For ethane, see:

http://dx.doi.org/10.1021/la803085h

There is one, however rather old, paper reporting experimental data for both species (this is not for the industrially produced Basolite, but the same system prepared using a different synthesis route):

http://dx.doi.org/10.1016/S1387-1811(02)00405-5

A paper including new experimental data has just been published by us (I wasn't responsible for the experiments, so I could not mention it earlier). You can find it as a "Just Accepted" publication here:

http://pubs.acs.org/doi/abs/10.1021/ie500310c

The corrected proofs should also be online in a few weeks. Please contact me if you cannot access the paper.