Unexpectedly Superhigh Toxicity of Superbase-Derived Deep Eutectic Solvents albeit High Efficiency for CO2 Capture and Conversion

Superbase-derived deep eutectic solvents (DESs) are considered as biodegradable, low toxic, and sustainable solvents for efficient capture and conversion of carbon dioxide. However, do superbase-derived DESs have low toxicity just as reported? Herein, contradictory to the conventional thought, we find that the toxicity of superbase-derived DESs is super high. The toxicity of superbase-derived DESs in this work could be ca. 266 times that of DESs previously reported. Moreover, toxicity could be tuned by changing hydrogen bond donors, hydrogen bond acceptors, and mole ratios. The results indicate that the types of hydrogen bond donors had a paramount effect on the toxicity of DESs, and increasing the molar ratio of higher toxic components will also increase the toxicity of DESs. This work will provide possible ways to reduce the toxicity of DESs for achieving sustainable and green capture and conversion of carbon dioxide.

Automated summary

Superbase-derived deep eutectic solvents (DESs) are considered as promising solvents for carbon dioxide capture and conversion due to their biodegradability, low toxicity, and sustainability. However, contrary to previous belief, this study reveals that superbase-derived DESs actually exhibit extremely high toxicity, about 266 times that of DESs reported before. The toxicity of DESs can be tuned by adjusting the types and ratios of hydrogen bond donors and acceptors. This research provides insights into reducing the toxicity of DESs and promoting their sustainable and green application in carbon dioxide capture and conversion.