Improved solubility of sparingly soluble pesticides in mixed ionic liquids

Abstract

Mixed ionic liquids (ILs) of 1-butyl-3-methylimidazolium bromide ([C₄mim][Br], A) and 1-decyl-3-methylimidazolium bromide ([C₁₀mim][Br], B) were used as solubilizers for six water-insoluble pesticides (i.e., metolachlor, acetamiprid, acetochlor, clethodim, thiamethoxam, and prochloraz). The solubilities of six pesticides were improved by increasing the B content of the mixed ILs. The aggregation behavior of the mixed IL systems was investigated by means of surface tension, conductivity, and fluorescence measurements. Enhancements in solubility were related to the surface activities of the mixed ILs, as indicated by measurements of their surface active and thermodynamic parameters. This work can reduce the cost and toxicity of using ILs, and the data shown in this paper provide valuable information for choosing a proper mixing proportion of suitable ILs for application to agriculture.