Solubility Behavior, Hansen Solubility Parameters, and Thermodynamic Modeling of l-Leucine in 12 Monosolvents from 283.15 to 323.15 K

Abstract

The solubility and solvent effects of L-leucine in monosolvent systems (water, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, acetonitrile, 1,4-dioxane, acetone, methyl acetate, and ethyl acetate) were investigated by the static gravimetric method in the temperature range from 283.15 to 323.15 K (with 5 K intervals). The solubility increased expectedly with the increase in temperature in all solvents. The solubility order of L-leucine in monosolvents was ranked as water > methanol > ethyl acetate > isopropanol > methyl acetate > isobutanol > ethanol > n-propanol > acetone >1,4-dioxane > acetonitrile > n-butanol. The polymorph of L-leucine was investigated by powder X-ray diffraction. Experiments confirmed that the crystal form did not change during the determination of solubility. The solubility of L-leucine in 12 monosolvents was analyzed by Dimroth and Reichardt's polarity parameters [E T (30)], hydrogen bonds, cohesive energy density, molecular structures, viscosity, and Hansen solubility parameters. Solubility in these monosolvents was well correlated by the modified Apelblat model and the Yaws model. According to the Akaike information criterion and Akaike weight analysis, the modified Apelblat model achieves relatively better fitting results..

Aqueous solution and solid-state behaviour of l-homophenylalanine: experiment, modelling, and DFT calculations

“…2 Different methods e.g. based on gravimetry, [3][4][5][6] spectroscopy, 6,7 titration, 8 laser techniques, 9 Differential Scanning Calorimetry (DSC), 10,11 refractive index, 12,13 or HPLC 14,15 can then be applied as analytical techniques. Some of these methods have been in use for decades indicating their reliability.…”

“…Some of these methods have been in use for decades indicating their reliability. 3,4,16 Depending on the availability of a specic compound or its manageability in lab scale experiments, a varying number of solubility data points are determined. To acquire additional data sets, either by interor extrapolation, modelling can be employed without the need for additional experiments, which, on the other hand, also can save elaborate and time-consuming lab work.…”

“…[19][20][21][22] Aer synthesis, L-Hpa needs to be separated from the reaction mixture or further puried for which crystallization is an attractive separation technique due to its cost efficiency and the usually high product purity achievable. Aqueous solubilities of amino acids are dependent on temperature 3,15,16,23,24 and pHvalue. 15,25,26 In our literature research, we only found one source for the solubility of L-Hpa in water and its dependence on pH which is represented in a graphical manner.…”