Diethylamine from Deet

These are actually helpful links. Reading through these threads (not all of which came up when I searched on this topic previously), it looks as though madscientist proposed using similar reaction conditions, which were eventually tried by ScienceSquirrel, who also tried using ethylene glycol as the solvent. The conclusion was that detectable amounts of amine were formed in an hour but that long reflux times were necessary to achieve good yields.

S.C. Wack mentioned an experiment under more dilute conditions using ethylene glycol as the solvent, resulting in a measurable amount of the product: http://www.sciencemadness.org/talk/viewthread.php?tid=11081&...

There are some other reports that suggest carrying out the reaction in a sealed media bottle in a water bath or in sulfuric acid, but S.C. Wack's appears to be the most credible.

Assuming that the hydrolysis is not reversible (I don't think it is), it looks like it would take 12-13 hours for the reaction to go 90% to completion. 24 hours should be plenty.

Since the product is volatile, it's probably a good idea to run the reflux condenser output through a dilute acid (with an appropriate suckback trap) if running a long reflux.

I'm thinking about giving this a try, but if I do, what should I do with the DEA afterwards?

I'm pretty sure there will be some water in the KOH, which I think should be present in excess. I don't see why water would be necessary in more than catalytic amounts if doing a base hydrolysis with a hydroxide, but I'm certainly not about to call you crazy.

I was thinking about catching the DEA with hydriodic acid just because it would be hilarious to have a bottle labeled DEA HI But HCl is certainly more practical, and I don't have any hydriodic acid, of course (though it does look easy to make). I remember seeing some practical reason for making DEA oxylate....

Quote: Originally posted by S.C. Wack

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. [Edited on 2-9-2008 by S.C. Wack]

Quote: Originally posted by Tsjerk

Hydroxide reacts one on one with DEET, and if you would do 45/45/10 you wouldn't have enough, no matter if there is water in the KOH or not. Edit: I like HI*DEA haha [Edited on 23-2-2017 by Tsjerk]

Quote: Originally posted by Tsjerk

btw: I don't think your glassware is going to like KOH in ethylene glycol at its boiling point, I guess a water at 90 degrees should be enough for this reaction.

It looks like I'll just need a cheap Erlenmeyer, a rubber stopper with a hole in it, and an oil bath with a candy thermometer. I can run any gaseous products through gas washing bottles filled with dilute HCl or a distillation apparatus. I only have Dreschel bottles, but I sure wish I had some of these!

Quote: Originally posted by Tsjerk

The boiling point of diethylamine is around 55 degrees Celsius, so it should also condense while bubbling through the acid, I think the absorption will be OK.