The stain on your hardwood is oil from a leak in your refrigerator,Freon 12 boils off at about-28 deg.F.The freon would boil off before it even hit the floor.You will have to get an absorbent material and try to draw the oil out.You could sand the floor down to bare wood and apply a coat of Refrigerator Compressor oil trying to match the stain and apply polyurethane over it.you may be able to get away with using just an oil based stain but try it on a piece of wood in an inconspicuous place first to try and match it. Good luck Iwould like to hear how you make out
Jerry