redman - 1-7-2016 at 13:10
I just want a little feedback. I think my design should work quite well, but would one to know what you think, preferably from someone who has
performed this reaction.
My goal is to extract NH3 from ammonium sulfate. I have done much reading, here and elsewhere, and gave come up with a design to implement.
First off, let me say that I am aware of the dangers of nh3, I do have a fume hood. The reaction will take place in a sealed environment, with air
intake coming from outside do nothing could get to me even if my exhaust failed. Exhaust is via 2x inline blowers pulling 445cfm each. This setup
could vacate an average sized house in 10 minutes or less.
I have decided that the reaction will occur in 2 liter soda bottles. Because they seal wonderfully, and are cheap. They can also be easily changed
when expired. The lid will have 1/4" vinyl tubing inserted through a hole and sealed in place.
Step 2, the pre cooler is to also utilize a 2 liter soda bottle. I actually plan on 2 bottles, run in series. They will be sitting in a brine/ice
bath. Tubing from the reaction vessel will enter the lid of the first precooler and travel 3/4 to the bottom, another length of 1/4 vinyl tubing will
be inserted near the top of the bottle and sealed. This will repeat into the second bottle. Hopefully this will provide adequate cooling. Do you think
it is overkill?
Step 3. The drying chamber, is to be elevated as far as possible. I will fill it with damprid drying crystals, NaOH is too expensive and I will
already be using a lot. I will likely use another 2 liter bottle. The intake of this is to be on the bottom of the bottle, with the exit on top. I
feel this would allow the most contact with the drying agent.
Now, this is the part I really want advice on. When it exits the drying tube, I plan to run it through a homemade condenser system, before entering
the collection bottle, as it seems rather inefficient to just put it into a cold container and hope it cools before escaping.
So, step 4. I will have a styrofoam cooler, the kind you might take fishing. Filled with dry ice/denatured alcohol. Inside, I plan to have the 1/4"
tubing coiled around a mesh tube several times, probably 10-15' of tubing moving in a downward spiral and exiting the bottom of the cooler. This will
feed into the bottom of a thin glass bottle submerged in another dry ice bath
Do how does my condensing system sound? Should this be sufficient? Is it likely the nh3 will have cooled to liquid by the time it reaches the
collection point
CharlieA - 1-7-2016 at 18:25
PETE is not recommended for ammonia and some ammonium salts, or bases. See the attached file (about page 8 or so).
Attachment: PETEresist.pdf (352kB)
This file has been downloaded 668 times
Anhydrous ammonia condenses to a liquid at -33* C, so I doubt you will get any if your collecting bottle is dry. If it contains water you should get a
high concentration of aqueous ammonia (solubility ca. 47wt%; see Google).
Good luck
redman - 1-7-2016 at 19:25
That's unfortunate. I did not know about the Pete. I will have to see what else I can come up with. I would prefer not to use glassware, I've heard
pressure can get too high, and cause breakage.
Why do you think I would get none? I mean, I could see a low efficiency. But the alcohol bath should sit well below -33. I would likely need to
circulate the alcohol to keep it performing well. But I honestly can't believe I wouldn't get any liquid ammonia out of the deal.
I am also considering adding anhydrous isopropanol to the collecting bottle to assist in condensation
j_sum1 - 1-7-2016 at 21:50
https://www.youtube.com/watch?v=gHokrNS1ask
The best video on ammonia production.
I recommend getting some glassware and following this procedure exactly.