Sulaiman
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Ammonia from ammonium bicarbonate ?
Ammonia solution is weak (typ. 3%) and expensive here,
so I bought ammonium bicarbonate (sold as a leavening agent for baking)
thinking that I could easily release ammonia
using either heat or a strong base, and dissolve it in water.
Unfortunately all paths I've found so far release CO2 as easily as NH3, so recombination is likely.
How can I selectively release ammonia or selectively absorb CO2. ?
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Keras
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NH₃ is basic and CO₂ is acid. Pass the mixture into a solution of concentrated sodium hydroxide. It will precipitate sodium carbonate and leave
ammonia unchanged.
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bnull
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You can use calcium hydroxide. Make a sludge of calcium hydroxide in a round-bottom flask, add ammonium bicarbonate, mix and then heat it. Easy to
clean, not too corrosive.
Or you can try a funnel instead (even the upper half of a soda bottle will do). Fit a filter paper to a funnel (a coffee filter in the case of the
soda bottle), fill it with calcium hydroxide, and then pour a strong solution of ammonium bicarbonate over it. Calcium carbonate stays in the filter,
a solution of ammonia passes through and can be purified. That's how I made some sodium hypochlorite from pool chlorine with sodium carbonate as
filtration aid.
Quod scripsi, scripsi.
B. N. Ull
P.S.: Did you know that we have a Library?
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woelen
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If you can get NaOH it is even simpler. Just mix solid NH4HCO3 and NaOH and add a few drops of water to start the reaction. Gaseous NH3 escapes
(beware, the reaction is quite violent and somewhat exothermic) and Na2CO3 remains behind. A similar method of preparation is possible with NH4Cl and
NaOH.
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Sulaiman
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@Keras, thanks. I didn't think of concentrated solutions
@bnull, excellent, thanks, but ...
@woelen, I like the idea, (I have sodium and potassium but not calcium hydroxide)
Is the reaction likely to melt HDPE ? (I guess yes)
I'll probably semi-sacrifice a glass rbf.
Thanks for answering my question 
that I should have been able to answer for myself 
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woelen
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What I did for this reaction is taking a simple small bottle from some booze (a small 100 ml bottle). I made a hole in the cap and put a PVC tube
through it. This works quite well. I, however, did not manage to get a long term slow flow of NH3. It is fine for having a fairly strong flow of NH3
for a snort time. You'd better use such a bottle, than (semi-)sacrifice an expensive roundbottom flask.
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Rainwater
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Short of condensing the gas and storing it in a pressure vessel, get a big birthday balloon.
"You can't do that" - challenge accepted
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Sulaiman
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my aim is to
make and store ammonia solution.
Storing the gas is too troublesome.
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SplendidAcylation
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Perhaps you could make a solution of ammonium bicarbonate and add calcium chloride, precipitating calcium carbonate, filter, and evaporate the
solution to obtain ammonium chloride, then act upon this with a strong base?
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Rainwater
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Using NaOH + NH3CO3
Quote: Originally posted by woelen  | | I made a hole in the cap and put a PVC tube through it. This works quite well. I, however, did not manage to get a long term slow flow of NH3. It is
fine for having a fairly strong flow of NH3 for a snort time |
Use thus method and feed the results into a balloon.
Then strap the balloon over a bottle of water. Giving the gas time to dissolve
If you bubble the gas through water you will lose a lot of it.
Nerd rage has a video about these reactions. Explaning the methods used to generate the gas. I disagree with the collection method, tho.
"You can't do that" - challenge accepted
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Sulaiman
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Ah, I get it now.
I misunderstood and thought that a balloon was suggested for long term storage.
An excellent idea
Thanks.
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chloric1
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| Quote: Originally posted by woelen | | What I did for this reaction is taking a simple small bottle from some booze (a small 100 ml bottle). I made a hole in the cap and put a PVC tube
through it. This works quite well. I, however, did not manage to get a long term slow flow of NH3. It is fine for having a fairly strong flow of NH3
for a snort time. You'd better use such a bottle, than (semi-)sacrifice an expensive roundbottom flask. |
I recently watched a YouTube video on an ammonia generator from Doug’s lab. Hey started out by adding concentrated ammonium sulfate solution to
solid sodium hydroxide in a round bottom flask with a reflux condenser with a gas outlet adapter with tubing running into a graduated cylinder with
water. His whole point was that ammonium sulfate and sodium hydroxide produced a byproduct that was liquid even at room temperature. That way after
the ammonium sulfate addition was completed, you can easily apply heat to drive the rest of the ammonia out. If you have an empty bottle between gas
outlet and water dissolution to prevent suckback, you could produce molar quantities of ammonia.
Fellow molecular manipulator
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