Efficient microwave-assisted synthesis of glycerol monodecanoate

International audience; Solvent-free microwave-assisted synthesis was carried out to prepare 2,3-dihydroxypropyl decanoate, by esterification of decanoic acid in the presence of two distinct glycerol derivatives, glycidol, and glycerol carbonate, respectively. The process described is based on microwaves heating source with electrical power in the range of 200–400 W, involving stoichiometric proportions of decanoic acid and glycerol derivatives, and using catalytic amounts of TBAI used as organocatalyst. Conversion and selectivity rates of esterification reactions were monitored by 1H and 13C{1H} NMR spectroscopy. The predominantly formed ester, 2,3-dihydroxypropyl decanoate was fully chara…

Formation and Reactivity of a Tantalocene Trihydride Containing an Aminoethyl‐Functionalised Ligand

The complex [Cp*{C5H4(CH2CH2NMe2)}TaCl2] (1) was synthesised by reaction of the lithium salt LiC5H4(CH2CH2NMe2) with the tantalum compound [Cp*TaCl3(PMe3)]. Reduction of 1 with NaAl(H)2(OCH2CH2OMe)2 leads to the trihydride derivative [Cp*{C5H4(CH2CH2NMe2)}TaH3] (2). The oxidation of 2 in THF with ferrocenium ion leads to a cationic dihydride intermediate [Cp*{C5H4(CH2CH2NMe2)}TaH2]PF6 (3) with an intramolecular stabilization by the aminoethyl side-chain of the cyclopentadienyl ligand. The hemilabile character of the functionalised cyclopentadienyl ligand was checked by treating 3 with electron-donating ligands (e.g. phosphanes, sulfides, anions); in all cases, no displacement of the amino g…

Undecylenic acid: A tunable bio-based synthon for materials applications

International audience; An undecylenic acid-based monoglyceride prepared from glycidol and undecylenic acid is used as suitable and tunable synthon for polymerization applications. Epoxidation and acrylation reactions lead to photopolymerizable monomers while transesterification with dimethyl carbonate, metathesis and aminolysis reactions provide access to polyhydroxyurethane-based materials. The successive intermediates were synthesized according to a green chemistry approach implicating solvent-less and catalyzed reactions, and were at each step fully characterized by infrared, 1H and 13C{1H} NMR spectroscopy, elemental analysis and mass spectrometry. Analyses of the resulting polymer mat…

Tantalocenehydridephosphorus chemistry.

Abstract The aim of this paper is to look for a better knowledge of the behaviour of bent tantalocenes that bear hydrides, phosphorus PR2X (R=Me, Ph; X=H, lone pair) and cyclopentadienyl (Cp=C5H5, Cp′=C5H2tBu(Me)2, Cp*=C5Me5) ligands. An orbital control of regioselectivity of insertion of the PR2 phosphide fragment of chlorophosphines PR2Cl into the central TaH bond of trihydrides Cp2TaH3 leading to the formation of metallophosphonium cations is discussed. Neutralisation of cationic complexes with strong bases leads either to the Ta(V)–phosphide or to the Ta(III)–phosphine species depending on the nature of the cyclopentadienyl ligand; good electron donor Cp′ and Cp* rings favour the forma…

Synthesis of polybutadiene-polycaprolactone multi-blokcs based on hydroxyl telechelic polybutadiene. Composition and kinetic study

International audience

Organo-catalyzed synthesis of aliphatic polycarbonates in solvent-free conditions

A new efficient and expeditious route to the synthesis of aliphatic polycarbonates, in solvent-free conditions and using 1-n-butyl-3-methylimidazolium-2-carboxylate (BMIM-2-CO2) as a catalyst precursor, is described. The protocol consists of a two-step polymerization process involving the transesterification of dimethyl carbonate (DMC) with linear alkane diols and leading to high molecular weight homopolymers. The reaction went to completion quantitatively with the liberation of methanol as the only by-product. The in situ formation of N-heterocyclic carbene species resulting from BMIM-2-CO2 decarboxylation is suggested to be a key feature of the condensation process. The protocol was then …

