Preparation and thermal decomposition of solid state cinnamates of alkali earth metals, except beryllium and radium

Solid state compounds of general formula ML2.nH2O [where M is Mg, Ca, Sr or Ba; L is cinnamate (C6H5 -CH=CH-COO-) and n = 2, 4, 0.8, 3 respectively], have been synthetized. Thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC) and X-ray diffraction powder patterns have been used to characterize and to study the thermal stability and thermal decomposition of these compounds.

Thermal behavior studies of solid state compounds of 4-dimethylaminocinnamylidenepyruvate with alkali earth metals, except beryllium and radium

Solid state compounds of general formula M(DMCP)2.nH2O, where M represents Mg, Ca, Sr, Ba, and DMCP is 4-dimethylaminocinnamylidenepyruvate, and n = 1, except for Ca, where n = 2.5, have been prepared. Thermogravimetry, derivative thermogravimetry (TG, DTG), differential scanning calorimetry (DSC), X-ray diffraction powder patterns and complexometry were used to characterize and to study the thermal decomposition of these compounds.

Thermal behavior studies of solid state compounds of 4-dimethylaminocinnamylidenepyruvate with alkali earth metals, except beryllium and radium

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Preparation and thermal decomposition of solid state cinnamates of alkali earth metals, except beryllium and radium

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Preparation and thermal decomposition of solid state compounds of 4-methoxybenzylidenepyruvate with alkali earth metals, except beryllium and radium

Solid compounds of general formula ML(2) . nH(2)O [where M is Mg, Ca, Sr or Ba; L=4 methoxybenzylidenepyruvate (4-MeO-BP); n = 4, 1 or 0] have been synthetized. Thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), x-ray diffraction powder patterns and elemental analysis have been used to characterize the compounds. The thermal stability of these compounds as well as that of the decomposition products were studied using Pt or Al2O3 crucibles in an air or a CO2 atmosphere.

Thermal studies on solid compounds of 4-chlorobenzylidenepyruvate of some alkali earth metals

Solid-state M-4-Cl-BP compounds, where M stands for bivalent Mg, Ca, Sr, Ba and 4-Cl-BP is 4-chlorobenzylidenepyruvate, have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), infrared spectroscopy, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to informations about the composition, dehydration, thermal stability and thermal decomposition of the isolated complexes.

Solid-state chelates of ethylenediamine-tetraacetate with alkali earth metals

Solid-state M-EDTA chelates, where M represents the divalent ions Mg(II), Ca(II), Sr(II) or Ba(II) and EDTA is ethylenediaminetetraacetate anion, were synthesized. Thermogravimetry, derivative thermogravimetry (TG, DTG), differential scanning calorimetry (DSC) and X-ray diffraction powder patterns have been used to characterize and to study the thermal behaviour of these chelates. The results provided information concerning the stoichiometry, crystallinity, thermal stability and thermal decomposition.

Biosorption and desorption of lanthanum(III) and neodymium(III) in fixed-bed columns with Sargassum sp.: Perspectives for separation of rare earth metals

Rare earth (RE) metals are essentials for the manufacturing of high-technology products. The separation of RE is complex and expensive; biosorption is an alternative to conventional processes. This work focuses on the biosorption of monocomponent and bicomponent solutions of lanthanum(III) and neodymium(III) in fixed-bed columns using Sargassum sp. biomass. The desorption of metals with HCl 0.10 mol L-1 from loaded biomass is also carried out with the objective of increasing the efficiency of metal separation. Simple models have been successfully used to model breakthrough curves (i.e., Thomas, Bohart-Adams, and Yoon-Nelson equations) for the biosorption of monocomponent solutions. From biosorption and desorption experiments in both monocomponent and bicomponent solutions, a slight selectivity of the biomass for Nd(III) over La(III) is observed. The experiments did not find an effective separation of the RE studied, but their results indicate a possible partition between the metals, which is the fundamental condition for separation perspectives. (C) 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012

Study of the alkaline earth metals with 8-hydroxyquinolinate derivatives - Calcium complexes

