Sciencemadness Discussion Board

Diethylamine Synthesis

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mbrown3391 - 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

panziandi - 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!

mbrown3391 - 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.

pantone159 - 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]

Ritter - 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.

mbrown3391 - 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]

Arrhenius - 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]

Nicodem - 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.

ScienceSquirrel - 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

mbrown3391 - 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]

ScienceSquirrel - 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.

mbrown3391 - 29-8-2008 at 05:24

that's aside the point. I found that source in the same way you did

mbrown3391 - 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.

querjek - 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

mbrown3391 - 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.

Arrhenius - 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.

mbrown3391 - 29-8-2008 at 12:03

not to mention that ergot will likely cause digit necrosis in those unfamiliar with mycology.

Arrhenius - 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.

mbrown3391 - 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]

Arrhenius - 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.

mbrown3391 - 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.

ScienceSquirrel - 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!

Attempted hydrolysis of DEET

ScienceSquirrel - 30-8-2008 at 10:40

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.

Ritter - 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?

ScienceSquirrel - 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.

mbrown3391 - 30-8-2008 at 11:17

I found 100% DEET at a rite aid (even though they said they didnt have it when i called): 1 ounce for $5. However they also had 40% deet, 5 ounces for $6, which equals 2 oz of deet, so i decided to go with that. I am now letting the alcohol evaporate, if i get a chance ill take it outside and boil it off. While i was out i picked up some 50% propylene glycol/distilled water humidor solution at the cigar shop. I will post the results of my experiment soon.

panziandi - 30-8-2008 at 11:39

Yes do! Sounds like you are making good progress. So you are definently going to go with the acid hydrolysis? DEA.HCl will be very hygroscopic so make sure if you dont use it straight away you store it well in a very dry place. Just to rub it in your face (not in a nasty way) I just got 500mLs of AR grade DEA and TEA haha!

mbrown3391 - 30-8-2008 at 12:18

Well im not sure if i want to do acid hydrolysis or with NaOH. i may try both. And just out of curiosity, how much did the DEA cost?

S.C. Wack - 30-8-2008 at 15:24

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


That is why one should use diethylene glycol as solvent instead of ethanol.

panziandi - 30-8-2008 at 16:57

DEA was around £6.00 I think not too sure off top of my head I don't have the order at hand.

I still don't understand why you need the glycol to be honest, hot reagents and stirring should work fine I'd imagine but I suppose using the glycol is worth a shot.

I see the benefits and downside to both H+ and OH- hydrolysis, the free base is probably easier to store than the chloride salt as the chlorides attract so much water they dissolve! But also the chloride is not smelly or corrosive. It depends how quick you will be using the amine I suppose. Hell why not make a bit of free base and a bit of chloride salt and see which yields the best product?!

panziandi - 30-8-2008 at 16:58

Oh also DEA is not just smelly and corrosive but it is also very flammable! So no naked flames if you are distilling the amine.

mbrown3391 - 30-8-2008 at 17:16

im thinking ill make the chloride salt. no distillation, easier to handle, and shouldnt be to hard to store if i just put it under some alcohol. But the question was to hydrolize with hcl or naoh. even if i hydrolize with NaOH i can still add hcl after to make the salt.

[Edited on 31-8-2008 by mbrown3391]

ScienceSquirrel - 30-8-2008 at 17:18

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


That is why one should use diethylene glycol as solvent instead of ethanol.


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.
The original post mentions using ethylene glycol not diethylene glycol.

panziandi - 30-8-2008 at 17:30

Well if you use HCl you'll end up with DEA.HCl and also m-Methylbenzoic acid in the recation mixture. Perhaps a better way would be to hydrolyse with boiling NaOH or KOH solution and lead the fumes out of the flask and into hydrochloric acid via an up turned funnel (like what you would do for absorbing NH3). Then once the reaction is complete you could either keep the DEA.HCl solution or you could evaporate it off to yield the dry salt.

mbrown3391 - 30-8-2008 at 17:41

That would be convenient, however from sciencesquirrel's experiment, it seems that the mixture will take refluxing for a few hours to fully react. i could reflux first, then remove the reflux condenser and switch to a simple rubber stopper with a glass tube leading to HCl

