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Author: Subject: Diethylamine Synthesis
mbrown3391
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[*] posted on 28-8-2008 at 14:10


http://cspoutdoors.stores.yahoo.net/10hourinrep.html

$3.89 for about 60 ml of DEET at the above website. pretty expensive shipping though. 8 dollars for 3 containers.

Also, any thoughts on dipropylene glycol in stead of PG or EG? it boils at a higher temp, cheaper, and is easier to find in small quantities
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panziandi
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[*] posted on 28-8-2008 at 14:18


I expect you dont need it. I would try just setting up an experiment where you heat under reflux the DEET with NaOH and then set up for distillation and distill say 50% of the reaction mixture over most of teh DEA should come over with the water and you can then redistil that through a fractionating colum, dry with solid NaOH and redistil. Just off the top of my head that but sounds feasible. Make sure to cool your collection flask in ice water so that the volatile amine does not evaporate off and perhaps vent it through a wash bottle of 2M HCl so that you don't fumigate yourself in the smell of fishy glue fumes!



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mbrown3391
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[*] posted on 28-8-2008 at 14:32


after further review of this discussion i have decided to go with the acid hydrolysis method suggested by ritter and arrhenius, as it allows me to save the m-methylbenzoic acid and does not require ethylene or propylene glycol, or distillation.
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[*] posted on 28-8-2008 at 17:02


I don't exactly understand why either EG or PG would be preferable. Why would PG polymerize in base while EG not (or whatever would make that tar/goo)?

As far as the m-toluic acid:

My DEET, which is basically 100%, is listed as '95% Diethyl meta-toluamide, 5% other isomers', where the other isomers are presumably the ortho and para toluamides. I think this is basically technical grade pure.

You wouldn't need to evaporate the toluene to recover the acid - instead extract with NaHCO3, then acidify this extract with conc HCl, and collect the precipitated acid.

Does anybody have any ideas for how to separate the other isomers of the toluic acids? Or interesting specific things to do with them? Maybe their esters have interesting smells.


[Edited on 28-8-2008 by pantone159]
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Ritter
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[*] posted on 28-8-2008 at 17:04


Quote:
Originally posted by mbrown3391
after further review of this discussion i have decided to go with the acid hydrolysis method suggested by ritter and arrhenius, as it allows me to save the m-methylbenzoic acid and does not require ethylene or propylene glycol, or distillation.


I only pointed out that acid hydrolysis was possible, not that you didn't need an organic co-solvent to solubilize the DEET. If it's practically insoluble in water it will also be the same in muriatic acid. The merits of either approach (acid or base) remain to be determined experimentally.

In the acidic approach you will form the m-methylbenzoic acid as an insoluble fraction so you will need to have the DEET in solution or you will only get DEET-contaminated acid. You still will be faced with recovering the DEA HCl salt from the aqueous phase. Adding NaOH to this aq fraction would liberate DEA free base but you would still have to distil & dry it.




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mbrown3391
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[*] posted on 28-8-2008 at 18:35


Sorry, i over looked that fact. So then, back to my previous question. Do you suspect dipropylene glycol would be a suitable substitute for a co-solvent? Seems to be about the same polarity, soluble in water, and has a high boiling point.

[Edited on 29-8-2008 by mbrown3391]
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Arrhenius
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[*] posted on 28-8-2008 at 20:48


I think it's best to leave out the 'co-solvent' on the first trial. Everything is 'soluble' in everything, it's only a matter of to what extent. Hence, as Ritter has suggested, DEET will not dissolve much in water. Stirring the reaction vigorously with a stir plate, or refluxing the reaction will probably create enough agitation to get some hydrolysis going. If it's difficult to dissolve, it may take a little bit longer to hydrolyze.

[Edited on 28-8-2008 by Arrhenius]
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Nicodem
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[*] posted on 29-8-2008 at 01:07


Quote:
Originally posted by Nicodem
You can reflux it with HCl for several hours. That should work and you don't have to use a cosolvent. I have not read the paper as I have other work now, but there is supposed to be an experimental procedure using HCl(aq) for the hydrolysis of N,N-diethyl-ortho-methylbenzamide in DOI: 10.1016/S0040-4039(00)94113-3 (you can find the Tetrahedron Letters volume 24 in References if you don't have access to the journal).

