References of "Alves, Margot"
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See detailDFT investigation of the reaction mechanism for the guanidine catalyzed ring-opening of cyclic carbonates by aromatic and alkyl-amines
Alves, Margot ULg; Méreau, Raphaël; Grignard, Bruno ULg et al

in RSC Advances (2017), 7(31), 18993-19001

The guanidine catalysed aminolysis of propylene carbonate has been investigated using the density functional theory (DFT) and highlights that different reaction pathways are involved depending on the ... [more ▼]

The guanidine catalysed aminolysis of propylene carbonate has been investigated using the density functional theory (DFT) and highlights that different reaction pathways are involved depending on the aromatic or aliphatic nature of the amine. The structural ability of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) to simultaneously give and receive protons was demonstrated by a detailed mechanistic investigation. The bifunctional activity (base/H-bond donor) of TBD significantly reduces the Gibbs energy of the reaction and allows understanding its higher efficiency compared to its methyl counterpart (MTBD). [less ▲]

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See detailOrganocatalytic coupling of CO2 with oxetane
Alves, Margot ULg; Grignard, Bruno ULg; Boyaval, Amélie ULg et al

in ChemSusChem (2017), 10(6), 1128-1138

The organocatalytic coupling of CO2 with oxetanes is investigated under solvent-free conditions. The influence of the main reaction parameters (type of organocatalytic system, pressure and temperature) on ... [more ▼]

The organocatalytic coupling of CO2 with oxetanes is investigated under solvent-free conditions. The influence of the main reaction parameters (type of organocatalytic system, pressure and temperature) on the yield, the product formed and the selectivity of the reaction are discussed. An onium salt combined with a fluorinated alcohol promotes the efficient and selective organocatalytic synthesis of α,ω-hydroxyl oligocarbonates by coupling CO2 with oxetanes at 130 °C and at a CO2 pressure as low as 2 MPa. NMR characterizations were correlated with MALDI-ToF analyses for elucidating the structure of the oligomers. Online FTIR studies under pressure, NMR titrations and DFT calculations allowed an in-depth understanding of the reaction mechanism. Finally, CO2- based poly(carbonate-co-urethane)s were synthesized by step- growth polymerization of hydroxyl telechelic oligocarbonates with MDI. The organocatalytic system described in this paper constitutes an innovative sustainable route to the selective preparation of hydroxyl telechelic carbonates, of high interest for many applications, notably for the polyurethane business, especially for coatings or foams. [less ▲]

Detailed reference viewed: 80 (26 ULg)
See detailOils and CO2, a promising combination for designing insulating foams and high performance coatings
Detrembleur, Christophe ULg; Alves, Margot ULg; Grignard, Bruno ULg et al

Conference (2017, March 21)

Making plastics more sustainable by valorizing waste CO2 as a cheap, inexhaustible and renewable feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic ... [more ▼]

Making plastics more sustainable by valorizing waste CO2 as a cheap, inexhaustible and renewable feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic driver for developing future low carbon footprint materials and technologies. With a global production estimated to 18 million tons for 2016, polyurethane (PU) is one of the most important polymers in our everyday life applications (automotive, building and construction, coatings, etc.). Industrially, PU is produced by step-growth polymerization between di- or polyisocyanates and di- or polyols. However, isocyanates are toxic and drastic changes in the REACH regulations limiting/banning the use of isocyanates are expected. There is a need today to develop new greener and safer alternatives to produce PU. Valorizing CO2 as C1 feedstock for producing precursors entering in the synthesis of polyurethanes by a non-isocyanate route (NIPU) is a promising strategy to solve this challenge. In this talk, we will focus on the synthesis and characterization of novel NIPUs foams for thermal insulation, and NIPUs coatings for metal protection. Our research highlights benefit of merging bio-resources (such as vegetable oils) with carbon dioxide transformation. In the first part of this talk, we will report on the fast synthesis of bio- and CO2-sourced cyclic carbonates by coupling CO2 with epoxides using a new highly efficient bicomponent homogeneous organocatalyst under solvent-free and mild experimental conditions. The mechanism of the activation of the reaction will be discussed, and scaling up of the technology will be demonstrated (15kg scale). In the second part, we will illustrate the use of these bio- and CO2-sourced cyclic carbonates for the production of microcellular NIPU foams with closed cells morphology for thermal insulating applications, but also for preparing hybrid NIPUs coatings for metal protection. [less ▲]

