Raman Spectroscopy and Chemometrics for Quantitative Analysis of Complex Flows in an Industrial Transesterification Process

A method based on Raman spectroscopy has been used for determination of ester acrylate mixture composition from an industrial production of acrylic monomers. Five molecules of the industrial mixture have been studied: main components and an impurity. Experiments were carried out with an immersion probe on the spectral range of 100–3425 cm−1. Usually, monitoring a complex industrial flow by spectroscopic analysis requires a lot of samples in order to have a representative prediction model. Here only 60 samples from the process were necessary to build the model. The statistics was then artificially increased by synthetically increasing the number of samples. A qualitative study by principal component analysis was at first done, and then a partial least squares method was performed to assess the feasibility of quantitative measurements in such transesterification process. Internal and external validations methods have been used and their results show a RMSEP below 1% of samples predicted concentration ranges. The repeatability and reproducibility of Raman measurements are also discussed. Copyright © 2014 John Wiley & Sons, Ltd.