Ludovic Josien

Easy Access to Phosphonothioates

A new and particularly mild method for the formation of phosphorus-sulfur bonds has been achieved through base-catalyzed addition of thiocyanate to the corresponding H-phosphine oxide, phosphinate, or phosphonate. This reaction procedure offers many advantages: the use as starting material of a stable and not oxygen-sensitive phosphorus(v) species, particularly mild and nonaqueous reaction conditions and workup (a pivotal point for these sensitive phosphonothioates), and, through optimized access to thiocyanates, a wider scope of substrates. This method has been applied to achieve the synthesis of substrate analogues for the study of antibody-catalyzed hydrolysis of acetylcholinesterase inhibitor PhX (11).

Synthesis and characterization of Mu-19, a new zincophosphate with a three-dimensional 12-membered ring channel system

Abstract A new three-dimensional open-framework zincophosphate [C 5 H 12 NO][ZnP 2 O 5 (OH) 3 ]·H 2 O, named Mu-19, was synthesized at room temperature from a ZnO/P 2 O 5 / N -methylmorpholine/H 2 O system. The crystal structure was determined by single crystal X-ray diffraction. The zincophosphate crystallizes in the orthorhombic space group P2 1 2 1 2 1 (no. 19) with a =9.976(4), b =10.359(6), c =12.980(10) A, V =1341.4(14) A 3 and Z =4. The structure consists of ZnO 4 , PO 2 O(OH) and PO 2 (OH) 2 tetrahedra linked to form an open structure with a three-dimensional channel system delimited by 12-membered ring openings. The organic structure-directing amine is hydrogen bonding to the inorganic framework via water molecules. The zincophosphate Mu-19 is further characterized by 13 C CP MAS/ 31 P MAS NMR with high power decoupling and 1 H CRAMPS NMR spectroscopy, SEM and thermal analyses.

Hydrothermal Synthesis and Characterization of the New Layered Fluorogallophosphate Mu‐23

Mu-23, [(C(6)H(15)N(2))(C(6)H(16)N(2))Ga(5)F(6)(H(2)O)(2)(PO(4))(4)] x 4 H(2)O, the first layered fluorinated gallophosphate with a Ga/P molar ratio of 5:4, was obtained in the presence of fluoride ions with 1,4-dimethylpiperazine as an organic template. It crystallizes in the triclinic space group P1 (no. 2) with unit cell parameters a=8.735(11), b=8.864(5), c=12.636(10) A, alpha=98.36(5), beta=100.18(8), gamma=115.84(7) degrees. The layers consist of GaO(2)F(3)(H(2)O), GaO(4)F(2) octahedra, and GaO(4) and PO(4) tetrahedra; these moieties share their oxygen and some of their fluorine atoms. The connectivity scheme of these different polyhedra leads to the formation of eight-membered rings.

The influence of the nature of organosilane surfactants and their concentration on the formation of hierarchical FAU-type zeolite nanosheets

FAU-type zeolite (NaX) materials were synthesized in the presence of 5 organosilane surfactants [(CH3O)3SiC3H6N(CH3)2–CxH2x+1]Cl (x = 4, 8, 12, 16, 18) (denoted QASiCx) in order to introduce intracrystalline mesoporosity in the FAU-type structure. The influence of the nature of organosilane surfactants (length of the alkyl chain) and their concentrations in the synthesis medium was investigated to determine their impact on the formation of hierarchical FAU-type zeolite nanosheets. Under the basic conditions of faujasite X synthesis, (CH3O)3Si– bonds hydrolyze to –Si–OH, and yield –Si–O–Al- and –Si–O–Si-linkages that anchor to a zeolite framework. These linkages and the formation of micelles by the alkyl chains of the surfactants lead to the formation of mesopores and inhibition of the NaX crystallite growth, leading to the formation of FAU-type nanosheets depending on the alkyl chain length. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed that FAU-type zeolite nanosheets were obtained only using surfactants composed of a minimum twelve carbon alkyl chain. X-ray diffraction results revealed that the optimum concentration of the organosilane to obtain a pure FAU-type material is 0.011 M. Above this concentration, the impurity phase and amorphous materials are observed. This simple approach paves a new way for obtaining hierarchical zeolite materials of controlled porosity by a direct approach for specific catalytic applications.

Synthesis and characterization of a new one-dimensional sodium silicate named Mu-29

Abstract The synthesis and the structure of a new one-dimensional sodium silicate, named Mu-29, are reported. This material was prepared in a quasi-non-aqueous medium using ethanol as the main solvent. Its structure was determined by single crystal X-ray diffraction. The symmetry is orthorhombic, space group Pna2 1 , with the following unit-cell parameters: a =27.32(2) A, b =15.40(2) A and c =8.241(8) A. Mu-29 is a new chain-like silicate. Its structure consists of double-crankshaft––[Si 2 O 5 ] 2− ––chains which are in strong interaction with hydrogen atoms and sodium cations. The material was characterized by elemental and thermal analyses, XRD, SEM and 1 H, 23 Na and 29 Si solid state NMR spectroscopy.

