Though more relaxed and colloquial to some persnickety ears, while may replace although and whereas in all formalities of writing, but take care not to introduce ambiguity with the word’s temporal sense. Prefer We ate although we were not hungry to We ate while we were not hungry, which implies eating during a period of satedness. Also avoid substituting and with while to indicate a sort of temporal, agreeing conjunction; avoid such temptation.
As with among and amid, prefer while to whilst, a lingering archaism often used for affected formality.