Acetone and NaOH

[Loveall]

Acetone separates well from concentrated NaOH/water (as Benz has noted before). Perhaps we can use this for a practical cacti extraction:

- Digest cacti power in small amount of concentrated NaOH water to make a drytek paste. Maybe add a salt to avoid high concentrated NaOH but still have good acetone/water separation (see attached paper for candidates to aid in acetone separation)
- Pull paste with acetone
- Dry acetone over MgSO4
- Titrate acetone

If it works, the tirated acetone could reused in principle. Unless someone sees an apriori issue (or has already tried it and found it does not work) I'll give it a shot.

 

[downwardsfromzero]

Mixing NaOH and CaCl2 produces poorly soluble Ca(OH)2, which as Matkovich and Christian observed:

Any precipitate occurring during an extraction procedure would have
a probability of coprecipitating test elements and therefore render the extraction process quantitatively useless.

MgCl2 would not substitute as Mg(OH)2 is even less soluble. I sometimes also wonder to what degree primary amines (such as mescaline) form stable coordination complexes with alkaline earth cations - this is an effect which prevents the use of calcium chloride for drying ammonia gas, for example.

All the rest of your plan seems to me to be worth a try.

It seems worth reproducing from the paper the salts which did not work at all (i.e. no phase separation):

Al(OH)3, AlBr3, Al(C2H3O2)3 Al2(SO4)3,
Ba(OH)2, BaF2, BaCl2, BaI2, Ba(ClO4)2,
Ca(OH)2, CaF2, CaBr2, Ca(NO3)2, CaCO3, CaSO4, Ca(C2H3O2)2,
CuSO4,
KC1, KBr, KI, KNO3, K2SO4,
LiOH, LiF, LiC1, LiBr, LiI, Li2SO4,
Mg(OH)2, MgBr2, MgI2, MgSO4, Mg(ClO4)2, MgH(citrate),
Mn(OH)2,
NaF, NaI, Na2SO4, Na2HPO4, NaNO3,
NH3, NH4Br, NH4I, NH4N03,
Sr(OH)z, SrBr2, SrI2, Sr(C2H3O2)2,
Zn(OH)2, ZnC12, ZnBr2, and ZnI2.
Partial precipitation occurred with 20 of these agents.

Looking at the next list:

Those compounds that caused phase separation accompa-
nied by partial precipitation of the salting-out agent in
the aqueous phase. These compounds include the fol-
lowing with the volume per cent acetone phase recovery in
parentheses: NaCl (76.4), NaBr (21.6), NaC2H3O2 (86.0),
Na2CO3 (131.6), NaH2PO4 (110.4), NaK(tartrate) (126.0),
NH4Cl (48.0), (NH4)2SO4 (117.6), and SnCl2 (73.3)

check the respective figures for sodium acetate and sodium tartrate - we might be lucky and see phase separation with sodium malate (which is kind of half way between acetate and tartrate). This would be very convenient for cactus extractions. So, one further variation to try out

 

[Loveall]

Thanks DWFZ. Good points about Ca and Mg salts, they won't do well in alkaline environment.

I think NaCl may be interesting to help separate the acetone. Some acetone may remain in the water, but the acetone layer is pretty pure (<2% water according to table II). Sugar could be interesting to help further (cacti, table salt, and sugar seems like we are cooking food ).

I may go for it with something like 20% NaOH, NaCl salt saturation, and on top of that sugar until acetone can be poured off (in practice sugar could also help control how runny the water layer is). This assumes no reaction between sugar and 20% NaOH. The way the paper explains it, the sugar and salt mechanism for separating acetone may be different, I hope that also means complementary. I searched for sucrose/salt/NaOH/acetone/water type of systems combined but no luck so far. Apparently papers that talk about using sugar call it "sugaring out". LoL.

 

[downwardsfromzero]

Attached, a review article which should be of some use - I get the feeling you may have seen this one already, Loveall! - plus an old article for background.

 

[Loveall]

Thanks DWFZ.

Thinking more about this, I'm a little worried about aldol condensation of acetone because of the NaOH.

NaCO3 was mentioned as separating water and acetone in the paper (but not as good as NaOH). I think I'll try this by making a basic cacti paste of sodium carbonate. Then add NaCl, or alternatively may test sugar as a helper since it avoids the common Na+ ion. Pull with acetone and dry over MgSO4. Then see if anything tirates out easily as a mescaline salt from the acetone.