Welcome to the madness, Optimus!
I believe energon has been revealed to be flammable in multiple continuities, so your theory stands! I think if there is a plasma substitute in the form of an acid, its concentration would have to be carefully regulated through homeostasis systems. The acid would also depends on the PH of the particular compound of energon (depending if it is regular, red or dark etc) though you're clearly more adept at chemistry than I so you may be more informed on the logistics of this (I'm a physics student ;-;). I had always assumed Cybertronians converted chemical energy the way we do, though them being mechanical species it seems either or both energy conversions would be valid.