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.