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Author: Subject: Diethylamine Synthesis
peach
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[*] posted on 16-7-2011 at 19:03


Look at it this way, if you'd checked it immediately after distillation, it'd still be warm, so the density would be different. ;)

The density of water changes by about 1 to 2% between 25 and 60 Celsius.

[Edited on 17-7-2011 by peach]




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Nicodem
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[*] posted on 18-7-2011 at 08:42


Good work!

You can derivatize your product in order to characterize them by a melting point measurement. The simplest derivatives are the hydrochlorides. The mp differences of the ethylamine hydrochlorides are large enough and you can evaluate the purity from the mp depression and interval.

Just because EtNH2 is a gas at room temperature, it does not mean that diethylamine can not dissolve large amounts of it. The purity depends on the fractionation efficiency of the distillation column used.

The use of ammonia gas appear terribly impractical. If you can obtain 25% aqueous ammonia, you could try using that instead as an alternative. I don't think you even need a cosolvent, if using good stirring and slowly adding ethyl bromide. The mixture should become monophasic at the end of the reaction. Concentration by evaporation of the water and excess ammonia should give a concentrated mixture of the amine hydrobromides to be worked up as you did. The diethylamine vs. triethylamine selectivity would be somewhat different though, possibly or not in favour of whatever product prefer.

If you ever optimize the process to produce and separate diethylamine and triethylamine, please post the whole report in the Prepublication.




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Rogeryermaw
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[*] posted on 18-7-2011 at 14:21


Quote: Originally posted by Nicodem  
Good work!

You can derivatize your product in order to characterize them by a melting point measurement. The simplest derivatives are the hydrochlorides. The mp differences of the ethylamine hydrochlorides are large enough and you can evaluate the purity from the mp depression and interval.



it is funny you should mention this! last night i had the inspiration to do this very thing. i began on a test tube scale to see if it would work so i poured a few oz. of 31.45% muriatic into a flask fitted with a one hole stopper with a hose led to a bent piece of glass tubing in the bottom of a test tube with about 5 ml of the crude amine product. i lightly heated the acid to drive off HCl gas into the test tube and was rewarded with about a gram and a half of bright white precipitate after a couple of hours.

i am currently in the process of trying a similar procedure, but by adding the acid directly to the amine. the reaction is highly exothermic but forms no immediate precipitate (i believe due to the water content in the acid which i am boiling off right now.

i will report back with results and if i can streamline and optimize this process i will be happy to do a formal write-up for the prepublications section complete with pictures.

my only concern is that any excess dissolved ammonia may form ammonium chloride and that may be difficult to separate. i have been searching for differences in solubility between the amine hydrochlorides and ammonium chloride to assist in the separation but since the solution is not water based, it is harder to find information.

perhaps it is time to take a trip to the library.

as far as the use of ammonia solution, i have plenty of concentrated ammonia solution from the previous experiment and will definitely give this a try. thanks for the tip! i note that you advise stirring during the process. is this due to the fact that EtBr is not miscible with water?

on another note i recently obtained about 30 ml of deet from walmart (repel 100 claims to be 98% +) for less than 6 dollars. i plan to attempt a hydrolysis with KOH solution. i will give report on this as well when i have completed it.



[Edited on 18-7-2011 by Rogeryermaw]

[Edited on 18-7-2011 by Rogeryermaw]




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jon
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[*] posted on 19-7-2011 at 10:27


i got this from a chemist who made it from deet

i used all OTC products aside from some ebay items for labware. made my own mini coil condenser from a 2 foot section of 5mm boro glass tube. used a regular mapp gas torch to bend it around a aluminum cigar tube. for the glass i used a 2 neck distillation flask 24/40 on the top neck and the angle side neck had #7 thread and a plastic cap. i drilled the cap and affixed the condencer through there sealing with a little JB weld.

