Sciencemadness Discussion Board

n n-diethylmethylamine synthesis

Khemi - 9-12-2016 at 01:41

Hi,

I am trying to learn more about this tertiary amine and its preparation. I did a good deal of searching in hopes of finding the synthesis for it. Can it be synthesized from diethylamine or triethylamine?

Thanks

Aqua-regia - 9-12-2016 at 02:17

Yes you can do this, if you have autoclave. Diethylamine react with formaldehyde on 120 C degrees under 1,4-1,5 MPa pressure with good yield (95%) Reactionstime min 8 hours. Molar ratio: 2: 3,2
diethylamine 98% : formaldehyde 30%. but be careful, this is precursor of LSD, unless you want appoitment with DEA


Reference: Celanese Chemicals Europe GmbH Patent: EP1466887

Khemi - 9-12-2016 at 05:21

Thanks Aqua! Not sure how I missed that ref. I spent a good 3-4 hours looking this info up.

I certainly don't want any appointments with anyone! I'm usually naked 99% of the day as I am allergic to clothing and if someone came to my door.. I would have to, at the very least, put on some socks. But yea, I read somewhere people used diethylamine to do bad things like make stupid LSD. Why people inject drugs like LSD is beyond my comprehension. Good thing I don't need to source anything. ;)

I take it a pressure cooker can not be used due to the inability to identify the internal temp. This is a pretty expensive endeavor for making a youtube video. A digital autoclave is going to hurt the pocketbook. =/

Thanks again Aqua

Tsjerk - 9-12-2016 at 06:21

If you have water inside your pressure cooker you can determine the temperature by measuring the pressure. Standard "fast cookers" go up to 120 degrees by default.

CuReUS - 9-12-2016 at 06:35

No need to jump to the nuclear option just yet.;),Why not try an eschweiler-clarke on diethylamine first ?
diethylamine can be obtained from weedicides.

Khemi - 9-12-2016 at 08:35

diethylamine is in stock..

Interesting Tsjerk! But now that CuRe mentions Eschweiler-Clarke with formaldehyde and formic acid.. That seems less of a hassle. Although the thought of having a autoclave around was starting to become enticing but who wants to spend more cash. This hobby is too damn expensive as is! :D

Im curious about yields on the E-C, but not worried about them as I just need a ml or so for analysis and plenty of DEA to go around.

[Edited on 9-12-2016 by Khemi]

Aqua-regia - 9-12-2016 at 09:51

Bad news, but eschweiler on DEA needs superatmospheric pressure too. It is no difference than using instead formaldehyde solution paraformaldehyde or formic acid.

Aqua-regia - 9-12-2016 at 09:54

"diethylamine can be obtained from weedicides"

What do you mean? 2,4D diethylamine salt basicified with NaOH and reflux?

[Edited on 9-12-2016 by Aqua-regia]

CuReUS - 9-12-2016 at 10:26

Quote: Originally posted by Aqua-regia  
Bad news, but eschweiler on DEA needs superatmospheric pressure too

reference ?
Quote: Originally posted by Aqua-regia  
"diethylamine can be obtained from weedicides"

What do you mean? 2,4D diethylamine salt basicified with NaOH and reflux?

yes

careysub - 9-12-2016 at 10:29

DEET (N,N-Diethyl-meta-toluamide) is generally a more accessible material to work with than 2,4-D. Google hydrolysis methods on the SM site.

All of the 2,4-D products I consulted use dimethylamine to form the amide of 2,4-dichlorophenoxyacetic acid, not diethylamine.

Aqua-regia - 9-12-2016 at 23:23


reference ?

SYNTHETIC COMMUNICATIONS, 32(3), 457–465 (2002)



[Edited on 10-12-2016 by Aqua-regia]

Aqua-regia - 9-12-2016 at 23:36



"All of the 2,4-D products I consulted use dimethylamine to form the amide of 2,4-dichlorophenoxyacetic acid, not diethylamine"

Yes you have right, i do not checked this before i wrote. But this product exist:
http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC35...

