Study On The Relationship Between The Structure And Toxicity Of Ionic Liquid

Ionic liquids(ILs)are organic salt composed of organic cations and organic/inorganic anions.Due to their unique physicochemical properties such as non-flammable,negligible vapor pressure,high thermal and chemical stability,ILs have been widely used in electrochemistry,biological field separation and extraction procedures.However,since most ILs have high solubility in water,it necessary to study the effects of IL’s toxicity on the aquatic environment.The experimental methods still cannot meet the increasing amount of ILs.Thus,the reliable calculation methods could effectively replace the time-consuming and labor-consuming experimental process.In this work,based on the concept of norm index and the overall optimization method,a series of atomic distribution matrices about the structure information of cations,anions and ILs were established,and a new set of norm descriptors were calculated.Two norm descriptors-based quantitative structure-activity relationship model for the toxicity of ILs to Leukemia rat cell line(IPC-81)and Vibrio fischeri were established by multiple linear regression method.The research work is as following:(1)Since the contribution of the interaction between cation and anion to the toxicity of overall structure cannot be neglect,the method for optimizing the whole structure of ILs was firstly proposed for representing the‘ion-ion interaction’.A set of norm descriptors about cation,anion and ILs were established based on the concept of norm index.Furthermore,a QSTR model was established to predict the eco-toxicity of 173 ILs toward IPC-81.Statistical results:The R2 values of this model,training set and testing set were 0.954,0.954 and 0.951,respectively;the Q2 of the left-one-out method were 0.935,and the F-value was 129.121.The above statistical results show that the model is stable and reliable.(2)Based on the concept of norm index and the overall optimization method,a QSTR models of 179 ILs on Vibrio fischeri was established with the R2 and the F-value were 0.929 and 132.272,respectively.Results of cross-validation,external validation and application domain analysis were also satisfactory.In addition,the stability of this model was re-verified by a new set of ILs toxicity data,which has obtained satisfactory statistical results.Therefore,some imidazole-based ILs were designed and their toxicity values were calculated by using this stable model,which is helpful for the use of ILs.The above results showed that the norm index is generalized and could be used to describe the relationship between the toxicity of ILs for different targets and their structural information.It is reliable and reasonable to describe the toxicity contribution of‘ion-ion interaction’to ILs by using the whole optimization method.Meanwhile,the norm index-based QSTR model could be used to predict the toxicity of ILs to IPC-81 and Vibrio fischeri,so as to reduce the risk of water pollution caused by the use of highly toxic ionic liquids.