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Abstract  

The dissolution enthalpies of glycine in aqueous solutions of acetamide, N-methylacetamide, N,N-dimethylacetamide, N-ethylformamide, N,N-diethylformamide and N,N-diethylacetamide were measured at 298.15 K. The enthalpic pair interaction coefficients of glycine zwitterion-amide molecules were determined by using standard solution enthalpies of glycine in water and aqueous solutions of amides. The additivity of groups concept of Savage and Wood was used to estimate the contribution of each of the functional groups of the studied amides.

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Abstract  

Low-temperature heat capacity of two polymorphs of glycine (α and γ) was measured from 5.5 to 304 K and thermodynamic functions were calculated. Difference in heat capacity between polymorphs ranges from +26% at 10 K to -3% at 300 K. The difference indicates the contribution into the heat capacity of piezoelectric γ polymorph, probably connected with phase transition and ferroelectricity. Thermodynamic evaluations show that at ambient conditions γ polymorph is stable and α polymorph is metastable.

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Abstract  

Two bismuth ferrite potential precursors systems, namely Fe(NO3)3·9H2O-Bi(NO3)3·9H2O-glycine/urea with different metal nitrate/organic compound molar ratios have been investigated in order to evaluate their suitability as BiFeO3 precursors. The presence into the precursor of both reducing (glycine and urea) and oxidizing (NO3 ) components, modifies dramatically their thermal behaviour comparative with the raw materials, both from the decomposition stoichiometries and temperature occurrence intervals points of view. Also, the thermal behaviour is dependent on the fuel nature but practically independent with the fuel content. The fuel nature influences also some characteristics of the resulted oxides (phase composition, morphologies). In the case of the oxides prepared using urea as fuel, a faster evolution toward a single phase composition with the temperature rise is evidenced, the formation of the BiFeO3 perovskite phase being completed in the temperature range of 500–550°C.

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Abstract  

The solid-state coordination reactions of lanthanum chloride with alanine and glycine, and lanthanum nitrate with alanine have been studied by classical solution calorimetry. The molar dissolution enthalpies of the reactants and the products in 2 mol L-1 HCl solvent of these three solid-solid coordination reactions have been measured using an isoperibol calorimeter. From the results and other auxiliary quantities, the standard molar formation enthalpies have been determined to be Δf H m θ[La(Ala)3Cl33H2O(s), 298.2 K]= -3716.3 kJ mol-1, Δf H m θ [La(Gly)3Cl35H2O(s), 298.2 K]= -4223.0 kJ mol-1 and Δf H m θ [La(Ala)4(NO3)3H2O(s), 298.2 K]= -3867.57 kJ mol-1, respectively.

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Abstract  

Four complexes of rare earth bromides with amino acids, REBr3·3L·3H2O (RE=La, Nd;L=glycine or alanine) were prepared and characterized by means of chemical analysis, elemental analysis, molar conductivity, thermogravimetry, IR spectra and X-ray diffraction. Their thermal decomposition kinetics from ambient temperature to 500°C were studied by means of TG-DTG techniques under non-isothermal conditions. The kinetic parameters (activation energyE and pre-exponential constantA) and the most probable mechanisms of thermal decomposition were obtained by using combined differential and integral methods. The thermal decomposition processes of these complexes are distinguished as being of two different types, depending mainly on the nature of the amino acid.

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Journal of Thermal Analysis and Calorimetry
Authors: E. Boldyreva, V. Drebushchak, T. Drebushchak, I. Paukov, Y. Kovalevskaya, and E. Shutova
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Abstract  

Rare-earth perchlorate complex coordinated with glycine [Nd2(Gly)6(H2O)4](ClO4)6�5H2O was synthesized and its structure was characterized by using thermogravimetric analysis (TG), differential thermal analysis (DTA), chemical analysis and elementary analysis. Its purity was 99.90%. Heat capacity measurement was carried out with a high-precision fully-automatic adiabatic calorimeter over the temperature range from 78 to 369 K. A solid-solid phase transformation peak was observed at 256.97 K, with the enthalpy and entropy of the phase transformation process are 4.438 kJ mol−1 and 17.270 J K−1 mol−1, respectively. There is a big dehydrated peak appears at 330 K, its decomposition temperature, decomposition enthalpy and entropy are 320.606 K, 41.364 kJ mol−1 and 129.018 J K−1 mol−1, respectively. The polynomial equations of heat capacity of this compound in different temperature ranges have been fitted. The standard enthalpy of formation was determined to be −8023.002 kJ mol−1 with isoperibol reaction calorimeter at 298.15 K.

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Journal of Thermal Analysis and Calorimetry
Authors: E. Boldyreva, V. Drebushchak, T. Drebushchak, I. Paukov, Y. Kovalevskaya, and E. Shutova
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glycine transporters. Eur. J. Pharmacol. 479, 249–262 (2003) Lopez-Corcuera B. Structure, function and regulation of glycine transporters Eur. J. Pharmacol

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one. Sufficient amount of information about enthalpy changes of reactions in water was accumulated for complex formation between transition metals ions and amino acids anions and glycine-ion [ 1 – 3 ] and for complex formation of glycine and

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