Aggie, as you know 22kt gold is 22/24ths gold, and 2/24ths something else. That is by weight, so by number of atoms it's about 90% gold at most.
Making gold chloride involves dissolving it in Aqua Regia (a particularly nasty mixture of nitric and hydrochloric acid). The other components must then be removed until you're left with 99% gold in the solution (pure enough for toning), and the acid removed until you're left with gold chloride only.
I would not like to try it.
Technically speaking, the correct name for "gold chloride" is "tetrachloroaurantic acid" if I remember correctly - or was it "hexachloro--"?
Try searching for the chemical under that name, sometimes it may turn up less expensive alternatives.