Abstract
In the present investigation, an attempt has been made to evaluate internal pressure (Pi)(Pi)<math><mrow><mo>(</mo> <msub><mi>P</mi> <mi>i</mi></msub> <mo>)</mo></mrow> </math> , energy (ΔEvap)(ΔEvap)<math> <mrow><mrow><mo>(</mo> <mrow><mi>Δ</mi> <msub><mi>E</mi> <mrow><mi>v</mi> <mi>a</mi> <mi>p</mi></mrow> </msub> </mrow> <mo>)</mo></mrow> </mrow> </math> , and enthalpy of vaporization (ΔHvap)(ΔHvap)<math> <mrow><mrow><mo>(</mo> <mrow><mi>Δ</mi> <msub><mi>H</mi> <mrow><mi>v</mi> <mi>a</mi> <mi>p</mi></mrow> </msub> </mrow> <mo>)</mo></mrow> </mrow> </math> along with excess entropy (SE)(SE)<math> <mrow><mrow><mo>(</mo> <msup><mi>S</mi> <mi>E</mi></msup> <mo>)</mo></mrow> <mo> </mo></mrow> </math> and excess isothermal compressibility (βET)(βTE)<math><mrow><mo>(</mo> <msubsup><mi>β</mi> <mi>T</mi> <mi>E</mi></msubsup> <mo>)</mo></mrow> </math> for binary solutions of alkanones (2-propanone, 2-butanone, and 2-heptanone) and aromatic amines (aniline, N-methylaniline, and pyridine) at 293.15, 298.15, and 303.15 K, respectively. The cohesive energy density (CED) and solubility parameter (δ)(δ)<math><mrow><mo>(</mo> <mi>δ</mi> <mo>)</mo></mrow> </math> are studied to understand the strength of molecular interactions. The coefficient of thermal expansion (α)(α)<math><mrow><mo>(</mo> <mi>α</mi> <mo>)</mo></mrow> </math> and isothermal compressibility (βT)(βT)<math><mrow><mo>(</mo> <msub><mi>β</mi> <mi>T</mi></msub> <mo>)</mo></mrow> </math> have also been investigated using empirical equations and have been employed to understand the molecular interactions. All the evaluated properties have been used to understand the nature and extent of intermolecular interactions taking place. The observed trends in the properties and their variations have been discussed in terms of varying chain lengths of the alkyl group and the hydrogen bonding capability of the components. The findings show that the extent of interactions follows an order: aniline > NMA > pyridine, keeping the alkanone constant at all the temperatures under study.