| Ionic liquids(ILs)are an appealing category of compounds,composed only of ions.Recently,the study of ILs,in both academic research and industry fields,has attracted worldwide attention.Because of the unique properties of ILs,such as ease of recycling,good solvability capacity for polar/nonpolar compounds,high thermal and chemical stability,etc.,ILs are widely applied in many areas of science and engineering,especially in the fields of electrochemistry,catalysis,gas separations,biotechnology and other engineering technology.The basic physical and chemical properties of the compounds are of great significance for scientific research and industrial application,therefore,the design,production and application of ILs must be based on accurate and reliable physical property data.Experiment is an effectual method to get the physical and chemical data.But it is not only difficult but also time and material consuming to obtain these data by experiments,especially for the easily decomposed and toxic substances.For the huge number of ILs,experimental investigation of each property at different temperatures and pressures is not practical.In this case,computational techniques could be an important alternative method to make up for the lack of experimental data.The basic idea of quantitative structure-activity relationship(QSPR/QSAR)is to describe the physical properties and activity of substances through the information of their molecular structure.QSPR/QSAR has a good effect on the estimation of the physical properties of homologues and are therefore widely used in the studies of drug activity and toxicity.However,the QSPR/QSAR method is difficult to establish a comprehensive model because of its poor universality.The new general molecular characteristic matrix norm-index descriptor is proposed based on the molecular structure information and the atomic position relationship in the molecule in this work,which will overcome the defect that the QSPR/QSAR method is difficult to establish a universal model.Applying the general norm-index descriptors proposed in this paper,the relationship between structures and properties models are established;multi-objectives including thermodynamics properties and toxicological properties of various ILs are evaluated and verified.The types of ILs used in this subject include imidazolium,pyrrolidinium,pyridinium,piperidinium,benzimidazolium,ammonium,phosphonium,sulfonium,quinolinium and morpholinium.The five models have achieved good results,as for the model of the relationship between the IL structure and viscosity,the squared correlation coefficient(R2)is 0.964;as for the model of the relationship between the structure and thermal conductivity,the R2 is 0.984;as for the model of the relationship between the IL structure and heat capacity model,the R2 is 0.996.With respect to the toxicity of ILs against Staphylococcus aureus,as for the minimum inhibitory concentration(MIC)model,the R2 is 0.919;as to the minimal bactericidal concentration(MBC)model,the R2 is 0.913.With respect to the toxicity of ILs against Candida albicans,as for the MIC model,the R2 is 0.930;as to the MBC model,the R2 is 0.873.The results obtained by the models all show that the descriptors proposed in this work can accurately predict the different physical properties and toxicity of polytype ILs,and the comparison between the models obtained by these five properties and their related literature has greatly improved in the accuracy and stability,and also great significance.The universal molecular characteristic matrix norm-index descriptors proposed in this subject study and with which the structure-property relationship models are established,the models have good universality,generality and accuracy for describing the different properties of various kinds of ionic liquids.Therefore,this method has a generalized direction for the multi-objective(physical/activity/toxicity)description of ILs,and the target system is no longer subject to homologues,but is commonly used for many types of ILs. |
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