OTC Hydrolysis of N,N-diethyl-meta-toluamide (DEET) to Diethylamine and M-toluic acid


To a 250ml autoclavable media bottle is added in order, 175ml N,N-diethyl-meta-toluamide (98.11% comerc grade, $15) followed by 40ml 70% EtOH. the media bottle is capped and vigorusly shaken for one minute. the EtOH and DEET should now be a homogenous mixture. to this solution is added 40g NaOH and once again capped. the media bottle containing the mix is now sealed and heated in a hot water bath (crock pot set on low) added to the bath at 55*C (125*F) ending at 70*C (160*F) periodicly agitating for the legnth of time it takes to compleatly desolve the NaOH plus 1.5hr. the solution should now be a deep yellow color the crock pot is turned off and allowed to cool to RT. it is removed from the bath and allowed to stand at RT for one day minimum. the bottle will then be carefuly opened after cooling in the refridgerator for 1hr. obsedved was the strong smell of diethylamine, no longer did it smell of DEET and EtOH. the solution is fractionaly distilled (dont forget boiling chips, this stuff likes to bump) collecting the fraction along a 9 degree tempeture arc centered on 55*C (51-59*C). the solution may solidify twords the end of the distilation and a small ammount of DH2O can be added to liquify the waxy mass of M-toluic acid and NaOH. total yeild form aprx 225ml of solution was 57ml of crystal clear diethylamine in freebase form. 25.3%

MeOH can be used in a pinch but i like EtOH, it mixes better with the DEET and has just enough water for the hydrolysis but not enough to cause separation.

Diethylamine C4H11N 73.14g/mol boiling point 55.5*C (131.9*F)

N,N-Diethyl-M-Toluamide C12H17NO 191.27g/mol boiling point 288-292*C (550.4-557.6*F)

M-toluic acid C8H8O2 136.15g/mol boiling point 263*C (505.4*F) (melt at 111-113*F)
-------------------------------------------------------------------------------------------------------------------------------------
Ethanol C2H6O 46.07g/mol boiling point 78.4*C (173.12*F)

Methanol CH4O 32.04g/mol boiling point 64.7*C (148.4*F)

water H2O 18.015g/mol boiling point 100*C (212*F)


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Rogeryermaw
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[*] posted on 20-7-2011 at 12:55


that is very interesting. have you performed this synthesis? it is next on my list to try out so it would be fortunate to know if this is from anecdote or personal experience.

sorry it took me so long to post again but there is some work being done up the street from my home and the tore up the phone line yesterday so i was without contact to the outside world via conventional methods.

i have checked MSDS information on the DEA(HCl) and the NH4Cl and they are both soluble in water and insoluble in Et2O but this is as far as the solubility data goes pertaining to both chemicals. this may get interesting.




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jon
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[*] posted on 20-7-2011 at 19:58


no this is no anectodote this is from a colleague i have no use for diethylamine, and he is rarely available but the information is accurate.
also i think if you peruse kirk othomer's encyclopeadia of industrial chemicals you will find a way to make pocl3 from sodium metaphosphate and chlorine gas catalyzed by a little hyderogen chloride gas.
this has also been done too, but that is another topic altogether.
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Rogeryermaw
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[*] posted on 20-7-2011 at 22:54


a quick search of this title gives kirk othmer's encyclopedia of chemical technology. i could not find encyclopedia of industrial chemicals. there is a title like this but it is from ullmann. aparently one can get free 30 day access. however POCl3 is not to hard to make from PCl3 and O2 gas. garage chemist has a lovely guide to synthesizing PCl3 but it is in german i believe. i translated most of it and this cat is ingenious. i just searched for over 20 minutes to find a link to this and then it tells me access forbidden. poop! good thing i already translated most of it and saved the synthesis in my files. thank you garage chemist!



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Chordate
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[*] posted on 17-9-2011 at 01:27


According to this guy right here:

http://pubs.acs.org/doi/pdf/10.1021/ar00010a001

Diethylamine synthesis can be achieved by a modified gabriel synthesis with sodium saccharin. First step is monoalkylation of the saccharin followed by basic hydrolysis of the amide side of the molecule (the ing-manske procedure would probably be counterproductive here). The intermediate is a stable sulfonamide which can then be dialkylated. In the reference they give the dialkylation is done in a one pot fashion by adding a 1:2 ratio of saccharine to the alkylating agent and then basifying in the same pot, but it might be possible to do an asymmetric alkylation by adding different alkylating agents in two separate steps before and after hydrolysis of the amide side of saccharin.

