I guess it depends on the distance between them. Akainu has insane range to say the least, if he is far enough he could make the entire thing explode and nothing would happen to him. There is also the question of whether the explosion would kill him even if he was close to it.
This wouldn't be a close fight. This is a bad match-up for the slime, Akainu would blow him up.
Would Akainu survive the explosion? Of course. Why wouldn't he?
There's only a few ways to harm a logia and the last time I checked, an explosion wasn't one of them.