- Thermally induced oxidative decarboxylation of copper complexes of amino acids and formation of strecker aldehyde
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In the Maillard reaction, independent degradations of amino acids play an important role in the generation of amino-acid-specific products, such as Strecker aldehydes or their Schiff bases. Such oxidative decarboxylation reactions are expected to be enhan
- Nashalian, Ossanna,Yaylayan, Varoujan A.
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- Low-temperature heat capacities and standard molar enthalpy of formation of the solid-state coordination compound trans-Cu(Ala)2(s) (Ala = l-α-alanine)
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Low-temperature heat capacities of the solid coordination compound trans-Cu(Ala)2(s) have been measured by a precision automated adiabatic calorimeter over the temperature range from T = 78 K to 390 K. The experimental values of the molar heat capacities in the temperature region were fitted to a polynomial equation of heat capacities (Cp,m) with the reduced temperatures (X), [X = f (T)], by a least square method. The smoothed molar heat capacities and thermodynamic functions of the complex trans-Cu(Ala)2(s) were calculated based on the fitted polynomial. The smoothed values of the molar heat capacities and fundamental thermodynamic functions of the sample relative to the standard reference temperature 298.15 K were tabulated with an interval of 5 K. Enthalpies of dissolution of {Cu(Ac)2·H2O(s) + 2Ala (s)} and 2:1 HAc (aq) in 100 ml of 2 mol dm-3 HCl, respectively, and trans-Cu(Ala)2(s) in the solvent [2:1 HAc (aq) + 2 mol dm-3 HCl] at T = 298.15 K were determined to be ΔS Hm ° [ Cu (Ac)2 s? H2 O (s) + 2 Ala (s) ] = (6.75 ± 0.04) kJ mo l- 1, ΔS Hm ° [ 2 : 1 HAc (aq) ] = - (1.63 ± 0.01) kJ mo l- 1, and ΔS Hm ° [ t r a n s -Cu (Ala)2 (s) ] = - (10.24 ± 0.08) kJ mo l- 1 by means of an isoperibol solution-reaction calorimeter. The standard molar enthalpy of formation of the compound was determined as Δf Hm ° (t r a n s -Cu (Ala)2 (s), 298.15 K) = - (1038.6 ± 3.5) kJ mo l- 1 from the enthalpies of dissolution and other auxiliary thermodynamic data using a Hess thermochemical cycle.
- Di, You-Ying,Chen, Jing-Tao,Tan, Zhi-Cheng
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- A thermochemical study of the solid-state coordination reactions of two α-amino acids with copper(II) acetate
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The two solid-state coordination reactions CuAc2·H2O(s) + 2Ala(s) → trans-Cu(Ala)2(s) + 2HAc(1) + H2O(1) (1) CuAc2·H2O(s) + 2Gly(s) → trans-Cu(Gly)2·H2O(s) + 2HAc(1) (2) have been studied by solution calorimetry. The molar dissolution enthalpies of the reactants and the products in some solvents (such as 2 mol 1-1 HCl or its solutions) of these solid-solid coordination reactions have been measured by an isoperibol solution calorimeter. The standard molar formation enthalpies of [trans-Cu(Ala)2(s), 298.15 K] and [trans-Cu(Gly)2(s), 298.15 K] have been determined to be - 1015.42 ± 0.06 and 1252.36 ± 0.05 kJ mol-1, respectively, from the results of the molar dissolution enthalpies and other auxiliary thermodynamic data.
- Di, You-Ying,Qu, Song-Sheng,Liu, Yi,Wen, De-Cai,Tang, Hou-Kuan,Li, Lin-Wei
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p. 115 - 119
(2008/10/08)
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- Thermal Decomposition of Copper Complexes of Aminoacids
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The thermal decomposition processes of copper complexes have been examined and their fundamental characteristics determined: the temperature and rate of decomposition and the activation energy.The stability series of the compounds investigated has been set up on the basis of the results and compared with the thermodynamic characteristics of the complex formation reactions.
- Eroshkin, V. I.,Shelkovnikov, V. V.,Tronov, A. B.,Durasov, V. B.
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p. 1472 - 1475
(2007/10/02)
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