ScienceSquirrel - 30-8-2008 at 18:16

Quote:
Originally posted by mbrown3391
That would be convenient, however from sciencesquirrel's experiment, it seems that the mixture will take refluxing for a few hours to fully react. i could reflux first, then remove the reflux condenser and switch to a simple rubber stopper with a glass tube leading to HCl


I think that you are looking at a 24 - 48 hr reflux with something like 10M potassium hydroxide in 75 : 25 % ethylene glycol : water to complete this reaction.
After that you can distill off the diethylamine.

mbrown3391 - 30-8-2008 at 18:44

So going back to your experimental, DEET does form a separate layer when mixed with water, right?

ScienceSquirrel - 30-8-2008 at 19:13

Quote:
Originally posted by mbrown3391
So going back to your experimental, DEET does form a separate layer when mixed with water, right?


There were two distinct layers in all of the mixtures.
I was using a big bar and a fast stir rate to create an emulsion.
DEET is quite soluble in ethanol / water but adding potassium hydroxide results in a very alkaline alcohol / water phase and an alcoholic / DEET phase.
Even the mixture with potassium hydroxide, ethylene glycol and water was an emulsion.

mbrown3391 - 30-8-2008 at 20:21

Well i just had a very scary experience. I was boiling my 40% DEET/Alcohol solution on a burner in a stoppered boiling flask with a glass tube running into cold water . There was intense boiling for around 10 minutes, then it slowed to small bubbles. I thought maybe all the alchol had boiled off and the deet was now boiling but there was way to much liquid left and i didnt think the deet would boil on this burner, since it BP is over 500 degrees. anyway, i thought just to be safe, i would take it off the burner and inspect it. while moving it off the burner, however the liquid was jostled and hit the upper parts of the flask, which must have been much hotter having not been in contact with any liquid. the solution flash vaporized and im not exactly sure what happened then but a second later the flask was broken on the floor, my shirt was wet with the hot solution and the room was filled with fog. i ran upstairs took off my clothes and got in the shower. my stomach has second degree scaldings on it but it doesnt seem to be too bad. Im not really sure how that happend but if i try that again it will be outside with no stopper.

ScienceSquirrel - 30-8-2008 at 20:31

Quote:
Originally posted by mbrown3391
Well i just had a very scary experience. I was boiling my 40% DEET/Alcohol solution on a burner in a stoppered boiling flask with a glass tube running into cold water . There was intense boiling for around 10 minutes, then it slowed to small bubbles. I thought maybe all the alchol had boiled off and the deet was now boiling but there was way to much liquid left and i didnt think the deet would boil on this burner, since it BP is over 500 degrees. anyway, i thought just to be safe, i would take it off the burner and inspect it. while moving it off the burner, however the liquid was jostled and hit the upper parts of the flask, which must have been much hotter having not been in contact with any liquid. the solution flash vaporized and im not exactly sure what happened then but a second later the flask was broken on the floor, my shirt was wet with the hot solution and the room was filled with fog. i ran upstairs took off my clothes and got in the shower. my stomach has second degree scaldings on it but it doesnt seem to be too bad. Im not really sure how that happend but if i try that again it will be outside with no stopper.


I think you really need to learn some practical laboratory skills.
You had a lucky escape this time.
Boiling 10M potassium hydroxide in alcohol will melt your eyeballs on contact rendering you a blind, ugly f**ker!

mbrown3391 - 30-8-2008 at 21:02

I couldn't even tell you what happened. It was a fluke. How would you have done it differently?

Edit: And its not like i wasn't wearing goggles. give me some credit. i would be an ugly f**ker, but not a blind one.

[Edited on 31-8-2008 by mbrown3391]

panziandi - 31-8-2008 at 05:19

You are refluxing the reaction mixture aren't you? Because reading your post it sounds like you are just boiling the mixture off and not refluxing it...

mbrown3391 - 31-8-2008 at 06:28

that was not the reaction. I was just boiling off the ethanol to get pure deet. but yes I will be refluxing

ScienceSquirrel - 31-8-2008 at 07:43

Boiling off the alcohol is like a walk in the park compared with what comes next.
You are going to have to reflux DEET and caustic for at least a day.
I would recommend a hot plate stirrer and a sand bath to hold the flask.
If it goes wrong then the chance of you having a nasty experience will be much less.
And you need a reliable source of water for the condenser, if the mains pressure drops while it is unattended then it could be nasty.

