Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Effect of glycine, DL-alanine and DL-2-aminobutyric acid on the temperature of maximum density of water

Romero, C. M.[Carmen M.], Torres, A. F.[Andres Felipe]
J. Chem. Thermodyn. 2015, 88, 121-125
ABSTRACT
The effect of glycine, DL-alanine and DL-2-aminobutyric acid on the temperature of maximum density of water was determined from density measurements using a magnetic float densimeter. Densities of aqueous solutions were measured within the temperature range from T = (275.65 to 278.65) K at intervals of T = 0.50 K over the concentration range between (0.0300 and 0.1000) mol kg 1. A linear relationship between density and concentration was obtained for all the systems in the temperature range considered. The temperature of maximum density was determined from the experimental results. The effect of the three amino acids is to decrease the temperature of maximum density of water and the decrease is proportional to molality according to Despretz equation. The effect of the amino acids on the temperature of maximum density decreases as the number of methylene groups of the alkyl chain becomes larger. The results are discussed in terms of (solute + water) interactions and the effect of amino acids on water structure.
Compounds
# Formula Name
1 C2H5NO2 2-aminoacetic acid
2 C3H7NO2 DL-2-aminopropanoic acid
3 C4H9NO2 (.+-.)-.alpha.-aminobutyric acid
4 H2O water
Datasets
The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type Compound-# Property Variable Constraint Phase Method #Points
  • POMD
  • 1
  • 4
  • Mass density, kg/m3 ; Liquid
  • Temperature, K; Liquid
  • Molality, mol/kg - 1; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Buoyancy - hydrostatic balance with magnetic suspension - one sinker
  • 56
  • POMD
  • 2
  • 4
  • Mass density, kg/m3 ; Liquid
  • Temperature, K; Liquid
  • Molality, mol/kg - 2; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Buoyancy - hydrostatic balance with magnetic suspension - one sinker
  • 56
  • POMD
  • 3
  • 4
  • Mass density, kg/m3 ; Liquid
  • Temperature, K; Liquid
  • Molality, mol/kg - 3; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Buoyancy - hydrostatic balance with magnetic suspension - one sinker
  • 56