Diffusion Coefficients of N₂O and H₂ in Water at Temperatures between 298.15 and 423.15 K with Pressures up to 30 MPa

The diffusion coefficients of CO2 and H-2 inaqueous solutions are important in numerous processes including carboncapture, geological carbon storage, and reservoir storage of hydrogen.As CO2 is reactive in some aqueous solutions, especiallyaqueous amine solvents for carbon capture, N2O is frequentlystudied as a surrogate. In this work, the Taylor dispersion techniquewas used to determine the diffusion coefficients of N(2)Oand H-2 at high dilution in water at temperatures between298.15 and 423.15 K and at pressures up to 30 MPa, with a standardrelative uncertainty of 1.6%. The new data are intended to resolvesignificant discrepancies in the literature. The results confirm thattemperature is the most important controlling factor and that thediffusion coefficients are nearly independent of pressure in the regionstudied. The experimental data were correlated using the Stokes-Einsteinequation, with average absolute relative deviations of 0.5% for bothsystems.