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See detailOrganocatalyzed coupling of carbon dioxide with epoxides for the synthesis of cyclic carbonates: catalyst design and mechanistic studies
Alves, Margot ULg; Grignard, Bruno ULg; Méreau, Raphaël et al

in Catalysis Science & Technology (2017), 7

The coupling of carbon dioxide (CO2) with epoxides with the formation of cyclic carbonates is a highly attractive 100% atom economy reaction. It represents a greener and safer alternative to the ... [more ▼]

The coupling of carbon dioxide (CO2) with epoxides with the formation of cyclic carbonates is a highly attractive 100% atom economy reaction. It represents a greener and safer alternative to the conventional synthesis of cyclic carbonates from diols and toxic phosgene. Today, cyclic carbonates find many applications as intermediates for fine chemicals synthesis, as electrolytes in Li-ion batteries, and polar aprotic solvents, but also serve for the synthesis of important polymers such as polycarbonates and polyurethanes. In view of their broad scope and their strong economic potential, there is a strong need to improve their synthesis and decrease their production costs. However, CO2 is a thermodynamically stable molecule, the use of catalysts is therefore mandatory for activating and facilitating the CO2/epoxide coupling reaction in a selective manner and under mild conditions. Recently organocatalysts deserved more and more interest in this field, and are viewed as alternatives to metal-based ones. Enormous progress has been made these last years to boost their performances, and some organocatalysts are now very competitive, cheap, readily available and exhibit good chemical stability towards moisture, water and air. This review is focusing on the recent advances in the development of metal-free organocatalysts for the synthesis of cyclic carbonates by CO2/epoxide coupling. Most of the state-of-the art organocatalysts used for this reaction are discussed, with a special emphasis to highlight the various routes employed to boost their performances. Their mode of action is also reported based on mechanistic considerations, supported by density functional theory (DFT) calculations that are becoming essential tools for modern catalysts design. Such detailed understanding of the mechanisms involving CO2 transformation should pave the way towards the definition of new modes of activation for converting CO2 with a large scope of substrates into various chemicals, monomers and polymers. [less ▲]

Detailed reference viewed: 30 (9 ULg)
See detailCarbon dioxide and vegetable oil for the synthesis of biobased polymer precursors
Alves, Margot ULg

Doctoral thesis (2016)

Although it is a thermodynamically and kinetically stable molecule, carbon dioxide can be converted into five- and six-membered cyclic carbonates by coupling with epoxides or oxetanes, respectively, using ... [more ▼]

Although it is a thermodynamically and kinetically stable molecule, carbon dioxide can be converted into five- and six-membered cyclic carbonates by coupling with epoxides or oxetanes, respectively, using appropriate catalysts. Cyclic carbonates are used as green solvents, electrolytes for Li-ion batteries or intermediates for the synthesis of polymers. However, the catalytic performance must be further enhanced in particular for the coupling of CO2 with epoxidized vegetable oils or oxetanes. In this context, we developed a new highly efficient bicomponent homogeneous organocatalyst composed of an ammonium salt as the catalyst and fluorinated single or double hydrogen bond donors as co-catalysts. First, a screening of onium-based catalysts and hydrogen-bond donors was performed. Performances of the catalysts and optimization of the reaction was realized through detailed kinetics studies using in-situ FTIR/Raman spectroscopy under pressure. We demonstrated that fluorinated alcohols showed unexpected co-catalytic activity due to synergisms between the onium salt and fluorinated co-catalysts enabling the fast and selective addition of CO2 onto model epoxides and epoxidized vegetable oils under solvent-free and mild experimental conditions. The use of this powerful dual catalyst was then extended to the first organocatalytic coupling of CO2 with less reactive oxetanes to produce hydroxyl telechelic oligocarbonates that were used as precursor of CO2-based polyurethanes by chain-extension with a diisocyanate. In addition, a fine comprehension of the mechanisms was investigated by DFT calculations highlighting that the co-catalytic performance of the onium salt/fluorinated alcohol binary catalyst arose from the strong stabilization of the intermediates and transitions states by hydrogen-bonding. To date, through comparative studies, we evidenced that this new catalyst is one of the most performing and versatile system enabling the coupling of CO2 both with epoxides or oxetanes. [less ▲]