Ritter - 31-8-2008 at 07:46

Quote:
Originally posted by mbrown3391
Well i just had a very scary experience. I was boiling my 40% DEET/Alcohol solution on a burner in a stoppered boiling flask with a glass tube running into cold water . There was intense boiling for around 10 minutes, then it slowed to small bubbles. I thought maybe all the alchol had boiled off and the deet was now boiling but there was way to much liquid left and i didnt think the deet would boil on this burner, since it BP is over 500 degrees. anyway, i thought just to be safe, i would take it off the burner and inspect it. while moving it off the burner, however the liquid was jostled and hit the upper parts of the flask, which must have been much hotter having not been in contact with any liquid. the solution flash vaporized and im not exactly sure what happened then but a second later the flask was broken on the floor, my shirt was wet with the hot solution and the room was filled with fog. i ran upstairs took off my clothes and got in the shower. my stomach has second degree scaldings on it but it doesnt seem to be too bad. Im not really sure how that happend but if i try that again it will be outside with no stopper.


If I were you I'd forget about chemistry & take up something a little less hazardous, such as needlepoint. On second thought, those needles are sharp. How about sodukos instead?

mbrown3391 - 31-8-2008 at 07:56

Quote:
Originally posted by mbrown3391
It was a fluke. How would you have done it differently?

ScienceSquirrel - 31-8-2008 at 08:09

I would not have tried to move a hot flask.

Were you boiling off alcohol with a naked flame?
I would be using a hotplate for that.

mbrown3391 - 31-8-2008 at 08:36

i said it was a hot plate. and be honest, would you have expected the flask to explode simply by moving it ever so slightly? its not like i shook it, it litterally tipped about 1cm up the side of the flask

[Edited on 31-8-2008 by mbrown3391]

Klute - 31-8-2008 at 08:49

If you had not agitation, it is perfectly normal. Boiling stones would have be the bear minimum. Most alcohols and other mixtures (especially if they ahve a high boiling consituant that can get themixture hotter than the bp of the alcohol) will do that, even with boiling stones.

If you heat methanol without good agitation, there will be vapors evolving but no boiling, and the minute you hardly move the flask, a volvano will spit up your condenser...

I agree with the others and strongly advise you to do more learning, and training with much less dangerous recations, and invest in some proper equipment. Sometime you can forget that very common reagents, such as KOH, are so dangerous.
Your goggles would have protected your eye against a drop or two flying by, but if you get spattered by boiling DEET/KOH mixture, well above 100°C, that won't be a few secondary burns.. You will see your bones by the time you get help. And the mixture running done your head will get to your eyes, melting them instantly. Not something i would call fun.

Sorry to say, but if you can't distill ethanol safely, things will get only worse in the next steps.

ScienceSquirrel - 31-8-2008 at 08:51

I think it is fair to say that as you gain more experience you develop a 'nose' for what is going on in an experiment.
Experienced chemists have less accidents because they tighten up clamps correctly, they can see when a liquid is boiling erratically and is likely to 'bump' and a hundred and one other things.

People who have just passed their driving test have a lot more accidents than people who have been driving for a few years. The person who has been driving for a few years may know less about the Highway Code etc than the person who has just passed but they have a lot of 'roadcraft'.

mbrown3391 - 31-8-2008 at 08:54

Quote:
Originally posted by Klute
If you heat methanol without good agitation, there will be vapors evolving but no boiling, and the minute you hardly move the flask, a volvano will spit up your condenser...


The mixture was already boiling when i took it off the burner. if i had seen the boiling stop i would have expected a superheated solution.

i will however get a hotplate with magnetic stirrer before i try the actual reaction.

Nicodem - 31-8-2008 at 09:02

Your experience is both the sum of what you were already told about your own attitude and the confirmation that irresponsible people should stay away from chemistry (or at least mature first).
You said you used a BURNER, only now you change your mind when other members told you how crazy that is.
I bet you did not even use any boiling chips or else you would not experience the delights of a high boiling liquid superheating.
And accident was only while trying to concentrate your solution. I dare not to think what you will do while doing the hydrolysis. Are we going to hear about fumes going into flames, flasks cracking, suckbacks of HCl into boiling KOH?