Anyhoo, after hydrolysis, the mess is then acidified to cleave the sulfonamide, which according to the lit is much easier than with most sulfonamides.

Gabriel without hydrazinolysis requires some harsh conditions and some experimentation would be necessary to figure out what kind of conditions and times would give the best yields, since the source for this procedure as cited in the above article is 50 years old, in japanese, and seemingly only the index is available. Still, this may be a good route if you have some alkylating agents on hand.
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[*] posted on 2-9-2012 at 16:14


The tek above, posted by jon, was posted on zoklet in 09.
the same dude has a tek for lysergamides from A. nervosa seeds, a tek on making POCl3, and his equivilants were pretty much shulgin scaled down.
I havent heard much else about it

[Edited on 3-9-2012 by al-k-mist]
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Rogeryermaw
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[*] posted on 3-9-2012 at 05:38


you offer no useful information and discuss the extraction of illegal substances. this is not the forum for you.
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[*] posted on 6-9-2012 at 01:41


For the small chance that anyone was interested in my experimentation with the ethanolic DEET and aqueous sulfuric acid.. previous page..

I did end up distilling about 20 mls at the correct still head temp, vapors were strongly alkaline with the typical diethylamine odor.. no formal confirmation though..

This even with the laziness and generation of the messy by-products..

It works but the NaOH sounds better..
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[*] posted on 11-11-2014 at 13:29


Sorry , I had to restart it!
A Rapid Procedure for the Hydrolysis of Amides to Acids

H. L. Vaughn , M. D. Robbins
J. Org. Chem., 1975, 40 (8), pp 1187–1189
DOI: 10.1021/jo00896a050

"An aqueous suspension of the amide is treated with 1equiv of sodium peroxide at 50' (or more conveniently on asteam bath). The amide rapidly dissolves and ammonia(for primary amides) is evolved. After 60 min, the reactionis essentially complete and only marginal yield increasesare observed if heating is continued for another hour. Isolationof the acid is accomplished by careful neutralization of the reaction mixture and yields are usually greater than85% (Table I). Primary, secondary, and tertiary amides are all hydrolyzed and either the acid or the amine can be recovered."

Copper complex catalyzed hydrolysis of amides
Mrejen, Karen
McGill University, 1991
Copper complex catalyzed hydrolysis of amides

Catalytic Hydrolysis of Amides at Neutral pH
Jik Chin, Vrej Jubian and Karen Mrejen
J. Chem. Soc., Chem. Commun., 1990, 1326-1328

Attachment: jo00896a050.pdf (375kB)
This file has been downloaded 520 times

Attachment: Catalytic hydrolysis of amides at neutral pH.pdf (275kB)
This file has been downloaded 624 times



[Edited on 11-11-2014 by Mush]
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[*] posted on 2-8-2015 at 11:04


http://en.wikipedia.org/wiki/Acetaldehyde_ammonia_trimer
https://www.erowid.org/archive/rhodium/chemistry/acetaldehyd... (Rhodium's Archive, describes AAT synthesis)

If this is peralkylated with EtBr the product is 1,3,5-triethyl-1,3,5-triaza-2,4,6-trimethylcyclohexane, which i'll call TTTC for short. Reduction of TTTC with a typical imine-reducing agent should produce diethylamine with no side products. Alkylation of TTTC should be impossible due to steric hindrance, although I hope TTTC isn't so incredibly unstable that it immediately reverts to ethylamine and acetaldehyde.

So acetaldehyde + ammonia >> AAT, AAT + 3EtBr >> TTTC, TTTC + HCOOH + Pd/C >> Et2NH. Not as elegant as we'd like I guess but overalkylation is impossible and the intermediates are both solid at r.t. and the reactions should happen relatively easily. The hardest part is acetaldehyde. Alkylation might occur in ethanol with heterogeneous Na2CO3. Precipitating TTTC might be tricky. Bon chance!

[Edited on 2-8-2015 by clearly_not_atara]
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[*] posted on 8-8-2015 at 10:30


Quote: Originally posted by S.C. Wack  
Back in the day, some people were happy with preparation of ethylamines from ethyl bromide, with separation of the mixed amines utilizing ethyl oxalate. Authors preparing their own amine reagent tend not to detail this separation method in their journal references decades after this was introduced, and there seemed to be some conflicting vague details, so I searched for the best way of doing this in the original lit and here it is; I suppose Houben-Weyl has details as well. There are other methods in the older lab manuals.