Chain-extending of Hydroxytelechelic Polybutadiene: Synthesis and Characterization

Extension of hydroxytelechelic polybutadiene oligomers ( 3200 g/mol) is performed in mild conditions, in order to avoid backbone modifications, using succinic anhydride or methylenedicyclohexyl diisocyanate. The two routes present significative extension of the initial oligomers. Extension through the anhydride route, in the presence of DCC and DMAP, leads to new hydroxytelechelic oligomers ( 8000 g/mol). Extension through the diisocyanate route, catalyzed by DBTL at 65°C leads to hydroxytelechelic oligomers of higher average molecular weight ( 20000 g/mol). New materials are characterized by FTIR/1H-NMR and changes in their Tg according to , are discussed. The influence of reaction time on…

Design and development of 100 % bio-based high-grade hemp/epoxy composites

International audience; In order to develop 100% bio-based high-grade epoxy composites, in this study, bio-based epoxy thermosets and hemp slivers are processed and characterized by different technologies. Epoxy resins are synthesized from the diglycidylether of Eugenol, extracted from cloves. They are cured with bio-based acid anhydrides. The physicochemical properties of the resulting epoxy resins are characterized using thermogravimetric analyses (TGA), differential scanning calorimetry (DSC), and nanoindentation. The mechanical properties of hemp fibres extracted from the slivers are also determined using tensile tests. After their processing and characterization, these bio-based consti…

Mono- and di-bridged heterobimetallic systems from group 5 hydride phosphido and hydride phosphino metalloligands. Crystal structure of Cp2Ta(H)( μ-H)( μ-PMe2)Cr(CO)4

Abstract The trihydrides Cp2MH3 (M  Nb, Ta) react with chlorophosphines PR2Cl (R  Me, Ph) affording phosphonium salts [Cp2MH2(PR2H)]+, Cl− (2 (a, b) 2′ (a, b)). Depending on the metal (Nb or Ta) and on the nature of the phosphine substituent (Me or Ph), deprotonation of these salts leads to hydride phosphino Cp2MH(PR2H) (3 (a, b) 3′a) or hydrided phosphido Cp2 TaH2(PPh2) (4′b) metalloligands. These two kinds of complexes are able to bind [M′(CO)5] or [M′(CO)4] (M′  Cr, Mo, W) organometallic fragments to give mono- or di-bridged heterobimetallic systems. The crystallographic analysis of Cp2Ta(H)(μ-H)(μ-PMe2)Cr(CO)4 (7′aCr) is reported and discussed.

New approach for synthesis of poly(ethylglyoxylate) using Maghnite-H + , an Algerian proton exchanged montmorillonite clay, as an eco-catalyst

International audience; In this works, we have explored a new method for a green synthesis of poly(ethylglyoxylate) (PEtG). This method consists on using a montmorillonite clay called Maghnite-H+ as an eco-catalyst to replace triethylamine which is toxic. Cationic polymerization experiments are performed in bulk conditions at three temperatures (-40 degrees C, 25 degrees C, 80 degrees C) and in THF solutions at room temperature (25 degrees C). At 25 degrees C, an optimum ratio of 5 wt% of catalyst leads to molar masses up to 22000 g/mol in THF solutions. Polymerizations in bulk conditions lead to slightly lower masses than experiments conducted in THF solutions. However, bulk polymerization…

Reactivity of bimetallic dibridged complexes Cp2Ta(H)(μ-H)(μ-PMe2)M′(CO)4 (M′ = Cr, Mo, W) toward two-electron donor ligands L (L = PR3, Me2P(CH2)nPMe2). Synthesis of linear trinuclear chain complexes Cp2Ta(H)2(μ-PMe2)M′(CO)4(Me2P(CH2)2PMe2)Cr(CO)5 (M′ = Mo, W)

