Search results for "Differential Thermal Analysis"
showing 6 items of 66 documents
Fast Solution Precursor Synthesis of the 2223 Phase: the Role of Lead in the Reaction Pathway
1994
ABSTRACTValuable mechanistic information, about the reaction pathway in the formation of the 2223 phase, has been obtained by the use of a solution synthesis route. The presence of lead in the starting mixture has remarkable effects on the nature and stability of the different intermediates: i) the grain size and morphology of Bi2CuO4 is severely changed, ii) calcium carbonate is partially decomposed to yield the calcium plumbate, iii) the 2201 phase results stabilized against the formation of the collapsed phase Bi17Sr16Cu7O49-δ, iv) the melting point of the intermediate 2212 is lowered by about 10 °C. All these effects, due to lead substitution, contribute to promote the formation of the …
A new copper(II) chelate complex with polyamines as fire retardant and epoxy hardener: Synthesis, crystal and electronic structure, and thermal behav…
2020
A new (ethylenediamine-N,N′)-(diethylenetriamine-N,N′,N″)-copper(II) hexafluoridosilicate complex, [Cu(eda)(deta)]SiF6 (1) (eda – ethylenediamine; deta – diethylenetriamine), was synthesized by direct interaction of anhydrous CuSiF6 with polyethylenepolyamine (pepa – H2N[C2H4NH]nH, where n = 1 (eda) and 2 (deta)). The crystals of 1 were characterized by IR spectroscopy and X-ray diffraction. Compound 1 consists of SiF62− discrete anions and [Cu(eda)(deta)]2+ complex cations whose Cu2+ ions are chelated by eda and deta. The coordination polyhedron of Cu(II) atom is an elongated square pyramid which consists of four nitrogen atoms belonging to NH2 groups of eda and NH2 and NH groups of …
Synthesis, structural, and thermal characterization of a new binuclear copper(II) chelate complex bearing an amine-hardener for epoxy resins
2016
A new di(μ-carbonato)bis[aqua(diethylenetriamine)copper(II)] hexahydrate complex, [{Cu(NH(C2H4NH2)2)(H2O)(μ-CO3)}2]⋅6H2O (1), was synthesized by direct interaction of malachite with diethylenetriamine (dien). The crystals of 1 were characterized by X-ray powder diffraction and IR spectra, as well as structurally characterized. Compound 1 consists of [{Cu(dien)(H2O)(μ-CO3)}2] discrete units whose CO32– anions play the role of bridging ligands combining two Cu(II) chelate cores into a centrosymmetric dimer. The elongated octahedral environment of Cu2+ consists of three nitrogens of dien and an oxygen from CO32– at the base of the bipyramid; the two apical positions of such polyhedron are occu…
Reduction and catalytic behaviour of heterobimetallic copper–lanthanide oxides
2008
Abstract The reduction of the heterobimetallic copper–lanthanide oxides 2CuO·CeO2 and 3CuO·Ln2CuO4 (Ln = La, Pr, Nd) was studied by H2-TG/DTA and H2-TPR. All systems exhibit two main reduction steps accompanied by mass losses in the temperature range 20–1000 °C. The first step was attributed to CuO reduction, whereas the second step is due either to copper reduction in the Ln2CuO4 phase with the concomitant formation of Ln2O3 or to the surface reduction of CeO2. The products were characterized by XRD, SEM, EDX, and BET techniques and are better described as supported copper type materials. They were active for the mesityl oxide (4-methyl-2-penten-2-one) gas phase hydrogenation.
Enrichment and activation of smectite-poor clay
2011
A new method of smectite clay enrichment has been developed. The method is based on dispersing clay in a phosphate solution and sequential coagulation. The product of enrichment is characterized with X-ray powder diffraction, wavelength dispersive X-ray fluorescence spectrometry, differential thermal analysis and thermogravimetry. Sorption of methylene blue and hexadecylpyridinium bromide on raw and purified clays was studied.