ABSTRACT
In this work, we present a comprehensive study of the thermodynamic properties of 3-and 4-ethoxyacetanilides. The heat capacities in crystalline, liquid, and supercooled liquid states from 80 to 475 K were obtained using adiabatic, differential scanning (DSC), and fast scanning (FSC) calorimetries. The fusion enthalpies at Tm were combined from DSC measurement results and the literature data. The fusion enthalpies at 298.15 K were evaluated in two independent ways: adjusted according to Kirchhoff's law of thermochemistry, and using Hess' law. For the latter approach, the enthalpies of the solution in DMF in crystalline and supercooled liquid states were derived. The values obtained by the two methods are consistent with each other. The standard thermodynamic functions (entropy, enthalpy, and Gibbs energy) between 80 and 470 K were calculated.
ABSTRACT
Within the last decade the Carbonate Based Ionic liquid Synthesis (CBILS®) has developed towards a widely applicable, greener and halogen free process for the industrial production of ionic liquids. A large number of diverse starting materials have been screened experimentally, to explore the structural limits of the core reaction step, which is the quaternization of nitrogen, phosphor or sulfur based nucleophiles with carbonic acid dialkyl or diaryl esters to the corresponding quaternary alkyl- or arylcarbonates. In order to overcome the large experimental effort of empirical screening, a practical method based on quantum-chemical calculation has been developed for an assessment of feasibility of chemical reactions. This method has been successfully tested with 16 typical CBILS® reactions by calculation of their thermodynamic functions. Thermodynamic equilibrium constants as a measure for the practical yield of the CBILS® reactions at 298 K and 393 K have been determined for both the gaseous state and the liquid state. The method has been evaluated by comparison of the theoretical results with experimental data and it can be considered as the powerful tool to reduce "trial and failure" for the industrial application of the CBILS® process.
