  UiO-66 is a well-known metal organic framework that proved to be promising
for various separation applications. In this report we study the molecular
mobility and transport of n-butane and isobutane through the UiO-66. We show
that n-butane propagates through the material significantly faster than
isobutane both in terms of energetics (diffusion barrier is 25 kJ mol-1 for
n-butane and 50 kJ mol-1 for isobutane) and rate (Di(303 K)/Dn(303 K) = 1700).
This result allows expecting very high kinetic driven separation selectivity of
n-butane/isobutane mixture in UiO-66.
