A Highly Active and Recyclable Catalytic System for CO2/Propylene Oxide Copolymerization

2008 ◽  
Vol 120 (38) ◽  
pp. 7416-7419 ◽  
Author(s):  
Sujith S ◽  
Jae Ki Min ◽  
Jong Eon Seong ◽  
Sung Jea Na ◽  
Bun Yeoul Lee
Keyword(s):  
Catalytic System ◽  
Propylene Oxide ◽  
Highly Active

A Highly Active and Recyclable Catalytic System for CO2/Propylene Oxide Copolymerization

2008 ◽  
Vol 47 (38) ◽  
pp. 7306-7309 ◽  
Author(s):  
Sujith S ◽  
Jae Ki Min ◽  
Jong Eon Seong ◽  
Sung Jea Na ◽  
Bun Yeoul Lee
Keyword(s):  
Catalytic System ◽  
Propylene Oxide ◽  
Highly Active

Deactivation of arenetitanium(II) bromoalane complexes in the cyclotrimerization of butadiene

1986 ◽  
Vol 51 (12) ◽  
pp. 2751-2759 ◽  
Author(s):  
Jindřich Poláček ◽  
Helena Antropiusová ◽  
Lidmila Petrusová ◽  
Karel Mach
Keyword(s):  
Catalytic Activity ◽  
Catalytic System ◽  
Model System ◽  
Highly Active ◽  
Catalytic Stability

The C6H6.Ti(II)(AlBr4)2 (Ib) catalyst deactivates during the butadiene cyclotrimerization to give a solid containing all titanium (mostly as TiBr3) and a mixture of AlBr3 and RAlBr2 compounds dissolved in benzene. The residual cationic catalytic activity of the deactivated Ib system is due to presence of AlBr3. In contrast to TiCl3, the deactivated Ib system and the model system TiBr3 + AlBr3 are not activated by the addition of EtAlCl2 in the presence of butadiene: the highly active benzenetitanium(II) system is re-constituted only after reduction of TiBr3 with Et3Al followed by the addition of EtAlCl2. The addition of Et2AlBr to Ib accelerates the deactivation of the system. Deactivation products of this system contain mainly Ti(II) species which forms benzenetitanium(II) catalytic system after addition of EtAlCl2. All the EtAlCl2 reactivated systems produce (Z, E, E)-1,5,9-cyclododecatriene with high catalytic stability and considerable selectivity (>90%). This behaviour points to the catalysis by benzenetitanium(II) chloroalane complexes containing only low amount of bromine atoms and ethyl groups.

Sodium complexes bearing cavity-like conformations: a highly active and well-controlled catalytic system for macrolactone homo- and copolymerization

2021 ◽  
Vol 12 (13) ◽  
pp. 1957-1966
Author(s):  
Xinya Wang ◽  
Xiaohua Wang ◽  
Nuo Zhen ◽  
Jin Gu ◽  
Hao Zhang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Highly Active ◽  
Sodium Complexes

Sodium complexes displaying cavity-like conformations and, therefore, suppressed transesterification during the ring-opening polymerization of pentadecalactone are disclosed herein.

Elucidation of the Structure of a Highly Active Catalytic System for CO2/Epoxide Copolymerization: A salen-Cobaltate Complex of an Unusual Binding Mode

2009 ◽  
Vol 48 (21) ◽  
pp. 10455-10465 ◽  
Author(s):  
Sung Jae Na ◽  
Sujith S ◽  
Anish Cyriac ◽  
Bo Eun Kim ◽  
Jina Yoo ◽  
...  
Keyword(s):  
Catalytic System ◽  
Binding Mode ◽  
Highly Active

scholarly journals Ruthenium-Based Catalytic Systems Incorporating a Labile Cyclooctadiene Ligand with N-Heterocyclic Carbene Precursors for the Atom-Economic Alcohol Amidation Using Amines

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2413 ◽  
Author(s):  
Cheng Chen ◽  
Yang Miao ◽  
Kimmy De Winter ◽  
Hua-Jing Wang ◽  
Patrick Demeyere ◽  
...  
Keyword(s):  
Catalytic System ◽  
High Resolution Mass Spectrometry ◽  
Amide Bond ◽  
Catalyst Loading ◽  
Catalytic Systems ◽  
Amide Bond Formation ◽  
Highly Active ◽  
Metal Catalyzed ◽  
Ru Species

Transition-metal-catalyzed amide-bond formation from alcohols and amines is an atom-economic and eco-friendly route. Herein, we identified a highly active in situ N-heterocyclic carbene (NHC)/ruthenium (Ru) catalytic system for this amide synthesis. Various substrates, including sterically hindered ones, could be directly transformed into the corresponding amides with the catalyst loading as low as 0.25 mol.%. In this system, we replaced the p-cymene ligand of the Ru source with a relatively labile cyclooctadiene (cod) ligand so as to more efficiently obtain the corresponding poly-carbene Ru species. Expectedly, the weaker cod ligand could be more easily substituted with multiple mono-NHC ligands. Further high-resolution mass spectrometry (HRMS) analyses revealed that two tetra-carbene complexes were probably generated from the in situ catalytic system.

