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Author: Subject: Diethylamine Synthesis
mbrown3391
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[*] posted on 31-8-2008 at 16:33


2 CH3CHO + NH4Cl --> CH3CH2NH3Cl + CH3CO2H
CH3CH2NH3Cl + CH3CO2H + 2 NaOH --> CH3CH2NH2 + NaCl + NaCH3CO2 + 2 H2O

Ethanal will react with ammonium chloride to form ethylamine and sodium acetate. Now if i can just find a source of Thionyl chloride...

[Edited on 1-9-2008 by mbrown3391]
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[*] posted on 31-8-2008 at 21:05


Quote:
Originally posted by Vdara
Propose a Grignard synthesis


What does that have to do with Et2NH? Nothing???
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[*] posted on 1-9-2008 at 02:27


Quote:
Originally posted by mbrown3391
2 CH3CHO + NH4Cl --> CH3CH2NH3Cl + CH3CO2H
CH3CH2NH3Cl + CH3CO2H + 2 NaOH --> CH3CH2NH2 + NaCl + NaCH3CO2 + 2 H2O

Ethanal will react with ammonium chloride to form ethylamine and sodium acetate. Now if i can just find a source of Thionyl chloride...

[Edited on 1-9-2008 by mbrown3391]


Ethanal does not react in the same way as methanal which has certain unique properties. One of them being that it is a much stronger reducing agent than any other aldehyde.

The reaction of ethanal (acetaldehyde ) and ammonia yields a trimer.

http://en.wikipedia.org/wiki/Acetaldehyde_ammonia_trimer

http://designer-drugs.com/pte/12.162.180.114/dcd/chemistry/a...
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mbrown3391
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[*] posted on 1-9-2008 at 06:31


i got my information from http://en.wikipedia.org/wiki/Ethylamine. Though now that i look at it, it does say "source needed" by that reaction. ill look into it some more
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mbrown3391
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[*] posted on 1-9-2008 at 06:55


Ok here's another possible route:

From Wikipedia:
Quote:
At various times in the past, ethyl chloride has also been produced from ethanol and hydrochloric acid


So:
CH3CH2OH + HCl --> CH3CH2Cl + H2O

From the Chemical Thesaurus:
Quote:
Bromoethane reacts with 2 moles of ammonia to give ethylamine and ammonium bromide.
... ethylamine can react further with bromoethane to give diethylamine...


If Chlorethane could replace bromoethane in this reaction, then:

CH3CH2Cl + 2 NH3 --> CH3CH2NH2 + NH4Cl
CH3CH2NH2 + CH3CH2Cl --> CH3CH2NHCH2CH3 + HCl
CH3CH2NHCH2CH3 + HCl --> [CH3CH2NHCH2CH3]HCl

Possible?
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Klute
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[*] posted on 1-9-2008 at 07:11


Man, don't use Wikipedia as a reference source....

That reaction is the oh-how-famous Hofmann alkylation of amines. If you would ahev opened even the most basic organic chemistry book, you would have learned about it, and knwo that what ever the condtiions, you get a mixture of priamry, secondary, tertiary and even quaternary amines.

I some industrial applications, it can be used to prepare amines, but it's often in gas phases, with catalyst, and a tough fractionnation/recycling of unreaced substarte. In other words, they am for good selectivity, even if the yield is equal to a few percents. Not something that would suit you.


EDIT:

BTW, Vogel doesn't make acetaldehdye from paraformaldehdye and sulfuric acid, but from paraldehdye (the trimer of acetaldehdye) and H2SO4.... Just think about it, where do you get that extra carbon? Even if there was some kind of condensation, how do you oxidize one alcohol, and get rid of another? You should try answering these questions to yourself before considering anything see (or think tosee) written. It will save you a lot of time and frustation, aswell as us.


If you had a look at the acetaldeyde thread, you would see how delicate it is to make without chromium salts. I very much doubt you isolated acetaldehdye in more than trace amounts but recating H2O2 and EtOh, if you would have read on the subject, you would know that aldheydes are much more easily oxidized that alcohols, so are oxidized as soon as they are formed, unless youuse a selective oxidant, or a way of removing the aldehdyes before it get oxidized.

Please, please, take time to read what others are done before throwing out any idea that crosses your head. This is getting boring.

[Edited on 1-9-2008 by Klute]




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[*] posted on 1-9-2008 at 07:20


1) You are going to need some fairly vigorous conditions to convert ethanol to chloroethane with hydrochloric acid, probably more vigorous than you will achieve in a home laboratory.