Detailed reference viewed: 47 (6 ULg)
See detailValorization of CO2 for the preparation of advanced materials
Gennen, Sandro ULg; Grignard, Bruno ULg; Thomassin, Jean-Michel ULg et al

Conference (2016, July 07)

Detailed reference viewed: 29 (6 ULg)
See detailMerging carbon dioxide utilisation, bioresources and CO2-based process for sustainable low carbon footprints polyurethanes
Alves, Margot ULg; Grignard, Bruno ULg; Gennen, Sandro ULg et al

Poster (2016, June 29)

Making plastics more sustainable by valorizing waste CO2 as a cheap, inexhaustible and renewable feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic ... [more ▼]

Making plastics more sustainable by valorizing waste CO2 as a cheap, inexhaustible and renewable feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic driver for developing future low carbon footprints materials and technologies. With a global production estimated to 18 million tons for 2016, polyurethane (PU) is one of the most important polymers in our everyday life with applications in automotive, in building and construction, in coating, in the medical field, as flexible and rigid foams for thermal and/or acoustic insulation. Industrially, PU is produced by step-growth polymerization between di- or polyisocyanates and di- or polyols. However, isocyanates are extremely toxic compounds and made from even more toxic and explosive phosgene. Prolonged exposure to isocyanates vapour results in serious health damages such as skin irritation, asthma or DNA mutation whereas phosgene causes death. Because of the toxicity issues of these compounds associated to drastic changes in the REACH regulations limiting/banning the use of isocyanates, there is a need today to develop new greener and safer alternatives to produce PU. Valorising CO2 as C1 feedstock for producing precursors entering in the synthesis of polyurethanes by a non-isocyanate route (NIPU) is a promising route to solve this challenge the polyurethane sector is facing. Through its global objective focussing on the synthesis of isocyanate-free low carbon footprint foamed materials for thermal insulation this research highlights benefits of merging bio-resources with carbon dioxide transformation and “physical” utilization. The success of the project relies on 3 key steps involving: i) The synthesis of bio- and CO2-sourced cyclic carbonates using new highly efficient organocatalysts: Due to the low reactivity of CO2 versus epoxides, addition of catalysts in the reaction medium is necessary. If lot of catalysts have been developed, their use generally suffers from some drawbacks. Indeed, most of the metal-based catalysts are highly sensitive to hydrolysis and oxidation or/and poorly selective and additionally, some of them are toxic whereas less/non-toxic and eco-friendly organocatalysts such as ionic liquids and halide salts are generally only efficient at very high temperature and pressure, so favouring the decomposition of catalyst. To overcome these limitations, we developed a new highly-efficient bicomponent homogeneous organocatalyst that showed unexpected catalytic activity for the fast (within a few minutes) and selective addition of CO2 onto model epoxides and epoxidized vegetable oils under solvent-free and mild experimental conditions. The use of this powerful dual organocatalyst was further extended to the first organocatalytic coupling of CO2 with less reactive oxetanes to produce hydroxyl telechelic oligocarbonate entering the synthesis of CO2-sourced conventional PUs. ii) The synthesis of sustainable non-isocyanate polyurethanes: Sustainable NIPUs were produced by step-growth polymerization between the so-produced bio- and CO2-sourced cyclic carbonates and biosourced amino-telechelic comonomers derived from linseed fatty acids according to a process compatible with existing industrial infrastructures (extrusion). iii) The foaming of NIPUs: Sustainable foams with thermal insulation were produced by the supercritical CO2 assisted foaming technology. Due to its solubility in polymers, CO2 can replace conventional flammable VOCs and ozone depletion chemical or physical blowing agents such as diazo compounds, hydrocarbons (pentane, isopentane…) or inert gases (nitrogen…) to produce (ultra)lightweight microcellular foams. By finely choosing the CO2 impregnation and the foaming conditions, foams with a thermal conductivity as low as 0.052 Wm-1K-1 were produced. Our study shows that CO2 is not only sequestered in the material for long-term application, but is also valorized as a blowing agent in the production of sustainable thermally insulating NIPU foams. Such low carbon footprints materials will contribute to energy conservation and savings by reducing CO2 emissions [less ▲]

