Synthesizing a novel precipitant for lithium recovery from aqueous solutions via Williamson’s reaction

The recovery of lithium from aqueous solutions presents significant opportunities for enhancing sustainable recovery methods in the oil and gas industries. This study focused on the synthesis of a novel precipitant, 2-(4-(3-ethylpentan-3-yl) phenoxy) acetic acid (PAAA), to improve lithium recovery. PAAA was synthesized via Williamson's reaction, with p‑tert-octyl phenoxyacetic acid (POAA) synthesized for comparative analysis. Optimization studies were conducted using Response Surface Methodology (RSM), targeting lithium recovery as the response variable. The results demonstrated that PAAA was successfully synthesized under optimal conditions: a pH of 12, a reaction time of 5 h, a temperature of 50 °C, and a molar dosage of amyl phenol of 0.06. The structures of PAAA and POAA were validated using NMR and FTIR spectroscopy, confirming C = O stretching frequencies at 1700 cm⁻¹ and 1730 cm⁻¹, respectively. Scanning Electron Microscopy (SEM) revealed that the rod-like shape of PAAA enhances lithium-ligand complex formation and precipitation. The study also examined various operating parameters for lithium recovery through the extraction-precipitation method, including reaction pH, reaction time, saponification rates, and molar ratios. A maximum lithium recovery of 84% was achieved under optimal conditions: pH 9, saponification at 85%, a reaction time of 40 min, and a molar ratio of PAAA to Li of 3. These findings highlight the potential of PAAA as an effective precipitant for lithium recovery in aqueous environments.