The m- and p- diacids have different melting points. Separate them by solidification of the vapour at low pressure? Though less easy in a lab, it would be an industrial process.
From what I read on Wiki, the diacids are made by catalytic oxidation of m- and p- xylene with oxygen. That looks affordable.
If you like polymers...https://www.chemicalforums.com/index.php?&topic=62053.0
I ignore what I obtained. A C2
polyketone might be a nice ferroelectric polymer. Or a C4
one, from CO and cyclopropane?