Detailed reference viewed: 154 (5 ULg)
See detailCatalytic transformation of CO2: from monomers to polymers
Alves, Margot ULg; Grignard, Bruno ULg; Boyaval, Amélie ULg et al

Conference (2016, May 24)

Valorising CO2 as a renewable C1 feedstock for producing added value building blocks is the scope of many academic and industrial researches. Carbon dioxide is a thermodynamically and kinetically stable ... [more ▼]

Valorising CO2 as a renewable C1 feedstock for producing added value building blocks is the scope of many academic and industrial researches. Carbon dioxide is a thermodynamically and kinetically stable molecule that can be converted into five membered cyclic carbonates by coupling with epoxides using organometallic complexes or organocatalysts. To date, the identification and development of highly efficient (organo)catalysts under mild experimental conditions still remains challenging. In particular, the synthesis of six membered cyclic carbonates by the CO2/oxetane coupling using such organocatalysts has never been reported to our knowledge. In this context, we developed a new highly efficient bicomponent homogeneous organocatalyst composed of an ammonium salt as the catalyst and fluorinated single or double hydrogen bond donor activators (HBD). First, the efficiency of this new organocatalyst for the fast and selective CO2/epoxide coupling was investigated through detailed kinetic studies by IR spectroscopy under pressure and results were compared with the most efficient organocatalysts reported in the literature. This study was completed by molecular modeling in order to elucidate the reaction mechanism. DFT calculations showed that the hexafluoroisopropanol functionalities of HBDs strengthened the proton donor capability and allowed a better stabilization by hydrogen bonding of the intermediates and transition states. Finally, the use of this dual organocatalyst was extended to the coupling of CO2 with less reactive oxetanes to produce hydroxyl telechelic oligocarbonates. [less ▲]

Detailed reference viewed: 97 (3 ULg)
See detailCyclic and oligo-carbonates by organocatalytic coupling of CO2 with epoxides or oxetanes
Alves, Margot ULg; Grignard, Bruno ULg; Boyaval, Amélie ULg et al

Conference (2016, April 20)

Valorising CO2 as a renewable C1 feedstock for producing added value building blocks is the scope of many academic and industrial researches. Carbon dioxide is a thermodynamically and kinetically stable ... [more ▼]

Valorising CO2 as a renewable C1 feedstock for producing added value building blocks is the scope of many academic and industrial researches. Carbon dioxide is a thermodynamically and kinetically stable molecule that can be converted into five and six membered cyclic carbonates by coupling with epoxides or oxetanes, respectively, using appropriate catalysts. Although transition metal catalysts are efficient under atmospheric pressure and ambient temperature, most of them are poorly selective, sensitive to hydrolysis and/or oxidation and/or toxic whereas less/non-toxic and eco-friendly organocatalysts such as ionic liquids and halide salts are generally only efficient at very high temperature and pressure favouring their thermal degradation. To overcome these limitations, we developed a new highly efficient bicomponent homogeneous organocatalyst composed of an ammonium salt as the catalyst and fluorinated single or double hydrogen bond donor activators. Through online FTIR kinetic studies, we demonstrated that this new organocatalyst showed unexpected catalytic activity for the fast and selective addition of CO2 onto epoxides under solvent-free and mild experimental conditions. The use of this dual catalyst was then extended to the coupling of CO2 with less reactive oxetanes to produce hydroxyl telechelic oligocarbonates. In the first part of this talk, based on kinetics of reactions followed by online FTIR under pressure, we will describe the reaction conditions required for the organocatalytic coupling of CO2 with epoxides and oxetanes. In the second part, the mechanism of the reaction will be approached and discussed based on DFT calculations. Finally, we will compare and discuss the efficiency of various organocatalytic systems for this type of reaction. [less ▲]

