Reaction monitoring using Raman spectroscopy and chemometrics

✍ Scribed by Olof Svensson; Mats Josefson; Frans W. Langkilde

• Book ID: 104309763
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 363 KB
• Volume: 49
• Category: Article
• ISSN: 0169-7439
• DOI: 10.1016/s0169-7439(99)00025-8

✦ Synopsis

The synthesis and hydrolysis of ethyl acetate was monitored with a Raman spectrometer equipped with a 785-nm laser, Ž . confocal optics, an optical fiber, a holographic transmission grating, and a charge coupled device CCD detector. In the Raman spectra, the signals were seen to vary in proportion to the concentrations of ethanol, acetic acid and ethyl acetate. First-order reaction, rate constants were determined for the hydrolysis reaction, under different experimental conditions according to a full factorial experimental design. The rate constants were determined either by using the peak height at one Ž . Ž . single wavelength, or by using score values from principal components analysis PCA or partial least squares PLS . The rate constants determined agree well with literature values. It is shown that the single wavelength and the PCArPLS ap-Ž . proaches give similar reaction profiles, where the standard normal variate SNV transformation was used for spectral pretreatment. The use of Raman spectroscopy for reaction monitoring in opalescent mixtures is also shown and discussed.