Influence of the composition of aqueous-alcohol solvents on enthalpic characteristics of l-glutamine dissolution at T=298.15

• Published in: Journal of molecular liquids Vol. 258; pp. 253 - 257
• Main Authors: Smirnov, Valeriy I., Badelin, Valentin G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.05.2018
• Subjects: Alcohols; Amino acids; Enthalpy of solution; Enthalpy of transfer; H2O; Mixed solvent; Enthalpy of transfer; Amino acids; Enthalpy of solution; Mixed solvent; H2O; Alcohols
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2018.03.013

The enthalpies of the solution of l‑glutamine in aqueous solution of ethanol (EtOH), 1‑propanol (1-PrOH) and 2‑propanol (2-PrOH) with alcohol content up to 0.25mol fractions, have been determined calorimetrically at T=298.15K. The standard enthalpies of the solution (ΔsolH∘) and transfer (ΔtrH∘) of l‑glutamine from water to aqueous alcohol have been calculated. The enthalpic coefficients of pairwise interactions (hxy) between l‑glutamine and alcohol molecules have been computed by the McMillan–Mayer formalism. It has been found that these coefficients become increasingly positive in EtOH, 1-PrOH, and 2-PrOH sequence. A linear relationship between the enthalpic coefficients of pairwise interactions of l‑glutamine-alcohol and those of alcohol-H2O is also established. A comparative analysis of the thermochemical characteristics of L‑glutamine dissolution and some amino acids in the mixtures studied has been made. [Display omitted] •Enthalpies of l‑glutamine dissolution have been measured in aqueous alcohols.•Dependence of ΔsolH∘of l‑glutamine dissolution on the mixture composition is established.•Results are compared with similar for six amino acids.•The enthalpic contribution of l‑glutamine side chain to hxy was determined.