Raman Spectroscopic Study of Five Typical Plasticizers Based on DFT and HF Theoretical Calculation

Area of Science:

• Computational Chemistry
• Spectroscopy
• Environmental Science

Background:

• Phthalic acid esters (PAEs) are widely used plasticizers with potential human health risks from exposure.
• Accurate theoretical methods are needed for identifying and quantifying PAEs.

Purpose of the Study:

• To determine the optimal computational method for calculating the theoretical Raman spectra of five PAEs.
• To assign Raman vibrations to specific peaks for PAE identification.
• To establish a basis for rapid PAE detection methods.

Main Methods:

• Calculated theoretical Raman spectra of five PAEs using Hartree-Fock (HF) and Density Functional Theory (DFT).
• Compared various hybrid methods (B3LYP, B3PW91) and basis sets (e.g., 6-311G(d, p)).
• Assigned Raman vibrations by comparing theoretical and experimental spectra.

Main Results:

• DFT proved more suitable than HF for PAE theoretical studies.
• The B3LYP hybrid method with the 6-311G(d, p) basis set yielded the most consistent results with experimental data.
• Raman vibrations were successfully assigned to specific spectral peaks.

Conclusions:

• The optimal computational approach (DFT/B3LYP/6-311G(d, p)) for PAE Raman spectra analysis was identified.
• This finding supports the development of Raman fingerprints for PAEs.
• The study paves the way for rapid and accurate detection of PAEs.