Process and reaction monitoring by low-field NMR spectroscopy

A study was conducted to demonstrate process and reaction monitoring by low-field nuclear magnetic resonance (NMR) spectroscopy. The study focused on the development of a robust low-field spectroscopic technique which had the potential to be widely applicable in an industrial or technical environment. The development was related to time-domain (TD-) NMR and high-field Fourier-transform (FT) NMR. Reaction monitoring by NMR had been performed inside the probe and the magnet, providing an in situ possibility for monitoring the reaction progress by diverse NMR methods. MAS-studies were also performed to observe polymerization, while heterogeneous catalytic reactions had been investigated by imaging methods. One of the most attractive features of quantitative NMR spectroscopy was that the proportionality of the peak area to the number of nuclei was essentially identical for all nuclei of the same species in a mixture.