Synthesis and Characterization of Double-Salt Herbicidal Ionic Liquids Comprising both 4-Chloro-2-methylphenoxyacetate and trans-Cinnamate Anions.

The synthesis and characteristics are presented of novel double-salt herbicidal ionic liquids (DSHILs) that contain 4-chloro-2-methylphenoxyacetate and trans-cinnamate anions. In the designed synthesis, an anion of natural origin and a herbicidal anion were combined with an amphiphilic bisammonium cation to obtain new DSHILs with high herbicidal activity while high biocompatibility is maintained. The NMR and HRMS spectral analysis confirmed that the target structures were formed. Furthermore, HPLC analyses indicated that, as assumed, both anions were present in equimolar amounts. Experiments regarding the herbicidal effectiveness confirmed that the synthesized DSHILs exhibited high biological activity. The solutions of DSHILs applied during greenhouse studies were characterized by a low contact angle (approx. 55-67°) and surface tension (approx. 32-35 mN m-1 ), which facilitated the contact of the active substance with the plant surface and penetration of the herbicide into the plant tissues.