The Experts below are selected from a list of 162 Experts worldwide ranked by ideXlab platform
Bernard Boutevin - One of the best experts on this subject based on the ideXlab platform.
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study of the Telomerization of dimethylaminoethyl methacrylate dmaema with mercaptoethanol application to the synthesis of a new macromonomer
Polymer, 2004Co-Authors: Cyrille Boyer, Gilles Boutevin, Jean Jacques Robin, Bernard BoutevinAbstract:Abstract The Telomerization of dimethylaminoethyl methacrylate (DMAEMA) with mercaptoethanol initiated by 2,2′-azobisisobutyronitrile was first investigated at 70 °C and the influence of the type of solvent was studied. The results showed that well-defined telomers of DMAEMA could not be synthetized via Telomerization of DMAEMA in water or water/acetonitrile mixture since the Telomerization reaction is in competition with the nucleophilic addition of thiol onto the monomer. Transfer constants for mercaptoethanol in benzene and acetonitrile were determined by Mayo's and O'Brien's methods. The transfer constant obtained in acetonitrile (0,6) was higher than that obtained in benzene. This difference can be explained by the fact that the thiol was consumed by two reactions: nucleophilic addition and Telomerization. The influence of solvents on the polymerization kinetics was enlightened. These results were applied to the synthesis of macromonomers of DMAEMA with isocyanatoethyl methacrylate (IEM). These macromonomers were copolymerized with styrene.
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Telomerization of acrylic acid with mercaptans part 2 kinetics of the synthesis of star shaped macromolecules of acrylic acid
Polymer International, 2001Co-Authors: Cedric Loubat, Bernard BoutevinAbstract:The Telomerization of acrylic acid with a polyfunctional transfer agent initiated by 2,2′-azobisisobutyronitrile, was first investigated in an organic medium (THF) at 65 °C. Transfer constants (CT) for three mercaptans, ethylene glycol bisthioglycolate, trimethylolpropane tris(2-mercaptoacetate) and pentaerythritol tetrakis(3-mercaptopropionate) of about 6.1, 6.3 and 7.3, respectively, were determined. From these results, it followed that a well-defined star poly(acrylic acid) could not be synthesized via Telomerization of acrylic acid in THF. Nevertheless, the same study was performed with the tetrafunctional transfer agent in water/THF mixtures. This work emphasized that the nature of the solvent plays an important role in determining the transfer constant. Thus, the value of CT for the tetrafunctional transfer agent decreased from 7.3 in THF to 1, the ‘ideal’ case for Telomerization (CT ≈ 1), for the mixture of solvents water/THF (80%, 20%, v/v). With this route, it seems that acrylic acid star-shaped macromolecules could be synthesized via Telomerization. © 2001 Society of Chemical Industry
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Telomerization of acrylic acid with mercaptans: Part 2. Kinetics of the synthesis of star‐shaped macromolecules of acrylic acid
Polymer International, 2001Co-Authors: Cedric Loubat, Bernard BoutevinAbstract:The Telomerization of acrylic acid with a polyfunctional transfer agent initiated by 2,2′-azobisisobutyronitrile, was first investigated in an organic medium (THF) at 65 °C. Transfer constants (CT) for three mercaptans, ethylene glycol bisthioglycolate, trimethylolpropane tris(2-mercaptoacetate) and pentaerythritol tetrakis(3-mercaptopropionate) of about 6.1, 6.3 and 7.3, respectively, were determined. From these results, it followed that a well-defined star poly(acrylic acid) could not be synthesized via Telomerization of acrylic acid in THF. Nevertheless, the same study was performed with the tetrafunctional transfer agent in water/THF mixtures. This work emphasized that the nature of the solvent plays an important role in determining the transfer constant. Thus, the value of CT for the tetrafunctional transfer agent decreased from 7.3 in THF to 1, the ‘ideal’ case for Telomerization (CT ≈ 1), for the mixture of solvents water/THF (80%, 20%, v/v). With this route, it seems that acrylic acid star-shaped macromolecules could be synthesized via Telomerization. © 2001 Society of Chemical Industry
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Telomerization of acrylic acid with thioglycolic acid Effect of the solvent on the CT value
Polymer Bulletin, 2000Co-Authors: Cedric Loubat, Bernard BoutevinAbstract:The Telomerization of acrylic acid (AA) with thioglycolic acid (TGA) initiated with 2,2'-azobisisobutyronitrile (AIBN) was first investigated in organic medium (THF, 65°C). The kinetic study of this Telomerization led to the determination of the TGA transfer constant (CT= 3,2). Then, the same study was performed both in aqueous medium and in water / THF mixtures. From these works it is emphasised that the nature of the solvent plays an important role on the transfer constant. Thus, the value of CT decreased from CT= 3,2 in THF to 0,5 in water. By this way, the "ideal" case of Telomerization (CT= 1) was reached for a mixture of solvents: water / THF (80%, 20%, v/v).
