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Poirier V.,French National Center for Scientific Research | Duc M.,Total Petrochemicals Research | Carpentier J.-F.,French National Center for Scientific Research | Sarazin Y.,French National Center for Scientific Research
ChemSusChem | Year: 2010

An efficient, practical, and industrially relevant procedure for the production of polymer materials, in which a part of the oilderived polyolefins has been replaced by a renewable, biodegradable, and biocompatible poly(lactide) block, is presented. Binary catalytic systems combining innocuous metals (yttrium, zinc, magnesium, or calcium) and bifunctional alcohols (acting as transfer agents) were developed to promote the immortal ring-opening polymerization of lactide directly in styrene. Up to 20000 equivalents of lactide were polymerized (metal catalyst loading of 50-100 ppm) in a controlled fashion in the presence of 10-100 equivalents of a double-headed transfer agent to give as many end-functionalized poly(lactide) macromolecules that can be used eventually as macroinitiators for the controlled nitroxide-mediated polymerization of styrene. The specific use of the sterically shielded complex [BDI-iPr]Zn-N(SiMe3)2 ([BDI-iPr]=bis(diketiminate) ligand) allowed the efficient, catalytic, and controlled production of poly(lactide)block-poly(styrene) materials in a one-pot, solvent-free sequential procedure, with nearly 100% atom-efficiency. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Asachenko A.F.,Moscow State University | Kononovich D.S.,Moscow State University | Zharov A.N.,Moscow State University | Razavi A.,Total Petrochemicals Research | Voskoboynikov A.Z.,Moscow State University
Journal of Organometallic Chemistry | Year: 2010

Tetrahydroindenes including spiro-cyclopentyl and -cyclohexyl fragments were successfully synthesized either via base-catalyzed cyclization of the respective γ-diketone or via acid-catalyzed Nazarov cyclization of the corresponding divinylketones. These substituted cyclopentadienes were metallated with nBuLi. The following reaction of the lithium salts with Cp (*)ZrCl3 gave three novel zirconocenes bearing spiro-cycloalkane fragments. One of these complexes, (η5- 5′,6′,7′-trihydrospiro[cyclohexane-1,4′-(2- methylindenyl)])(η5-pentamethyl-cyclopentadienyl)zirconium dichloride, has been characterized by X-ray crystal structure analysis. Tetrahydroindenes including spiro-cyclopentyl and -cyclohehyl fragments were successfully synthesized either via base-catalyzed cyclization of the respective γ-diketone or via acid-catalyzed Nazarov cyclization of the corresponding divinylketones. These substituted cyclopentadienes were metallated with nBuLi. The following reaction of the lithium salts with Cp (*)ZrCl3 gave three novel zirconocenes bearing spiro-cycloalkane fragments. © 2010 Elsevier B.V. All rights reserved.


Grasso G.,CNRS Research on Catalysis and Environment in Lyon | Grasso G.,Total Petrochemicals Research | Schaefer G.,Atotech Deutschland Gmbh | Schuurman Y.,CNRS Research on Catalysis and Environment in Lyon | Mirodatos C.,CNRS Research on Catalysis and Environment in Lyon
Topics in Catalysis | Year: 2011

The steam reforming of methane was studied over microstructured platelets coated with catalysts and assembled as microreactors. Three different bonding procedures have been applied to assemble the microchannel platelets. The effect of the assembly procedure on the catalytic performance has been investigated for both nickel and rhodium based catalysts. The brazing technology leads, contrary to laser welding, to fully connected platelets resulting in a superior catalytic activity due to better heat transfer and gas flow distribution. Outstanding performances in term on hydrogen productivity and catalytic stability are obtained on the low temperature brazed system washcoated with a Rh-alumina catalyst. © 2011 Springer Science+Business Media, LLC.