Look, it is all very nice that you are interested in chemistry (at least I hope you are) and I would encourage you 100% if you would only show some maturity. But it is obviously from your posting style that you are simply lazy, don't think about what you are doing, purposefully ignore theory, have no experience with simpler procedures, don't understand the information already provided to you... and so on. Please reconsider and first obtain some practical and theoretical skills by performing some simple reactions and read some books and articles. Maybe one day you will not only learn to use the shift key on your keyboard, but even understand the mechanisms of the chemical transformations going on in your reaction flask. That day you will be grateful to what I told you, because the satisfaction in chemistry can only be achieved trough comprehension and scientific approach - all the rest is just trying to be kewl, and kewls either grow up (with permanent injuries or not) or just die.

mbrown3391 - 31-8-2008 at 09:13

I did the boiling on a stove top burner with a wire mesh/ceramic divider between the flask and the coils, not a Bunsen burner. There was no open flame.

Have you never had an accident in the lab?

And once again you point out grammatical errors, so i will do the same.

Quote:
Originally posted by Nicodem
I bet you did not even use any boiling chips or else you would not experience the delights of a high boiling liquid superheating.
And accident was only while trying to concentrate your solution.
...But it is obviously from your posting style that you are simply lazy


Hopefully this time you will do the mature thing, and not delete this post simply because i pointed out your hypocrisy.

[Edited on 31-8-2008 by mbrown3391]

ScienceSquirrel - 31-8-2008 at 09:26

I have had accidents in the lab, everybody does.

But most of my accidents were in the earlier part of my career when I was using aqueous copper sulphate and sodium carbonate etc while doing 'O' and 'A' level.

By the time I was using carbon monoxide under pressure I had got my 'newbie' accidents out of the way and had years of experience.

mbrown3391 - 31-8-2008 at 09:31

A fair point. I do not pretend not to be a "newbie." However i do feel that with the correct precautions taken, it is more a matter of equipment than experience in this case (i.e. magnetic stirrer, sand bath as you described. I did not take the correct precautions while boiling that ethanol because of a false sense of security from all the other distillations i have done, and i now can can see the situations where experience is vital. I will put a lot of thought into the decision to go through with this reaction.

On a different note, what are the possibilities of this reaction occurring at room temperature over, say, months?

[Edited on 31-8-2008 by mbrown3391]

ScienceSquirrel - 31-8-2008 at 09:43

Quote:
Originally posted by mbrown3391

On a different note, what are the possibilities of this reaction occurring at room temperature over, say, months?




To be honest I think the chances are that Hell will freeze over first.
I reckon the sort of thing that will give you a reasonable rate of reaction is concentrated caustic alkali, potassium hydroxide for preference, in a glycol / water solvent system at reflux temperature.

See my experimental post further up thread.

mbrown3391 - 31-8-2008 at 09:49

I have to admit i didn't quite understand your notation: 90% potassium hydroxide. Does this mean 90% saturation? If not, how close was your solution to the maximum amount of dissolved hydroxide?

[Edited on 31-8-2008 by mbrown3391]

ScienceSquirrel - 31-8-2008 at 09:56

Quote:
Originally posted by mbrown3391
I have to admit i didn't quite understand your notation: 90% potassium hydroxide. 90% by weight? 90% saturation? how close was your solution to the maximum amount of dissolved hydroxide?

[Edited on 31-8-2008 by mbrown3391]


That is a reference to the fact that potassium hydroxide is seldom purchased as a pure material. It is so hygroscopic that even when molten it still contains some water.
The molten caustic is formed into small beads known as prills or rolled out into flakes.
Usually it is sold as containing anywhere between 70 and 90% potassium hydroxide, when making up solutions one allows for the water.

100mM of 100% potassium hydroxide would weigh 5.6g but my sample is ca 90+% so I use 6g. My resultant solution will be roughly 5M in terms of concentration but I am not that bothered if it is say 4.8 or 5.2M as I am using it in large excess and if the experiment had worked I would have calculated my yield on the basis of my limiting reactant which is DEET.