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Telomerization of vinylidene fluoride with methanol elucidation of the reaction process and mechanism by a structural analysis of the telomers
Macromolecular Chemistry and Physics, 1998Co-Authors: Michel Duc, Bernard Boutevin, Bruno Ameduri, Mohamed Kharroubi, Jeanmarc SageAbstract:Telomerization of vinylidene fluoride (VDF) with methanol was investigated to synthesize fluorinated telomers bearing a functional end-group. Improvements of the conversion of VDF were attempted by using different radical initiators and reaction processes. The solvent effect on the reaction yield was also studied. Radically initiated Telomerizations led to VDF oligomers, whereas thermal and photochemical initiations seemed ineffective. Di-tert-butyl peroxide is the most effective radical initiator. All these experiments revealed the low chain transfer activity of methanol in the presence of VDF. For instance, an average cumulated degree of polymerization DP n cum of 4.6 was obtained from an initial methanol/VDF mole ratio of 5. A minute structural study of typical VDF-methanol telomers was performed by NMR spectroscopy, proving, on the one hand, the non-regioselectivity of the addition of hydroxymethyl radicals to VDF and, on the other hand, the competitive formation of non-functional telomers issued from direct chain initiations by the radical initiator (mainly methyl radicals when di-tert-butyl peroxide was used as the initiator). An overall mechanism of the VDF-methanol Telomerization initiated with di-tert-butyl peroxide was thus deduced.
Bert M Weckhuysen - One of the best experts on this subject based on the ideXlab platform.
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pd catalyzed Telomerization of 1 3 dienes with multifunctional renewable substrates versatile routes for the valorization of biomass derived platform molecules
ChemInform, 2013Co-Authors: Pieter C A Bruijnincx, Peter J C Hausoul, Robin Jastrzebski, Robertus Klein J M Gebbink, Bert M WeckhuysenAbstract:The dimerization of 1,3-dienes (e.g. butadiene) with the addition of a protic nucleophile (e.g. methanol) yields 2,7-octadienyl ethers in the so-called Telomerization reaction. This reaction is most efficiently catalyzed by homogeneous palladium complexes. The field has experienced a renaissance in recent years as many of the platform molecules that can be renewably obtained from biomass are well-suited to act as multifunctional nucleophiles in this reaction. In addition, the process adheres to many of the principles of green chemistry, given that the reaction is 100% atom efficient and produces little waste. The Telomerization reaction thus provides a versatile route for the production of valuable bulk and specialty chemicals that are (at least partly) green and renewable. The use of various multifunctional substrates that can be obtained from biomass is covered in this review, as well as mechanistic aspects of the Telomerization reaction.
