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DraconicAcid
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What does it decompose to in basic solution?
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Boffis
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Oh dear.....!
When you guys have have stopped slagging each other off can we get back to my original question? Irrespective of whether curcumin (di-ferulylmethane
where ferulyl = 3-(3-methoxy-4-hydroxyphenyl)-2-propenoyl unit) is a potential drug of abuse or effective pharmaceutical my question was whether
anyone had ever obtained it in a crystalline form. I have extracted some from 100g of turmeric and now have about 4.5g of crude orangy yellow powder
and would like to try recrystallising it. Any useful comments?
@DraconicAcid, since curcumin is a 1,3-diketone I suspect that under basic conditions the carbonyl groups on one molecule will condense with the
active methylene group on another and very soon will result in polymerised crap  .
Another possibility would appear to be a reverse Aldol resulting in vanillin and a ketonic residue.
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zed
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Yielding Vanillin might require Ozoneolysis.
Reverse Aldol, I think not. But it is and interesting idea.
Polymerization seems likely.
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TriiodideFrog
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Ethanol works well. Isopropanol also works, but I prefer ethanol.
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DraconicAcid
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I wonder if it would make acac-like complexes with transition metals.
I really should google instead of idly wondering: https://pubs.rsc.org/en/content/articlehtml/2015/cs/c5cs0008...
[Edited on 27-11-2020 by DraconicAcid]
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Boffis
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@DraconicAcid, That is an interesting find! Looks like further purification of my curcumin will be worth while after all. I like the sound of the
ligands derived from oxime, semicarbazones etc.
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Metacelsus
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I'm not sure because the paper didn't say, but I'd guess that when it's deprotonated, it's easily oxidized by atmospheric oxygen (like most other
electron-rich phenols). The enolate (easily formed from the 1,3-diketone moiety) might also react with things.
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Boffis
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I tried to recrystallise my de-oiled from methanol. I dissolved 0.5g in increasing amounts of boiling methanol, I eventually ended up with 25ml of
solution but it was still hazy so I added a pinch of charcoal and kieselguhr and filtered it hot. Very little crystallised on cooling the deep yellow
solution so I left it to evaporate. At first dark orange pompoms and blades formed with a few coarse golden yellow blades. However, by the time the
methanol had almost evaporated the dark orange crystals were by far the more abundant, I presume these to be the curcumin. Methanol is not a good
solvent for the recrystallisation of curcumin though, its solubility is too low and the temp/solubility curve too flat.
Anyone have any ideas for a better solvent?
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pneumatician
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tested cucurmin powder if contain lead cromate???
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karlos³
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You mean, how to test for lead chromate in turmeric?
Thats seems pretty simple, click that link: test for lead chromate in turmeric
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pneumatician
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wow, I are saying if the guy make this test!
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