Interesting. I know that aromatics used to be removed with sulfolane/dimethyl sulfone. Is there some catalyst that hydrogenates both without being poisoned, now?
I used to work for Shell about 20 years ago, but certainly things have moved on in the world of catalysts.
Well, you might know more about than I do! I'm looking to get into
the refining industry after my PhD / Post-doc right now.,,,,.
But yes, I think the Co-Mo-W catalysts do both. "Brim" sites or some such; had pretty cool looking STM images of the active sites; I think the trick is that they are pre-sulfided. Haldor Topsoe makes some good ones.
The Pd-Pt catalysts also work for aromatic saturation in the presence of S but high cost constrains their commercialization. The literature is very interesting especially the activity synergy of Pt-Pd at a 4:1 composition.
OTOH the latest ULSD specs. are so stringent (~5 ppm S in on-road diesels) that it is almost impossible to get the last bits of S out without doing some aromatic saturation. The S left after reaching 40 ppm levels is almost exclusively the dimethyl-dibenzo-thiophenes (and analogs). The steric shielding of the S part of the molecule prevents access to the S unless partial hydrogenation happens.
At least that's as much of it as I know and understand..
PS. I'm only an engineer so apologies if I messed up any of the details.