Examination of the inert solvent assumption in the ideal associated solution model. Enthalpy of chloroform-triethylamine complex dissociation

• Published in: Canadian journal of chemistry 1989-07, Vol.67 (7), p.1153-1157
• Main Authors: Smith, John F, Hepler, Loren G
• Format: Article
• Language: English
• Subjects: Chemical thermodynamics; Chemistry; Elements, mineral and organic compounds; Exact sciences and technology; General and physical chemistry; General. Theory; Metals and alloys; Mixtures; Thermodynamic properties
• ISSN: 0008-4042; 1480-3291
• DOI: 10.1139/v89-174

We have made new measurements of the enthalpies of adding cyclohexane to mixtures of chloroform + triethylamine + cyclohexane at 25 °C. The results of these measurements have been analysed in terms of the ideal associated solution model to obtain ΔH θ for the dissociation of the chloroform-triethylamine complex. Our value of ΔH θ is in excellent agreement with a published value that was obtained from results of measurements on binary mixtures of chloroform + triethylamine. This agreement indicates that it is usefully accurate to treat mixtures of chloroform + triethylamine + cyclohexane as ideal mixtures of chloroform, triethylamine, cyclohexane, and chloroform-triethylamine complex. This result has important implications for studies of associated systems dissolved in "inert" solvents and helps to provide a connection between complex formation in dilute solutions and in binary systems (A + B, no solvent). Keywords: ideal associated solution model, chloroform, triethylamine, inert solvent, hydrogen bonded complex.