The effect of ionic liquids with the tetrafluoroborate anion on terrestrial plants

Abstract

Ionic liquids have attracted considerable interest as excellent alternatives to organic solvents to be used in homogeneous and biphasic processes. Ionic liquids are non-volatile, non-flammable and their "green" character has usually been justified with their negligible vapour pressure. However, the marketing of any chemical substance requires the determination of their impact on all elements of nature. Determination of the potential ecotoxicity of new chemical compounds is associated with conducting research on the effects of those compounds on the growth and development of selected organism. The phytotoxic properties of chiral ionic salts with the alkylimidazolium cation and the tetrafluoroborate anion were assessed for selected weeds popular in Poland: gallant soldier (Galinsoga parviflora Cav.), white goosefoot (Chenopodium album L.) and common sorrel (Rumex acetosa L.). It was found that 3alkyl-1-[(1R,2S,5R)-(-)-menthoxymethyl]imidazolium tetrafluoroborates-([C8-Im-Men][BF4]) and ([C9-Im-Men][BF4]) were low toxic to plants. A higher toxicity to terrestrial plants was characterized by ([C11-Im-Men][BF4]). The toxicity effect of compounds depended non only on the length of the alkyl chain in the function group but also on the concentration of the used compound and the type of plant which was sprayed with the tested compound.