Novel Ionic Conducting Composite Membrane Based on Polymerizable Ionic Liquids.

In this work, the design and characterization of new supported ionic liquid membranes, as medium-temperature polymer electrolyte membranes for fuel-cell application, are described. These membranes were elaborated by the impregnation of porous polyimide Matrimid® with different synthesized protic ionic liquids containing polymerizable vinyl, allyl, or methacrylate groups. The ionic liquid polymerization was optimized in terms of the nature of the used (photo)initiator, its quantity, and reaction duration. The mechanical and thermal properties, as well as the proton conductivities of the supported ionic liquid membranes were analyzed in dynamic and static modes, as a function of the chemical structure of the protic ionic liquid. The obtained membranes were found to be flexible with Young's modulus and elongation at break values were equal to 1371 MPa and 271%, respectively. Besides, these membranes exhibited high thermal stability with initial decomposition temperatures > 300 °C. In addition, the resulting supported membranes possessed good proton conductivity over a wide temperature range (from 30 to 150 °C). For example, the three-component Matrimid®/vinylimidazolium/polyvinylimidazolium trifluoromethane sulfonate membrane showed the highest proton conductivity-~5 × 10-2 mS/cm and ~0.1 mS/cm at 100 °C and 150 °C, respectively. This result makes the obtained membranes attractive for medium-temperature fuel-cell application.

Hydrophobization of chitosan films by surface grafting with fluorinated polymer brushes.

Chitosan with its surface-properties and biodegradability is a promising biomaterial for green packaging applications. Till now, this application is still limited due to chitosan high sensitivity to water. Some existing studies deal with the incorporation of hydrophobic additives to enhance water-proof performances of chitosan films. As these additives may impair the film properties, our study focuses on chitosan efficient hydrophobization by means of simple and successful surface grafting reactions. Chitosan films prepared by solvent casting were modified by means of surface-initiated activators regenerated by electron transfer atom radical polymerization (SI-ARGET-ATRP) of 2-hydroxyethyl methacrylate (HEMA) followed by esterification reaction with fluorinated acyl compound. X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) highlighted the surface chemical changes after each step. Surface properties were investigated by contact angle measurements and surface energy calculations. Hydrophobic surfaces with low surface energy and good water-repellent properties were obtained using a simple handling polymerization procedure. This is the first study in applying ARGET ATRP to prepare hydrophobic biopolymer films offering potential applications in packaging.

Access to Constrained Fluoropseudopeptides via Ring-Closing Metathesis of Fluoroalkenes.

Bis-alkene substrates, containing one fluoroalkene and linked by an amide moiety, have been designed and synthesized to be subjected to ring-closing metathesis reactions. The substitution of fluoroalkene by a phenyl group enhanced the reactivity, and the resulting fluorinated lactams were obtained in high yields except when a hindered alkyl group was present in the molecule. The cycles were then subjected to ring opening in order to develop a new route to constrained fluoropseudopeptides bearing a fluoroalkene as a peptide bond mimic.

Biopolymer-supported ionic-liquid-phase ruthenium catalysts for olefin metathesis.

Original ruthenium supported ionic liquid phase (SILP) catalysts based on alginates as supports were developed for olefin metathesis reactions. The marine biopolymer, which fulfills most of the requisite properties for a support such as widespread abundance, insolubility in the majority of organic solvents, a high affinity for ionic liquids, high chemical stability, biodegradability, low cost, and easy processing, was impregnated by [bmim][PF6 ] containing an ionically tagged ruthenium catalyst. These biosourced catalysts show promising performances in ring-closing metathesis (RCM) and cross-metathesis (CM) reactions, with a high level of recyclability and reusability combined with a good reactivity.

Enantioselective synthesis of bio-relevant 3,5-diaryl pyrazolines.

The straightforward asymmetric construction of bio-relevant Δ(2)-pyrazolines having either N-(thio)amide or N-acetyl functional groups and flanked by aryl substituents such as phenol at C3 and C5 has been achieved through an enantioselective phase transfer organocatalytic addition of N-Boc hydrazine to chalcones followed by a transprotection sequence allowing N-Boc transformation into N-CXNHR (X = S, O) or N-Ac functional groups. This approach was applied to a straightforward elaboration of chiral monoamine oxidase inhibitor derivatives.

Study of Alginate-Supported Ionic Liquid and Pd Catalysts.

New catalytic materials, based on palladium immobilized in ionic liquid supported on alginate, were elaborated. Alginate was associated with gelatin for the immobilization of ionic liquids (ILs) and the binding of palladium. These catalytic materials were designed in the form of highly porous monoliths (HPMs), in order to be used in a column reactor. The catalytic materials were tested for the hydrogenation of 4-nitroaniline (4-NA) in the presence of formic acid as hydrogen donor. The different parameters for the elaboration of the catalytic materials were studied and their impact analyzed in terms of microstructures, palladium sorption properties and catalytic performances. The characteristics of the biopolymer (proportion of ß-D-mannuronic acid (M) and α-L-guluronic acid (G) in the biopolymer defined by the M/G ratio), the concentration of the porogen agent, and the type of coagulating agent significantly influenced catalytic performances. The freezing temperature had a significant impact on structural properties, but hardly affected the catalytic rate. Cellulose fibers were incorporated as mechanical strengthener into the catalytic materials, and allowed to enhance mechanical properties and catalytic efficiency but required increasing the amount of hydrogen donor for catalysis.

Thermo sensitive behavior of cellulose derivatives in dilute aqueous solutions: from macroscopic to mesoscopic scale.

Thermal behaviors of thermo sensitive hydroxypropyl cellulose (HPC), methyl cellulose (MC) and methyl hydroxypropyl cellulose (MHPC) solutions have been investigated in dilute regime of concentration (C

TBD-organocatalysed synthesis of pyrazolines.

It was found that TBD, a cheap and commercially available guanidine, easily catalysed the synthesis of biologically important 3,5-diarylpyrazolines from chalcones and acylhydrazines via a selective secondary amine alkylation.

Microspheres based on inulin for the controlled release of serine protease inhibitors: preparation, characterization and in vitro release.

The pharmacological activity of serine protease inhibitors, potential drugs for the treatment of thrombosis, is often linked to the presence of amidine functions. With the aim of developing a suitable formulation for these compounds, inulin and inulin acetate associated or not with 1,12-dodecanedicarboxylic acid, were chosen to prepare microspheres. Using a coacervation method, these biocompatible polymers led to microspheres of about 0.5-5 microm. The encapsulation of a water-soluble model drug (E,E)-bis(amidinobenzylidene)cycloheptanone [(E,E)-BABCH] in these microspheres was studied. In this investigation, factorial designs were used to determine the joint influence of several variables (drug mass, speed and time of formulation stirring, centrifugation time) for an optimum encapsulation efficiency. Results revealed that encapsulation efficiency reached 65% whatever the nature of the biopolymer, by using a stirring time of 30 min, a high stirring speed and a centrifugation time of 15 min. (E,E)-BABCH release from microspheres was examined in an in vitro model. The profiles were characterized by three phases strongly dependent on the microspheres and the diacid association displayed a crucial role. With inulin and inulin acetate, the initial phase was a rapid 'drug burst'. Within the first 5 min, 58-62% of the drug were delivered. Microspheres of inulin acetate associated with 1,12-dodecanedicarboxylic acid, showed a slower release with only 32% of the drug delivered after 15 min. After a slow diffusion phase (33 h), an increasing rate until complete drug release was observed for 2.5 days.