FTIR and NMR spectra of polymeric ionic liquids – Products of reaction between hydroxycontaining amidines and carbon dioxide

Abstract

Two hydroxy-containing amidine derivatives have been synthesized by condensation of amino-alcohols such as monoethanolamine (MEA) and tris(hydroxymethyl)aminomethane (TRIS) with N,N-dimethylformamide dimethyl acetal. Their interaction with carbon dioxide, leading to the formation of polymeric ionic liquids, was studied by FTIR and NMR spectroscopy. Dilute solutions of polymeric ionic liquids are also investigated by measuring the relative viscosity during the reaction. It has been found that during interaction of MEA-based amidine with CO2 within first 60 min of reaction the intensities ratio of absorbance bands at 1644 and 1705 cm− 1 dropped from 2.84 to 1.33. The linear relationship between the time of reaction and the mentioned ratio of intensities has been established. In the similar manner the changes in the intensities ratio of absorbance bands at 1696 and 1629 cm− 1 can be used for monitoring the reaction between TRIS-based amidine and CO2. Solution of polymeric ionic liquid prepared by reaction of TRIS-based amidine with CO2 in i-propanol has been used for measuring molecular weight (Mw = 637, Mn= 349; Mw/Mn = 1.828) by gel-permeation chromatography.