Optimization of the synthesis conditions of sodium and potassium dihydrogen phosphates and study of their agrochemical properties

Abstract

This study focuses on the optimization of synthesis conditions for sodium dihydrogen phosphate (NaH₂PO₄) and potassium dihydrogen phosphate (KH₂PO₄) and the evaluation of their agrochemical properties. The target salts were prepared via controlled neutralization of phosphoric acid with the corresponding alkali metal bases under varying temperature, pH, and concentration conditions. The effects of these parameters on product yield, phase purity, and crystallization behavior were systematically investigated. The obtained samples were characterized using physicochemical methods, including solubility assessment, pH measurement, and thermal analysis. The results demonstrated that precise control of the neutralization degree and crystallization temperature significantly improves product quality and process efficiency. Agrochemical evaluation indicated that the synthesized dihydrogen phosphates possess favorable nutrient availability and buffering characteristics suitable for fertilizer applications. The optimized synthesis approach provides a cost-effective and scalable route for producing high-purity NaH₂PO₄ and KH₂PO₄ for agricultural use.