A Highly Active, Isospecific Cobalt Catalyst for Propylene Oxide Polymerization

2005 ◽  
Vol 127 (33) ◽  
pp. 11566-11567 ◽  
Author(s):  
Kathryn L. Peretti ◽  
Hiroharu Ajiro ◽  
Claire T. Cohen ◽  
Emil B. Lobkovsky ◽  
Geoffrey W. Coates
Keyword(s):  
Propylene Oxide ◽  
Cobalt Catalyst ◽  
Highly Active

scholarly journals Gas-Phase Epoxidation of Propylene to Propylene Oxide on a Supported Catalyst Modified with Various Dopants

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 638 ◽  
Author(s):  
Sugiyama ◽  
Sakuwa ◽  
Ogino ◽  
Sakamoto ◽  
Shimoda ◽  
...  
Keyword(s):  
Gas Phase ◽  
Propylene Oxide ◽  
Active Catalyst ◽  
Supported Catalyst ◽  
Acid Base ◽  
Epoxidation Of Propylene ◽  
Highly Active ◽  
Acidic Catalysts ◽  
Carbonate Species ◽  
Metal Doped

In the present study, the production of propylene oxide (PO) from propylene via gas-phase epoxidation was investigated using various catalysts. Although Ag is known to be a highly active catalyst for the epoxidation of ethylene, it was not active in the present reaction. Both Al and Ti showed high levels of activity, however, which resulted in confusion. The present study was conducted to solve such confusion. Although the employment of MCM-41 modified with Ti and/or Al was reported as an active catalyst for epoxidation, the combination resulted in the formation of PO at a less than 0.1% yield. Since this research revealed that the acidic catalyst seemed favorable for the formation of PO, versions of ZSM-5 that were both undoped and doped with Na, Ti, and Ag were used as catalysts. In these cases, small improvements of 0.67% and 0.57% were achieved in the PO yield on H‒ZSM-5 and Ti‒ZSM-5, respectively. Based on the results of the Ti-dopant and acidic catalysts, Ag metal doped on carbonate species with a smaller surface area was used as a catalyst. As reported, Ag‒Na/CaCO3 showed a greater yield of PO at 1.29%. Furthermore, the use of SrCO3 for CaCO3 resulted in a further improvement in the PO yield to 2.17%. An experiment using CO2 and NH3 pulse together with SEM and TEM examinations for Ag‒Na/CaCO3 revealed that the greatest activity was the result of the greater particle size of metallic Ag rather than the acid‒base properties of the catalysts.

scholarly journals The effect of the components of the PdCl2/Fe/I2/Py catalytic system on nitrobenzene carbonylation to ethyl N-phenylcarbamate

2005 ◽  
Vol 3 (1) ◽  
pp. 28-39 ◽  
Author(s):  
Jadwiga Skupińska ◽  
Monika Karpińska ◽  
Maria Ołówek ◽  
Teresa Kasprzycka-Guttman
Keyword(s):  
Catalytic System ◽  
Considerable Increase ◽  
Constant Level ◽  
The Other ◽  
Reaction Products ◽  
Highly Active

AbstractThe PdCl2/Fe/I2/Py catalytic system (Py-pyridine), reported to be highly active in the reaction of nitrobenzene carbonylation to ethyl phenylcarbamate was studied. The present paper describes the role of catalyst components and its effect on the activity and selectivity of the catalyst. The increase in the amount of PdCl2 in the system while retaining a constant level of the other catalyst components, results in the increase of both carbamate and aniline yields. The increase in the amount of iron while retaining the other components constant, initially causes an increase in the carbamate yield; however, at Fe: Pd ratios higher than 36, the carbamate yield remains constant. The change in the amount of iron has no effect on the amount of aniline formed in the system. An increase in the amount of iodine in the system while retaining the other components constant, results in a decrease in carbamate yield and a considerable increase in the aniline yield of the reaction products.

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