[Edited on 31-8-2008 by ScienceSquirrel]

Nicodem - 31-8-2008 at 09:57

Quote:
Originally posted by mbrown3391
Have you never had an accident in the lab?

Several times. Though luckily never anything serious. Excepts for a couple of minor burns&cuts, I never had any injury and I hope it will remain like that till retirement. However, what you constantly ignore is that you are obviously autodestructive with your attitude and that makes it a completely different situation. I do not go working in the lab disregarding what is going on during the reaction or reaction work up. Just think about it. You don't use boiling chips and then you act surprised when the thing blows up in your face. Is that supposed to be a responsible attitude? It is the same type of attitude as when I criticize your spelling and you don't do anything about it, yet act surprised and offended (and I’m not even a native English speaker, so I dare not to think what your teachers might think of your spelling).
To reiterate what is wrong with your attitude: If you don't even use the shift key after you are being asked to do so, then how can you act surprised if someone think you are lazy?
… or in other words: If you don't use boiling chips to prevent superheating, how can you act surprised when the flask contents blow out of the flask?
All you have to do is change your attitude and you might become a good chemist, but until then you will only be continuously surprised as to why your experiments blow up or just don't do anything at all.

mbrown3391 - 31-8-2008 at 10:05

I am utterly dumbfounded at the way you continuously criticize my grammar and yet just as continuously make grammatical errors yourself.

mbrown3391 - 31-8-2008 at 10:10

Quote:
My resultant solution will be roughly 5M in terms of concentration


Can't the reaction be expected to proceed at least a little more quickly with a higher concentration of hydroxide? I cant calculate Molarity because i dont know how NaOH displaces water, but a saturated solution is around 27 molal

[Edited on 31-8-2008 by mbrown3391]

ScienceSquirrel - 31-8-2008 at 10:12

Quote:
Originally posted by mbrown3391
I am utterly dumbfounded at the way you continuously criticize my grammar and yet just as continuously make grammatical errors yourself.


To be fair, English is not Nicodem's first language while English is yours.
Nicodem had to learn English at the same time as he learnt chemistry as most journals etc are in English.
I learnt some German so I could read Beilstein etc but I would have been pretty stumped if all of Chemical Abstracts etc had been in German.

ScienceSquirrel - 31-8-2008 at 10:19

Quote:
Originally posted by mbrown3391
Quote:
My resultant solution will be roughly 5M in terms of concentration


Can't the reaction be expected to proceed at least a little more quickly with a higher concentration of hydroxide? I cant calculate Molarity because i dont know how NaOH displaces water, but a saturated solution is around 27 molal


Increasing the molarity is an option but you have to consider that fact that you are using water and glycol as a solvent so the caustic will be less soluble in that than pure water.
Also potassium hydroxide is more soluble in alcoholic liquors so it is preferred over sodium hydroxide eg for biodiesel manufacture.
You also have to factor in other considerations. 27M sodium hydroxide would be more like a thick oil than a normal solution and this may cause complications with stirring etc.
Experimental conditions tend to be a trade off.
One of the advantages of having read a lot of experimental and done a lot of experiments is that you can devise a reasonable protocol for a new reaction from your knowledge of the 'prior art'.

[Edited on 31-8-2008 by ScienceSquirrel]

[Edited on 31-8-2008 by ScienceSquirrel]

mbrown3391 - 31-8-2008 at 10:20

And his fluency is impressive. However, hypocrisy is hypocrisy.

Edit: Also, most of his errors are clearly typos and not misunderstandings of the language.

[Edited on 31-8-2008 by mbrown3391]

Nicodem - 31-8-2008 at 10:31

Stop being pathetic!
If you don’t have anything rational to say about my criticism, then just don’t say anything. Post only chemistry related things, like literature examples and references which you still had not provided. It is unbelievable that you managed to push this thread to its 6th page and yet did not bother to provide a single example of tertiary benzamide hydrolysis. It appears to me you did not even bother to check the most basic sources like Vogel’s or similar.

mbrown3391 - 31-8-2008 at 10:45

Unless it is available in some OTC product, I don't see why I would have posted an example of it. This is clearly about synthesizing DEA without ordering chemicals, or else I would just order the DEA.

