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Can anybody please help me find a way to separate caffeine from coffee that uses a solvent other than DCM, ethyl acetate, or diethyl ether?

This an experiment for science class, but I don't have access to any of the above-mentioned solvents.

Can you suggest any alternatives that are easily obtainable?

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closed as off-topic by Mithoron, Todd Minehardt, A.K., user55119, Mathew Mahindaratne Apr 9 at 19:59

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  • $\begingroup$ Supercritical $CO_2$? $\endgroup$ – Buck Thorn Apr 8 at 20:49
  • $\begingroup$ It is kind of silly for us to guess 50 solvents to try and find one that you can use. I suggest you use Google "Extraction of Caffeine" and find a suitable solvent yourself. // I know that you are not going to have the equipment to use supercritical carbon dioxide. $\endgroup$ – MaxW Apr 8 at 20:53
  • $\begingroup$ Can you use Acetone? $\endgroup$ – Waylander Apr 8 at 21:25
  • $\begingroup$ @Waylander thanks for the reply but i don't think it would work all for the fact that acetone is miscable in water this is the same reason i can't use ethanol aswel if it weren't miscable it would work. Thanks for taking the time to reply! I apreciate it. $\endgroup$ – Adam Quayle Apr 8 at 21:59
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    $\begingroup$ It would be better to re-word your question by stating the names of solvents which are available to you. $\endgroup$ – M. Farooq Apr 8 at 23:00
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Following is the list of solvents previously checked for the solubility (From reference 1 below):

$$ \begin{array}{|c|c|c|c|c|c|} \hline \textrm{Solvent} & \textrm{Temperature, } \pu{^{\circ}C} & \textrm{Solubility, } \pu{\%} (w/w) \\ \hline \textrm{Water} & 25 & 2.2 \\ \hline \textrm{water} & 100 & 66.7 \\ \hline \textrm{Ethanol} & 25 & 1.2 \\ \hline \textrm{ Ethanol} & 60 & 4.5 \\ \hline \textrm{Ether} & 25 & 0.3 \\ \hline \textrm{Ethyl Acetete} & 25 & 2.5 \\ \hline \textrm{Chloroform} & 25 & 18.0 \\ \hline \textrm{Acetone} & 25 & 2.0 \\ \hline \textrm{Benzene} & 25 & 1.0 \\ \hline \end{array} $$

My suggestion is to use ethanol in $\pu{60 ^{\circ}C}$. However, I'm not sure how ethanol would behave with the presence of tannins. For example, in a separate literature report, $\pu{1.0 mg}$ of tannin was isolated from a $\pu{g}$ of grape skins using 100% ethanol while the amount was increased to about $\pu{5.5 mg}$ when solvent was switched to 100% acetone (Ref.2).

References:

  1. Q. V. Vuong, P. D. Roach, “Caffeine in Green Tea: Its Removal and Isolation,” Separation & Purification Reviews 2014, 43(2), 155-174 (DOI: 10.1080/15422119.2013.771127).
  2. M. O. Downey, R. L. Hanlin, “Comparison of Ethanol and Acetone Mixtures for Extraction of Condensed Tannin from Grape Skin,” South African Journal for Enology and Viticulture 2010, 31(2), 154–159 (DOI: https://doi.org/10.21548/31-2-1412).
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