The simultaneous etherification of isobutene and isoamylenes with ethanol has been studied using macroreticular acid ion-exchange resins as catalyst. Most of the experiments were carried out over Amberlyst-35. In addition, Amberlyst-15 and Purolite CT-275 were also tested. Chemical equilibrium of four chemical reactions was studied: ethyl tert-butyl ether formation, tert-amyl ethyl ether format...

Amyloid fibril deposition is associated with over 20 degenerative diseases, including Alzheimer's, Parkinson's, and prion diseases. Although research over the last few years has revealed the morphology and structural features of the amyloid form, knowledge about the thermodynamics of amyloid formation is limited. Here, we report for the first time a direct thermodynamic study of amyloid formati...

Phase stabilities of Hf-Si-O and Zr-Si-O have been studied with first-principles and thermodynamic modeling. From the obtained thermodynamic descriptions, phase diagrams pertinent to thin film processing were calculated. We found that the relative stability of the metal silicates with respect to their binary oxides plays a critical role in silicide formation. It was observed that both the HfO2/...

The activity of thermo-transient receptor potential (TRP) channels is highly dependent on temperature, and thus thermo-TRP reactions have a high temperature coefficient Q 10. In thermodynamics, a high value of Q 10 indicates the existence of a large activation energy (i.e., a large enthalpy) over a short period during the transition process between the closed and open states of the channels. Th...

2014 The formation enthalpy and entropy of a Schottky defect in alkali halides depend on temperature due to anharmonic effects. Thus the experimental values of these parameters obtained at high temperatures do not coincide with the true ones. In the case of NaCl the experimental value of the formation enthalpy exceeds by 7 % the real formation enthalpy at absolute zero. The experimental value o...

To eludicate the role in conformational stability of Cys residues buried in the interior of a protein, the thermodynamic properties of denaturation of mutant alpha subunit of Escherichia coli tryptophan synthase, in which Ser, Ala, Val or Gly was substituted for each of the three Cys residues, were analyzed using calorimetry. The mutants were less stable than the wild type, indicating that Cys ...

In this work the molar enthalpy of formation of the ionic liquid 1-ethyl-3-methylimidazolium dicyanoamide in the gaseous phase [C(2)MIM][N(CN)(2)] was measured by means of combustion calorimetry and enthalpy of vaporization using transpiration. Available, but scarce, primary experimental results on enthalpies of formation of imidazolium based ionic liquids with the cation [C(n)MIM] (where n = 2...

The thermodynamic functions such as enthalpy, H°, Gibbs free energy, G°, and entropy, S°, of Arginine and Lysine amino acids were theoretically studied at different polar solvents by using ²Gaussian o3², software. First, the structural optimization of isolated Arginine and Lysine were done in the gas phase by applying the Density Functional Theory (B3LYP) level ...