To extract caffeine from coffee, I tried reacting it with baking soda to make tannins more soluble. I then put in salt to push caffeine out of solution. I saturated it with salt and then mixed the solids with acetone to get the caffeine out. There is also some salt in the acetone. Washes with water should remove the salt and tannin salts leaving behind the caffeine(not pure). Would this procedure work? Is there another procedure that would be more efficient and not require DCM.
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2$\begingroup$ What is the question? The text says nothing about DCM and doesn't actually ask a question. $\endgroup$– bonCommented May 24, 2016 at 13:56
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1$\begingroup$ There is a lot of stuff in coffee. If you try to selectively wash away the non-caffeine stuff you will probably fail. You would do better to try extracting it into a non-water-soluble solvent (DCM might work). $\endgroup$– matt_blackCommented May 24, 2016 at 14:57
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$\begingroup$ Thank you. Are there any household solvents that are not soluble in water $\endgroup$– Arvin KushwahaCommented May 24, 2016 at 15:04
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1$\begingroup$ In the organic practical we used black tea: less contamination and higher caffeine content. It is a nightmare though. I think it was about 10 gram tea for 100 milligram caffeine. $\endgroup$– Martin - マーチン ♦Commented May 24, 2016 at 15:19
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1$\begingroup$ Supercritical CO2 is used but I doubt you find it in house :) $\endgroup$– MithoronCommented May 24, 2016 at 20:24
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2 Answers
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The popular procedure to experimentally isolate caffeine is sublimation.
Slowly heat a teaspoon of coffee or tea from 150°C to 250°C. Let the sublimated caffeine precipitate at a watch glass cooled with ice. The resublimated caffeine forms white needles that can be identified under a microscope.
The sublimation temperature of caffeine is 178°C.
answered May 24, 2016 at 15:26
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$\begingroup$ Sorry, are we talking liquid coffee here? How exactly are you heating it to 250C? $\endgroup$ Commented May 24, 2016 at 16:18
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$\begingroup$ Solid coffee, preferably powder. $\endgroup$ Commented May 24, 2016 at 16:40
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I did this in a practical lesson in chemistry. We filtered the coffee (1.2um filter paper), concentrated it 10x using distillation and then extracted the caffeine into an equal volume of chloroform in a separatory funnel. After evaporating the solvent, we were left with fairly white powder. It was probably impure, containing lots of other alkaloids.
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$\begingroup$ Do you think i could use isopropyl alcohol instead of chloroform $\endgroup$ Commented Oct 14, 2017 at 0:02
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$\begingroup$ Not really. Although the caffeine would dissolve in it ok, you would have the problem that it would also mix well with the water, so the separatory funnel would not work. The whole idea of using one is to get two separate layers, so that you can drain off and discard the water layer, leaving the stuff you want in the chloroform. Hexane is an alternative, though. $\endgroup$ Commented Oct 16, 2017 at 14:49
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$\begingroup$ Oh :( I was looking for a home-and-teenager-friendly alternative. $\endgroup$ Commented Oct 26, 2017 at 2:04