As it seems nobody went trough the enormous trouble to check the above paper. I did that today and what it actually says (in the footnote!) about the hydrolysis of N,N-diethyl-ortho-methylbenzamide is: "Hydrolysis of N,N-diethyl-o-methylbenzamide did not occur under these conditions." The described conditions were reflux in 6N HCl. N,N-Dialkylbenzamides are said to be extremely resistant to hydrolysis. I saw literature examples where the amide was refluxed in HCl(aq) for a week to obtain useful yields. Apparently only tertiary benzamides that can count on neighboring group assistance, like the N-benzoil-N,N',N'-trimethylethylenediamines described in the above paper, hydrolyze easily while normal ones (like DEET is) require harsh conditions and long reaction times.




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[*] posted on 29-8-2008 at 03:40


I have had a look round the Internet on the subject of the hydrolysis of DEET and it seems that it may be more reactive towards base hydrolysis.
I am not going to post the URL's as they lead to recipes for the expected 'pounds, shillings & pence' :D

However an interesting quote from one of the sites is;

If Ergotamine was as available as diethylamine is, we would be knee deep in microdots by now. really, the only bottleneck are the ergoloid precursors.

You can heat DEET bug repellant with lye in ethylene glycol antifreeze, and out comes diethylamine gas. You can buy ethylchoride aerosol cans and react it with the proper amount of ammonia to form diethylamine HCl. Alcohol, battery acid and ammonia.

Really, getting any simple amine is.. simple!

Compare that with the original post me hearties :D
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[*] posted on 29-8-2008 at 04:42


i would have just told you my source if you asked, you know.

You seem to be suggesting that this source proves my aim to use diethylamine to synthesize lsd.

but just as you found this website while looking for information on the topic of diethylamine synthesis, so did i. the nature of that particular website has nothing to do with my intentions, which are purely experimental.

Besides, as the source says, ergotamine precursors aren't exactly easy to come by.

[Edited on 29-8-2008 by mbrown3391]
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[*] posted on 29-8-2008 at 04:51


Quote:
Originally posted by mbrown3391
i would have just told you my source if you asked, you know.

You seem to be suggesting that this source proves my aim to use diethylamine to synthesize lsd.

but just as you found this website while looking for information on the topic of diethylamine synthesis, so did i. the nature of that particular website has nothing to do with my intentions, which are purely experimental.

Besides, as the source says, ergotamine precursors aren't exactly easy to come by.

[Edited on 29-8-2008 by mbrown3391]


You don't need ergotamine you need LSA, diethylamine and a coupling agent.
I can think of one good way to obtain a few hundred mgs of LSA off the top of my head and I could make the coupling agent.
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mbrown3391
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[*] posted on 29-8-2008 at 05:24


that's aside the point. I found that source in the same way you did
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mbrown3391
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[*] posted on 29-8-2008 at 06:49


though now that I think about it, it does seem almost too easy to make lsd from only otc chemicals when you start from lsa, which is present in hawaiian baby woodrose seeds at about %.12. just a couple ounces of these seeds would be enough theoretically to make 10 grams of lsd! now even hoffman himself only achieved about a %20 yield, but still. it seems feasable, but if lsd synthesis was this easy, however, I'm sure everyone would have a few multimillion dollar batches going.
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[*] posted on 29-8-2008 at 10:45


Quote:
Originally posted by mbrown3391
though now that I think about it, it does seem almost too easy to make lsd from only otc chemicals when you start from lsa, which is present in hawaiian baby woodrose seeds at about %.12. just a couple ounces of these seeds would be enough theoretically to make 10 grams of lsd! now even hoffman himself only achieved about a %20 yield, but still. it seems feasable, but if lsd synthesis was this easy, however, I'm sure everyone would have a few multimillion dollar batches going.

0.12%, not 12% ;-)

4 ounces (~114g) at 0.12% = 0.1368g = 136.8mg of extract




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mbrown3391
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[*] posted on 29-8-2008 at 11:10


well that is a pretty serious miscalculation on my part. So you would need a couple hundred ounces of seeds. that definately makes it a bit more difficult to undertake.
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[*] posted on 29-8-2008 at 11:56


Extracting LSA is not the slam dunk that some sources make it out to be. Realistically, one would need to perform an acid/base extraction of maybe a kilo of seeds. The isolation would realistically require appropriate partitions, SPE, and either some very skilled column chromatography or HPLC. Attainable, but you'll need appropriate spectroscopic techniques as well, or you'll be in the dark. Ergotamine is probably equal in difficulty to obtain from 'nature'. Overall, a pita.
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[*] posted on 29-8-2008 at 12:03


not to mention that ergot will likely cause digit necrosis in those unfamiliar with mycology.
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Arrhenius
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[*] posted on 29-8-2008 at 12:07


I've not read into it that thoroughly, but fungus cultures in general are an art in their own right. Aseptic techniques take plenty of practice.
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[*] posted on 29-8-2008 at 12:12


Anyway, i think i think i have found the perfect over the counter source of a co-solvent. My local cigar shop sells a 50% propylene glycol solution in distilled water. 8oz for $4.95. I figure i can make an NaOH solution directly with this and then add the DEET to that.

