Here's a good version: "The Exchange between teacher and student promotes learning far different from that which results when the student listens but does not participate."
I agree with your teacher's judgment, but I'm not sure about the reason. I suspect that instead of time intervals, what is involved is giving an argument of the verb "result", and "as" does not work for that. "Result" has two arguments: a cause and an effect. "Which" is the effect, and "when the student listens but does not participate" is the cause. "From" would also work here to give a cause -- "... that which results from the student listening but not participating."
"As" doesn't work, because it just introduces an adverb, giving an accompanying circumstance; it doesn't specify an argument. I'll confess, though, I don't understand why "when" does work here to specify an argument of "result". But it does.