Klute - 31-8-2008 at 10:55

Oh my.... He is not asking for the brand aname of whatever product, but a litterature reference, a procedure detailing the recation you want to perform. ANy example of someone trying this out, to show htat you have done soem minimal research on your own, and not just arrived empty handed, waiting to be spoon-fed.

Agin, I would really recommend waiting some more before trying anything of this sort, if you don't knwo what a reference is...

mbrown3391 - 31-8-2008 at 11:15

Ok i see, DEET is a tertiary benzamide. Sorry. But the post was confusing. I did post an example, i did not post a reference (there may not be one). And Vogel's contains no mention of DEA synth, only dimethylamine synth.

mbrown3391 - 31-8-2008 at 11:39

Seeing as the deet method has not seemed to work for science squirrel, i may try the Ethanal method i beleive someone mentioned earlier. This would be comparable to the dimethylamine synth found in vogel's

mbrown3391 - 31-8-2008 at 12:46

This is speculation:

If
2 CH2O + NH4Cl --> [CH3NHCH3]HCl + O2

Then
2 CH3CHO + NH4Cl --> [CH3CH2NHCH2CH3]HCl + O2

Vogel's says the first reaction takes around 5 hours at around 115 degrees C, so i assume the second reaction would be similar.

Does this seem more feasible? It would certainly be less expensive.

Klute - 31-8-2008 at 15:52

And where do you get your acetaldehdye?

I fyou can buy acetaldehyde, you can surely buy Et2NH... Making acetaldehdye without K2Cr2O7 isn't really trivial.

[Edited on 1-9-2008 by Klute]

mbrown3391 - 31-8-2008 at 16:18

Vogel's describes synthesis of acetyldehyde from paraformaldehyde and sulfuric acid alone. I once accidentally made a considerable amount of acetyldehyde from conc. sulfuric acid, 12% h2o2 and ethanol at low temperatures

CH3CH2OH + H2O2 --> CH3CHO + 2 H2O

[Edited on 1-9-2008 by mbrown3391]

ScienceSquirrel - 31-8-2008 at 16:19

Quote:
Originally posted by mbrown3391
This is speculation:

If
2 CH2O + NH4Cl --> [CH3NHCH3]HCl + O2

Then
2 CH3CHO + NH4Cl --> [CH3CH2NHCH2CH3]HCl + O2

Vogel's says the first reaction takes around 5 hours at around 115 degrees C, so i assume the second reaction would be similar.

Does this seem more feasible? It would certainly be less expensive.


Methanal ( formaldehyde ) reacts with ammonia to form dimethylamine but not in any way like that.

Ethanal ( acetaldehyde ) reacts with ammonia but not to form diethylamine.

Back to the books!

mbrown3391 - 31-8-2008 at 16:22

Quote:
Ethanal ( acetaldehyde ) reacts with ammonia but not to form diethylamine.


Any idea what it does form?

ScienceSquirrel - 31-8-2008 at 16:25

Quote:
Originally posted by mbrown3391

Any idea what it does form?


Why don't you go and find out for yourself :D

mbrown3391 - 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]

pantone159 - 31-8-2008 at 21:05

Quote:
Originally posted by Vdara
Propose a Grignard synthesis


What does that have to do with Et2NH? Nothing???

ScienceSquirrel - 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...

mbrown3391 - 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

mbrown3391 - 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?

Klute - 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]

ScienceSquirrel - 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.

mbrown3391 - 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.

ScienceSquirrel - 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.

Klute - 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]

ScienceSquirrel - 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]

Klute - 1-9-2008 at 08:07

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

ScienceSquirrel - 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.

mbrown3391 - 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.

ScienceSquirrel - 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?

mbrown3391 - 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

ScienceSquirrel - 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]

S.C. Wack - 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]

Attachment: jcs_113_899_1918.pdf (253kB)
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panziandi - 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.

ScienceSquirrel - 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.

panziandi - 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?!

ScienceSquirrel - 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]

mbrown3391 - 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.

zed - 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]

Klute - 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 ºCafter 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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