The problem is, i have not been able to find 100% deet in any stores around me, including an outdoors/camping kind of store. the highest ive found is 30% in ethanol. maybe i should just use this with the ethanol as the co-solvent and omit the propylene glycol?

[Edited on 29-8-2008 by mbrown3391]
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[*] posted on 29-8-2008 at 12:33


I think you will find a cosolvent to cause problems. For instance, if your mixture contains ethanol you'll find this will complicate the distillation, and will make partition efficiencies (if you use a partition instead of distillation) will be not very good, as your aqueous phase will be somewhat non-polar because of the ethanol. I'm not sold on the propylene glycol idea, but give it a shot I guess. You do also have the option of concentrating a 30% solution by distilling off the ethanol.
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[*] posted on 29-8-2008 at 13:01


Good point, i will boil off the ethanol. But im getting alot of conflicting opinions on the co-solvent issue, so how does this sound. i will initially try the reaction with no co-solvent. If the reaction works, i should see a considerable drop in volume as 192ml of DEET produces 103ml DEA. If the reaction does not work, then no harm should have been don to the reactants and i can cool them and add a co-solvent, then try again.
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[*] posted on 29-8-2008 at 16:31


Quote:
Originally posted by mbrown3391

The problem is, i have not been able to find 100% deet in any stores around me, including an outdoors/camping kind of store. the highest ive found is 30% in ethanol. maybe i should just use this with the ethanol as the co-solvent and omit the propylene glycol?

[Edited on 29-8-2008 by mbrown3391]


My local pharmacists / chemists sell various DEET formulations up to 50% and one of my local camping stores sell mixtures up to about the same concentration.
However one store deals with the sort of client that is off to Nepal to soak up the atmosphere for a few months :D
They sell 90+% DEET, mosquito nets, multifuel stoves, water purification tablets, seriously scary medical kits, big knives etc.
I suggest that you seek out a similar establishment!
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[*] posted on 30-8-2008 at 10:40
Attempted hydrolysis of DEET


Experimental

A 50ml flask was charged with 90% potassium hydroxide (6.0g 100mM), 10mL of deionised water was added and the mixture was stirred. 95% DEET ( 4.0mL, 20mM) was added followed by 10mL of 96% ethanol. The mixture was refluxed for 1hr after which the vapours were carefully tested with universal indicator paper and found to be neutral.
The ethanol was distilled off and the residual aqueous alkali was then refluxed with the DEET for a further hour, at the end of this time the vapours were alkaline to indicator paper and a faint smell of amine could be detected. However a large amount of DEET remained in the flask.
Ethylene glycol 10mL was added and the mixture was refluxed for a further hour. A strong smell of amine could be detected and the vapour was noticably alkaline but on adding the cooled reaction mixture to hydrochloric acid (17ml 150mM ) and deionised water 75 ml a large amount of DEET separated out as a mobile oil.

Conclusion

Refluxing DEET with ca 5M 50% ethanolic potassium hydroxide, 10M aqueous potassium hydroxide and a 5M solution in 50/50 ethylene glycol and water for periods of about 1 hr is singularly ineffective as a means of hydrolysis.
I would estimate that the hydrolysis of this material would require many hours of reflux. This is in line with the paper quoted by Nicodem above.
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[*] posted on 30-8-2008 at 10:50


Quote:
Originally posted by ScienceSquirrel
I would estimate that the hydrolysis of this material would require many hours of reflux.


I think your experiment is a good proof of concept that the base/co-solvent approach works. Can you set it up with a distillation condenser/receiver-in-an-ice-bath & let it run for a few days or even just overnight?




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[*] posted on 30-8-2008 at 11:13


I am not that interested in the reaction.
If the DEET had hydrolysed fairly readily then I might be tempted to carry on with it.
Leaving something of this sort refluxing in the shed overnight is not on.
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