Efficacy of herbicidal ionic liquids and choline salt based on 2, 4-D. (August 2017) - Marcinkowska, Katarzyna
Abstract: Five quaternary ammonium salts with the 2, 4-dichlorophenoxyacetate [2, 4-D] anion were synthesized and their physicochemical properties and efficacy against weeds was investigated. The following cations were used in the synthesis: (2-hydroxyethyl)trimethylammonium [Choline], (2-chloroethyl)trimethylammonium [CC], cocotrimethylammonium [Arq], bis(2-hydroxyethyl)cocomethylammonium [Etq C] and bis(2-hydroxyethyl)methyloleylammonium [Etq O]. Among them, four compounds: [CC][2, 4-D], [Arq][2, 4-D], [Etq C][2, 4-D] and [Etq O][2, 4-D] were classified as herbicidal ionic liquids (HILs). Data from greenhouse studies showed similar or better efficacy of ionic liquids based on 2, 4-D compared to commercial formulations of 2-ethylhexyl ester and dimethylammonium salt and also to choline salts which is recently marketed but in the mixture with glyphosate (Enlist Duo, Dow AgroSciences LLC). HILS with 2, 4-D anion also showed excellent efficacy in field experiments. In this case, all tested HILs demonstrated several times higher efficacy compared to choline, dimethylammonium salts and 2-ethylhexyl ester. All the described results suggest that selection of an appropriate cation allows to control the physicochemical properties of studied herbicidal ionic liquids, which proved to have a significant impact on its biological activity. Graphical abstract: Highlights: The synthesis of HILs with 2, 4-D anion is simple and occurs with a high yield. HILs' properties depend on the type of cation used in the synthesis. Selection of appropriate cations allows to obtain. More active compounds compared to origin form of 2, 4-D were obtained. HILs with 2, 4-D anion have great application potential.