Quantitative Raman determination of hydrogen peroxide using the solvent as internal standard: Online application in the direct synthesis of hydrogen peroxide

摘要

H2O2 concentrations in aqueous solutions have been determined by means of a 532 nm Raman spectrometer. H2O2 is a highly demanded green oxidant agent, and its direct synthesis from H2 and O2 is a promising alternative to the traditional production process. Raman spectroscopy is a fast, non-destructive and reliable analytical technique for H2O2 quantification, which avoids the drawbacks of traditional iodo-metric determinations (sample extraction, preparation of the reagents and a long time of analysis). A high pressure view cell has been designed to facilitate the measuring at high pressures, which are often found in a direct synthesis process. A thorough calibration model has been developed, and it has been validated at high pressure (5.0 MPa) and temperature (up to 45 °C). The solvent (water) was used as internal standard to correct multiplicative distortions. The validation of the analytical technique produced reproducible and accurate results compared against classic iodometric titration, allowing the use of a single calibration model for a range of reaction conditions. The feasible use of Raman spectroscopy for real-time quantitative reaction monitoring has been established by analysing the decomposition reaction of H2O2 under different conditions.