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Author: Subject: another question - ethanol , hot or cold?
mordoh
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[*] posted on 21-6-2004 at 04:16
another question - ethanol , hot or cold?


hey ,

i wanted to know, can i do extraction of plant/herb with 70% ethanol (hot) for 3-4 hours and it will be exactly the same to extraction with cold ethanol for 2 weeks?

if not , whats the diffrence?

thanks
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Blind Angel
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[*] posted on 21-6-2004 at 07:57


hot liquid usually have a greater solving power than cold liquid, thus if your hot ethanol can solve more with less than with cold, but if the amount isn't a problem (like you don,t plan to recrystallize or you have plenty of ethanol) then the short answer is yes.



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Marvin
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[*] posted on 21-6-2004 at 11:20


Heat and light destroy some of the compounds you want in tinctures of plants. If a specific tincture says 2 weeks in the cold, then its best not to make assumptions.
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thunderfvck
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[*] posted on 22-6-2004 at 22:59


Isn't it the case that some compounds are slightly soluble in a certain cold solvent, but soluble when the solvent is hot?

I think it is!

So the cold solvent will only pull out whichever compounds are soluble in the cold solvent (compounds x dissolve in solvent when cold), while the hot solvent will pull out all of compound x plus the stuff that is only slightly soluble in it while cold.

Of course it all depends on what you're trying to isolate.

Hot solvents will generally pull out more than you'd like, probably.

I'd stick with cold though, as Marvin's right about the decompostion.

Just make sure that you powder your plant material very finely. Increased surface area = more places the solvent can access easily, to grab the goods.




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mordoh
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[*] posted on 23-6-2004 at 11:52


thanks guys for the answers...

im extracting catechins and flavonoids from the plants (thats mainly the chemicals i need) , and as i read they dont detroy in hot extraction (catechin need hot water to extract in) ... if anyone knows else, please correct me ...


i have another question (yeah , i know i dont stop asking but i need to know things)

i know that delivery into skin is best achived with spray , better then lotion/cream.. if i take plant tinctures and add to them penetration enhancers (oleic acid , propylene glycol , dmso) and put them on the skin , will it absorb better then take them with the penetration enhancers and combine them with a commercial cream (hand cream , body cream etc) ?

which way is better ?

thanks
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Double Jack
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[*] posted on 3-8-2004 at 23:40


If I were you I would go with the penetration enhancers alone. The commercial cream contains many more functional components like conservants, light stability, odour and your aim is only to have a manner to let the plant tinctures enter the skin.


i know that delivery into skin is best achived with spray , better then lotion/cream.. if i take plant tinctures and add to them penetration enhancers (oleic acid , propylene glycol , dmso) and put them on the skin , will it absorb better then take them with the penetration enhancers and combine them with a commercial cream (hand cream , body cream etc) ?
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Dodoman
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[*] posted on 4-8-2004 at 09:14


Hot ethanol 70% will decolorize green parts of the plant. So what ur gonna get is the product ur extracting plus chlorophyll to the best of my knowledge.
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