Versatile High-Pressure Gas Apparatus For Benchtop Nmr: Design And Selected Applications

A simple, yet highly versatile setup is presented for benchtop NMR analyses of gases at high-pressure. It consists mostly of commercial parts and includes multiple safety features while maintaining a small size to fit into a 1.20 m wide fume hood. Pressures up to 200 bar can be adjusted independently of the sample gas-bottle pressure in a matter of seconds. Mixtures of multiple gases can be produced in situ in a mixing chamber, which also serves to adjust the pressure. The high-pressure hardware and benchtop NMR spectrometer have been tested for long-term stability and repeatability of the measurements. The versatility of the setup is demonstrated by analyzing hydrocarbon-gas with attention to linewidths as well as their H-1 relaxation times, by improving the resolution of H-1 NMR spectra from solid polymers with pressurized CO2, and by visualizing the ingress of gaseous and supercritical methane into liquid benzene. (C) 2021 Elsevier Inc. All rights reserved.