Here is a description of this procedure for separating the ethylamines from Journal of the Chemical Society, Volume 69, 1896, p. 662-663.

"Although they differ considerably in boiling point it is impossible the separate the ethylamines by fractional distillation. The “simple and elegant process,” as he himself originally termed it, devised by Hofmann (Proc. Roy. Soc., Nov., 1860, xi, 66) is based on the observation that when submitted to the action of ethylic oxalate, ethylamine is converted into diethyloxamide, a crystalline substance, only sparingly soluble in water; whilst diethylamine yields ethylic ethyloxamate, a liquid boiling at a high temperature; triethylamine remaining unchanged. Hence, after subjecting the mixture to the action of the oxalate, it is possible to separate the terrtiary base by distillation, and to mechanically separate the crystalline amide from the oily oxamate; the amide may then be purified by recrystallization from boiling water, and distilled with alkali, the oxamate being similarly treated after separating the dissolved oxamide by cooling to 0C, and then fractionally distilling the liquid.

It was subsequently pointed out (ibid., p. 526) that a simpler and more perfect separation of the oxamide and oxamate might be effected by submitting the mixture at once to the action of boiling water, when diethyloxamide dissoves, the oxamate remaining as an insoluble layer floating upong the hot solution."

It would seem to me that the oxalic amine salts would be convenient forms in which to store the amines until needed.

With the above separation procedure in hand it looks to me that the Werner ethyl bromide, ammonia, ethanol reaction, and variants, should be the preferred method for obtaining all three ethylamines.

Although Werner's lengthy room temperature procedure produced very little triethylamine (about an equal split between ethylamine and diethylamine) Rajit's [1] use of a two hour steam oven heating produced almost all triethylamine. So you can get all three ethylamines in good quantity by varying temperature and duration.

Diethyl oxalate is made from oxalic acid (found in Bartender's Friend) and ethanol; ethyl bromide is made from sodium bromide (available as a spa treatment), sulfuric acid (drain cleaner), and ethanol; and the final procedure uses ammonia (can be ammonium hydroxide), ethanol and the ethyl bromide.

So all three ethylamines can be obtained with reasonable ease from entirely OTC cheap chemicals.

[1] http://chemistry.mdma.ch/hiveboard/chemistrydiscourse/000330...

Googling "Rajit triethylamine" brings up a paper on Sciencemadness you can download through the search link, I don't know where the paper is attched ona thread.
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S.C. Wack
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[*] posted on 8-8-2015 at 13:42


Houben-Weyl it turned out had nothing to say about ethyl oxalate. Werner's details were on page 35 of the relevant 1957 volume 11.

Hofmann:

The product of the reaction of oxalate of ethyl upon the mixture of the ethyl-bases, when distilled in the water-bath, yields triethylamine free from ethylamine and diethylamine.

The residue in the retort solidifies on cooling into a fibrous mass of crystals of diethyloxamide, which are soaked with an oily liquid. They are drained from the oil and recrystallized from boiling water. Distilled with potassa, these crystals furnish ethylamine free from diethylamine and triethylamine.

The oily liquid is cooled to 0°, when a few more of the crystals are deposited; it is then submitted to distillation. The boiling point rapidly rises to 260°. What distils at that temperature is pure diethyl-oxamate of ethyl, from which, by distillation with potassa, diethylamine free from ethylamine and triethylamine may be obtained.

* The separation of the ethyl-bases has been since repeatedly carried out. The process, as described in the 'Proceedings,' admits of a slight improvement. I proposed to separate the mixture of diethyloxamide and diethyloxamate of ethyl by filtration, and to purify the former by recrystallization from boiling water, the latter by exposure to a temperature of 0°. The separation is simpler and more perfect by submitting the mixture at once to the action of boiling water, when diethyloxamide dissolves, the diethyloxamate of ethyl remaining as an insoluble layer floating upon the hot solution, from which it may be separated by a tap-funnel.




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