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Author: Subject: Diethylamine Synthesis
mbrown3391
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[*] posted on 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.
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panziandi
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[*] posted on 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!



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mbrown3391
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[*] posted on 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?
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[*] posted on 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.
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panziandi
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[*] posted on 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?!




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panziandi
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[*] posted on 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.



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mbrown3391
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[*] posted on 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]
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[*] posted on 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.
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[*] posted on 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.



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[*] posted on 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
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[*] posted on 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.
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[*] posted on 30-8-2008 at 18:44


So going back to your experimental, DEET does form a separate layer when mixed with water, right?
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[*] posted on 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.
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[*] posted on 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.
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[*] posted on 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!
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[*] posted on 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]
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[*] posted on 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...



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[*] posted on 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
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[*] posted on 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.
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[*] posted on 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?




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[*] posted on 31-8-2008 at 07:56


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




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[*] posted on 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'.
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