Detailed reference viewed: 90 (10 ULg)
See detailCO2-based sustainable polymers: from CO2-sourced monomers to low CO2 emission foamed materials
Grignard, Bruno ULg; Gennen, Sandro ULg; Alves, Margot ULg et al

Conference (2016, April)

Due to concerns about the climate change combined with the decrease of fossil resources, the use of CO2 as a C1 feedstock for producing added value chemicals and materials has become a huge challenge in ... [more ▼]

Due to concerns about the climate change combined with the decrease of fossil resources, the use of CO2 as a C1 feedstock for producing added value chemicals and materials has become a huge challenge in academic laboratories and in industry. The coupling of CO2 with epoxide has emerged as one of the most promising way to convert CO2 into cyclic carbonates finding application as green solvents or electrolyte for batteries. Interestingly, these cyclic carbonates can also be valorised as monomers to produce new non-isocyanate polyurethanes by step-growth polymerization with amines. Polyurethane (PU) is one of the most important polymers in our everyday life with numerous applications such as thermosets, thermoplastics, elastomers, adhesives, sealants, coatings, rigid and flexible foams for wellness or acoustic and/or thermal insulation. In this talk, we will discuss the preparation of all green bio- and CO2-sourced non-isocyanate polyurethane (NIPU) microcellular foams with thermal insulation properties by using an eco-efficient process based on the supercritical carbon dioxide (scCO2) foaming technology. This talk will be divided in three sections: The synthesis of CO2-sourced cyclic carbonates by coupling CO2 with epoxides using a new highly-efficient bicomponent homogeneous organocatalyst combining the use of an ammonium salt as the catalyst and a fluorinated hydrogen bond donor activator that allows the fast and solvent-free coupling of CO2 with (biosourced) epoxides under mild experimental conditions. The synthesis of (bio- and) CO2-sourced isocyanates-free PUs by melt step-growth copolymerization, eliminating the toxicological issues associated to the conventional synthesis of polyurethanes from diols and isocyanates. The foaming of NIPUs by exploiting the scCO2 foaming technology. By finely choosing the appropriate CO2 impregnation and foaming conditions, thermally insulating CO2-blown microcellular NIPUs foams were produced. [less ▲]

Detailed reference viewed: 189 (5 ULg)
See detailTheoretical study of the organocatalyzed synthesis of NIPUs
Alves, Margot ULg; Méreau, Raphaël; Grignard, Bruno ULg et al

Poster (2016, March)

Detailed reference viewed: 15 (3 ULg)
See detailCarbon dioxide and vegetable oil for the synthesis of bio-based polymer precursors, theoretical study of the organocatalyzed synthesis of non-isocyanate polyurethanes
Alves, Margot ULg; Jérôme, Christine ULg; Tassaing, Thierry

Conference (2016, March)

Non-isocyanate polyurethanes (NIPUs) represent a green alternative to the classical synthesis route of polyurethanes involving toxic isocyanates. This “greener” approach based upon renewable feedstocks ... [more ▼]

