Figure 1.

ALTADENA single-scan NMR spectroscopy of HP propane-d₆ with detection at 9.4 T: (a) experimental setup diagram, (b) the diagram of pairwise addition of p-H₂ (shown as H_A – H_B) to propene-d₆ resulting in propane-d₆, (c) T₁ measurements for thermally polarized propane-d₆ by the inversion–recovery method³⁶ at 9.4 T, (d) ALTADENA spectrum of HP propane-d₆ with ε(app,flow) = 100 ± 5 with respect to the spectrum (e) of stopped thermally polarized propane-d₆ gas, where unequal thermal resonances for CHD and CD₂H protons are formed due to fast H–D exchange reaction over the metal surface of heterogeneous catalyst, and (f) 32-scan spectrum of thermally polarized propene-d₆ gas showing residual ¹H proton signals in propene-d₆ groups.