Chemometric optimization of chemical reactions with spectroscopic measurements

Jean-Nicolas Aebischer, Michael Amrhein*, Ennio Vanoli, Gregory Corminboeuf, Olivier Naef

Ecole d’ingénieurs et d’architectes de Fribourg, Blvd de Pérolles 80, 1705 Fribourg, Switzerland
* Online control SàRL, av. de la Gare 10, 1003 Lausanne, Switzerland

This project aims at the optimization of chemical reactions by using online analytical and chemometric methods.

The experiments are carried out in a fully automated chemical reactor (1 liter). The host computer controls the standard process variables such as mixture temperature, jacket temperature, pressure, added mass, pH, … In addition, it receives in real-time the online analytical data (Raman, FT-IR and mass spectrometry). These data are then processed by chemometric methods without calibration. These methods reveal reaction events such as start points of the main and the secondary reaction, end points of these reactions and changes in physical quantities.

As a model reaction, the aldol condensation between acetone and benzalde-hyde was chosen. This reaction fulfills the following criteria: suitable reaction time, formation of two reaction products and affordable starting material. In parallel to the online measurements, the reaction is followed by conventional chemical analysis (liquid chromatography, NMR).

[1]	Matthias Otto in ‘Chemometrics, Statistics and Computer Application in Analytical Chemistry’, Wiley-VCH, 1999, New York.
[2]	Malinowski, E. R. in ‘Factor Analysis in Chemistry’, John Wiley & Sons, 1991 (2nd edition), New York.
[3]	Amrhein, M. in ‘Reaction and Flow Variants/Invariants for the Analysis of Chemical Reaction Data’, EPFL - these No 1861, 1998, Lausanne.