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Author: Subject: Triethylamine synthesis
Ramium
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[*] posted on 7-6-2015 at 03:02


I just had an idea.

Liquified ethyl chloride is poured into a conical flask. A cork with a hole in it is attached to the top of the conical flask. Tubing is push through the hole in the cork untill it touches the bottom of the conical flask. The other end of the tubing is pushed through another corked conical flask containing ammonia solution untill it's about 2 inches above the surface of the solution.

You said that the main proplem with my original plan was that ethyl chloride isn't soluble in water. So anyway, the solution of ammonia is heated gently, being VERY careful not to let the solution boil, since the solubility of ammonia in water decreases as the temperature of the water increases. Semi anhydrous ammonia gas should be given off from the solution. The gas will travel through the tubing and into the flask of ethyl chloride. No water will be present to stop the reaction.

C2H5Cl + NH3 = C2H7N + HCl

The 2 products would then react with each other.

C2H7N + HCl = C2H7N.HCl

So after the reaction I should be left with reasonably pure crystals of ethylamine hydrochloride. Right?

Does this sound possible?

I'm sorry. I know you said i should look for a well developed procedure but i think i'll learn more if i try and think it through myself.




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[*] posted on 7-6-2015 at 03:44


Ammonia reacts sluggishly with alkyl CHLORIDES in a neutral medium. I think it take few days, in case there's enough energy for the reaction to proceed at all. I want to remind you that the guys in the hive quote had to heat the reaction mixture.
Ammonia has solubility near 5% in chorobenzene, it might be even lower for chloroethane.
You should really consider usage of a universal solvent (DMSO, DMF, PTC), which is a well developed procedure. Also, once again, I have no idea about the temperature needed to perform the reaction.
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Ramium
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[*] posted on 7-6-2015 at 20:32


Ok how about this?

Same setup as last time except some anhydrous ethanol is poured into the flask of ethyl chloride. When the ammonia gas enters the flask of ethyl chloride and ethanol, any of the ammonia that doesn't react straight away will disolve in the ethanol and keep reacting with the ammonia over time.

Ammonia and ethyl chloride are both soluble in ethanol, so I thought it would be a good solvent to use. The flask containing the reaction mixture (ethyl chloride, ammonia, ethanol) would then be corked and heated on a hotplate for several hours.

C2H5Cl + NH3 = C2H7N + HCl

Ethyl chloride, ammonia, ethylamine and hydrochloric acid are all soluble in ethanol.

C2H7N + HCl = C2H7N.HCl

Don't know if ethylamine hydrochloride is soluble in ethanol.

But it doesn't matter because if it is insoluble, it would precipitate and could be collected by filtration. If it is soluble then the ethanol can be evaporated.

Thanks for your responses. I'm learning a lot.




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[*] posted on 7-6-2015 at 21:49


As far as I remember you've just explained the procedure I linked.
I don't have precise number on solubilities of those gases (and ethyl chloride probably will be a gas in your case), in case you run too much gas into reaction you might lose some yield.
ammonia solubility in absolute ethanol at 0°C : 20% (w/w)
ammonia solubility in absolute ethanol at 25°C : 16% (w/w)
I like this data.

[Edited on 8-6-2015 by byko3y]
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[*] posted on 8-6-2015 at 17:25


C2H5Cl + NH3 = C2H7N + HCl

so I need

ethyl chloride = 64.51g excess of 20% to ensure there is no left over ammonia which might react with the HCl produced in the reaction.
ammonia gas = 17.031g (400ml ammonia solution 42g/L concentration)

divide by 2

42g/L ammonia solution = 200ml
ethyl chloride = 32.255g plus 20% excess

based on the solubility of the chemicals I have decided to use 200ml of ethanol

once my ethyl chloride arrives in the mail I will perform the synthesis.




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[*] posted on 8-6-2015 at 21:30


If that is not acceptable. See JACS (1913), 35;11 p1781-3 as linked by gdflip. While the halide solubilities vary, you may consider that quaternary ammonium salts are often useful as phase transfer catalysts, so modify accordingly. Interested in seeing how things go.

[Edited on 9-6-2015 by Chemosynthesis]
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[*] posted on 2-11-2015 at 02:27


hydroxides + any given ammonia salt should produce anh ammonia
calcium hydroxide would probably even work
or maybe just dump some ammonium carbonate into the EtCl, turns into CO2 and NH3 around 70*C
this could probably work out very easily if both reagents were dumped into a steel container with a screw lid and heated to around 80*C, pressure building up inside container should help reaction a slight bit too

i have before stored IPN in stainless steel container similar to this
http://ecx.images-amazon.com/images/I/71m014PIg0L._SX425_.jp...

however in freezer, but it does seem to be well airtight
maybe the CO2 building up inside could get problematic if you were to not attend the reaction for longer time




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
http://www.trimen.pl/witek/calculators/stezenia.html
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