Solvent for caffeine extraction [closed]








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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?




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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