Gamo makes some respectable Airguns.
In this video they show a Hunter Extreme .177 dispatching a hog at 25 feet. I am sure it can handle a Raccoon at 2 ft. You do not need gun powder for such a simple task.
Gamo Hunter Extreme .177 - Muzzle velocity 1650 FPS with PBA (7.1 grain) or 1250 with...