Non-isocyanate polyurethanes (NIPUs) represent a green alternative to the classical synthesis route of polyurethanes involving toxic isocyanates. This “greener” approach based upon renewable feedstocks and carbon dioxide consists in a two-step reaction. In a first step, carbonated vegetable oils are obtained using an appropriate catalyst by the chemical fixation of CO2 onto vegetable oils formerly epoxidized. Finally, the ring-opening polymerization (ROP) of the carbonated vegetable oil by a diamine provides hydroxy urethanes. In this las step, some organocatalysts have been recently proposed that allows achieving good conversion rates in particular in the case of aromatic diamines. However, the activation mechanism of these organocatalysts is not fully elucidated. In this context, the aim of the present project relies on the theoretical study of a model reaction using DFT calculations. Bicyclic guanidine based catalysts, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and 7-methyl-TBD (MTBD), were investigated as catalysts for the reaction between propylene carbonate and aliphatic or aromatic amines. The structural ability of TBD to simultaneously give and receive protons was highlighted by the detailed mechanism investigation. The bifunctional activity of TBD significantly reduces the Gibbs energy of the reaction and allows understanding its higher efficiency compared to its methyl counterpart (MTBD). [less ▲]

Detailed reference viewed: 114 (2 ULg)
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See detailA comprehensive density functional theory study of the key role of fluorination and dual hydrogen bonding in the activation of the epoxide/CO2 coupling by fluorinated alcohols
Alves, Margot ULg; Méreau, Raphaël; Grignard, Bruno ULg et al

in RSC Advances (2016), 6(43), 36327-36335

The activation mechanism of the CO2/propylene oxide coupling catalysed by a bicomponent organocatalyst combining the use of TBABr with (multi)phenolic or fluorinated hydrogen bond donors (HBDs) was ... [more ▼]

The activation mechanism of the CO2/propylene oxide coupling catalysed by a bicomponent organocatalyst combining the use of TBABr with (multi)phenolic or fluorinated hydrogen bond donors (HBDs) was investigated using the Density Functional Theory (DFT). Thus, it was shown that increasing the number of electron withdrawing trifluoromethyl substituents in HBDs strengthens their proton donor capability and allows a better stabilization by hydrogen bonding of the intermediates and transition states. In addition, the high efficiency of fluorinated monoalcohol activators is related to a dual hydrogen bonding mechanism by two fluorinated molecules that cooperatively contribute to the CO2/propylene oxide coupling. [less ▲]

Detailed reference viewed: 49 (11 ULg)
See detailOrganocatalytic coupling of carbon dioxide with epoxides: the unexpected booster effect of fluoroalcohols
Grignard, Bruno ULg; Gennen, Sandro ULg; Alves, Margot ULg et al

Poster (2015, December 19)

Valorising CO2 as a C1 feedstock for producing added value building blocks is seducing as it is a free and in exhaustive waste resulting from human activity. Carbon dioxide is a thermodynamically and ... [more ▼]

Valorising CO2 as a C1 feedstock for producing added value building blocks is seducing as it is a free and in exhaustive waste resulting from human activity. Carbon dioxide is a thermodynamically and kinetically stable molecule that can be converted into cyclic carbonates by coupling with epoxides. Cyclic carbonates are valuable products that find applications as solvents, electrolytes or as monomers for polyurethanes synthesis. Although the CO2/epoxide coupling reaction has been extensively studied, the development of organocatalysts that are highly efficient under mild experimental conditions still remains a challenge. Onium salts are the most common catalysts that show reasonable catalytic activity at high pressure (> 100 bars) and high temperature (> 100°C) only. Fortunately, the efficiency of these organocatalysts can be improved by addition of appropriate hydrogen bond donors activators (HBD). In this talk, we will report the development of a new highly efficient catalytic platform consisting in an onium halide salt combined with HBD activators for the fast and solvent-free synthesis of cyclic carbonates by coupling CO2 with epoxides. The cocatalytic effect of series of HBDs will be demonstrated by detailed online kinetics studies under pressure using Raman or IR spectroscopy. We will show that our new organocatalytic platform facilitates the fast conversion of epoxy groups into cyclic carbonates under mild experimental conditions, and can be easily implemented to the modification of epoxidized vegetable oils. The synergistic effects between HBDs and onium salt will be highlighted by a detailed mechanistic study of the reaction through DFT calculations. [less ▲]

Detailed reference viewed: 55 (3 ULg)
See detailNew efficient organocatalytic system for solvent-free chemical fixation of CO2 into epoxides
Panchireddy, Satyannarayana ULg; Gennen, Sandro ULg; Alves, Margot ULg et al

