Application of band-target entropy minimization to on-line raman monitoring of an organic synthesis. An example of new technology for process analytical technology

Abstract

The hydrolysis of acetic anhydride to acetic acid in water as solvent was monitored by Raman microscopy. Both static and flow-through configurations were used in the experiments, and various experimental designs, i.e., multiple-experimental runs and multiple-perturbation semibatch mode, were considered. Various spectral data preprocessing was performed and band-target entropy minimization (BTEM) was used in the spectral analysis to recover the pure-component spectra from the multicomponent data. Good and consistent spectral estimates of the solutes acetic anhydride and acetic acid were recovered. In addition, the pure-component spectrum of white-light interference was recovered. Together, these estimates permitted very good estimates of the individual time-dependent signal contributions. Taken together, the present results suggest that the combination of Raman spectroscopy and BTEM has considerable potential for organic syntheses and process analysis. The combination of Raman spectroscopy and BTEM represents another approach for reaction monitoring in process analytical technologies (PAT). © 2007 American Chemical Society.