Search results for "thermogravimetric analysis"
showing 10 items of 212 documents
Selective guest inclusion of linear C6 hydrocarbons in a Zn(ii) 1D coordination polymer
2021
Trapping of volatile unbranched C6 hydrocarbons (hexane, 1-hexene, and 1-hexyne) in a 1D coordination polymer is reported. The guest inclusion was studied quantitatively by 1H-NMR analysis and thermogravimetric measurements, while synchrotron single-crystal diffraction data allowed advancing the view of their confinement into linear CP channels. Adsorption experiments performed through solid/vapour processes on microcrystals of CP 1 showed a certain degree of selectivity for 1-hexyne, which could be rationalized by its larger dipole moment.
Structure analysis of titanate nanorods by automated electron diffraction tomography
2011
A hitherto unknown phase of sodium titanate, NaTi3O6(OH)·2H2O, was identified as the intermediate species in the synthesis of TiO2 nanorods. This new phase, prepared as nanorods, was investigated by electron diffraction, X-ray powder diffraction, thermogravimetric analysis and high-resolution transmission electron microscopy. The structure was determined ab initio using electron diffraction data collected by the recently developed automated diffraction tomography technique. NaTi3O6(OH)·2H2O crystallizes in the monoclinic space group C2/m. Corrugated layers of corner- and edge-sharing distorted TiO6 octahedra are intercalated with Na+ and water of crystallization. The nanorods are typically …
Crystal Structure and Local Dynamics in Tetrahedral Proton-Conducting La1-xBa1+xGaO4
2010
La1-xBa1+xGaO4-0 (LBG) compounds, based on unconnected GaO4 moieties, were recently proposed as proton conductors. Protonic defects in the lattice are inserted through self-doping with Ba2+, to create oxygen vacancies subsequently filled by hydroxyl ions. We present a combined structural analysis on self-doped LBG using X-ray diffraction (XRD) and X-ray absorption (EXAFS): these results unravel the finer structural details on the short-range and long-range scales, and they are correlated with the dynamical properties of protonic conduction coming from vibrational spectroscopy. The structure of the GaO4 groups is independent of the oxide composition. On hydration, an array of short intertetr…
Pulicaria glutinosa plant extract: a green and eco-friendly reducing agent for the preparation of highly reduced graphene oxide
2014
The environmentally friendly synthesis of nanomaterials using green chemistry has attracted tremendous attention in recent years due to its easy handling, low cost, and biocompatibility. Here we demonstrate a facile and efficient route for the synthesis of highly reduced graphene oxide (PE-HRG) by the green reduction of graphene oxide (GRO) using the Pulicaria glutinosa plant extract (PE). The phytomolecules present in the P. glutinosa extract are not only responsible for the reduction of GRO, but also for the functionalization of the surface of the PE-HRG nanosheets and stabilize them in various solvents, thereby limiting the use of any other external and harmful chemical reductants and su…
New approach for synthesis of poly(ethylglyoxylate) using Maghnite-H + , an Algerian proton exchanged montmorillonite clay, as an eco-catalyst
2017
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…
Undecylenic acid: A tunable bio-based synthon for materials applications
2016
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…
Hydrogen Sorption Properties of Metal Hydride and Glass Phase
2009
This work is devoted to the development of a new composite material for hydrogen storage and to investigation of physical and chemical characteristics of material. The new composite material is formed by combination of AB5 type lanthanum nickel alloy with a glass based on silica. Thermogravimetric and XRD measurements prove that the new material absorbs more hydrogen than both constituents separately. That is explained by hydrogen sorption in the composite material due to the hydrogen spillover phenomena, where the hydrogen molecules dissociated on the surface of catalyst in atoms and spills over to the inert surface. That causes the increase of catalytic activity of an alloy and the presen…
A novel oxovanadate structural type – Synthesis, single crystal structure and magnetic properties of a mixed-valence polyoxovanadate formed by {V17O4…
2007
Abstract A novel polyoxovanadate structural type, with an average nuclearity of V16, formed by a mixture of two different polyoxovananadates: {V15O36(Cl)} and{V17O40(Cl)} has been synthesized and characterized. The title compound, formulated as [Ni(phen)3]2{[V15O36(Cl)]0.5[V17O40(Cl)]0.5} · H2O (1) (phen = 1,10′-phenanthroline), presents two different polyoxovanadate architectures: {V15O36(Cl)} and {V17O40(Cl)}, with the last one representing a new framework type in polyoxovanadate chemistry. Here, we present the synthesis of this novel polyoxovanadate under hydrothermal conditions and its characterization by IR and XPS spectroscopies, elemental and thermogravimetric analysis, redox titrati…
Iron(II) Spin Transition Complexes with Dendritic Ligands, Part I
2008
The ligands G1- and G2-oligo (benzyl ether) (PBE) dendrons and their iron(II) complexes [Fe(Gn-PBE)3]A2·xH2O (with n = 1, 2 and A = triflate, tosylate) were prepared. The magnetic properties of the complexes were investigated by a SQUID magnetometer. All complexes exhibit gradual spin transition below room temperature. At very low temperatures the magnetic behaviour reflects zero-field splitting (ZFS) effects. 57Fe-Mossbauer spectroscopy was performed to distinguish between ZFS of high spin species and spin state conversion into the low spin state. Further characterisation was carried out by thermogravimetric analysis (TGA) and FT-IR spectroscopy. Structural features have been determined by…
Tin(II) Derivatives of 2,3-Dihydroxynaphthalene
1983
Abstract The reaction of aqueous solutions of tin(II) chloride and 2,3-dihydroxynaphthalene (H2A) gives a white precipitate of SnA. This compound has been characterized by chemical analysis, IR spectra and thermogravimetric analysis. A spectrophotometric study of tin(II) and H2A in DMF shows the formation of two species with stoichiometric ratios Sn:H2A 1:1 and 1:2.