2) It is a low boiling liquid / gas at room temperature bp 12 C, so storage and reactions with it are going to be difficult.

3) Alkyl bromides are preferred in the laboratory as they are a lot more reactive than alkyl chlorides.

4) Once again you are going to end up with a mixture of ethylamine, diethylamine and triethylamine.
Fine if you have your own chemical works with a 50ft column but a nightmare on a lab scale.
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[*] posted on 1-9-2008 at 07:37


Quote:
Originally posted by Klute
I very much doubt you isolated acetaldehdye in more than trace amounts but recating H2O2 and EtOh


I distillled approximately 40ml of liquid from the mixture which boiled at around 20 degrees C. it smelled characteristically fruity. I posted the experiment on this forum, and was told it was ethanal, which boils at 20 degrees C.
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[*] posted on 1-9-2008 at 07:49


Quote:
Originally posted by mbrown3391
Quote:
Originally posted by Klute
I very much doubt you isolated acetaldehdye in more than trace amounts but recating H2O2 and EtOh


I distillled approximately 40ml of liquid from the mixture which boiled at around 20 degrees C. it smelled characteristically fruity. I posted the experiment on this forum, and was told it was ethanal, which boils at 20 degrees C.


Could you repost your results giving quantities of reagents used etc as I can't find your original post.
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[*] posted on 1-9-2008 at 07:56


Yes, I have read this thread now, but I'm still septical. Have you tried forming the trimer? Acetaldehyde itself isn't very stable. try making a Tollens test, or bisulfite, or ammonia adduct.

Please give use details, you said you mixed in the cold, then heated to distill? How much H2O2 did you use?

[Edited on 1-9-2008 by Klute]




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[*] posted on 1-9-2008 at 07:58


Quote:
Originally posted by Klute
Yes, I have read this thread now, but I'm still septic.


Sceptical, dear heart, sceptical.

Septic is nasty :P

[Edited on 1-9-2008 by ScienceSquirrel]
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Klute
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[*] posted on 1-9-2008 at 08:07


He he my bad, in french it's "sceptique" :)



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[*] posted on 1-9-2008 at 08:11


Quote:
Originally posted by Klute
He he my bad, in french it's "sceptique" :)


Your English is a lot better than my French, near non existent the last time I looked.
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[*] posted on 1-9-2008 at 08:17


Quote:
Just a quck question-- how does ethanol react with hydrogen peroxide with an acid catylist? i basicly followed the synthesis for acetone peroxide but used ethanol instead of acetone. When I came back to my basement an hour after i added the sulfuric acid, the entire room smelled recognizably sweet. I cant put my finger on the smell, but it smells almost like some sort of artificially flavored drink. But esters are formed with carboxylic acids, so it couldn't be an artificial flavor. Any idea what was formed?


that was my orriginal post. As you can see i did not list any specific quantities and i do not remember them now, other than to say that they were similar to the ratios used in acetone peroxide synthesis, say 1 volume each of ethanol and 12%H2O2 and 1/10 of a volume of conc. h2so4. The ethanol and hydrogen peroxide were cooled to 0 degree C and H2SO4 was added slowly. Then the mixture was placed in the freezer for a few hours.
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[*] posted on 1-9-2008 at 08:25


You must have carried out the experiment on a substantial scale to distill out 40mL of product.
How many moles do you reckon 40mL of ethanal works out to be?
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[*] posted on 1-9-2008 at 08:30


I did not measure it, thats just an approximation. The reaction was carried out in a 500ml beaker, almost full. Since i was not trying to make ethanal, i did not use the stoichiometrically correct amounts of reactants. and 40ml is about .7 mols
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[*] posted on 1-9-2008 at 08:45


Interestingly alcohols can be oxidised with hydrogen peroxide to form aldehydes and ketones under some conditions.

http://www.ias.ac.in/currsci/jul252007/133.pdf

But it really does not matter anyway.

Ethanal will not react with ammonia to form ethylamine unless under some fancy industrial conditions that you will not be able to achieve.



[Edited on 1-9-2008 by ScienceSquirrel]
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[*] posted on 1-9-2008 at 23:41


I like to point fingers too. Indignant finger-pointing...people don't think much about how much of their own house is made of glass. As for spoonfeeding requests, many long time non-idiot members here make them. Note that very little of this site is people detailing syntheses that they have done. About a quarter of it now is the posts of just a dozen people. It is often questions and conjecture that goes nowhere. And, not often enough instead of too often, presentation of some relevant literature by a few members. The um, advice to read what is available is wise though. Maybe the interest in drugs will be impetus to study, like explosives were for other generations of chemists.

