# Designing Safer Functionalized Ionic Liquids: Monoterpene-Derived Compounds for Greener Agrochemical Development

## TL;DR

Researchers designed safer ionic liquids using monoterpene derivatives to reduce environmental harm in agrochemicals.

## Contribution

A workflow for green-by-design criteria of ionic liquids based on phytotoxicity and physicochemical properties.

## Key findings

- Menthol-based sulfonylimide FILs showed higher phytotoxicity than sulfonate analogues.
- Linear cation FILs were more phytotoxic and had higher log KOW/BCF than cyclic ones.
- Fluorinated anions increased hydrophobicity, bioaccumulation, and toxicity.

## Abstract

The environmental
behavior and phytotoxicity of functionalized
ionic liquids (FILs) featuring imidazolium cations bearing a cyclic
(−)-menthol or a linear 1-decanol-derived substituent and fluorinated
anions were evaluated in a soil bioassay (Raphanus
sativus). Structure–activity relationships
were determined by integrating measurements (water solubility, surface
tension, molecular volume) with in-silico descriptors (n-octanol–water partition coefficient, log K
OW; bioconcentration factor, log BCF; asymmetry). Lipophilicity
and bioaccumulation correlated with fresh-mass inhibition (EC50). More-fluorinated, larger, and charge-delocalized anions
were more hydrophobic, elevating bioaccumulation and toxicity. Within
menthol-based series, sulfonylimide-based FILs were more phytotoxic
(EC50 74.7, 107.3 mg·kg–1 soil dry
weight) than sulfonate analogues (e.g., 299.1 mg·kg–1). FILs with linear cations were more phytotoxic and showed higher
log K
OW/BCF than cyclic analogues, consistent
with greater molecular volume, higher asymmetry, and reduced hydration.
Antioxidant responses paralleled EC50, implicating oxidative
stress. This workflow improves risk assessment and provides green-by-design
criteria to prioritise safer ILs.