You might be able to make purer material with a slightly longer separation workup. Firstly, remember to vent your separation funnel after you shake it to avoid popping the cap off. If you washed your aqueous extract with several small washed of DCM rather than one, you would get a large % of the extractable caffeine out, especially if you chilled the water for the later extracts. Then, combine the DCM layers and wash those with iced water to back-extract any of the water-soluble impurities which disslove slightly in the DCM. I think you would end up with material that was purer with much less loss than your sublimation method. re-crystallisation from boiling water would also be a good purification method because caffeine is much more soluble in hot water than cold.
Dear Ben, you may be able to increase the yield of caffeine extraction by washing the grinds with aqueous HCl - caffeine will likely be protonated and be pulled into the aqueous layer, you can then basify with NaOH and then extract multiple times with DCM. Having a finer grind will also probably increase the amount of caffeine you can extract - a finer grind may allow for better solvation of the coffee and better diffusion of dissolved products.
I just figured you might be a teacher/professor because of your ability to explain something thoroughly without losing your audience. You would do well in a college setting :)
Every time I've done it in lab, it helps clear it up. I do agree though that adding a base will increase yeild, as it will protonate the caffeine, making it hydrophobic.
Ben, you seem to imply that espresso is stronger than drip coffee, but I think that drip is stronger, since, the longer water stays in contact with the coffee, the more caffeine is released. And, of course, in an espresso, as the name implies, the water stays in contact with the coffee for a very, very short time. Anyway, awesome videos! Keep up the great work!
I just did this in my first organic chemistry lab. We brewed tea then used the same liquid-liquid process. It was interesting, very different from the amine based process I used for Ti at my las co-op job.
Nice video, I loved the information. One possible improvement would be to dissolve the caffeine deposited on the test tube in acetone or DCM, and then let it crystallize. You could also add a few mL of water to this before evaporation, so the water left behind could dissolve some of the impurities.
Just a second note, there is a large amount of nasty emulsion formed by the dichloromethane - aqueous agitation. It is better just to swirl it slowly and let the concentration gradient move the caffeine onto the organic. That was probably the source of most of your impurities. It also helps to dry the organic before boiling.
I would suggest, after your first water extraction, adding activated charcol to it (same as what's in a britta water filter), heat to boiling, allow it to cool, then sucking it through a bukner again. This should clear up the solution significantly by adsorbing any very fine particulates, and cut back on the impurities.
nice video! I really like the way you explain and demonstrate all your work! and yes I think we all would like to see you extract methylene chloride from acrylic cement....or the paint stripper if you can..lol
Some handmade equipment :P Great video but I would recommend to use instant coffee. Faster and less messy... results are very similar to these you've achieved. Also the easier way to check caffeine content in caffeinated drinks is to use spectro. Good video anyway!
It makes me thing a bit, when I see the concept of "sous vide" that is controlling the temperature exactly to achieve the desired doneness for food, and it makes me wonder, would a precisely controlled temperature bath help in this situation? I always see chemists measuring the temperature of the distillate stream, but would it not be better to precisely measure the heat input to the system instead?
Try brewing ground coffee with water at room temperature, over a period of 24-48 hours, to increase the caffeine concentration of the original solution. Although I am used to having 2-3 cups of coffee in the morning, the first time I had a cup of cold brewed coffee, I suffered serious palpitation from the caffeine concentration. Cold brewed coffee also tastes insipid. I assume that some of the volatile compounds that gives taste to the coffee also does not get dissolved in the water.
To increase your yield you could add about 5 grams of sodium carbonate or even sodium hydroxide to extract more caffeine into the water. Worked well for me.
A flash chromatography would be the best way to remove those colorful impureties, which are probably of organic nature as well. You will be able to see them in the column. You only need to find a way to identify, which, among the fractions that you will collect, contain your caffeine.
Oddly enough, he actually works for a game-development/game-delivery-platform/other-tidbits-here-and-there company called Valve. If I recall correctly, most of the work he does relates to hardware development, but I don't remember the details.
Hey, the reason why coffee is brown is because of the tannins in the coffee beans. They are acidic but if you add a base it will neutralize the tannins.
Great explanation! Thanks. I knew adding a base helped, but usually the reason given is just "caffeine is more soluble when it's in a basic solution", but your reason sounds much more accurate.