Metal complexes of calcium with 5,7-dibromo, 7-iodo and 5-chloro-7-iodo-8-hydroxyquinolate were precipitated in aqueous ammonia and acetone medium, except for the solid state compound with 5,7-dichloro-8-hydroxyquinoline which hasn't been obtained under these conditions. The complexes obtained through the mentioned precipitation are Ca[(C9H4ONBr2)(2)](3).H2O, Ca[(C9H5ONI)(2)].2H(2)O and Ca[(C9H4ONICl)(2)].2.5H(2)O. Their intermediate from the thermal decomposition found through TG/DTA curves in air indicated the presence of different kinds of calcium carbonates related to the reversibility and crystalline structure, depending on the original compounds. The initial compounds and the intermediate from the thermal decomposition were also characterized through IR spectra and X-ray diffraction.

Synthesis and thermal study of 8-hydroxy-quinoline derivatives of the alkaline Earth metals: I. Strontium complexes

Strontium complexes of 5,7-dibromo-, 5,7-dichloro-, 7-iodo- and 5-chloro-7-iodo-8-hydroxyquinoline were precipitated from an aqueous ammonia and acetone medium. The complexes obtained were Sr[(C9H4ONBr2)2]·2.5H 2O; Sr[(C9H4ONCl2)(OH)]·1.5H2O; Sr[(C9H5ONI)2]·5H2O and Sr[(C9H4ONICl)(OH)]·1.25H2O. The residues of their thermal decomposition were SrBr2; a mixture of SrCl2, SrCO3 and SrO3 SrCO3, and SrCO3, respectively. All were characterized by means of thermogravimetry, differential thermal analysis, complexometry with EDTA, atomic absorption spectroscopy, IR spectroscopy and X-ray diffraction. © 1999 Akadémiai Kiadó.

Study of biosorption of rare earth metals (La, Nd, Eu, Gd) by Sargassum sp. biomass in batch systems: Physicochemical evaluation of kinetics and adsorption models

This work evaluated kinetic and adsorption physicochemical models for the biosorption process of lanthanum, neodymium, europium, and gadolinium by Sargassum sp. in batch systems. The results showed: (a) the pseudo-second order kinetic model was the best approximation for the experimental data with the metal adsorption initial velocity parameter in 0.042-0.055 mmol.g -1.min-1 (La < Nd < Gd < Eu); (b) the Langmuir adsorption model presented adequate correlation with maximum metal uptake at 0.60-0.70 mmol g-1 (Eu < La < Gd < Nd) and the metal-biomass affinity parameter showed distinct values (Gd < Nd < Eu < La: 183.1, 192.5, 678.3, and 837.3 L g-1, respectively); and (c) preliminarily, the kinetics and adsorption evaluation did not reveal a well-defined metal selectivity behavior for the RE biosorption in Sargassum sp., but they indicate a possible partition among RE studied. © (2009) Trans Tech Publications.

Thermal study and characterization of nicotinates of some alkaline earth metals using TG-DSC-FTIR and DSC-system photovisual

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The metallurgy of yttrium and the rare earth metals.

"Materials Central, Contract No. AF33(616)-5905, Project No. 7351."

Eutectic modification of Al-Si alloys with rare earth metals

The effects of different concentrations of individual additions of rare earth metals (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) on eutectic modification in Al-10mass%Si has been studied by thermal analysis and optical microscopy. According to the twin-plane re-entrant edge (TPRE) and impurity induced twinning mechanism, rare earth metals with atomic radii of about 1.65 times larger than that of silicon, are possible candidates for eutectic modification. All of the rare earth elements caused a depression of the eutectic growth temperature, but only Eu modified the eutectic silicon to a fibrous morphology. At best, the remaining elements resulted in only a small degree of refinement of the plate-like silicon. The samples were also quenched during the eutectic arrest to examine the eutectic solidification modes. Many of the rare-earth additions significantly altered the eutectic solidification mode from that of the unmodified alloy. It is concluded that the impurity induced twinning model of modification, based on atomic radius alone, is inadequate and other mechanisms are essential for the modification process. Furthermore, modification and the eutectic nucleation and growth modes are controlled independently of each other.