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mechanistic study of the pd tompp catalyzed Telomerization of 1 3 butadiene with biomass based alcohols on the reversibility of phosphine alkylation
Chemcatchem, 2011Co-Authors: Peter J C Hausoul, Andrei N Parvulescu, Pieter C A Bruijnincx, Robertus Klein J M Gebbink, Martin Lutz, Anthony L Spek, Bert M WeckhuysenAbstract:Liquid-chromatography electrospray-ionisation mass spectrometry (LC-ESI-MS) studies on reaction mixtures of the Telomerization of 1,3-butadiene with biomass-based polyols revealed that the TOMPP (TOMPP=tris(2-methoxyphenyl)phosphine) ligand is converted towards the corresponding (2,7-octadienyl)phosphonium species during catalysis. The extent of ligand alkylation is substrate dependent and was identified as the primary cause of deactivation for carbohydrate substrates with anomeric hydroxyl groups. Coordination studies of the phosphonium cation with [Pd(dba)2] (dba=dibenzylideneacetone) gave insight into the alkylation mechanism and showed that the formation of the phosphonium cation is fully reversible. The reaction yields the key cationic intermediate [Pd(1,2,3,7,8-η5-octa-2,7-dien-1-yl)(TOMPP)]+, which, in the presence of the iodide anion, results in the formation of [Pd(1,2,3-η3-octa-2,7-dien-1-yl)(I)(TOMPP)]. Both complexes were fully characterized by various techniques including single crystal X-ray crystallography. Based on these results, an extension to the Pd/TOMPP-catalyzed Telomerization mechanism was formulated to include the 2,7-octadienylphosphonium cation as a ligand reservoir. Catalytic tests show that the use of [Pd(dba)2] as precatalyst improves the Telomerization of glucose and xylose.
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Telomerization of 1 3 butadiene with biomass derived alcohols over a heterogeneous pd tppts catalyst based on layered double hydroxides
ACS Catalysis, 2011Co-Authors: Andrei N Parvulescu, Peter J C Hausoul, Pieter C A Bruijnincx, Satu Korhonen, C Teodorescu, R Klein J M Gebbink, Bert M WeckhuysenAbstract:The Telomerization of 1,3-butadiene with homogeneous palladium/phosphine catalysts is an efficient method to transform biomass-based oxygenates into useful fine and bulk chemicals, e.g. surfactants. Recovery and reuse of the expensive noble metal-based catalyst is highly desired for these systems and therefore a heterogeneous Telomerization catalyst would be preferred. Layered double hydroxides (LDH) were investigated as supports for the heterogenization of the Pd/TPPTS (trisodium salt of 3, 3′,3′′-phosphanetriyl benzene sulfonic acid) Telomerization catalyst. Turn over numbers (TONs) up to 1300 were obtained with heterogeneous (immobilized palladium and ligand) and pseudo-heterogeneous (immobilized ligand) catalysts in the Telomerization of 1,3-butadiene with ethylene glycol (EG) and methanol (MeOH) under solvent- and base-free conditions; TONs are comparable to those obtained with the homogeneous catalysts under similar conditions. Importantly, the LDH support was found to induce a change in product sel...
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Telomerization of 1 3 butadiene with various alcohols by pd tompp catalysts new opportunities for catalytic biomass valorization
Green Chemistry, 2009Co-Authors: Regina Palkovits, Andrei N Parvulescu, Peter J C Hausoul, Cornelis A Kruithof, J Klein M Gebbink, Bert M WeckhuysenAbstract:The Telomerization of 1,3-butadiene with various alcohols has been investigated using a catalyst based on a Pd(acac)2 precursor and a phosphine ligand, TOMPP (TOMPP = tris-(o-methoxyphenyl)phosphine). We were able to demonstrate the capability of the catalyst to telomerize 1,3-butadiene with various multifunctional nucleophiles having primary and secondary alcohol functions. High yields of telomer products (>98%) were obtained in very short reaction times (<2 h). The Telomerization activity and selectivity of the Pd/TOMPP complex was strongly influenced by the type of alcohol used as substrate. When diols were used, Telomerization of 1,3-butadiene with 1,2-propanediol and 1,2-butanediol afforded the highest yield of mono-telomer (over 70%) and for 1,2-butanediol a turnover frequency (TOF) of 300 000 h−1 was reached, combined with a turnover number (TON) of 7800.
Bruno Ameduri - One of the best experts on this subject based on the ideXlab platform.
