For an examples class on thermodynamics, I would like to fit Van der Waals law on data of real gasses, say $CO_2, H_2O_2, CH_4$.
I want to set out measurements of pressure and volume at constant temperature in a P-V diagram, and make a fit to determine the van der Waals parameters a and b. Only I have no idea where to look for experimental data.
Is such data available in databases or articles?
Would I have to extract them by hand from plots or are there (electronic) tables available? Any suggestion is welcome.