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.

Automated summary

The setup presented provides a simple yet highly versatile solution for benchtop NMR analysis of gases at high-pressure. It allows for independent adjustment of pressures up to 200 bar and the production of gas mixtures in situ, demonstrating long-term stability and repeatability in measurements. The versatility of the setup is showcased through various applications, including analyzing hydrocarbon gases, improving resolution of NMR spectra from solid polymers, and visualizing the ingress of gases into liquids.