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Telomerization Reaction of 3,3,3-Trifluoropropene
Modern Synthesis Processes and Reactivity of Fluorinated Compounds, 2017Co-Authors: G. Kostov, Bruno AmeduriAbstract:Various strategies for syntheses from original telomers toward controlled fluoropolymers based on 3,3,3-trifluoropropene (TFP) are depicted in this review. Telomerization involves a telogen or a transfer agent (X–Y), and one or more (n) molecules of a polymerizable compound M (called taxogen or monomer), under radical polymerization conditions, leading to X–(M)n–Y telomers, as follows: Figure options Download full-size image Download as PowerPoint slide More specifically, (co)Telomerizations of TFP involving different X–Y chain transfer agents (CTAs, phosphonated or halogenated) are summarized. The kinetics of Telomerization enabled the assessment of the transfer constants to the CTAs, whereas coTelomerization has also been of great interest. This chapter also focuses on the applications of these functional (co)telomers as potential intermediates for the synthesis of well-architectured fluoropolymers including telechelics, macromonomers, and block copolymers. Various examples are supplied to illustrate the wide potential of applications of these fluoropolymers and potential nonbioaccumulable surfactants. Another feature deals with the controlled radical polymerization of TFP in the presence of various CTAs (1-iodofluoroalkanes or xanthates) for original surfactants, the properties of which are discussed. Applications will be the main highlight of this chapter.
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Telomerisation Reaction of 3,3,3-Trifluoropropene
2016Co-Authors: G. Kostov, Bruno AmeduriAbstract:Radical Telomerizations of 3,3,3-trifluropropene involving different X-Y chain transfer agents (CTAs, phosphonated, halogenated) was summarized. The kinetics of Telomerization enabled one to assess the transfer constants to the CTAs, while coTelomerization have also shown a great interest. The second part deals with the applications of these functional telomers as potential intermediates for the synthesis of well-architectured fluoropolymers including telechelics, block copolymers, macromonomers, graft copolymers. Various examples are supplied to understand the wide potential of applications of these fluoropolymers and potential non-bioaccumulable surfactants. Then, the controlled radical polymerization (CRP or RDRP) of fluoroalkenes in the presence of various chain transfer agents (1-iodofluoroalkanes or xanthates) is also presented. Industrial applications from CRP of fluoroalkenes will illustrate this book chapter.
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Recent Advances in the Telomerization of Vinylidene fluoride and application Therefrom
2012Co-Authors: Bruno AmeduriAbstract:Telomerization involves a telogen or a transfer agent (X-Y), and one or more (n) molecules of a polymerizable compound M (called taxogen or monomer), under radical polymerization conditions, leading to X-(M)n-Y telomers, Various examples of Telomerization of vinylidene fluoride, VDF (H2C=CF2) involving different X-Y transfer agents (hydroxylated, phosphonated3, halogenated have been investigated. The kinetics of Telomerization enabled us to assess the transfer constants to the telogens and an increasing series regarding the efficiency of these transfer agents is supplied, correlated with the bond dissociation energy of the cleavable bond of the telogens: CF3CH2OH
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From Telomerization to Controlled Radical Polymerization of Vinylidene fluoride
2011Co-Authors: Bruno AmeduriAbstract:The radical Telomerization of vinylidene fluoride (VDF) with various chain transfer agents (methanol, dialkyl phosphonates, 1-iodoperfluoroalkanes) is presented. ) First, Telomerization 1 involves a telogen or a transfer agent (X-Y), and one or more (n) molecules of a polymerizable compound M (called taxogen or monomer), under radical polymerization conditions, leading to X-(M)n-Y telomers, as follows: Various examples of Telomerization of vinylidene fluoride, VDF (H2C=CF2) involving different X-Y transfer agents (hydroxylated, phosphonated, halogenated have been investigated. The kinetics of Telomerization enabled us to assess the transfer constants to the telogens and an increasing series regarding the efficiency of these transfer agents is supplied, correlated with the bond dissociation energy of the cleavable bond of the telogens: CF3CH2OH
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From Telomerization to Controlled Radical Polymerization of Vinylidene fluoride
2011Co-Authors: Bruno AmeduriAbstract:Telomerization involves a telogen or a transfer agent (X-Y), and one or more (n) molecules of a polymerizable compound M (called taxogen or monomer), under radical polymerization conditions, leading to X-(M)n-Y telomers, Various examples of Telomerization of vinylidene fluoride, VDF (H2C=CF2) involving different X-Y transfer agents (hydroxylated, phosphonated, halogenated) have been investigated. The kinetics of Telomerization enabled us to assess the transfer constants to the telogens and an increasing series regarding the efficiency of these transfer agents is supplied, correlated with the bond dissociation energy of the cleavable bond of the telogens: CF3CH2OH
Oscar Navarro - One of the best experts on this subject based on the ideXlab platform.
