Novel eco-friendly ionic liquids to solubilize seven hydrophobic pesticides

In line with the requirements of green chemistry, the preparation of eco-friendly pesticide formulations has become art inevitable development trend. In this work we explored the feasibility of four new ionic liquids (Rs, [Octyl trimethyl ammonium] anions, anions = proline, valine, leucine, tartaric acid) as environmentally-friendly solvents for pesticide emulsifiable concentrates, and also as alternatives to traditional imidazole-based ILs since they do not contain the imidazole ring and the anions are natural substances. The results showed that the solubility of pesticides (clethodim, metolachlor, acetochlor, prochloraz, thiamethoxam, glyphosate, acetamiprid) in water with 25%w/vILs was significantly improved, especially for acetamiprid, where the solubility was increased 19-fold, while it only increased about 4 to 5-fold after adding imidazole-based ILs in our previous work. In addition, the solubilization mechanism was explored by many methods and found that the solubilization effect does not completely depend on the critical micelle concentration (CMC) value but has a great relationship with the hydrophilicity of the ILs which may affect the size of micelles and release behavior to pesticides. Finally, H-1 NMR was used to investigate the solubilization sites of ILs for glyphosate, and the interaction between pesticides and anions was explored by the quantum chemical method. (C) 2019 Elsevier B.V. All rights reserved.