Surely there are methods out there to produce the secondary amine only. Some quite old, well-documented, and available perhaps and quite doable though troublesome for various reasons. The aniline method comes to mind.

Quote:
Originally posted by ScienceSquirrel
If you read my report you will see that I used potassium hydroxide in a mixture of ethylene glycol and water in an attempt to hydrolyse the amide.


I don't feel that you approached it from a realistic preparative angle with the glycol, so it seems unfair to chemistry to say that it is so difficult. Adding 10 ml. of solvent for 4 ml. of precursor, after doing whatever else first? That's not a lot of solvent and for all we know your hydroxide was carbonate by then. As for the oil, how do you know that it wasn't toluic acid? Because the acid can and does oil out, even though it also precipitates on addition of H2SO4 to the mixture. The oily acid crystallizes in the freezer. But boiling the acid/oil in 100 parts of water makes it dissolve, giving a milky suspension on slight cooling, and with further cooling and time it is transformed to easily filtered light and thin needles.

Your later suggested conditions sound rather more severe than necessary.

Using only 11 g. KOH, 4.25 g. DEET, 100 ml. ethylene glycol, 8 g. water, and 2 hours at 140C, there was obtained, with little care in the isolation, a 33% yield of snow white recrystallized toluic acid crystals. The purity is likely pretty good given the massive disparity in solubility in hot vs. cold water. I suspect that the missing yield has little to do with unreacted material, even though the amine (as the hydrobromide, for hahas) was isolated in even lower yield, 19%, from recrystallization in IPA/toluene.

I feel that this says more about the isolation methods used than anything else.

Amine was escaping during the reflux (out of a 19/22 Liebig, not the best choice), even though later, a large amount of (added) water was distilled off (at 120C) before the distillate became neutral.

In methods that produce mixed ethylamines, separation methods other than fractionation of the base might be easier. Example:

[Edited on 2-9-2008 by S.C. Wack]

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[*] posted on 2-9-2008 at 00:53


I'm finding this thread hard to keep up with! Whoever asked for literature references seems to have gotten more than they bargained for! The most viable OTC preparations of DEA has got to be from DEET giving a pure clean product. Why are people looking at reductive aminations of aldehydes and ammonolysis of alkyl halides? These methods a wholely unsatisfactory for DEA if you are after a lab prep for the pure compound OTC. If people want a reference for DEET reaction all you have to do is look in any standard organic chem lab book to find experiements for the hydrolysis of amides which can be adopted for DEET. I have no interest in the reaction as a source of DEA but I think we are loosing the point of the thread somewhat as whats recently been posted seems to be about other routes to amines generally which wont yield DEA well IMHO.



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[*] posted on 2-9-2008 at 03:25


I did suggest the reaction of calcium cyanamide with sodium hydroxide to form the dianion earlier in this thread.
The disodium cyanamide is then reacted with two equivalents of the alkyl bromide to form a dialkylcyanamide which is then hydrolysed to yield the dialkylamine.
I have seen this preparation for dibutylamine somewhere in a book of organic preparations, I thought it was in Organic Syntheses but it isn't.
There is a good preparation of ethyl bromide on these boards so this should be a viable method.
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[*] posted on 2-9-2008 at 04:09


Yes that would prove a viable method especialy if sacling to larger batches too as calcium cyanamide can be had cheaply as a N fertilizer especially in farming areas I'd imagine, although I have never come across it sold as such. I'd imagine OTC cyanamides are probably in huge lots kilos at a time, could be unwanted if only making a small quantity of DEA?!



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[*] posted on 2-9-2008 at 05:13


Calcium cyanamide is quite widely available in the European Union as Perlka.

http://www.garden-supply.co.uk/information.php?info_id=6

I found some US sites that mention using it as a lawn dressing and its toxicity to pets so I would guess that it may be available in smallish quantities from a specialist supplier.

And it seems that it may be prepared quite readily from OTC materials anyway.

http://www.sciencemadness.org/talk/viewthread.php?tid=8594&a...

The warning about not consuming alcohol is because cyanamide has a similar effect to Antabuse

http://www.osha.gov/SLTC/healthguidelines/cyanamide/recognit...

And the reaction is referenced here by a large producer of cyanamide.

http://www.cyanamide.com/content/reactions_1.htm


[Edited on 2-9-2008 by ScienceSquirrel]
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[*] posted on 2-9-2008 at 08:20


Due to the post by panziani, I think I will have a go at DEET hydrolysis after all, using higher conentrations of hydroxide and longer reaction times. I will, of course, take several safety preautions which I failed to observe in my previous incident.
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[*] posted on 7-9-2008 at 00:49


With a high pressure reaction vessel, Diethylamine is easy to produce. Clean, cheap, and OTC.