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room temperature solventless Telomerization of isoprene with alcohols using n heterocyclic carbene palladium catalysts
Catalysis Science & Technology, 2015Co-Authors: Irene Maluenda, Mingtsz Chen, Daniel Guest, Mark S Roe, Michael L Turner, Oscar NavarroAbstract:The use of a custom-made palladium complex for the telomerisation of isoprene with alcohols under green conditions is described. Using a very low catalyst loading (0.1 mol%), this protocol allows for the reactions to be carried out without the need of high pressure equipment, at room temperature and under solventless conditions, affording high yields of Telomerization products with high selectivity towards linear head-to-head and tail-to-head telomers.
Arno Behr - One of the best experts on this subject based on the ideXlab platform.
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Towards a process for the Telomerization of butadiene with N-methylglucamine
Chemical Engineering Science, 2018Co-Authors: Thiemo A. Faßbach, Arno Behr, Sebastian Püschel, Steffen Romanski, Dirk Leinweber, Andreas J VorholtAbstract:Abstract The Telomerization of 1,3-dienes with functionalized nucleophiles presents an atom efficient and selective synthesis of potential non-ionic surfactants. Crucial for application of these synthetic pathways is the effective recycling of the homogeneous palladium catalyst. In this work, we present the Telomerization of 1,3-butadiene with the renewable aminopolyol N -methylglucamine to a non-ionic surfactant in an aqueous solvent system. In order to achieve phase separation, the addition of freshly added 1,3-butadiene instead of an additional solvent offers an elegant way of catalyst recycling. With this method, recycling of the catalyst is feasible; a total turnover number of 1456 was reached.
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Telomerization of myrcene and catalyst separation by thermomorphic solvent systems
Chemcatchem, 2010Co-Authors: Arno Behr, Leif Johnen, Andreas J VorholtAbstract:Telomerization of common petrochemical 1,3-dienes such as butadiene and isoprene have long been successful with different nucleophiles; however, the Telomerization of the C10 hydrocarbon myrcene was not known until now. Herein, the first Telomerization of the monoterpene myrcene with diethylamine is discussed, which provides an atom-economical way of generating C20 amines in a single step. Variation of the palladium precursors and phosphorous ligands and optimization of solvent and additives led to the optimum catalyst system [Pd(MeCN)4](BF4)2/PPh3. By using a thermomorphic solvent system, the Pd complex can be easily separated with low leaching values.
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Telomerization: Advances and Applications of a Versatile Reaction
Angewandte Chemie (International ed. in English), 2009Co-Authors: Arno Behr, Marc Becker, Leif Johnen, Thomas Beckmann, Julia Leschinski, Sebastian ReyerAbstract:The transition-metal catalyzed Telomerization of 1,3-dienes with different nucleophiles leads to the synthesis of numerous products, such as sugar ethers, substituted lactones, or terpene derivatives, which can be applied in the cosmetic and pharmaceutical industry as well as in polymers and flavors. The reaction can be controlled by the choice of the catalytic system, the feedstock, and the reaction conditions. Since Telomerization was developed in 1967, there have been many efforts to utilize this reaction. Herein we give an overview of the versatility of Telomerization based on examples from research and industry, particular emphasis is placed on catalyst and process development as well as mechanistic aspects.
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the telomerisation of 1 3 butadiene and carbon dioxide process development and optimisation in a continuous miniplant
Dalton Transactions, 2006Co-Authors: Arno Behr, Marc BeckerAbstract:The telomerisation of 1,3-butadiene and carbon dioxide is one of the first homogeneously catalyzed reactions using carbon dioxide as a C1-building block. In this article we describe the process development for a miniplant applying this telomerisation in a continuous scale. Through repeated optimisation of the plant setup combined with parallel laboratory batch experiments the overall space-time-yield of the plant was enhanced significantly.
