Herbicidal ionic liquids based on esterquats

Abstract

Novel herbicidal ionic liquids (HILs) containing different anions and cations derived from ammonium esterquats were prepared by employing a simple, inexpensive pathway. The basic physicochemical properties of the synthesized salts (such as density, viscosity, refractive index, solubility and thermal stability) were determined.Additionally, their herbicidal efficacy was evaluated under greenhouse and field conditions with a subsequent assessment of biodegradability and toxicity (acute oral toxicity towards rats and rainbow trout, the growth inhibition test of green algae and the acute immobilization test using water flea). The results of greenhouse and field experiments revealed that the herbicidal activity of HILs comprising long alkyl chains has exceeded that of commercial plant protection products. The HIL containing the di(tallowoyloxyethyl)dimethylammonium cation exhibited notable biodegradability (63% after 28 days) and various toxicity classifications depending on the tested organism: category V towards rats with LC 50 4 2000 mg, category II towards fish with LC 50 /96 h at 10.62 mg L À1 , category I towards algae and daphnids with E r C 50 /72 h at 1.73 mg L À1 and EC 50 at 0.28 mg L À1 , respectively. These findings provide evidence that the synthesis of HILs with a specifically designed structure may be successfully employed for obtaining novel, efficient and environmentally friendly plant protection agents. † Electronic supplementary information (ESI) available: 1 H and 13 C NMR spectra, detailed testing procedures for: the acute toxicity test towards rats, the acute oral toxicity test towards rainbow trout, the growth inhibition test of green algae, the acute immobilization test using water flea. See

Synthesis and Structure–Property Relationships in Herbicidal Ionic Liquids and their Double Salts

“…Moreover, owing to their liquid or greasy appearance at 25 °C, all the compounds are room‐temperature ionic liquids (RTILs). The structure of the herbicidal anion has a major influence on their viscosity . Therefore, all the ILs with the MCPA anion ( 1 b – 7 b ) exhibited much lower viscosities in comparison to dicamba‐based ILs ( 1 c – 7 c ), which were highly viscous greases.…”

Ammonium ionic liquids with anions of natural origin

“…The product was then dried under vacuum (10 mbar) at 60 o C for 24 h. Analysis 1 H NMR spectra were recorded on a Mercury Gemini 300 spectrometer operating at 300 MHz with TMS as the internal standard. 13 C NMR spectra were obtained with the same instrument at 75 MHz. Water content was determined using an Aquastar volumetric Karl Fischer titration with Composite 5 solution as the titrant and anhydrous methanol as a solvent.…”

“…5 They can be prepared directly from pharmaceutically-active ingredients [6][7][8][9][10] and also from commonly used pesticides. [11][12][13][14][15][16] Another potential application is associated with the control of crop pests, which are a worldwide cause of crop loss and an overall decrease of crop quality. Chemical compounds called antifeedants or feeding deterrents were introduced in order to prevent such pest activity.…”

Synthesis, Surface Properties and Biological Activity of Long Chain Ammonium Herbicidal Ionic Liquids

“…10,[13][14][15][16][17][18] Reduced volatility contributes to their safer use by operators and reduction of overall environmental impact of the employed herbicide. 16 Solubility in water can be reduced Vol.…”