Sciencemadness Discussion Board

Sodium acetate solubility?

AirCowPeaCock - 11-1-2012 at 11:23

According to wiki NaOAc is "soluble in ethanol (5.3 g/100 mL (trihydrate)" I take it that does not apply to the anhydrous form?
What else is it soluble, I have some organic contaminates in my NaOAc from a runaway reaction that happened near by (sorta.) They should be soluble in isopropanol, acetone, or MEK. Thinking I could convert the Trihydrate I have to anhydrous by heating then solvate the impurities in one of the three solvents above--the NaOAc shouldn't solvate in them--right?

entropy51 - 11-1-2012 at 17:19

Dude, if you think like you write, I will send you a prescription for methylphenidate.

If you want to get rid of impurities in NaOAc you can probably just recrystallize it from water. If need be wash the crystals in a little cold solvent, like maybe absolute isopropanol (Iso-Heet from the hardware store).

If you don't have a Merck Index, get one. It often lists the solubilities in common solvents.

Converting the trihydrate to anhydrous is possible, but it takes practice to do it without carbonization. Rumor has it that a microwave works and this is on my list of things to try soon.

AirCowPeaCock - 11-1-2012 at 18:44

Sadly I have one, but its burried in piles and piles of my books, and I havnt seen it for over a year..but I could look again. Recrystalization doesn't really work, because its hard to get it to crystalize without having enough water to....it just turns into one big crystal or no crystals atall. Acetone worked fine, it needs a second rinse, but no problems there. Iso-heet has 1% propitwry additives, any idea what they might be? Its kinda orange, its sopposed to chelan your engine, but I doubt it really does anything, isopropanol wouldnt

entropy51 - 11-1-2012 at 20:34

Quote: Originally posted by AirCowPeaCock  
Recrystalization doesn't really work, because its hard to get it to crystalize without having enough water to....it just turns into one big crystal or no crystals atall.
What you describe must not have been NaOAc. I've recrystallized it at least 50 times without anything like that happening. Use enough water so that it's not a syrup and it will make nice crystals, and get quite hot when it does so.

AirCowPeaCock - 11-1-2012 at 21:02

Hmm.. its definetly NaOAc, maybe I chilled it too much.. doesn't really matter, I've got it reasonably pure now. Maybe the impurities messed up the recrystalization somehow

Arthur Dent - 12-1-2012 at 09:31

@entropy51: Most drugstores carry isopropanol in the regular 70% solution and in the 99% grade, that's my main solvent since it's quite inexpensive ($2.50 for 500ml) and best of all, it has no additives.
Robert

AirCowPeaCock - 12-1-2012 at 19:33

Ive never seen anything over 97% for antiseptic use. But ive got a bottle of 97% now. Could I distil it the same way ethanol is distiled to 99+%?

Bot0nist - 12-1-2012 at 19:53

Quote: Originally posted by AirCowPeaCock  
Ive never seen anything over 97% for antiseptic use. But ive got a bottle of 97% now. Could I distil it the same way ethanol is distiled to 99+%?


Shake with some anhydrous CuSO<sub>4</sub> or MgSO<sub>4</sub> (epsom salt, dehydrate in oven) and decant. Then distill to get near anhydrous IPA. I even like to add a bit more of the anhydrous salt in the boiling flask before final distillation. Some argue that heating a solution with the desiccant in it is not very effective due to the dehydration of the pentahydrate or heptahydrate salt on boiling. I still think it help keep things dry. Remember to cap the receiving flask soon after collection to helps keep it dry from the possibly humid air.

[Edited on 13-1-2012 by Bot0nist]

AirCowPeaCock - 12-1-2012 at 20:16

Thanks Bot0nist! Ill save that and use it next time I need isopropanol!(: