Real time NMR analyses of phenolic resin reactions

Abstract

The current investigation presents the development and application of a Rapid NMR acquisition method, capable of identifying transient species and quantitatively monitoring their changes in real time during an in situ phenolic resin preparation. This quantification was only possible after the determination of phenolic resin relaxation times (T1) and nuclear Overhauser enhancements (NOE).

Rapid NMR spectra were recorded with an inter-pulse delay time of 0.6 s and broadband decoupling, which resulted in the acquisition of sequential qualitative spectra at 2.5 min intervals. The obtained qualitative spectral data were then converted into quantitative spectral data via the derived cross calibration (fc) and NOE (η) factors, resulting in quantitative reaction profiles for the phenoic resin species under investigation.

Extension of this work will allow the effects of varying synthesis parameters (i.e. temperature, pH, stoichiometry, catalyst type, etc.) on the final structure and hence on the final physical properties of the resin to be determined and inevitably leading to the development of new, more innovative and cost-effective resins.