Thermolysis of 1,3-dioxin-4-ones: fast generation of kinetic data using in-line analysis under flow?

Reaction Chemistry & Engineering Pub Date: 2015-11-04 DOI: 10.1039/C5RE00007F

Abstract

Rapid acquisition of kinetic data is demonstrated with a commercial meso-scale flow reactor, using a step-change in flow rate or ‘push-out’ from the flow line. For thermolysis of 1,3-dioxin-4-ones (1), we obtain excellent reproducibility in the activation energies measured from spectroscopic data collected by in-line UV or transmission FT-IR monitoring of the output during the transitional period between two flow rates (±3 kJ mol?1, 0.7 kcal mol?1). Analysis of multi-component UV and IR data is conducted using an orthogonal projection approach (multivariate curve resolution by alternating least squares) for complex spectra, or by calibration-less integration of non-overlapping peak absorbance. All analysis methods were validated using off-line 1H NMR analysis, and kinetic parameters obtained using the method of a flow rate step-change were validated against conventional steady-state measurements in which time-series data were acquired across multiple experiments. Thermal transfer and dispersion effects are addressed. The experimental methods described herein are valuable for accelerated reaction study and in process development.

Graphical abstract: Thermolysis of 1,3-dioxin-4-ones: fast generation of kinetic data using in-line analysis under flow
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