Spectroscopic Analysis Of Tetrafluoroborate Ionic Liquid

Ionic liquids are of wide interest due to their physicochemical properties such as low vapour pressure,high thermal stability and good electrical conductivity.Qualitative and quantitative analysis of ionic liquids using infrared,ultraviolet and fluorescence spectroscopy can provide a better understanding of ionic liquids and lay the foundation for their development in other fields.In this paper the analysis of two ionic liquids,BP-BF₄ and BMI-BF₄,is divided into three parts as follows.Part 1:Qualitative and quantitative analysis of the infrared spectra of two ionic liquids,BP-BF₄ and BMI-BF₄.In particular,the qualitative analysis refers to the characterisation of the two ionic liquids,as different organic compounds are made up of different combinations of functional groups,and the IR spectra can be used to determine whether the synthesised ionic liquids are BP-BF₄ and BMI-BF₄ ionic liquids based on the characteristic peaks.The quantitative analysis is based on the linear relationship between the concentration and absorbance of the ionic liquids at very low concentrations in the IR spectra,which leads to a standard curve and spiked recoveries.However,IR spectra have many peaks and are heterogeneous,so it is necessary to determine which peak to use as the peak for quantitative IR analysis.In this paper,two peaks for quantitative IR analysis of ionic liquids,BP-BF₄ and BMI-BF₄,were determined using the least squares method,and the standard curves and spiked recoveries were derived to demonstrate the feasibility of quantitative IR analysis.Part 2:qualitative and quantitative analysis of two ionic liquids,BP-BF₄ and BMI-BF₄,and investigation of the effect of different conditions on the UV spectra of ionic liquids.The qualitative analysis is to measure the effect of solvent effect of different polar solvents on the maximum absorption wavelength of the UV spectra of the ionic liquids;the quantitative analysis is to investigate whether the concentration is linearly related to the absorbance at the maximum absorption wavelength,to make a standard curve and to find the spiked recovery;this paper also investigates the effect of temperature,p H and solvent mixture on the UV spectra of the ionic liquids,and concludes that temperature does not affect the UV The effects of temperature,p H and solvent mixture on the UV spectra of ionic liquids were investigated and concluded as follows:temperature does not affect the UV spectrum,p H affects the peak shape and position of the ionic liquid solution,and solvent mixture affects both the maximum absorption wavelength and the fine structure of the ionic liquid solution.Part 3:Quantitative analysis of two ionic liquids,BP-BF₄ and BMI-BF₄,investigation of the effect of different conditions on the fluorescence spectra of the ionic liquids and determination of the light fading resistance of the two ionic liquids.Firstly,the maximum excitation wavelength and maximum emission wavelength of the solvents with different polarities were measured separately to find the suitable solvents for the next experiments.The sensitivity of the fluorescence spectrum was the highest of the three spectra in this paper and only one peak was evident with increasing concentration.This peak was used as the quantitative analysis peak for the fluorescence spectrum and its standard curve and spiked recovery were derived.The chapter then goes on to investigate the effects of solvent mixtures,different temperatures and different p H values on the fluorescence spectra of ionic liquids.Finally,the loss of integrated peak areas for both BP-BF₄ and BMI-BF₄ were obtained in 40 consecutive scans,demonstrating that both ionic liquids have good resistance to light fading.