Liquid-liquid extraction (or separation)

[ninjamonky7]

dmt omw

[crudeoilsystems]

thanks for the experiment info

[thrasha666]

he talks about common mistakes (not removing the stopper) but then goes and does an even bigger mistake, when your separating liquids, one layer goes out the bottom, then you flip the sf upside down and decant the other layer out the top, this ensures that there will be no contamination of the layer that is removed last

[TheVokality]

@thrasha666 LOL great catch. This guy is a fail

[tartredarrow]

@thrasha666

You usually discard the aqueous layer. So let a bit of orgo layer into the separated aqueous layer then toss that, What you have left is your separated orgo layer. Dry and purify further as needed.

[anastasismusic]

@ Jsoh21 thanks but it's too late :(((( it was a stupid question in one excercise....

[anastasismusic]

how can we find which is the organic phase and which the aqua phase???

[Jsoh21]

@anastasismusic Put some water in it. Whichever layer the water goes into is the aqua layer.

[36thurlow]

@anastasismusic check the density of your solvent, less then 1 and the organic is the top layer, more than 1 and its the bottom

[Psilocybe85]

Send me some ether !!!



[MennoBakkerFB]

thanx i got a B for my seperations test

[81Kush]

thats not a bong!



[shauryaification]

The best thing Ive learned that ether is to be pored out from the top of the separatory funnel........

[Hydroxybenzeen]

Nice demonstration, I love the organic lab :P.

[sistamary2k6]

the magnetic rod shouldn't be placed into the funnel itself, it should be placed on the outside, leading the magnetic stirrer out of the funnel

[pr0gressi0n]

that was a clear story helpfull indeed.

[StopSocialismUSA]

The Upper layer must be poured out the top to ensure less of the (aq) and organic mix.

[Lorentz5]

what are these chem video series called?

[lilpolo20]

Im going to tell yall a trick to determine which layer is which. if you poured your solution in the seprating flask, extracted using ether, got two layer but not sure which is which. pour off the bottom layer in a Er flask and add a portion of ether to it. if you notice two layers then you know that is the aq layer because ether and water dont mix. if you pour in the Er flask and dont notice two layers but just a volume increase then you know that layer is ether.

[lilpolo20]

another thing I noticed he did wrong was he left the glass stopper on top of the separating funnel. you are releasing pressure for a reason. if you still have pressure in the funnel the glass stopper will shoot off the funnel. when you place the separating funnel back on the split ring always remove the stopper ASAP.

[lilpolo20]

ok I saw a mistake in the first 14 sec of this video. He contaminated his solution when he stuck that rob in the solution. you never do things like that. if you want to remove the stir bar. get a plastic filter put plug it up with some glass wool and pour. the stir bar will remain in the filer. or if your not scared just pour slowly into the funnel.

[dougbott]

@lilpolo20 I am sure the rod was cleaned with some DI water or some cleaning agent. Acetone could have been used, but most likely rinsed before with ether as the extraction solution was using ether.

[lilpolo20]

i understand what you are saying but it is just not a good technique to use. Mainly because one of those magnetic bars are used for an entire lab. if you show them this technique, there is bound to be cross contamination everywhere. I just would never do something like that. plus Acetone doesn't really clean anything. A lot of organic materials are soluble in Acetone but the question lies in if you know exactly what that rob has come into contact with. The answer is always no.

[lilpolo20]

truthfully he could have poured the solution containing the bar through that glass funnel. The stir bar is too big to pass through.

[dougbott]

If that was the case about the mag. rod, why are they still made if they are always contaminated, Basically it comes down to Lab cleanliness. I have my own rod I clean myself, and know how and what to use it for. That same argument could be used for the funnel, how sure are you about the cleanliness of the funnel itself? Based on cleanliness, and proper lab procedures.

[lilpolo20]

There are some cases in which using a mag rod is ok but sticking in inside your reaction flask isn't one of them. If you were to do that at my school you would get fused at. if a stir bar is stuck inside solid, like after you do a sucking filtration. then its cool. but sticking it inside of a reaction flask isn't. and futhermore, my school has one mag bar for an entire class, so it is understandable to say sticking a mag rod in your compound is dumb. it leads to cross contamination.

[lilpolo20]

but if that is how you do things then that is how you do things but most people in sophmore chemistry dont take the precaution of cleaning that well. I proctor organic chemistry all the time, and they just aren't at that point yet.

[BonanzAA]

I'll be doing this in lab today!

[Princess101Chik]

Me too, well, ok you did this 2 months ago but still :p. it seems pretty straightforward enough though even though our steps include adding a second extraction stage and other chemicals are going to be used :)

[Chichihualtepec68]

thanks alot very helpful

[kekeid0620]

why did he let the ether run down the funnel? shouldnt the ether-h20 mixed solved extracted out first in a clean flask, and the ether portion poured out of the funnel (where the cork is) so that the two dont get contaminated?

[MattyMatt761]

I agree with you on that. The upper layer should be poured out of the top of the sep funnel.

[apexify]

I agree. He should have removed the organic ether layer from the top of the seperatory funnel in order to prevent any more water from entering the ether ("wetting the ether").

B.S. Chemistry (University of California, Los Angeles) H.M.

[optics011288]

this demo has enlightened me a lot... we are about to extract gibberellic acid from a novel acetic acid bacterium... cant wait for it!!!

[anthonychemistry]

i like that demo...

[tsurara11]

thank you very much for this demo, it was most helpful

[mazzon86]

Thanks heaps!!!!!!!

[Fr33artist]

Very helpful. Thanks alot.