Poster (2015, September 11)

Due to concerns about global warming combined with the decrease of fossil resources, the chemical transformation of carbon dioxide (CO2) into added-value products has gained interest in both academic and ... [more ▼]

Due to concerns about global warming combined with the decrease of fossil resources, the chemical transformation of carbon dioxide (CO2) into added-value products has gained interest in both academic and industrial fields. To date, the chemical fixation of CO2 onto epoxides with the formation of cyclic carbonates (CC) is one of the most promising ways to valorise CO2 at an industrial scale. Indeed, CC are useful monomers for polycarbonate synthesis and they can react with primary amines to produce 2-hydroxyethylurethane. This reaction can be extrapolated to the synthesis of non-isocyanate polyurethanes (NIPUs) by a step growth polymerization between bifunctional CC and diamines. [less ▲]

Detailed reference viewed: 138 (12 ULg)
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See detailOrganocatalytic promoted coupling of carbon dioxide with epoxides: a rational investigation of the cocatalytic activity of various hydrogen bond donors
Alves, Margot ULg; Grignard, Bruno ULg; Gennen, Sandro ULg et al

in Catalysis Science & Technology (2015), 5(9), 4636-4643

A catalytic platform based on an onium salt used in combination with organic cocatalysts of various structures was developed for the efficient CO2/epoxide coupling under mild conditions. Through detailed ... [more ▼]

A catalytic platform based on an onium salt used in combination with organic cocatalysts of various structures was developed for the efficient CO2/epoxide coupling under mild conditions. Through detailed kinetic studies by in-situ FT-IR spectroscopy, a rational investigation of the efficiency of a series of commercially available hydrogen bond donors co-catalysts was realized and the influence of different parameters such as the pressure, the temperature, the catalyst loading, and the nature of the epoxide on the reaction kinetics was evaluated. Fluorinated alcohols were found to be more efficient than other hydrogen bond donor activators proposed previously in the literature under similar conditions. [less ▲]

Detailed reference viewed: 93 (25 ULg)
See detailEfficient hydrogen-bond donor activators for the synthesis of bio-based cyclic carbonates from CO2 and vegetable oils: a combined in-situ FT-IR and DFT study
Alves, Margot ULg; Méreau, Raphaël; Grignard, Bruno ULg et al

Conference (2015, July 06)

The present research aims at developing new very efficient organocatalysts for the chemical fixation of carbon dioxide onto epoxides that are precursors of non-isocyanate polyurethanes (NIPUs). Although ... [more ▼]

The present research aims at developing new very efficient organocatalysts for the chemical fixation of carbon dioxide onto epoxides that are precursors of non-isocyanate polyurethanes (NIPUs). Although this area of research is the subject of many works, the catalytic performance must be further enhanced in particular for the carbonatation of vegetable-based precursors while respecting environmental standards. In this context, we developed a new organocatalytic platform based on the combination of ammonium salts with single or double hydrogen bond donor activators that showed unexpected catalytic activity for the fast addition of CO2 onto epoxidized oils under mild conditions. First of all, in situ kinetic studies of the cycloaddition of CO2 onto model epoxidized oils were monitored by FT-IR spectroscopy in order to evaluate the influence of the hydrogen bond structure and various parameters such as the pressure, the temperature, the catalyst loading, and the nature of the epoxide on the reaction kinetics. Thanks to this catalyst screening, we found that ammonium salt/fluorinated hydrogen bond donors bicomponent organocatalysts were by far more efficient than that proposed in the literature under mild conditions (60°C, 2MPa). Then, the reaction mechanism of the organocatalyzed cycloaddition of propylene oxide onto CO2 was elucidated by performing Density Functional Theory (DFT). Our theoretical results highlighted the key role of the hydrogen bond interaction between the epoxide and the activators for the enhancement of the catalytic platform’s efficiency. [less ▲]

Detailed reference viewed: 118 (7 ULg)