bsoul ◽  
Sami Mahmood ◽  
Deeb Taher ◽  
...  
Keyword(s):  
Visible Light ◽  
Selective Oxidation ◽  
Vanillyl Alcohol ◽  
Reaction Conditions ◽  
Excellent Photocatalytic Activity ◽  
Lignin Model ◽  
Turn Over Frequency ◽  
Average Size ◽  
Turn Over

Here, we report an efficient and highly selective oxidation of lignin model substrate using phyto-mediated ZnFe2O4 nanoparticle using Boswellia carterii extract. The nanocatalyst with an average size of 8 nm showed excellent photocatalytic activity of the synthesized carbonyl containing products under visible light irradiation. The catalytic activity and selectivity towards oxidation of vanillyl alcohol to vanillin with selectivity up to 99% at conversion over 98% and turn-over frequency values up to 1600 h−1 were obtained in the presence of H2O2 and base. The cubic spinel nano-ZnFe2O4 catalyst was characterized by powder-XRD, FESEM, HR-TEM and Mössbauer analysis. The demonstrated catalyst was robust and stable under the reaction conditions. Furthermore, it was easy to be separated from the reaction mixture and be reused for subsequent reactions up to 5 times without significant reactivity or selectivity loss.

Synthesis of long chain aliphatic ester and its titanium complexes for ethylene polymerization

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Umesh Makwana ◽  
Bhavesh K. Desai ◽  
Hiren M. Bhajiwala ◽  
Gurmeet Singh ◽  
Rajendra B. Patankar ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Nmr Spectroscopy ◽  
Energy Efficient ◽  
Ethylene Polymerization ◽  
Titanium Tetrachloride ◽  
Thermal Characteristics ◽  
Isopropyl Myristate ◽  
Co Catalyst ◽  
Aliphatic Ester ◽  
Long Chain

AbstractLong chain aliphatic ester, isopropyl myristate, was synthesized using energy efficient microwave irradiation technique. The iso propyl myristate forms complexes with titanium tetrachloride in different mole ratios. The nature of chemical bonding between the titanium and the ester functionality was investigated by FTIR and NMR spectroscopy. The performance of synthesized complexes with methylalumoxane as co-catalyst for ethylene polymerization was found to depend on the nature of complex and polymerization parameters. Molecular weight and thermal characteristics of polyethylene was also investigated.

Facile synthesis of cubical Co3O4 supported Au nanocomposites with high activity for the reduction of 4-nitrophenol to 4-aminophenol

RSC Advances ◽  
2016 ◽  
Vol 6 (39) ◽  
pp. 32430-32433 ◽  
Author(s):  
Yuwen Yang ◽  
Yongyun Mao ◽  
Bin Wang ◽  
Xianwei Meng ◽  
Jiao Han ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Activity ◽  
Impregnation Method ◽  
Facile Synthesis ◽  
Turn Over Frequency ◽  
Turn Over

A facile impregnation method has been successfully applied for synthesis of a cubical Co3O4 supported Au nanocomposites, which leads to the excellent catalytic activity for the reduction of 4-nitrophenol with a high turn over frequency of 9.83 min−1.

scholarly journals Inverse single-site Fe1(OH)X/Pt(111) model catalyst for preferential oxidation of CO in H2

Nano Research ◽  
2021 ◽  
Author(s):  
Chunlei Wang ◽  
Heloise Tissot ◽  
Markus Soldemo ◽  
Junling Lu ◽  
Jonas Weissenrieder
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Redox Properties ◽  
Model Catalyst ◽  
Single Site ◽  
Oxide Nanoparticles ◽  
Preferential Oxidation ◽  
Oxidation Of Co ◽  
Reaction Conditions ◽  
Preferential Oxidation Of Co

