| Pages:
1
2 |
Picric-A
National Hazard
Posts: 796
Registered: 1-5-2008
Location: England
Member Is Offline
Mood: Fuming
|
|
quantities used, reaction time, problems encountered, colour changes ect!
|
|
|
panziandi
Hazard to Others
Posts: 490
Registered: 3-10-2006
Location: UK
Member Is Offline
Mood: Bored
|
|
I agree, molar quantities used, method chosen, yield obtained ought to be enough, just to provide some experimental clarity to the extensively waffley
and hard to follow crap thats come out of the DEA thread to date.
|
|
|
entropy51
Gone, but not forgotten
Posts: 1612
Registered: 30-5-2009
Member Is Offline
Mood: Fissile
|
|
Please check out the thread on hydrolysis of DEET and you will see that the devil is in the details.
That's the reason that papers in chemical journals normally include a section entitled "experimental" in which the details are explicitly described.
"It is a hydrolysis!" is analagous to "He was a man!" in reply to the policeman who asked you who shot you in the arm. Such a reply doesn't convey
much information that is helpful.
|
|
|
sonogashira
National Hazard
Posts: 555
Registered: 10-9-2006
Member Is Offline
Mood: No Mood
|
|
Thank you for you nice analogy and (ironic?) response - you begin to remind me of someone who left not so long ago (perhaps before your time?)
Please tell me what the devil in the details is. Heating for extended periods with excess 20% NaOH/ethylene glycol - as described in nearly every
organic chemistry book - does not work? I would be surprised.
I can see no devil in the details - just poor experiments and impatient experimenters.
|
|
|
entropy51
Gone, but not forgotten
Posts: 1612
Registered: 30-5-2009
Member Is Offline
Mood: Fissile
|
|
Well, exactly. Now someone hints at having done a GOOD experiment so some of us would like to know how it was done. That's sort of why we're here on
the forum.
It would just be nice to have a happy ending to a long and confused thread.
You say NaOH/ethylene glycol and that sounds reasonable. But AgentMadHatter may have found a better way. Perhaps a better solvent? Sometimes KOH is
better than NaOH. How long is "extended periods"? How did he purify the product? What was the yield? Who can say?
|
|
|
Agent MadHatter
Harmless
Posts: 45
Registered: 22-7-2009
Member Is Offline
Mood: No Mood
|
|
Ok. After thinking the thread was done by confirming all I needed was an amber bottle with a proper seal...I didn't look back until today. If you guys
honestly don't believe this was my procedure.
I got a lot of bottles of 30ml of 98% DEET and 2% other (Suspected Alcohol since it allowed water and the DEET to mix)
I threw in 500mls of the DEET with Dilute Sulfuric acid at a 28% concentration. Once the PH was at 3, I refluxed for 8 hours at 70C, using water to
prevent any evaporation.
After adding distilled water and seeing that it did not form two layers, I knew the hydrolysis was complete. At which Point I added KOH until the
mixture was at 7 pH.
Distilled off the DEA through my condenser into a cooled container of HXl in EtOH. Forming DEA.HCl.
I have the liquid sitting in an amber glass. Trying to figure out if letting it evaporate under a vacuum will cause any DEA vapors or anything.
That was my procedure.
|
|
|
entropy51
Gone, but not forgotten
Posts: 1612
Registered: 30-5-2009
Member Is Offline
Mood: Fissile
|
|
Fantastic! So it was an acid hydrolysis rather than base. Good to know. So by distilling into HCl/EtOH you didn't get any crystals of the HCl salt?
I'm still not sure what you meant by this: Because the BP of Et2NH is 55.5 C, I don't know what you mean by "disappear into the air".
Did you recover the m-toluic acid product? Did you calculate a percent yield? BP during distillation?
Good job.
[Edited on 17-9-2009 by entropy51]
|
|
|
Agent MadHatter
Harmless
Posts: 45
Registered: 22-7-2009
Member Is Offline
Mood: No Mood
|
|
Like I said...I'm not chemistry major. If I get product, thats good enough for me. I don't know how to calculate percent yield compared to theoretical
yield, I do know the BP was around 60 C but not over it. 55-60C.
But whats the best way to get the DEA HCl crystals out of the ethanol now? Just evaporation? Or will the DEA evaporate?
|
|
|
Picric-A
National Hazard
Posts: 796
Registered: 1-5-2008
Location: England
Member Is Offline
Mood: Fuming
|
|
Is it DEA or DEA.HCl????
