CNRS Laboratory of Chemistry, Catalysis, Polymers and Process

Lyon, France

CNRS Laboratory of Chemistry, Catalysis, Polymers and Process

Lyon, France
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Zetterlund P.B.,University of New South Wales | Thickett S.C.,University of New South Wales | Perrier S.,University of Warwick | Perrier S.,Monash University | And 2 more authors.
Chemical Reviews | Year: 2015

An update to the comprehensive review on controlled/living radical polymerization (CLRP) is discussed. The two most well-known CLRP systems that operate based on the persistent radical effect (PRE) are NMP and ATRP, and both have been studied extensively with regard to compartmentalization. xanthates are suitable as RAFT agents for implementation of ab initio RAFT emulsion polymerization due to their low reactivity. Xu and colleagues employed RAFT miniemulsion polymerization to prepare cross-linked chiral nanoparticles comprising well-defined glycopolymers by use of the chiral monomer 6-O-p-vinylbenzyl-1,2:3,4-di-O-isopropylidene-D-galactopyranose (VBPG) and poly-(VBPG) as the macro-RAFT agent. Emulsion ATRP has been conducted in aqueous dispersed systems as ab initio emulsion polymerization using direct and reverse ATRP, as well as in seeded emulsion systems using both direct ATRP and AGET ATRP. One of the most significant steps forward in recent years is the realization that emulsion/dispersion CLRP systems can be effectively employed to prepare polymeric nano-objects of nonspherical morphologies, such as rods and vesicles; this is currently one of the most active areas in this field.


Coperet C.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Coperet C.,ETH Zurich
Beilstein Journal of Organic Chemistry | Year: 2011

Stereoselectivity in alkene metathesis is a challenge and can be used as a tool to study active sites under working conditions. This review describes the stereochemical relevance and problems in alkene metathesis (kinetic vs. thermodynamic issues), the use of (E/Z) ratio at low conversions as a tool to characterize active sites of heterogeneous catalysts and finally to propose strategies to improve catalysts based on the current state of the art. © 2011 Copéret; licensee Beilstein-Institut.


Conley M.P.,ETH Zurich | Delley M.F.,ETH Zurich | Siddiqi G.,ETH Zurich | Lapadula G.,ETH Zurich | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2014

The insertion of an olefin into a preformed metal-carbon bond is a common mechanism for transition-metal-catalyzed olefin polymerization. However, in one important industrial catalyst, the Phillips catalyst, a metal-carbon bond is not present in the precatalyst. The Phillips catalyst, CrO3 dispersed on silica, polymerizes ethylene without an activator. Despite 60 years of intensive research, the active sites and the way the first Cr=C bond is formed remain unknown. We synthesized well-defined dinuclear CrII and CrIII sites on silica. Whereas the CrII material was a poor polymerization catalyst, the CrIII material was active. Poisoning studies showed that about 65 % of the CrIII sites were active, a far higher proportion than typically observed for the Phillips catalyst. Examination of the spent catalyst and isotope labeling experiments showed the formation of a Si-(μ-OH)-CrIII species, consistent with an initiation mechanism involving the heterolytic activation of ethylene at CrIII=O bonds. Three is better than two: CrIII silicates, in contrast to the CrII analogues, were found to be efficient ethylene-polymerization catalysts that initiate the reaction without a cocatalyst through the heterolytic splitting of an ethylene C=H bond across a Cr=O bond (see picture). This study provides clues about the active sites and initiation mechanism of the industrial Phillips catalyst. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Charleux B.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | D'Agosto F.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Delaittre G.,Radboud University Nijmegen
Advances in Polymer Science | Year: 2010

The synthesis of hybrid and core-shell nanoparticles using controlled/ living radical polymerization in aqueous dispersed systems is reviewed. The processes involve emulsion, miniemulsion, and dispersion polymerizations as well as grafting techniques, with the aim of producing submicrometric latex particles with well-defined morphologies that might not be accessible via classical radical polymerization. Those morphologies include organic/inorganic hybrids, nanostructured particles, (nano)capsules, and particles with a hydrophobic core and hydrophilic shell. © 2010 Springer-Verlag Berlin Heidelberg.


Popoff N.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Mazoyer E.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Pelletier J.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Gauvin R.M.,University of Lille Nord de France | Taoufik M.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process
Chemical Society Reviews | Year: 2013

Olefin metathesis is increasingly incorporated in polyfunctional industrial processes. The classical WO3/SiO2 olefin metathesis catalyst is combined to other catalysts in order to afford higher added-value chemicals. However, the combination of several reactions, not only in a single reactor, but also stemming from a single, multifunctional surface species is a desirable improvement regarding process issues. Well-defined surface organometallic tungsten species can be designed to implement targeted functionalities (carbene, hydride, alkyl, ...). By tuning the metal's coordination sphere, it is possible to combine metathesis with several reactions, such as (de)hydrogenation, dimerization or isomerization. Novel, unconventional reactions for the production and upgrading of alkanes and alkenes have thus been uncovered. The reactivity of this library of supported catalysts is discussed based on the type of mediated transformations: monofunctional (alkene and alkyne metathesis), bifunctional (1-butene or 2-butenes to propylene), trifunctional (ethylene to propylene, alkane metathesis, ...). Mechanistic considerations will be discussed to put these results in a wider perspective for future developments. This journal is © The Royal Society of Chemistry.