Abstract The reaction of the heterobimetallic phosphido- and hydrido-bridged complexes Cp 2 TaH(μ-H)(μ-PMe 2 )M′(CO) 4 (M′ = Cr, Mo, W) ( 1–3 ) with phosphines (L = PPh 2 Me, PMe 2 Ph) or diphosphines (L = dmpm, dmpe) leads to Cp 2 Ta(H) 2 (μ-PMe 2 )M′(CO) 4 (L) ( 1a, 1b, c, d-3b, c, d ) with L regiospecifically coordinated to M′. Except for L = PPh 2 Me, the reaction is stereospecific, since a cis arrangement (with respect to the PMe 2 bridge) on the M′ site is obtained. The new compounds Cp 2 Ta(H) 2 (μ-PMe 2 )M′ (CO) 4 (Me 2 P(CH 2 ) 2 PMe 2 ) (M′ = Mo, W) are able to bind [Cr(CO) 5 ] fragments affording the linear trinuclear chain compounds Cp 2 Ta(H) 2 (μ-PMe 2 )M′(CO) 4 (Me 2 P(CH 5 )…

Design and synthesis of biobased epoxy thermosets from biorenewable resources

International audience; Biobased diepoxy synthons derived from isoeugenol, eugenol or resorcinol (DGE-isoEu, DGE-Eu and DGER, respectively) have been used as epoxy monomers in replacement of the diglycidyl ether of bisphenol A (DGEBA). Their curing with six different biobased anhydride hardeners leads to fully biobased epoxy thermosets. These materials exhibit interesting thermal and mechanical properties comparable to those obtained with conventional petrosourced DGEBA-based epoxy resins cured in similar conditions. In particular, a high Tg in the range of 90–130 °C and instantaneous moduli higher than 4.3 GPa have been recorded. These good performances are very encouraging, making these n…

Synthesis and Complexation of the Metalloligand {(η5-C5H5)[η5-C5Me3-1,2-(PPh2)2]TiCl2} (TiPHOS): The First Example of a 1,2-Bis(diphenylphosphanyl)titanocene Derivative

The reaction of lithium 1,2-bis(diphenylphosphanyl)trimethylcyclopentadienide (1) with CpTiCl3 leads to the formation of the titanocene diphosphane {(η5-C5H5)[η5-C5Me3-1,2-(PPh2)2]TiCl2} (TiPHOS, 2). This metalloligand reacts readily with (NBD)Cr(CO)4 and W(CO)5(THF) to give, in both cases, the bimetallic chelate complexes (TiPHOS)Cr(CO)4 (3) and (TiPHOS)W(CO)4 (4). The structure of 4 has been determined by X-ray diffraction. The synthesis of a new early-late heterobimetallic complex (TiPHOS)Rh(CO)Cl (5) is reported.

Development and characterization of a bio-based epoxy matrix for high-grade bio-based composites

This study aims to develop 100% bio-based hemp/epoxy composites for semi-structural and structural applications. The thermal and mechanical performances of a 100% bio-based matrix derived from biomassare evaluated and reveal properties in the same order of magnitude as those obtained for polyepoxides based on DGEBA, that means a glass transition temperature of approximately 150°C and mechanical properties in the order of 120MPa for the maximum stress and 3.2 GPa for the tangent apparent modulus. This natural origin matrix is then used for the manufacture of composites reinforced with hemp rovings. The bending properties of these 100% bio-based materials are equivalent to those determined fo…

Tantalocene complexes as bidentate métalloligands: (C5Me5)(C5H4X)Ta(H2)(PPh2) (C5Me5) (C5H4X)Ta(CO) (PPh2) (X = PPh2, CH2CH2NMe2)

Abstract The synthesis of new bidentate metalloligands derived from tantalocene (C5Me5)(C5H4X)Ta(H2)(PPh2) (X = PPh2, 2P; X = CH2CH2NMe22N) and (C5Me5)(C5H4X)Ta(CO)(PPh2) 4(P,N) is described. When opposed to chromium unsaturated fragments the phosphino functionalised complexes 2P and 4P act as chelating bidentate ligands affording Ta(V) (C5Me5)(C5H4PPh2)Ta(CH2) (μ-PPh2)Cr(CO)4 or Ta(III) (C5Me5)(C5H4PPh2)Ta(CO)(μ-PPh2)Cr(CO)4 bimetallic complexes. The same reaction carried out starting from 2N gives rise to a μ-phosphido, μ-hydrido dibridged complex Cp*(C5H4CH2CH2NMe2)TaH(μ-H)(μ-PPh2)Cr(CO)4.