CuReUS - 10-12-2016 at 00:13

Quote: Originally posted by careysub  
DEET (N,N-Diethyl-meta-toluamide) is generally a more accessible material to work with than 2,4-D. Google hydrolysis methods on the SM site.

that thread ran for 11 pages and was inconclusive.Hydrolysis of DEET is not as easy as it looks.http://www.sciencemadness.org/talk/viewthread.php?tid=11081&...
Quote: Originally posted by Aqua-regia  

SYNTHETIC COMMUNICATIONS, 32(3), 457–465 (2002)

this article does not mention diethylamine anywhere:P

Aqua-regia - 10-12-2016 at 00:36

This is general procedure for the methylation of primary or secondary amines solventfree. For sure it is exist other ways too, like classical eschw. with formic acid, but a do not deeply "investigated" away. Maybe i was wrong with my opinion about superathmosferic circumstances. I never cooked something with Eschweiler methode, just tought if reagent are low boiling point, for good yields needs elevated temerature.

careysub - 10-12-2016 at 15:55

Quote: Originally posted by CuReUS  
Quote: Originally posted by careysub  
DEET (N,N-Diethyl-meta-toluamide) is generally a more accessible material to work with than 2,4-D. Google hydrolysis methods on the SM site.

that thread ran for 11 pages and was inconclusive.Hydrolysis of DEET is not as easy as it looks.http://www.sciencemadness.org/talk/viewthread.php?tid=11081&...


Yes, indeed - that long running thread was remarkably free of any reports on actual success, and I raised that point on another thread more recently:
http://www.sciencemadness.org/talk/viewthread.php?tid=24131&...

And as a result there was an actual report of a successful procedure by nlegaux :

"I was able to successfully prepare freebase diethylamine with the following procedure. I refluxed 50ml DEET with 32ml 8M HCl(aq) for 1.5h. Following this, I added 15g NaOH (which was first dissolved in 20ml water) and distilled off the resulting diethylamine with a 75% yield. It may be easier to purify the freebase in this way and form the salt afterwards than attempt to purify the salt from the m-toluic acid produced."

Also this possibly useful observation:
"I've seen a couple reports claiming success with DEET but not on SM. What successful reports have in common is that they're done in small batches using alkaline hydrolysis with excess NaOH or KOH and the NHEt2 is distilled right out of the rxn mixture."

Also it seems the all three ethylamines (mono, di, tri) are available with entirely OTC reagents, but some work using diethyl oxalate. See my post on this page:
http://www.sciencemadness.org/talk/viewthread.php?tid=11081&...

[Edited on 11-12-2016 by careysub]

Eschweiler-Clarke

Khemi - 11-12-2016 at 02:11

So I am trying to grasp this the best I can. I have excellent lab technique but am learning about the actual molecular structures of a molecule and how a amateur chemist would go about looking at a structure and determine what reaction would best be needed to change that molecule to arrive at the desired compound. If that wasn't clear already lol.

So I did some reading and I am unsure if I am comprehending what I am reading.

Per. https://www.erowid.org/archive/rhodium/pdf/eschweiler-clarke...

"A clean methylation of secondary amines in yields above 90% was achieved with an equimolar ratio of secondary amine and paraform- aldehyde along with the fivefold molar amount of oxalic acid dihydrate (5a) within one hour."

So essentially we have:

Diethylamine with a mol-mass of 73.14g in a freebase solution.

Paraformaldehyde with a mol-mass of 30.03g as a monomer.

Oxalic Acid dihydrate with a mol-mass of 126.07g

So that would mean a 1:1:5 mol of reactants is needed which is 73.14g of diethylamine added to 30.03g of paraformaldehyde along side 630.35g of oxalic acid which is then heated to 100-120c for 1 hour to yield 87.16g (1 mol) of n,n diethylmethylamine if yields were to be quantitative, which according to the literature will not be the case as 90% yields were returned.

Am I correct thus far? If so, then I am confused as to the following passage.

"Paraformaldehyde can be depolymerized to formaldehyde gas by dry heating[1] and to form a formaldehyde solution by water in the presence of a base or heat. The very pure formaldehyde solutions obtained in this way are used as a fixative for microscopy and histology."

If diethylamine is a weak base and a large amount of oxalic acid is added alongside it, wouldn't the reaction contents turn acidic now allowing paraformaldehyde to decompose to give formalin is situ?

Would the final n,n diethymethylamine be in freebase form, or as a salt?

Im sure this isn't the case as it wouldn't be in the literature. I am just hoping someone could explain what I am misunderstanding.

Thanks for your patience. I appreciate all the input you all have contributed thus far. :)


[Edited on 11-12-2016 by Khemi]

CuReUS - 11-8-2017 at 07:56

Quote: Originally posted by Khemi  
If diethylamine is a weak base and a large amount of oxalic acid is added alongside it, wouldn't the reaction contents turn acidic now allowing paraformaldehyde to decompose to give formalin is situ?

Quote:
"Paraformaldehyde can be depolymerized to form a formaldehyde solution by water in the presence of a base or heat

Quote:
Would the final n,n diethymethylamine be in freebase form, or as a salt?

It will be in the form of a salt,you have to freebase it using CaO as mentioned in the erowid paper (pg 7/10 in pdf under "General Procedure for the Methylation of Primary or Secondary Amines" )