Helou M.,CNRS Chemistry Institute of Rennes | Miserque O.,Total Petrochemicals Research | Brusson J.-M.,Total Petrochemicals Research | Carpentier J.-F.,CNRS Chemistry Institute of Rennes | Guillaume S.M.,CNRS Chemistry Institute of Rennes
ChemCatChem | Year: 2010

abs The controlled "immortal" ring-opening polymerization of trimethylene carbonate (TMC) using a two-component catalyst system based on a metal Lewis acid, such as a metal triflate M(OTf)n (M=Ca, Sc, Zn, Al, Bi; OTf=CF3SO3 -) or the metallic salt Fe(acac)3, (acac=acetylacetonate) and an alcohol (ROH) as co-initiator and chain-transfer agent, is carried out in bulk at 110-150°C. As a result of the water-tolerance of these systems, experimental operating conditions do not require any special care. The approach, valorized both with various ROH transfer agents and with either purified or unpurified monomer sources, is highly versatile. Functional telechelic polycarbonates H-PTMC-OR, devoid of decarboxylation sequences, are obtained [PTMC=poly(trimethylene carbonate)]. The molar mass of the PTMCs can be readily predicted by a simple model, taking into account the [TMC]0/[ROH]0 ratio and the amount of transferring impurities present in the raw/unpurified reagents. Such simple, air- and moisture-robust catalytic systems, which display quite high activities (TOF up to 28200 h-1) and productivities (TON up to 45000) are thus extremely valuable, especially industrially. The performances of these systems are described in comparison to the previously established valuable inorganic and organometallic catalytic systems, namely metal amido complexes ([M{N(SiMe3)2}3]) and [(BDI)Zn{N(SiMe3)2}] (BDI=β-diiminate ligand) derivatives. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Bader M.,CNRS Chemistry Institute of Rennes | Marquet N.,CNRS Chemistry Institute of Rennes | Kirillov E.,CNRS Chemistry Institute of Rennes | Roisnel T.,CNRS Chemistry Institute of Rennes | And 3 more authors.
Organometallics | Year: 2012

Chiral racemic, sterically crowded fluorene-cyclopentadiene derivatives having a monoaryl-substituted methylene bridge, (R1R 2C)-((R2',R3',R6',R 7'-Flu)H)(3-R3-5-R4-C5H 3) (2a-f), or an unsubstituted (nonstereogenic) isopropylidene bridge (2g) were synthesized via nucleophilic additions onto substituted fulvenes. The corresponding dichlorozirconocene complexes, namely, {Ph(H)C-(Flu)(3-tBu-5-Me- C5H2)}ZrCl2 (3a), {Ph(H)C-(3,6-tBu 2Flu)(3-tBu-5-Et-C5H2)}ZrCl2 (3b), {Ph(H)C-(3,6-tBu2Flu)(3-tBu-5-Ph-C5H2)} ZrCl2 (3c), {Ph(H)C-(2,7-tBu2Flu)(3-tBu-5-Me-C 5H2)}ZrCl2 (3d), {Ph(H)C-(Oct)(3-tBu-5-Me- C5H2)}ZrCl2 (3e) (Oct = octamethyloctahydrodibenzofluorenyl), {Ph(H)C-(Oct)(3-tBu-5-Et-C 5H2)}ZrCl2 (3f), and {Me2C-(3,6-tBu- Flu)(3-tBu-5-Me-C5H2)}ZrCl2 (3g), were prepared in 10-91% yields. Complexes 3a-f, in which the most bulky phenyl substituent in the methylene bridge is anti to the 5-R substituent in the Cp ring, were isolated diastereomerically pure and characterized by elemental analysis, NMR spectroscopy, and X-ray crystallography. Among them, metallocenes 3b, 3e, and 3f, upon activation with MAO, proved highly active (14 330-34 470 kg(PP)·mol(Zr)-1·h-1) in the polymerization of propylene at 60 C in toluene, yielding highly isotactic polypropylenes (iPP) with [m]4 up to 94.1% and Tm up to 152 C. At elevated temperatures (80-100 C), these {R1R2C-(Flu)(Cp)} catalysts produce isotactic-enriched oligomers having both vinyl and vinylidene end-groups arising from β-Me elimination and β-H elimination/transfer to monomer, respectively. The catalytic system 3c/MAO showed the highest vinyl selectivity, with up to 66% of vinyl chain-ends at 80 °C. © 2012 American Chemical Society.

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