Types Of Contact Surfaces Research Articles

Linear alkanoates + aromatic hydrocarbon binary mixtures: new excess enthalpy measurements and disquac analysis of thermodynamic properties

Excess enthalpies at 298.15 K and atmospheric pressure are reported for 8 binary liquid mixtures of n-alkanoates (propyl methanoate, butyl methanoate, ethyl ethanoate, propyl ethanoate, butyl ethanoate, methyl propanoate, ethyl propanoate, propyl propanoate) + toluene. These experimental results along with literature data on vapour-liquid equilibrium (VLE), excess molar Gibbs energies ( G E), excess molar enthalpies ( H E), activity coefficients at infinite dilution ( γ i ∞) and excess molar heat capacities ( C p E) of n-alkanoates + benzene, or + toluene are examined on the basis of the DISQUAC group contribution model. The components in the mixtures are characterized by three types of contact surfaces: carboxylate (COO group), aliphatic (CH 3 or CH 2 groups) and aromatic (C 6H 6 or C 6H 5 groups, in benzene or in toluene, respectively). Interaction parameters for aliphatic/aromatic and aliphatic/COO contacts have been estimated previously. In this work, we have determined the missing heat capacity interaction parameters of the aliphatic/COO contact and all the interaction parameters of the aromatic/COO contact. The aromatic/COO contact is best described by entirely dispersive parameters. The Gibbs energy and enthalpy parameters decrease, whereas the heat capacity parameters increase, with the n-alkyl chain of the n-alkanoate.

Calorimetric study of nitrile-carbonyl group interactions. Comparison with DISQUAC predictions

Marras G., Artal M., Otin S. and Marongiu B., 1994. Calorimetric study of nitrile-carbonyl group interactions. Comparison with DISQUAC predictions. Fluid Phase Equilibria, 98: 149-162. Excess enthalpies, HE, at 298.15 K and atmospheric pressure are reported for binary liquid mixtures of alkanenitriles + n-alkanones. These experimental results, along with literature data on liquid-vapor equilibria (excess Gibbs energies), GE, excess enthalpies, HE, and activity coefficients at infinite dilution, γi∞, are interpreted in terms of the DISQUAC group contribution model. The systems are characterized by three types of contact surfaces: nitrile (CN), carbonyl (CO) and alkane. The interchange energies of the alkane/CN and alkane/CO contacts were determined independently from the study of n-alkane + nitrile and n-alkane + ketone systems. The interaction parameters of the CN/CO contacts are reported in this work. The quasi-chemical parameters for alkanenitrile + ketone are zero except for ethanenitrile-containing mixtures. The dispersive parameters depend on the environment of the CN and CO groups. In general, the model provides a fairly consistent description of the excess functions GE and HE as functions of composition of the n -alkanenitrile + n-alkanone mixtures investigated.

Excess enthalpies of dibromoalkane + tetrachloromethane mixtures. Measurement and analysis in terms of group contributions (DISQUAC)

Blanco S.T. Munoz Embid J. and Otin S., 1993. Excess enthalpies of dibromoalkane + tetrachloromethane mixtures. Measurement and analysis in terms of group contributions (DISQUAC). Fluid Phase Equilibria , 91: 281-290. Excess enthalpies at 298.15 K and atmospheric pressure are reported for binary liquid mixtures of dibromomethane, 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane and 1,8-dibromooctane + tetrachloromethane (CCl 4 ). These experimental results, along with literature data, on liquid-vapor equilibria (excess Gibbs energies) are interpreted in terms of the DISQUAC group contribution model. The systems are characterized by three types of contact surfaces: bromine (Br) and alkane, in α,ω-dibromoalkanes, and solvent CCl 4 . The interchange energies of the alkane/CCl 4 and alkane/Br contacts were determined independently from the study of n -alkane + CCl 4 , and α,ω-dibromoalkane + n -alkane systems, respectively. The interchange energies of the alkane/Br contact of dibromomethane and of the Br/CCl 4 contact were estimated in this work. The Br/CCl 4 parameters of α,ω-dibromoalkanes are entirely dispersive and increase regularly with increasing separation u of the two bromine atoms in the molecule (proximity effect) in the same regular manner as observed previously for α,ω-dichloroalkane + CCl 4 , mixtures, and reach the values of 1-bromoalkanes when u ≧ 5. In general, the model provides a fairly consistent description of H E and G E as a function of composition and dibromoalkane chain length.