Surface activity and phytotoxicity of morpholinium herbicidal ionic liquids
Marta Wojcieszak, Barbara Krupa, Anna Syguda, Filip Walkiewicz, Michalina Wilkowska, Maciej Kozak, Katarzyna Materna
Abstract
The use of efficient synthesis methods to obtain novel herbicidal ionic liquids (HILs) with biological activity is extremely important because it can eliminate certain negative environmental impacts. The authors of this work succeeded in the experiment, which resulted in the synthesis of 18 novel ionic liquids with high yields. Furthermore, a number of physicochemical and biological properties have been investigated, including surface activity, thermal analysis, and phytotoxicity. In addition, it was proven that morpholinium ionic liquids with phenoxyacid anions were more effective against cress than HILs previously studied in the literature. To the best of our knowledge, this is the first report of surface-active ionic liquids with herbicidal anions where leaf surfaces were used for analysis. An important aspect of this work was to compare the wettability of the surfaces of wheat leaves and weeds. Moreover, it was shown that using paraffin as a reference surface was not sufficient to describe the wetting properties of HILs. The research reported here proved that morpholinium ionic liquids were effective in wetting weed surfaces while they do not adversely affect wheat leaf surfaces. Our results could be significant for meeting the environmental challenges and agricultural demands of the future.