Can you make napalm out of gasoline and orange juice concentrate?
Here's an excerpt from an interview with the author of Fight Club, Chuck Palhniuk.


  How to make Napalm with Frozen Orange Juice and Gasoline?
  
  Well, Ed Norton changed one ingredient in every one to make them useless. So, that really pissed me off because I really research those really well. Actually its styrofoam and gasoline - it make the most incredible explosive.


http://www.dvdtalk.com/interviews/chuck_palahniuk.html

So no, Fight Club does not accurately convey any of the recipes. All were clearly modified. And most likely for safety reasons - i.e. you wouldn't want someone to walk out the theatre with a "bright" idea. On the other hand I would still expect a mixture of gasoline and orange juice concentrate to be rather flammable ...