Calibration of spectral reaction data

Calibration is the first step in the prediction of concentrations from spec tral measurements of chemical reaction systems. It is a well-known fact tha t the species in the calibration set must include those in the new set. Typ ically, the calibration set is constructed from nonreacting mixtures of kno wn concentrations. In this paper, it is proposed instead to use the calibra tion data from reacting mixtures, thereby avoiding the independent variatio n of possibly highly-reactive intermediates. However, for the prediction to be correct, restrictions on the initial and inlet concentrations of the ne w data set must be imposed. When these restrictions cannot be met, calibrat ion of data in reaction-variant form is proposed. The methodology is illust rated experimentally using an esterification reaction. (C) 1999 Elsevier Sc ience B.V. All rights reserved.