Figure 3.

2D MRI of HP propane gas in ~5.5 mL spherical phantom. HP propane was produced by hydrogenation of cyclopropane with 82% enriched p-H₂ over 280 mg of 1 wt.% Rh/TiO₂ catalyst at 140 °C and 240/480 sccm cyclopropane/H₂ gas flow rate. Images (a-d) were acquired on a 4.7 T Varian MRI scanner after interruption of gas flow every ~0.35 sec with the following imaging parameters: 2D GRE pulse sequence, 64×64 matrix with TR ~4.5 ms, no slice selection, field of view 64×64 mm², pixel size 1×1 mm². The imaging artifacts in the areas of reduced intensities are due to tubing and glue inside the phantom. The HP gas flow was stopped immediately before image acquisition. The intensity reduction in images b), c), and d) is due to T₁ relaxation of HP state.