Incremental Identification of Kinetic Models by Online Spectroscopy and Multivariate Calibration

Extent-based kinetic identification is a modeling technique that uses number of moles / concentrations measurements to compute extents and identify reaction kinetics (partial orders of reactions and reaction rate constant) by the integral method of parameter estimation. This project uses infrared spectroscopic data with calibration models to predict moles / concentrations via a PLS1 regression method. The calibration set (design of experiment) is constructed from a seven-level design for multivariate calibration in molar fraction with reacting material. The extent-based kinetic identification using number of moles predicted from spectroscopic data is tested through experiments in a homogeneous liquid-phase reaction system. The experiments were conducted in an RC1 calorimeter from Mettler Toledo with two inlet streams, without outlet stream, and a ReactIR 10 FT-IR probe. The reaction studied was the transesterification of methanol and hexanol with acetic anhydride producing methyl, hexyl acetate and acetic acid. No solvents or catalyst were used, only pure species at a reaction temperature of 50°C. Results in terms of calibration design and model, computation of extents and extent-based kinetic identification are discussed.