Spectroscopic Analysis Of Alkyl Pyridine Acetate Ionic Liquids

Ionic liquids are widely used in many fields such as analytical chemistry and material chemistry due to their unique physical and chemical functions.The spectra of ionic liquids show the relationship between their internal structures and their interactions,thus opening up the application range of ionic liquids themselves.In this experiment,UV,IR and fluorescence spectra of EP-OAC and BP-OAC were analyzed,and the following results were obtained.The solubility of the ionic liquid was measured before the ultraviolet spectrum was measured.Ionic liquids have good solubility if they exist in polar solvents,such as water,ethanol,acetic acid,methanol,acetonitrile,n-butanol,isopropanol,etc.EP-OAC and BP-OAC ionic liquids were qualitatively and quantitatively analyzed in different solvents?such as water,ethanol and acetonitrile?by ultraviolet spectroscopy.The maximum absorption wavelength of ionic liquid in different solvents was measured and the corresponding standard working curve was obtained.The correlation coefficient was above 0.99800 and the recovery was within the range of96.7%¹02.5%.IR spectra were used to measure the infrared spectra of BP-OAC ionic liquid in five solvents in the middle infrared region:ethanol,glacial acetic acid,methanol,acetonitrile and n-butanol,and the optimal analytical peaks were found.At the same time,the standard curve,slope,square of slope and square of correlation coefficient of linear equation are obtained according to the different spectra of solution concentration.Finally,according to the standard addition method,the recoveries of the standard samples were between 95%and 105%,and the correlation coefficients were all above 0.99500.Fluorescence spectrometry was used to measure the fluorescence spectra of EP-OAC ionic liquids in six different solvents,such as water,ethanol,glacial acetic acid,CCl₄,acetonitrile and n-butanol.The restriction of ionic liquid concentration on fluorescence intensity was also discussed,so the corresponding standard curve was obtained,the correlation coefficient and the standard recovery rate were obtained,and the detection limit of low-concentration ionic liquid solution was measured several times to calculate,and the detection limit was below 0.30?g/mL.Subsequently,the fluorescence spectra of EP-OAC ionic liquid were measured.When the optimal ratio of water to ethanol,acetic acid,acetonitrile and n-butanol was 2:8,the fluorescence spectrum showed the best fluorescence intensity.In addition,when the degree of restriction of PH on fluorescence spectrum was measured,it was found that when pH=10,the fluorescence intensity of EP-OAC and BP-OAC ionic liquid aqueous solutions was the highest,and too strong acidity or alkalinity would inhibit the fluorescence intensity.Finally,the experiment proved that the aqueous solution and acetonitrile solution of EP-OAC ionic liquid had good light fading resistance,and the calculated fluorescence quantum yield was between 0.2000 and 0.4000.