Effect of Hydrogen Bonding Network on Raman Modes of Methanol-Hydrogen Peroxide Binary Solutions

Raman spectroscopy and density functional theory (DFT) calculations were used to explore the interaction between methanol (MeOH) and hydrogen peroxide (HP). Raman spectra of MeOH-HP binary solutions with different concentrations were measured at room temperature and atmospheric pressure. Anomalous change in hydrogen bonding (H-bond) was observed when V-M (volume fraction of the MeOH) was 0.1. Based on Gaussian deconvolution, the influence of MeOH on the O-H stretching mode is analyzed. The results indicate that at V-M > 0.1, the symmetric and asymmetric O-H stretching vibrational modes of HP located at 3264 and 3462 cm(-1), respectively, shifted to lower wave numbers, and the free O-H vibrational mode (weak shoulder peak) at 3600 cm(-1) disappeared. This phenomenon showed that the Raman shifts of O-H symmetric and asymmetric stretching vibrational modes reversed when V-M is 0.1, which reveals that the H-bond structure of this binary solution undergoes a phase transition from HP-HP to MeOH-HP as V-M increases. Furthermore, the blueshift of the C-H symmetric and asymmetric vibrational stretching modes of MeOH and the redshift of the C-O vibrational mode of MeOH demonstrate that no H-bond formed between the methyl group of MeOH and HP molecules. Finally, the DFT calculation at the B3LYP/6-311 + G(d,p) level of theory was carried out to obtain the optimized geometry, vibrational spectra, bond length, and interaction energies of MeOH-HP complexes. This work can be used as a reference for exploring the H-bond network in systems involving alcohol and hydrogen peroxide.