If it is the latter then no it will not evaporate, you can gently remove the ethanol by heating on a steam bath.
If it is the former i would convert it to its HCl salt then do as above.
|
|
|
entropy51
Gone, but not forgotten
Posts: 1612
Registered: 30-5-2009
Member Is Offline
Mood: Fissile
|
|
Quote: Originally posted by Agent MadHatter  | Like I said...I'm not chemistry major. If I get product, thats good enough for me. I don't know how to calculate percent yield compared to theoretical
yield, I do know the BP was around 60 C but not over it. 55-60C.
But whats the best way to get the DEA HCl crystals out of the ethanol now? Just evaporation? Or will the DEA evaporate? |
Chem major or not you should keep a notebook recording what you did and what you observed. Then when you need to ask a question you could give us
some background information.
Do you have crystals? The amine HCl is soluble in both EtOH and H2O.
But the amine HCl is not volatile, so you may be able to evaporate off the solvents and get crystals. The way this is usually done is to add the amine
to Et2O saturated with HCl gas, forming nice crystals that can be filtered off.
And you still haven't clarified your statement that you watched the product evaporate into the air when you "removed the acid". I'm starting to
wonder if you have any product at all.
|
|
|
panziandi
Hazard to Others
Posts: 490
Registered: 3-10-2006
Location: UK
Member Is Offline
Mood: Bored
|
|
Personally, Agent MadHatter, I would have made the reaction mixture far more basic than pH7! I would have added KOH until I got pH10 or something,
using saturated aqueous KOH. Then Distilled the liquid collecting anything coming over below 60, collected using ice-cold water in the condenser and
submerging the flask in salt/ice bath. then I would have dried the liquid of solid KOH (atleast a few hours! Perferably a day) and then redistilled
it. I wouldn't bother with the HCl salt as it is too hygroscopic! If you REALLY want the salt, I would distill the dried amine into ether saturated
with HCl (or ether solution of amine treate dwith HCl). Alcohol contains too much water to get nice crystals.
|
|
|
UnintentionalChaos
International Hazard
Posts: 1454
Registered: 9-12-2006
Location: Mars
Member Is Offline
Mood: Nucleophilic
|
|
| Quote: Originally posted by Agent MadHatter | Ok. After thinking the thread was done by confirming all I needed was an amber bottle with a proper seal...I didn't look back until today. If you guys
honestly don't believe this was my procedure.
I got a lot of bottles of 30ml of 98% DEET and 2% other (Suspected Alcohol since it allowed water and the DEET to mix)
I threw in 500mls of the DEET with Dilute Sulfuric acid at a 28% concentration. Once the PH was at 3, I refluxed for 8 hours at 70C, using water to
prevent any evaporation.
After adding distilled water and seeing that it did not form two layers, I knew the hydrolysis was complete. At which Point I added KOH until the
mixture was at 7 pH.
Distilled off the DEA through my condenser into a cooled container of HXl in EtOH. Forming DEA.HCl.
I have the liquid sitting in an amber glass. Trying to figure out if letting it evaporate under a vacuum will cause any DEA vapors or anything.
That was my procedure.
|
The 2% are other isomers of DEET (Probably with ortho and para methyl groups instead, or with only one ethyl group present)
The reason for this is simply that it's not worth industry's time or money to refine their starting materials to ultra-high purity unless the
contamination is a hazard instead of just being inert. If N,N-diethyl-o-methylbenzamide is harmless, boils within a half degree of the desired DEET,
and the average consumer won't know or care if the product is 98% or "100%"(nothing is ever 100%) DEET, then why throw away 2% of profit, plus spend
money fractionating the two compounds better? Perhaps people would care if it was around 95% but I tend to think that the average shopper rounds 98%
up to 100% in their head.
It's simple economics.
[Edited on 9-21-09 by UnintentionalChaos]
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
|
|
|
Ephoton
Hazard to Others
Posts: 463
Registered: 21-7-2005
Member Is Offline
Mood: trying to figure out why I need a dark room retreat when I live in a forest of wattle.
|
|
who cares how he made it or even if he did. it was a simple question how too store it.
simple amines dont react with them selves and dont oxidise over time. they do absorbe water though. dark bottle simple
nearly getting laid as a post whore.
e3500 console login: root
bash-2.05#
|
|
|
| Pages:
1
2 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