Such a reactor, can be bought, begged, borrowed, or built. Alternately, the reaction mix can be forced through a long, small diameter reaction tube, heated by a salt bath, but how such wizardry is achieved, I do not understand.

Check local regulations before proceeding.

Take Glacial Acetic Acid, Ammonia, Ethanol, and a Catalyst ( Cupric Chloride works well) Put 'em in your reaction vessel, seal it up, and flush it with N2 (or use a vacuum) to evacuate the air.

Heat to 200 to 300 degrees C, with stirring or shaking, for a few hours....And Shazzam! A reasonable yield of DiethylaminoAcetamide.

Works best if you start with Acetamide, and Anhydrous Ethanol. It's a reversable reaction,(The reaction is driven forward by the removal of water from the reaction mixture) and excess water slows the rate of reaction.

Since the Ammonia substituent of Acetamide only has two free hydrogen atoms to react with ethanol, the reaction tends to go no further than Di-substitution.

The reaction is widely applicable, and there really isn't much waste, as between runs, the water formed during the reaction can be distilled off, and any unreacted organic material , augmented, and re-reacted.

Check out the Patent.

US Patent 3,674,851 July 4th, 1972

Oh yeah. If you're kind of inexperienced, or your not sure about the service-ability of your reaction vessel, don't even think about trying this. High pressure reactors can develop pressures of thousands of pounds per square inch. They are sometimes referred to as "bombs". If something goes wrong and the vessel ruptures while it is pressurized, if you're near by, there's a good chance you will be heading off for a new incarnation.

[Edited on 7-9-2008 by zed]
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[*] posted on 7-9-2008 at 05:25


That's actually a very good idea Zed!

Basicly, you are forming acetamide in-situ, and alkylating it. But you can use alkyl halide instead of alcohols with much less harsh reaction conditions....

This reminded me of a serie of article I bumpe dinto when I was looking to methylate a N-substitued formamide... And its seems di-ethylation of phenylacetamide is acheiveable under smooth condtions (reflux, PTC):

Quote:

In our study of the alkylation reaction of 2-phenylacetamides under basic conditions,
different systems were used as reaction models. At the beginning, N-ethyl-2-phenylacetamide
was alkylated under phase-transfer conditions using ethyl bromide,4 n-butyl bromide,
5 allyl bromide6 and benzyl bromide.7 When ethyl bromide was used, the N-alkylation
product was the only product at 60 ÂșCafter 2.5 h.
(ref given: D. @. Mijin, N. D. Stojanovi, S. D. Petrovi, Ind. J. Chem. 35B (1996) 1201 )


Alkylation of N-substitued 2-phenylacetamides: Benzylation of N-(4-chlorophenyl)-2-phenylacetamide

Acetamide would be even less hindered, so I think di-ethylation could evry well be possible with 2.2eq of EtX and PTC in the solvent of choice.


Here is a revelant article on the n-monoalkylation of acetamides using KOH on alumina:The Selective N-Monoalkylation of Amides With Alkyl Halides In The Presence Of Alumina and KOH

One could start off the alkylation with KOH:Al2O3 and 1eq of RX, then add some PTC and another eq. of RX. Or just add both equivalents and heat to relfux with a PTC. Then hydrolyze the di-alkylated amide by refluxing in HCL, and you have your diethylamine hydrochloride.


This could also be a good preparation of ethylamine: prepare aectamide (AcOEt + NH3), mono-ethylate, and hydrolyze.


Other interesting read:
Alkylation of N-substitued 2-phenylacetamides



Now, this could be a better approach for th ethread starter: get yourhands dirty with some simple synthesis: ethyl bromide from ethanol and KBr/H2SO4, acetamide form ethyl acetate and conc. NH3, preparation of tetraethylammonium bromide (PTC) from NH3 and excess ethyl bromide, and then ethylation of acetamide and subsequent hydrolysis. Now that's a nifty project to get started with intermediate organic chemistry. By the time to get through this, you will haev developped some knowledge and experience in handling reagents and performing organic reactions. But that does means handling pretty dangerous reagents (H2SO4, NH3, KOH), so don't go doing stupid mistakes like before....

If, and I mean if, you ever wanted to get that diethylamine to cook some acid, hopefully by the time to obtain it you will realize this is a dead end :) But of course this is pur speculation on my part, feel free to shut me up and prove otherwise :)




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