The Research On Toxicity Effect And Its Prediction Method For Imidazolium-Based Ionic Liquids

Ionic liquids(ILs) has been used in industry for its idiographic physicochemical properties,especially when it was used as solvents and catalyst.It was indicated that it is possible for ILs to become persistent pollutants,which make it sense to discuss toxicity mechanism and ecological risk assessment through researching on their aquatic toxicity.In order to assess the toxic effect of Imidazolium-based ILs to Scenedesmus obliquus,a method of static toxicity test was used to determine the EC₅₀ values of the ten ILs.Besides the influence of Imidazolium-based ILs structure and physicochemical properties on the toxic effect was discussed elementarily.The results indicated that all the tested ILs had relatively strong toxicity to Scenedesmus obliquus,and the order is as follows: [HMIM]PF₆＞[HMIM]BF₄＞[BMIM]PF₆＞[BMIM]BF₄＞[BMIM]Cl＞[BMIM]DMP＞[EMIM]PF₆＞[EMIM]BF₄＞[EMIM]DMP＞[MMIM]DMP. Imidazolium-based ILs' physicochemical properties and molecular structure also affected their toxicity to algae:the toxic effects is almost aroused by cation,the ability to dissolved in ester will become stronger with the length increasing of their R₁ chains,and so does their toxic effect; the toxic effect of anions is little in contrasted with that of cation,but the toxic effect is different with the anions changed.In this article the order of the tested 4 kinds of anions is as follows:PF₆＞BF₄＞Cl＞DMP.Moreover,a QSAR model which can reflect the relations between the acute toxicity caused by ILs and molecular structure parameters including core-core(CCR),total energy(TE) and so on,was established.The results indicated that the toxicity to algae caused by ILs was related to the molecular volume.When the value of molecular weight was higher and the value of TE was lower,the toxicity of ILs has the trend to become higher. All these mean that it is easy for the big molecular to translate from polar phase to non-polar biology phase.