can someone explain how recrystallization works? i'm a bit confused.

[mrh125]

i'm very confused, do you want the product to be soluble with the solvent at higher temperatures and insoluble at low temperatures so you can filter the product's crystals out? or is the reverse (where you filter impurities out?)

what's the basic process of recrystallization? i've drilled myself on this a bunch and have been through o-chem labs over a year ago but didnt think much of it.

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[jcb123]

So if you heat a solution that has things dissolved then slowly cool you can cause recrystallization to occur due to precipitate falling out of solution (this precipitate can be filtered out like u probably did in lab) so the point is to select for a certain product using solubility rules and temperature.

That's all I can remember on the topic but I would also appreciate if anyone has any corrections or anything to add. It's been a while since I took orgo lol

 

[ipmed]

Thats exactly right. The first compounds to recrystallize will be the ones with the smallest Ksp. Recrystallization involves heating a compound to dissolve many solutes, and then lowering the heat to crystallize out the pure compound or impurities depending on which has the lower Ksp, as this will come out first.