AbstractInverse oxide/metal model systems are frequently used to investigate catalytic structure-function relationships at an atomic level. By means of a novel atomic layer deposition process, growth of single-site Fe1Ox on a Pt(111) single crystal surface was achieved, as confirmed by scanning tunneling microscopy (STM). The redox properties of the catalyst were characterized by synchrotron radiation based ambient pressure X-ray photoelectron spectroscopy (AP-XPS). After calcination treatment at 373 K in 1 mbar O2 the chemical state of the catalyst was determined as Fe3+. Reduction in 1 mbar H2 at 373 K demonstrates a facile reduction to Fe2+ and complete hydroxylation at significantly lower temperatures than what has been reported for iron oxide nanoparticles. At reaction conditions relevant for preferential oxidation of CO in H2 (PROX), the catalyst exhibits a Fe3+ state (ferric hydroxide) at 298 K while re-oxidation of iron oxide clusters does not occur under the same condition. CO oxidation proceeds on the single-site Fe1(OH)3 through a mechanism including the loss of hydroxyl groups in the temperature range of 373 to 473 K, but no reaction is observed on iron oxide clusters. The results highlight the high flexibility of the single iron atom catalyst in switching oxidation states, not observed for iron oxide nanoparticles under similar reaction conditions, which may indicate a higher intrinsic activity of such single interfacial sites than the conventional metal-oxide interfaces. In summary, our findings of the redox properties on inverse single-site iron oxide model catalyst may provide new insights into applied Fe-Pt catalysis.

Single-Site Heterogeneous Catalysts for Olefin Polymerization Enabled by Cation Exchange in a Metal-Organic Framework

2016 ◽  
Vol 138 (32) ◽  
pp. 10232-10237 ◽  
Author(s):  
Robert J. Comito ◽  
Keith J. Fritzsching ◽  
Benjamin J. Sundell ◽  
Klaus Schmidt-Rohr ◽  
Mircea Dincă
Keyword(s):  
Cation Exchange ◽  
Heterogeneous Catalysts ◽  
Olefin Polymerization ◽  
Metal Organic Framework ◽  
Single Site ◽  
Metal Organic ◽  
Organic Framework

The Effect of Dicarboxylic Acid Catalyst Structure on Hydrolysis of Cellulose Model Compound D-Cellobiose in Water

2021 ◽  
Vol 08 ◽  
Author(s):  
Harshica Fernando ◽  
Ananda S. Amarasekara
Keyword(s):  
Dicarboxylic Acid ◽  
Model Compound ◽  
Acid Catalyst ◽  
Catalytic Activities ◽  
Polycarboxylic Acids ◽  
Hydrolysis Of Cellulose ◽  
Phthalic Acids ◽  
Turn Over Frequency ◽  
Turn Over ◽  
Hydrolysis Of

Background: Polycarboxylic acids are of interest as simple mimics for cellulase enzyme catalyzed depolymerization of cellulose. In this study, DFT calculations were used to investigate the effect of structure on dicarboxylic acid organo-catalyzed hydrolysis of cellulose model compound D-cellobiose to D-glucose. Methods: Binding energy of the complex formed between D-cellobiose and acid (Ebind), as well as glycosidic oxygen to dicarboxylic acid closest acidic H distance were studied as key parameters affecting the turn over frequency of hydrolysis in water. Result: α-D-cellobiose - dicarboxylic acid catalyst down face approach showed high Ebind values for five of the six acids studied; indicating the favorability of down face approach. Maleic, cis-1,2-cyclohexane dicarboxylic, and phthalic acids with the highest catalytic activities showed glycosidic oxygen to dicarboxylic acid acidic H distances 3.5-3.6 Å in the preferred configuration. Conclusion: The high catalytic activities of these acids may be due to the rigid structure, where acid groups are held in a fixed geometry.

scholarly journals Molecular weight control in organochromium olefin polymerization catalysis by hemilabile ligand–metal interactions

2016 ◽  
Vol 12 ◽  
pp. 1372-1379 ◽  
Author(s):  
Stefan Mark ◽  
Hubert Wadepohl ◽  
Markus Enders
Keyword(s):  
Ethylene Polymerization ◽  
Weight Control ◽  
Transfer Reactions ◽  
High Catalytic Activity ◽  
Co Catalyst ◽  
Metal Centers ◽  
Molecular Weights ◽  
Metal Interactions ◽  
Polymerization Catalysis ◽  
Very High

A series of Cr(III) complexes based on quinoline-cyclopentadienyl ligands with additional hemilabile side arms were prepared and used as single-site catalyst precursors for ethylene polymerization. The additional donor functions interact with the metal centers only after activation with the co-catalyst. Evidence for this comes from DFT-calculations and from the differing behavior of the complexes in ethylene polymerization. All complexes investigated show very high catalytic activity and the additional side arm minimizes chain-transfer reactions, leading to increase of molecular weights of the resulting polymers.

Sign in / Sign up

Export Citation Format

Share Document