Redox properties of titanocene-pyrrole derivative and its electropolymerization

A new titanocene dichloride derivative in which one cyclopentadienyl ligand (Cp) is functionalized with a pyrrolyl ring, Tc3Py (Cl2TiCpC5H4(CH2)3NC4H4), has been synthesized and characterized with NMR. Its redox properties have been studied by CV in acetonitrile (AN), tetrahydrofurane (THF) and dichloromethane (DCM), in comparison with unsubstituted titanocene dichloride (Tc) and pyrrole. Ti(IV/III) transition observed within the negative potential range is a quasi-reversible reaction in THF and DCM (but without a complete recuperation of the initial reagent in the back scan) while the reoxidation peak in AN is strongly shifted in the positive direction. These results are interpreted within…

Biomass-derived phenylpropenes as precursors of thermosetting epoxy resins : from synthesis to materials

International audience; As demonstrated by the current international awareness, and supported by several independent studies, the replacement of fossil fuels and the need to find competitive alternatives are crucial issues to reduce global warming, and to limit the consequences for life on Earth [1]. As part of this challenge, the biomass and molecules from the living can be considered as providential pools of renewable building blocks dedicated to the chemistry of the future. This is particularly true in polymer science, where the use of renewable resources for the synthesis of fully or partially biobased materials arouses a great deal of interest, in academia and industry [2].

The plant resistance inducer β-aminobutyric acid (BABA) induces an iron deficiency response in A. thaliana

β-aminobutyric acid (BABA) is a well-known plant resistance inducer. However, the molecular mechanisms underlying its effects are poorly understood. In the present study, we investigated whether BABA could act through the modification of iron homeostasis in Arabidopsis thaliana. Supporting this assumption, we obtained first evidences that BABA chelates iron with high affinity. We showed that pre-treatment of plants with BABA induced a drastic but transient iron deficiency response. Quantification of iron indicated that this response is related to the perturbation of iron distribution/availability rather than a reduction of iron assimilation. Finally, we provided evidence that the iron defic…

New reactive isoeugenol based phosphate flame retardant : toward green epoxy resins

A biobased reactive phosphate flame retardant derived from isoeugenol was synthesized and fully characterized (1H, 13C, 31P NMR, FTIR, MS) with the aim of improving flame retardancy behavior of bio...

Development and characterization of a bio-based epoxy matrix for high-grade bio-based composites

This study aims to develop 100% bio-based hemp/epoxy composites for semi-structural and structural applications. The thermal and mechanical performances of a 100% bio-based matrix derived from biomassare evaluated and reveal properties in the same order of magnitude as those obtained for polyepoxides based on DGEBA, that means a glass transition temperature of approximately 150°C and mechanical properties in the order of 120MPa for the maximum stress and 3.2 GPa for the tangent apparent modulus. This natural origin matrix is then used for the manufacture of composites reinforced with hemp rovings. The bending properties of these 100% bio-based materials are equivalent to those determined fo…

Étude d'un procédé de traitement innovant des fibres de chanvre sous condition de fluide supercritique et propriétés induites

International audience

In VitroRelease of Local Anaesthetic and Anti-Inflammatory Drugs from Crosslinked Collagen Based Device

