(Eco)toxicity and biodegradability of selected protic and aprotic ionic liquids

Area of Science:

• Green Chemistry
• Environmental Toxicology
• Chemical Safety

Background:

• Ionic liquids (ILs) are proposed as environmentally benign alternatives to volatile organic solvents.
• The environmental impact and toxicity of ILs, particularly protic ILs, require thorough investigation.
• A comparative assessment of protic and aprotic ILs' environmental safety is crucial.

Purpose of the Study:

• To evaluate the aquatic toxicity and biodegradability of selected protic and aprotic ionic liquids.
• To compare the environmental hazard profiles of these two distinct classes of ionic liquids.
• To determine if protic ionic liquids represent a safer alternative in chemical applications.

Main Methods:

• Assessed aquatic toxicity using Vibrio fischeri, Pseudokirchneriella subcapitata, and Lemna minor.
• Conducted biodegradability tests for protic and aprotic ionic liquids.
• Performed additional toxicity evaluations using acetylcholinesterase enzyme and IPC-81 leukemia rat cells.

Main Results:

• Protic ionic liquids demonstrated EC50 values >100 mg L(-1) across most aquatic toxicity tests, with good biodegradability.
• Aprotic ionic liquids exhibited significantly lower EC50 values, indicating higher toxicity, and lower biodegradability potential.
• Three protic IL representatives showed some toxicity towards Lemna minor, but overall protic ILs were less hazardous.

Conclusions:

• Protic ionic liquids present a more environmentally favorable profile compared to commonly used aprotic ionic liquids.
• Protic ionic liquids can be considered safer alternatives to certain aprotic ILs and traditional organic solvents.
• Further research into the environmental safety of ionic liquids is essential for sustainable chemistry.