This study reports the results of a comprehensive physicochemical investigation of the urea–L-valine binary system, conducted to validate its potential as a modified base for liquid nitrogen fertilizers. By utilizing the methods of isomolar series, visual-polythermal analysis, X-ray phase (XRD) and single-crystal X-ray diffraction (SC-XRD), synchronous thermal analysis (TGA/DTA), and FT-IR spectroscopy, it was determined that the interaction between components in both aqueous solutions and the solid phase results in the formation of molecular associates stabilized by hydrogen bonds, without the formation of new stoichiometric compounds. The concentration and temperature limits of the system's stability were defined, revealing a reduction in the crystallization rate and enhanced thermal stability of the composition compared to the individual components. The data obtained form a scientific foundation for developing technologies for the production of stabilized liquid nitrogen fertilizers modified with amino acids.
Nurmonov et al. (2026) studied this question.