Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: yusubeen on April 06, 2017, 02:57:47 AM
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hi guys.
i have a question.
i'm separated my compound at silica culum. that eluent is Hexane : Ethyl acetate = 4 : 1.
i separated just one spot, and then evaporated using rotary evaporater
in other reference my compound is white solid, but in my case sticky oil.
my compound is non-polar, and my compound is not soluble in diethyl ether, dichloromethane, ethyl acetate.
when i was soluble in that solvents, there is a little powder at the bottom of round flask.
but evaporating again my compound is sticky oil.
and i vacuumed 1 day and checked NMR. that NMR is not clear. hexane, water is remain.
how to remove the hexane that case?
how to solidify the compound?
if you know please talk to me.
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It could be an an oil because of the water. Redissolve it in a low boiling organic solvent, then dry using magnesium sulfate or sodium sulfate. Rotovap it down and use high vacuum to ensure all organic solvent is gone. Hexane should be easily removed by the vacuum. If your NMR still shows water, its possible your NMR solvent is wet.
Another option is to try to vitrify it with an anti-solvent. Basically just pour on something it has poor solubility in, and see if it causes it to solidify. If it does, then just filter and dry. Ether is the go to choice for this technique, but perhaps methanol or ethanol will work too.
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if your compound is air stable you should try pressurized air to displace all the remaining hex.
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Try to triturate small amount of oil in an ignition using about double quantities diethyl ether or petroleum ether or methanol.