Determination of the Conformational Composition of Ethylene Glycol by RAS Spectroscopy and DFT Calculations

The objectives of the study of ethylene glycol (EG) are to determine the Raman lines of glycols that can be used to analyze the conformational and isomeric composition of molecules, as well as to assess the conformational composition of glycol molecules. Based on the calculations, it was found that the Raman lines in the region of about 800 cm−1are indicators of the presence of EG molecules in conformations of the xGyor xG'y type, where x and y can be t, g or g'. In the experimental Raman spectra of liquid EG, this line is highly intense, therefore, molecules in the indicated conformations are present in large quantities in liquid EG. This result is also confirmed by the obtained contents of EG molecules in various conformations based on calculations. In order to describe the 2600-4000 cm−1 region of the Raman spectra of glycols, it is necessary to take into account intermolecular interactions.