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Author: Subject: Diethylamine Synthesis
ScienceSquirrel
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[*] posted on 28-8-2008 at 07:36


Quote:
Originally posted by mbrown3391
Sorry, i was thinking of the amine. so does the ethylene glycol raise the boiling point of the diethylamine?


No.

It is just a higher boiling solvent to carry out the hydrolysis in.
The higher the temperature the quicker the reaction.
Watch out for the hot potassium hydroxide in ethylene glycol and water though. It will strip skin like hot water will remove wallpaper.
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[*] posted on 28-8-2008 at 07:37


Quote:
Originally posted by ScienceSquirrel
If you want to make anhydrous diethylamine ( eg free from water or alcohol ) then you are getting into a whole new ballgame.


Yes. The alkaline hydrolysis would allow you to distill over the amine but it would be wet with water. $17 would get you 5 lbs of anhydrous sodium sulfate on eBay item # 270268727018 .




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[*] posted on 28-8-2008 at 07:39


Quote:
Originally posted by mbrown3391
Sorry, i was thinking of the amine. so does the ethylene glycol raise the boiling point of the diethylamine?


I think you should consider taking a couple of basic chemistry courses including organic before you injure yourself or others.

Basic rule of thumb for insuring personal safety: "If you don't know what you're doing, don't do it."

[Edited on 28-8-2008 by Ritter]




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[*] posted on 28-8-2008 at 07:41


Quote:
Originally posted by Ritter
Quote:
Originally posted by ScienceSquirrel
If you want to make anhydrous diethylamine ( eg free from water or alcohol ) then you are getting into a whole new ballgame.


Yes. The alkaline hydrolysis would allow you to distill over the amine but it would be wet with water. $17 would get you 5 lbs of anhydrous sodium sulfate on eBay item # 270268727018 .


Sodium sulphate will not dry the amine to any appreciable degree.
The only practical home method is to prepare the hydrochloride and then dry distill from solid potassium hydroxide.
It f**ks up the flask but it works!
Alternatively you can reflux it with loads of calcium hydride but that is like rocking horse sh*t to the average home chemist.

And I would echo Ritter's remark above.
You need a lot of knowledge and experience before you attempt this!


[Edited on 28-8-2008 by ScienceSquirrel]
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[*] posted on 28-8-2008 at 07:46


i read that the amine was water soluble and remembered it as the amide. That doesn't mean i cant carry out a simple distillation at 55 degrees c. The dangers of this distillation aren't more than many other distillations.
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[*] posted on 28-8-2008 at 07:49


Quote:
Originally posted by mbrown3391
i read that the amine was water soluble and remembered it as the amide. That doesn't mean i cant carry out a simple distillation at 55 degrees c. The dangers of this distillation aren't more than many other distillations.


If you ignore the fact that you are distilling from a hot solution of potassium hydroxide in ethylene glycol.
It will remove your skin and give you a deep flesh burn in seconds if you spill it on yourself.
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[*] posted on 28-8-2008 at 07:59


First of all, there is no reason to believe that experience in chemistry is proportional to ability not to spill something on yourself.

Second of all, if used in stoichiometrically correct proportions, will all the KOH not be neutralized by the m-Toluic acid?

[Edited on 28-8-2008 by mbrown3391]
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[*] posted on 28-8-2008 at 08:05


Quote:
Originally posted by mbrown3391
First of all, there is no reason to believe that experience in chemistry is proportional to ability not to spill something on yourself.

Second of all, if used in stoichiometrically correct proportions, will all the KOH not be neutralized by the m-Toluic acid?

[Edited on 28-8-2008 by mbrown3391]


You are going to have to use say two moles of potassium hydroxide for each mole of DEET.
This will ensure complete hydrolysis of the DEET which is your most expensive reagent and it will suppress protonation of the amine making it easier to distill it from the reaction mixture.
The waste caustic component left in the flask should be allowed to cool, treated with acid until neutral and disposed of appropriately.

[Edited on 28-8-2008 by ScienceSquirrel]
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[*] posted on 28-8-2008 at 08:18


Good point. So are there any known, interesting uses of Sodium Phenylacetate, which will be the waste salt i believe.
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[*] posted on 28-8-2008 at 08:24


Quote:
Originally posted by mbrown3391
Good point. So are there any known, interesting uses of Sodium Phenylacetate, which will be the waste salt i believe.


Your waste salt will be potassium 3-methylbenzoate.
If you could get sodium phenylacetate out of potassium hydroxide and DEET you would be a miracle worker and a friend to every drug cook in the world. :D

This is the structure of DEET

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

This is 3-methylbenzoic acid

http://en.wikipedia.org/wiki/M-Toluic_acid

This is phenylacetic acid

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




[Edited on 28-8-2008 by ScienceSquirrel]
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[*] posted on 28-8-2008 at 08:28


1. Prepare a solution of 80g NaOH in 73ml H2O.
2. To this solution, add 192ml of DEET. Two layers will form.
3. While stirring, slowly add propylene glycol to the mixture until homogeneous.
4. Heat to 55 degrees C in a distillation apparatus and maintain this temperature until boiling ceases.
5. Theoretical Yield: 103.39ml Diethylamine

Any problems with this procedure?
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[*] posted on 28-8-2008 at 08:28


Quote:
Originally posted by mbrown3391
First of all, there is no reason to believe that experience in chemistry is proportional to ability not to spill something on yourself.


You bet there is. Even more so for people who cannot discern phenylacetates from benzoates...