Bernhardt C.,CNRS Chemistry Laboratory | Stoffelbach F.,CNRS Chemistry Laboratory | Charleux B.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process
Polymer Chemistry | Year: 2011

A new alkene-functionalized SG1-based alkoxyamine was synthesized and used to prepare well-defined functional polymers by nitroxide mediated polymerization. The latter were characterized by NMR, SEC and MALDI-TOF mass spectrometry. Livingness was assessed by chain extension toward AB-type block copolymer. The alkene functionality located at the α-chain-end allowed the post-modification of the polymer by thiol-ene coupling reaction. © The Royal Society of Chemistry.


Mazzolini J.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Espinosa E.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | D'Agosto F.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Boisson C.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process
Polymer Chemistry | Year: 2010

The incorporation of functional groups at the end of polyolefin chains offers an opportunity to prepare polyolefin building blocks. The latter can be used to construct polymer architectures based on polyolefins with many desirable properties. For this purpose, the reactivity of the carbon-metal bond formed during a catalytic olefin polymerization process is particularly appealing. The possibility of taking advantage of this reactivity has indeed been enhanced by the discovery of systems in which fast and reversible chain transfer reactions between the active metal center and a main group metal centre are occurring. The recent developments of this catalyzed chain growth (CCG) concept are briefly reviewed. A specific system using a (C5Me5) 2NdCl2Li(OEt2)2 complex in conjunction with n-butyloctylmagnesium is then employed to synthesize an array of end functional polyethylene chains. The potential of these building blocks to build up new macromolecular architectures is discussed. © 2010 The Royal Society of Chemistry.


Polshettiwar V.,King Abdullah University of Science and Technology | Thivolle-Cazat J.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Taoufik M.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Stoffelbach F.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Tantalizing hydrocarbons: Tantalum hydride supported on fibrous silica nanospheres (KCC-1) catalyzes, in the presence of hydrogen, the direct conversion of olefins into alkanes that have higher and lower numbers of carbon atoms (see scheme). This catalyst shows remarkable catalytic activity and stability, with excellent potential of regeneration. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Chaduc I.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Lansalot M.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | D'Agosto F.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Charleux B.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process
Macromolecules | Year: 2012

Reversible addition-fragmentation chain transfer (RAFT) polymerization of methacrylic acid was successfully performed in water in the presence of a trithiocarbonate, the 4-cyano-4-thiothiopropylsulfanylpentanoic acid (CTPPA), as a RAFT agent. Several parameters such as the temperature, the concentration, the pH, the targeted polymerization degree, and the initiator concentration were studied. For pH value below the pK a of MAA, well-defined PMAA chains with different molar mass up to 92 000 g mol -1 exhibiting low dispersity ( < 1.19) were obtained under a broad range of synthetic conditions. © 2012 American Chemical Society.


Larabi C.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process | Quadrelli E.A.,CNRS Laboratory of Chemistry, Catalysis, Polymers and Process
European Journal of Inorganic Chemistry | Year: 2012

The known MOF UiO-67 of general formula [Zr 6O 4(OH) 4(bpdc) 6] [bpdc = biphenyldicarboxylate, O 2C(C 6H 4) 2CO 2] has been synthesized on a 3 g scale and characterized by BET, TGA, XRD, IR and 13C NMR spectroscopy, and elemental analyses. The chemical accessibility of the hydroxy ligand Zr 3(μ-OH) was assessed by the addition of D 2O: The expected isotopic shift of ν(OH) = 3673 cm -1 to ν(OD) = 2709 cm -1 in the IR spectrum was observed. The OH content in bulk UiO-67, previously mildly activated at 120 °C under vacuum (10 -5 Torr) overnight, was quantitatively determined by three methods: (1) By integration of the IR ν(OH) region and comparison with calibrated spectra of MCM-41 previously dehydroxylated at 500 °C, which gave a spectroscopically measured OH content in bulk UiO-67 of 2.2 mmol/g (37 mg OH/g); (2) by extrapolation of the OH content from the measured weight loss between 250 and 400 °C in TGA, which corresponded to 1.6 mmol OH/g (27 mg OH/g); and (3) by chemical titration of UiO-67 with CH 3MgBr and GC determination of the evolved methane, which gave 1.8 mmol OH/g (31 mg OH/g). The three methods, and in particular the latter chemical titration, are in very good to excellent agreement with the nominal OH content based on the molecular formula [Zr 6O 4(OH) 4(bpdc) 6] (expected: 1.9 mmol OH/g, 32 mg OH/g; experimental/calculated OH content = 110, 85, and 95 %, respectively, for the three methods). The weak acidity of the OH moiety in UiO-67 was assessed by IR and 31P NMR monitoring of the physisorption of PMe 3 in the UiO-67 cavities. Inclusion of the organometallic Au I complex [AuMe(PMe 3)] in a 1:1 molar ratio with respect to [Zr 6O 4(OH) 4(bpdc) 6] was achieved. Some chemisorption at 20 % of the cornerstone hydroxy sites also occurred to yield [Zr 6O 4(OH) 3(bpdc) 6(OAuPMe 3)]. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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