An Automated, Highly Selective Reaction Monitoring Instrument Using Molecular Rotational Resonance Spectroscopy.

Online monitoring of chemical reactions by using analytical chemistry tools is a powerful way to maximize control over these processes. In this paper, we demonstrate the use of molecular rotational resonance, an emerging and extraordinarily selective spectroscopic technique, to perform automated reaction monitoring measurements. An interface using a six-port valve with a calibrated sample loop, coupled to a temperature controlled inlet for analyte volatilization, was developed and tested. Two reactions were chosen for initial characterization: an amine-aldehyde condensation reaction to form an imine product and an isotopic exchange reaction of a β-ketoester with keto-enol tautomerization. The spectrometer was able to provide kinetic information about the reaction and determine reaction completion. In the future, this system can be extended to detect and quantify impurities and characterize reaction selectivity, in addition to the reaction progress.