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[*] posted on 28-8-2008 at 08:29


Quote:
Originally posted by mbrown3391
i read that the amine was water soluble and remembered it as the amide.


An example of not knowing what you are doing. If you can't visualize the difference between an amide and an amine or between your target product and your starting material you should not be attempting this.

Quote:
That doesn't mean i cant carry out a simple distillation at 55 degrees c. The dangers of this distillation aren't more than many other distillations.


This, of course, depends on your apparatus setup, what kind of glassware you'll be using, what kind of heating you will be using, and most especially your technique. Assuming for the moment that you will not be using a magnetic stirrer, how will you be preventing 'bumping' that could propel hot caustic glycol all over you and your work area?




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[*] posted on 28-8-2008 at 08:29


Quote:
Originally posted by mbrown3391
1. Prepare a solution of 80g NaOH in 73ml H2O.
2. To this solution, add 192ml of DEET. Two layers will form.
3. While stirring, slowly add propylene glycol to the mixture until homogeneous.
4. Heat to 55 degrees C in a distillation apparatus and maintain this temperature until boiling ceases.
5. Theoretical Yield: 103.39ml Diethylamine

Any problems with this procedure?


Where did you get it from?
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[*] posted on 28-8-2008 at 08:32


C12H17NO + H2O --> C4H11N + C7H7COOH
C7H7COOH + NaOH --> NaC8H7O2 + H2O

NaC8H7O2 is Sodium Phenylacetate according to http://www.encyclo.co.uk/define/NaC8H7O2
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[*] posted on 28-8-2008 at 08:32


Quote:
Originally posted by ScienceSquirrel
Quote:
Originally posted by mbrown3391
1. Prepare a solution of 80g NaOH in 73ml H2O.
2. To this solution, add 192ml of DEET. Two layers will form.
3. While stirring, slowly add propylene glycol to the mixture until homogeneous.
4. Heat to 55 degrees C in a distillation apparatus and maintain this temperature until boiling ceases.
5. Theoretical Yield: 103.39ml Diethylamine

Any problems with this procedure?


Sounds like an Internet recipe.



[Edited on 28-8-2008 by Ritter]




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[*] posted on 28-8-2008 at 08:33


i just wrote it based on the discussion in this thread.
Im assuming that NaOH can be used in place of KOH since i already have plenty of NaOH

[Edited on 28-8-2008 by mbrown3391]
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[*] posted on 28-8-2008 at 08:34


Quote:
Originally posted by mbrown3391
C12H17NO + H2O --> C4H11N + C7H7COOH
C7H7COOH + NaOH --> NaC8H7O2 + H2O

NaC8H7O2 is Sodium Phenylacetate according to http://www.encyclo.co.uk/define/NaC8H7O2


What does this have to do with making diethylamine? I think you're lost.




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[*] posted on 28-8-2008 at 08:35


Quote:
Originally posted by mbrown3391
C12H17NO + H2O --> C4H11N + C7H7COOH
C7H7COOH + NaOH --> NaC8H7O2 + H2O

NaC8H7O2 is Sodium Phenylacetate according to http://www.encyclo.co.uk/define/NaC8H7O2


Have a look at my post above!

3-Methylbenzoic acid and phenylacetic acid have the same molecular formulas but different structural formulas.
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[*] posted on 28-8-2008 at 08:37


to be fair, you edited your post after i posted that reply
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[*] posted on 28-8-2008 at 08:38


but thats irrelevant. Can anyone point out any mistakes with the procedure i posted?
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[*] posted on 28-8-2008 at 08:39


Quote:
Originally posted by mbrown3391
to be fair, you edited your post after i posted that reply


I edited the post to include the structures so that it was clearer for you.
The proper chemical names were in there to start with.
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[*] posted on 28-8-2008 at 08:42


Quote:
Originally posted by stoichiometric_steve
Quote:
Originally posted by mbrown3391
First of all, there is no reason to believe that experience in chemistry is proportional to ability not to spill something on yourself.


You bet there is. Even more so for people who cannot discern phenylacetates from benzoates...


Good one!
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[*] posted on 28-8-2008 at 08:47


Quote:
Originally posted by mbrown3391
but thats irrelevant. Can anyone point out any mistakes with the procedure i posted?


Where do I start;

1) Too big a scale, a reaction like this should be executed on a scale of say 10 - 50 millimoles to start with. You do not know how hot it is going to get or how quickly it is going to react.

3) A mixture like that will have to heated above 55 C to get a hydrophilic substance like diethylamine to distill out. I would guess that 80 - 100 C would be reasonable.

2) You have substituted sodium hydroxide for potassium hydroxide. It is a lot less soluble in alcohols, it may not matter but it is still a stupid change.

3) You have switched ethylene glycol for propylene gycol

4) Your product will be a low boiling, corrosive and irritant liquid.The apparatus should have a cooled receiver and a gas take off connected to a pipe that goes outside your workplace.

[Edited on 28-8-2008 by ScienceSquirrel]
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[*] posted on 28-8-2008 at 08:49


1. Prepare a solution of 80g NaOH in 73ml H2O.
2. To this solution, add 192ml of DEET. Two layers will form.
3. While stirring, slowly add ethylene glycol to the mixture until homogeneous.
4. Add a small amount to a distillation apparatus and heat to 55 degrees C. If all goes well, add the rest and maintain 55 degrees C until boiling ceases
5. Theoretical Yield: 103.39ml Diethylamine

[Edited on 28-8-2008 by mbrown3391]
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