Versatile high-pressure gas apparatus for benchtop NMR: Design and selected applications

Refined high-pressure tube design for improved resolution in high-pressure NMR spectroscopy

“…Except for the HP tube and the connecting capillary, the HP setup is identical to that used in ref. 19 where a detailed description can be found. Still, key features are given here.…”

“…The immense improvement in spectral resolution, as demonstrated by various comparisons, allows the utilization of HP benchtop NMR spectroscopy for an analysis of even more complex spectra than those presented in ref. 19 and 33. Within the frame of the current work, the pressure-dependent H 2 solubility in 2-methylfuran and 2-methyltetrahydrofuran (2-MTHF) is reported.…”

“…However, a HP vessel in shape similar to a standard NMR tube is predominantly employed in commercially available NMR spectrometers. Such tubes are most often made of sapphire (Al 2 O 3 ), 17,18,19 zirconia (ZrO 2 ), 20–22,23 or polyether ether ketone (PEEK). 24,25 Among them, sapphire is often chosen because of its high tensile strength, straightforward and inexpensive material production, as well as temperature, pressure, and chemical resistance.…”

“…While such material imperfections may not affect other analytical techniques, they lead to distortions and lower sensitivity in NMR spectra and, hence, should be avoided for optimal NMR signal. 19,28,29,32…”

“…To demonstrate the capabilities of this HP NMR tube, it was used in conjunction with the same compact NMR spectrometer by replacing the previous tube used in ref. 19 and 33. The immense improvement in spectral resolution, as demonstrated by various comparisons, allows the utilization of HP benchtop NMR spectroscopy for an analysis of even more complex spectra than those presented in ref.…”