Author Topic: Absorbants for purification?  (Read 627 times)

0 Members and 1 Guest are viewing this topic.

spectralshift

  • Guest
Absorbants for purification?
« on: December 09, 2003, 05:01:00 AM »
What would you use to remove a 20% impurity of MEK, and a 10% impurity of butanol impurity from toluene?

Is it even do-able by drying agent's, dessicant's and absorbants?

MEK holds a lot of water...a lot. (Constant boiling mixture with water, bp 73.4degrees , contains 88.7% methyl ethyl ketone.)

Rhodium

  • Guest
toluene cleanup
« Reply #1 on: December 09, 2003, 06:09:00 AM »
Washing the toluene with loads of bisulfite solution could remove the MEK.

Are the boiling points too close for separation by distillation?

Antibody2

  • Guest
and washing with water should take care of the
« Reply #2 on: December 09, 2003, 02:47:00 PM »
and washing with water should take care of the butenol. But not salt saturated so it would need to be a separate wash from the bisulfite wash

Rhodium - i think n-butyl alcohol has a high bp around 104C (if memory serves), toluene is 110C


spectralshift

  • Guest
wow!
« Reply #3 on: December 10, 2003, 01:27:00 AM »
I don't have bisulfite, how would that work to remove the MEK? If you think it'd bee really beneficial, it'll appear.

No it really looks like they've designed the mixture to be difficult to separate using distillation.

and washing with water should take care of the butenol.

Like it a lot. That should hopefully remove a lot of MEK aswell.

The MEK's solubility in water decreases as the temperature is raised so I'm just thinking I can bring the toluene mix down to 5 degrees, then do a warm water wash to leech the last of the MEK out of the cold toluene, and in to the fresh warm water.

r.t water washes till satisfied, warm water wash of cold mixture, then a brine wash.
How does that sound?

Title: n - Butyl Alcohol.
CAS Registry number: [71-36-3]
CAS name(s): 1-Butanol, butyl alcohol;

Additional name(s): propyl Molecular formula: C 4 H 10 O Molecular weight: Percent Composition: C 64.82%, H 13.60%, O Line Formula: CH 3 CH 2 CH 2 CH 2 O

Properties:  Highly refractive liquid; burns with a strongly luminous flame; leaves a transitory greasy spot on paper. Odor simi lar to that of fusel oil, but weaker. d 4 20 0.810 . bp 117-118degrees . mp minus90degrees . Flash pt 36-38degrees. n D 20 1.3993 . A mixture of 63% of the alcohol and 37% water forms a constant boiling mixture, boiling at 92degrees. Soly at 25degrees, 9.1 ml/100 ml H 2 O: Booth, Everson, Ind. Eng. Chem. 40, 1491 (1948). Miscible with alc, ether and many other organic solvents. LD 50 orally in rats: 4.36 g/kg (Smyth)



MEK/Methyl Ethyl Ketone

Properties:  Flammable liquid; acetone-like odor. d 4 20 0.805 . mp minus86degrees . bp 79.6degrees . Flash pt, closed cup: 21degreesF (minus6degreesC). n D 15 1.3814 . Sol in approximately4 parts water (27.5%); less sol at higher temp; miscible with alcohol, ether, benzene. Constant boiling mixture with water, bp 73.4degrees , contains 88.7% methyl ethyl ketone. Soly of water in methyl ethyl ketone: 12.5% at 25degrees. LD 50 orally in rats: 6.86 ml/kg (Smyth) .

Antibody2

  • Guest
sodium bisulfite is available at wine making...
« Reply #4 on: December 10, 2003, 08:33:00 AM »
sodium bisulfite is available at wine making stores (for bottle washing). It will form a bisulfite adduct with most(maybe all) ketones, which precipitates as a solid which can be filtered off.

there are several write-ups for the proceddure on the board if you do a search.

i'm not sure if water washs will cut it for the MEK as you will likely still end up with some in your toluene as i xpect the MEK is more soluble in toluene than water (Ab2 speculates here)

good luck


roger2003

  • Guest
potassium bisulfite
« Reply #5 on: June 02, 2004, 10:08:00 AM »
The (sodium)bisulfite of commerce consists chiefly of sodium metabisulfite (Na2S2O5) and reacts with H2O at RT:

Na2S2O5 + H2O --> 2 NaHSO3

Will potassium (meta)bisulfite react in the same manner ?