[AoisPokemaster]

Hey guys, I am the idiot who was researching curcumin extracted from turmeric powder a while back, I hope you guys remember me T^T thanks to all of you I have reached the final stages of my investigation. I am troubled by one thing right now...Why is curcumin insoluble in hexane, one of the most non-polar solvents, and ALSO in water. Additionally, can anyone find literature on the EXACT value of the solubilites of curcumin in a many different organic solvents? It is really hard to find as I don't think there are anyone who has done studies on it before, thank you everyone here in advance! T^T

[MOTOBALL]

Like you , I cannot find exact solubilities in different solvents.

However, curcumin is listed as soluble in methanol, ethanol, glacial acetic acid.

Looking at the structure of curcumin, I wonder if toluene, one of the xylenes, or ethylbenzene may be suitable.

[Meter]

Solubility doesn't work like that. It might very well be soluble in solvents that fall in between water and hexane (in terms of polarity).

[rolnor]

If you scroll down on this page you have some data, curcumin is not very soluble:
https://www.scbt.com/p/curcumin-458-37-7

Its probably a lot different in alkaline water, it should be very soluble in 0.1M NaOH.

[Babcock_Hall]

@OP,
Why would solubility of curcumin be dependent upon pH?  Also, there is acetone to consider as a possible solvent.  What are its properties?

[MOTOBALL]

The solvent to use depends somewhat on the proposed use of the solution.

Some higher boiling solvents, NOT really suitable for chromatography, to try would be

DMSO (dimethyl sulfoxide)
N,N-DMF (N, N-dimethylformamide)
HMPA (hexa-methyl-phosporic triamide)
Pyridine.

Maybe even glycerol or hydroxymethyl-benzene.

[rolnor]

Solubility in DMSO is in my last post if you scroll down. HMPA is carcinogenic so its in most labbs forbidden to use, at least here in Sweden.

[jeffmoonchop]

I just asked a friend who did their PhD in curcumin. Said acetone is best, about 50mg/ml, then ethanol and method about 10mg/ml depending on the purity of curcumin.