Influence of the porous texture of SBA-15 mesoporous silica on the anatase formation in TiO2–SiO2 nanocomposites

Two series of TiO2–SiO2 composites have been prepared by post-synthesis impregnation of a TiO2 precursor onto SBA-15 silica matrices and subsequent thermal treatment at 400 °C in air. The influence of the textural properties of the SBA-15 and the TiO2 content was evaluated upon the dispersion of TiO2 and its crystallization in anatase. The morphology of the samples before and after impregnation was observed by electronic microscopy while the textural and structural properties were evaluated by different techniques such as XRD, nitrogen sorption manometry, and Raman spectroscopy. The quantity of crystallized anatase in the composites was determined by XRD quantification using an internal standard. The bandgap energy (Eg) of the composites was evaluated by diffuse reflectance spectroscopy and the results show that Eg decreases as a function of the titania content. The photoactivity of the prepared materials was evaluated by following the degradation of methyl orange (MO) in water under UV irradiation. For the same amount of catalyst, the MO degradation rate in the presence of the composites containing 28 and 44 wt% of crystallized anatase was found to be similar to the one in the presence of commercial fully crystallized anatase.

The relationship between mineral contents, particle matter and bottom ash distribution during pellet combustion: molar balance and chemometric analysis

This paper aims to identify the correlation between the mineral contents in agropellets and particle matter and bottom ash characteristics during combustion in domestic boilers. Four agrifood residues with higher mineral contents, namely grape marc (GM), tomato waste (TW), exhausted olive mill solid waste (EOMSW) and olive mill wastewater (OMWW), were selected. Then, seven different pellets were produced from pure residues or their mixture and blending with sawdust. The physico-chemical properties of the produced pellets were analysed using different analytical techniques, and a particular attention was paid to their mineral contents. Combustion tests were performed in 12-kW domestic boiler. The particle matter (PM) emission was characterised through the particle number and mass quantification for different particle size. The bottom ash composition and size distribution were also characterised. Molar balance and chemometric analyses were performed to identify the correlation between the mineral contents and PM and bottom ash characteristics. The performed analyses indicate that K, Na, S and Cl are released partially or completely during combustion tests. In contrast, Ca, Mg, Si, P, Al, Fe and Mn are retained in the bottom ash. The chemometric analyses indicate that, in addition to the operating conditions and the pellet ash contents, K and Si concentrations have a significant effect on the PM emissions as well as on the agglomeration of bottom ash.

UV aerosol synthesis: a one-step route to silica, organic-silica and surfactant/silica nanostructured materials

Aerosol flame technology has been used for decades to fabricate on an industrial scale a range of inorganic (nano)particles, including carbon blacks, titania, and fumed silica. Nevertheless, the high local temperatures inherent to this technique prevent direct organic functionalization or loading by organic derivatives, which is essential in many applications to achieve specific properties and optimal dispersion within an organic matrix. We describe herein a novel eco-friendly UV process allowing single-step manufacture of high-value silica and organosilica particles at ambient temperature. Atomized alkoxysilane precursor droplets are produced within an annular photoreactor including 6 fluorescent UV lamps (maximum emission: 312 nm), and photocondensed continuously after a 1 min single pass. Droplet condensation is controlled by the release of a photoacid catalyst localized in the droplets, affording spherical polydisperse powder particles with a mean diameter ranging around 400–700 nm. In the presence of an amphiphilic block copolymer template, a silica/surfactant mesostructured film was deposited using this UV aerosol technology, resulting in a wormlike mesoporous structure after calcination.

Stripping the latex: the challenge of miniemulsion polymerization without initiator, costabilizer and surfactant

When finally processed to provide the function for which the latex was selected―binding, protecting, finishing―components such as surfactant, costabilizer or initiator become generally useless, not to say detrimental. In this study, we show that miniemulsion photopolymerization provides a suitable method to create latex without the apparent addition of these three compounds. Indeed, UV-driven monomer self-initiation can create initiating radicals without the aid of initiator, the fast in situ photogenerated polymer can hinder Ostwald ripening with the assistance of external costabilizer, and finally, UV-transparent clay can replace conventional surfactant to ensure colloidal stabilization. Each strategy has been developed individually before being combined together to end up with a unique miniemulsion procedure free of initiator, costabilizer and surfactant. Such approach paves the way to a simplified and environmentally improved pathway towards aqueous polymer dispersions.

Hydrothermal synthesis and characterization of new phosphate-based materials prepared in the presence of 1,4-dimethylpiperazine

Two new phosphate-based materials, Mu-23 and Mu-25, are prepared with 1,4-dimethylpiperazine as structure directing agent. Mu-23 is the first two-dimensional fluorinated gallophosphate with a Ga/P molar ratio of 5/4. This new phosphate-based material, with the chemical formula [(C 6 H 15 N 2 )(C 6 H 16 N 2 )Ga 5 F 6 (H 2 O) 2 (PO 4 ) 4 ]⊙4H 2 O, crystallizes in the triclinic space group P-1 with the following unit cell parameters: a=8.735(11) , b=8.864(5) , c=12.636(10) , α=98.36(5)°, β=100.18(8)°, γ=115.84(7)°. The symmetry of the three-dimensional zincophosphate Mu-25, [(C 6 H 16 N 2 )Zn 2 (HPO 4 ) 3 ], is monoclinic (space group P 2 1 /n) with a=8.641(5) , b=14.364(9) , c=12.581(11) , β=96.39(6)°. The layers of the gallophosphate consist of GaO 2 F 3 (H 2 O), GaO 4 F 2 octahedra and GaO 4 , PO 4 tetrahedra which share their oxygen and some of their fluorine atoms. The connectivity scheme of these different polyhedra leads to the formation of 8-membered rings. The framework of Mu-25 results from tetrahedrally coordinated zinc and pphosphorus atoms linked through oxygen vertices. The interrupted framework (presence of P-OH and P=O bondings) displays channels with 4-, 8- and 12-membered ring openings. Structures were determined by single crystal X-ray diffraction and characterized by Solid State NMR spectroscopy, thermogravimetric (TGA) and differential thermal (DTA) analyses.