Diethyl Ether Re-x?

[Complexity]

So, I used all my petroleum ether to do my last extraction, but I still have about 1L of diethyl ether.

Could I use it to recrystallize? I've read about diethyl ether + heptane, but don't know about just ether.

 

[downwardsfromzero]

If you're having to ask this question, you very probably shouldn't be using diethyl ether.

It's several orders of magnitude more dangerous than naphtha, being highly volatile, extremely flammable and a narcotic anaesthetic - and it forms explosive peroxides to boot. Thus here at the Nexus, use of Et2O is generally highly discouraged.

Recrystallisation in heptane or petroleum ether relies on the temperature/solubility gradient for its efficacy. This won't work in the same way with Et2O.

So, unless you have the facilities, skills and experience to handle ether safely, I strongly suggest you wait until you've got a safer solvent for your recrystallisation - which will probably work better in any case.

 

[Complexity]

If you're having to ask this question, you very probably shouldn't be using diethyl ether.

It's several orders of magnitude more dangerous than naphtha, being highly volatile, extremely flammable and a narcotic anaesthetic - and it forms explosive peroxides to boot. Thus here at the Nexus, use of Et2O is generally highly discouraged.

Recrystallisation in heptane or petroleum ether relies on the temperature/solubility gradient for its efficacy. This won't work in the same way with Et2O.

So, unless you have the facilities, skills and experience to handle ether safely, I strongly suggest you wait until you've got a safer solvent for your recrystallisation - which will probably work better in any case.

Thanks for the answer.
I know about the dangers and properties of ether, certainly I wouldn't have used in next to an open flame.

By the way, just to try to understand the theory well, the main problem is that DMT won't easily freeze precipitate since it's too much soluble in ether?

 

[Ulim]

By the way, just to try to understand the theory well, the main problem is that DMT won't easily freeze precipitate since it's too much soluble in ether?

That and because the solubility curve. See in this example for example if you have a saturated 100c solution of KNO3 you can crash out nearly 80% of it if you cool the solution down.

But for NaCl this doesnt really work much because you only have so little most of it stays in solution.

The same should apply here. The solubiliy curve for DMT in naptha rapidly drops when its below 0°c and thus most DMT drops out. Thats also the reason you can heat naptha pulls to increase yield but the other way around. The DMT in naptha acts like the KNO3

For other solvents where freeze percip doesnt work the curve just simply doesnt fall hard enough. The DMT is like NaCl then.

 

[downwardsfromzero]

I know about the dangers and properties of ether, certainly I wouldn't have used in next to an open flame.

Remember, it's not just open flames we're talking about, e.g. here:

C-1.6 Sparks

You should eliminate the possibility of sparks of all kinds in the work area. Electric sparks may come from switches. relay contacts, or thermostatic devices; the latter are found in heaters, hot plates, and refrigerators. For this reason these devices, whenever possible, should be sealed so that solvent vapors cannot get in or sparks or flame get out; refrigerators used in the laboratory should be of the "explosion‑proof' type, with switches and thermostat contacts sealed or mounted outside the box. Electric sparks from electric motors can be avoided by employing induction motors for stirrers and pumps instead of series‑wound and other brush‑containing motors. Electric sparks can also arise from the buildup of "static electricity", especially in the dry indoor conditions during the winter. Avoid excessive wiping or swirling of flasks or bottles containing solvents before pouring; when dealing with more than about a liter of Class I solvents in metallic systems, ground the apparatus and the container. Sparks can arise also from metal striking metal or concrete, and, since solvent vapors are denser than air, a fire could be produced from a metal object falling onto a concrete floor or even shoe nails scraping on the concrete. This fact should be remembered if there is any spillage of solvents.

And there is, of course, the question of autoignition temperature:

In the absence of a flame, a spark or an incandescent electric heating element, the auto‑ignition temperature is ordinarily of serious concern only with a few substances. Carbon disulfide has an auto‑ignition temperature of about 100°C and the vapors can be ignited by contact with an ordinary low‑pressure steam line; the auto‑ignition temperature for diethyl ether is 180[160]°C, low enough so that use of an electric hot plate has caused ignition. A McMaster chemistry graduate student was seriously injured when ether was ignited by a hot plate. Such liquids should be heated with a water bath or a steam bath in a hood so that vapour from the boiling liquid does not accumulate.

The autoignition temperature for lower saturated hydrocarbons is somewhat more forgiving. Just to be absolutely clear.

Finally, let's not forget Diethyl ether peroxide, the main reason why this and a number of other ether solvents are avoided in industry.

 

[Complexity]

Well, I didn't know all this.

Thank you both.