The drug delivery systems that are the object of this article take the form of a hydrophilic matrix (collagen or crosslinked collagen) containing a drug. These devices can be used as The model active agents, were chosen from the range of local anaesthetics (lidocaine hydrochloride), anti-inflammatory (diclofenac sodium salt) and antioxydant (caffeic acid). Whatever the drug affinity for water, in the first time of the experiments, the release appears to be systematically delayed when the matrix is crosslinked. For lidocaine hydrochloride based systems, as the amount of drug increases in the matrix, the high gap concentration between the matrix and the buffer solution promote the diffusion a…

Characterizations of Thermoplastic Block Elastomers Based on Polybutadiene and ε -Caprolactone

A broad series of tri- and multiblock copolymers based on linear and branched oligomers of polybutadiene as central blocks and polycaprolactone (PCL) as block extremities are characterized by SEC, DSC, DMA, Dynamical Rheology and DRX. DSC analyses reveal phase separation between the two amorphous PB and PCL phases. By thermal analysis, the glass transition temperature of PCL is only detected for materials containing at least 80% w/w of PCL. This is attributed to the small length of the polyester blocks for copolymers containing less than 80% w/w of PCL. The increase of fusion heat with increasing PCL content in the copolymers is correlated to the greater ability of PCL chains to rearrange a…

Development of Novel Flame-Retardant Polymers Based on Eugenol or Isogenol

Crystal structure of the diglycidyl ether of eugenol

The diep­oxy monomer (DGE-Eu) was synthesized from eugenol by a three-step reaction. It consists of a 1,2,4-tris­ubstituted benzene ring substituted by diglycidyl ether, a meth­oxy group and a methyl­oxirane group. The three-membered oxirane rings are inclined to the benzene ring by 61.0 (3) and 27.9 (3)°. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds, forming layers parallel to the ab plane.

1-n-Butyl-3-methylimidazolium-2-carboxylate: a versatile precatalyst for the ring-opening polymerization of ε-caprolactone and rac-lactide under solvent-free conditions

The ring-opening polymerization of ε-caprolactone (ε-CL) and rac-lactide (rac-LA) under solvent-free conditions and using 1-n-butyl-3-methylimidazolium-2-carboxylate (BMIM-2-CO2) as precatalyst is described. Linear and star-branched polyesters were synthesized by successive use of benzyl alcohol, ethylene glycol, glycerol and pentaerythritol as initiator alcohols, and the products were fully characterized by 1H and 13C{1H} NMR spectroscopy, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). BMIM-2-CO2 acts as an N-heterocyclic carbene precursor, resulting from in situ decarboxylation, either by heating under vacuo (method A) or by addition of NaBPh4 (method B)…

β-Aminobutyric Acid (BABA)-Induced Resistance in Arabidopsis thaliana: Link with Iron Homeostasis

International audience; Bêta-Aminobutyric acid (BABA) is a nonprotein amino acid inducing resistance in many different plant species against a wide range of abiotic and biotic stresses. Nevertheless, how BABA primes plant natural defense reactions remains poorly understood. Based on its structure, we hypothesized and confirmed that BABA is able to chelate iron (Fe) in vitro. In vivo, we showed that it led to a transient Fe deficiency response in Arabidopsis thaliana plants exemplified by a reduction of ferritin accumulation and disturbances in the expression of genes related to Fe homeostasis. This response was not correlated to changes in Fe concentrations, suggesting that BABA affects the…

Electrosynthesis and properties of poly(3,4-ethylenedioxythiophene) films functionalized with titanocene dichloride complex

Synthesis of a titanocene dichloride derivative functionalized with 3,4-etylenedioxythiophene group, Tc1EDOT (Cl 2TiCpC5H4(CH2) (3,4ethylenedioxythiophene)) has been described. Redox behavior of the monomer in tetrahydrofuran (THF), dichloromethane (DCM) and acetonitrile (AN) at different scan rates has been discussed in terms of different ability of these solvents to coordination with the reduced titanocene (Tc) complex and the solvation of Cl − anions. Electrooxidation of Tc1EDOT to get a conducting polymer film with immobilized titanocene dichloride centers and electrochemical properties of its polymer matrix in background acetonitrile solution have been compared with those of non-substi…