BTW i think you can get the best temperature for extracting with water by simply measuring the temp of a good coffee maker. i suspect this is the best temperature for extracting caffeine as well as flavor.
great video, hypothetically if I had a solution of say caffeine water and a strongly basic compound, and i added the methlene chloride, would the methlene chloride leave the more basic compound it in the aquas layer of you're seperatory funnel or would it bring it in with the caffeine?
how many times did you extract with methylene chloride? If you only did one then your loss would probably be mainly in the left over coffee. I believe it is general practice to do at least three extractions.
I would add that methylene chloride has a low boiling point around 40 degrees C, thus for anyone wanting to try this at home: COOL the coffee before adding the methylene chloride, or you might have yourself a bomb, especially if the sep funnel plug is on.
I recommend that you do at least 3 x washings with MeCl to assure complete trasnfer from the aq phase (maybe you did, but not showing in the vid?). Btw you really need to vent your sep when doing extractions like this! Cheers maid;)
so what do you use the caffeine for once its extracted? also if you are interested in a similar challenge, how about extracting and isolating a chemical that can be dissolved in both polar and non polar solvent?
I've had a terrible time with this. I even have a nice cold finger condenser. And a very reasonable vacuum pump. It won't boil water at room temperature, but warm it up a little bit and it boils readily. My problem is, I keep getting some moisture (water I believe) showing up after the liquid liquid extraction using methylene chloride. The water condenses on the cold finger, drips down to the bottom of the flask, mingling with my dried, crude caffeine then re-evaporating, back on to the cold finger. By the time the moisture is evacuated, I'm guessing the caffeine may have sublimated but must've gone right out through my vacuum pump. The tip of the cold finger is as clean as when it went in. Methylene chloride can't solvate any water, can it? I figure the water comes from not letting the sep funnel sit long enough after the very mild shakeup? - Mystified
I want to know more about this bright yellow substance that sublimated with the caffeine. Just to start with an obvious, and probably incorrect, guess: it being so yellow makes me wonder if it is a sulfur compound. What's your take on it?
Why don't you extract the caffein from the powder with methylenchlorid right away? boil the solvent off and then recrystalize it with water? i think this should work.....sorry for my bad spelling i'm not from the usa xD But it's a great channel you have there, like it :)
Just so you guys know, the grind for drop filtration is finer than espresso grind. That is the major reason why filtered coffee usually has more caffeine per volume than espresso coffee, even if with the espresso coffee you apply 15psi of pressure. The strenght of espresso is provided by the torrefaction procedure, which provides a more strong taste, but the taste of coffee beans has absolutely no correlation with its caffeine content.
Hey Ben great video, I have a question about the extraction. I know that adding brine makes the extraction more effective but what if you over saturate the aqueous phase. Would it ruin the extraction? My best guess is that the salt that precipitates from the aqueous phase falls into the methylene chloride and start to dissolve. Thus making the extraction less effective
You are one clever dude! Have to say - methylene chloride is nasty! Even with boiling off methinks there will still be residual contamination at molecular level .. strikes me that 'removing' any solvent at the end of a process cannot be reliably a true 100%. Good work tho ... as always, fascinating stuff you put out, thanks.
It looks like you only did one extraction with the methylene chloride on that coffee liquor. If you did 3-4 extractions I'm sure you would get a higher yield of caffeine. You don't even have to used much more methylene chloride, but if you only do one extraction the caffeine solubility will reach an equilibrium in both the water and methylene chloride and a large amount will be lost. By doing multiple extractions you reach the equilibrium more often and more caffeine will be pulled out.
you said boiling the caffeinated water will give a tar like substance is that just boiling by heat or boiling by depressurization? would it work with out a solvent if you just kept the pressure really low till all of the water boils off? I'm just interested i cant do these experiments all of my money is going into college so I cant do more than what the chem teacher lets us. p.s. someone should give you a t.v. show where you just do interesting experiments all day like this I would watch it.
Hey I'm still learning chemistry and part of my experiment is to extract caffeine from coffee. I might try with this technique but is there any idea why do you use ice on the test tube ? and what is with the hose that is connected to the flask ?
There is another way to get caffeine. From green tea, caffeine is sublimated by heating in the presence of magnesium carbonate. This experience is described in one children's book on chemistry.
Applied Science, why not use a closed loop pressurized with propane and use butane as the solvent. The proper mixture for this is 70% pure propane and 30% pure butane. Also it would be important to freeze the grounds first so that no fats come through. The result would be a tar like substance. Step two: remove any butane in a vacuum oven for two days. The final step would be to remove plant matter and separate the flavor from the caffeine. This would be done with a roto-vap set up using an alcohol solvent like Everclear. Using a triple trap the flavoring would come out first. as the product starts to clear, turn the triple trap to the second bell. at this point your waiting until the product is clear; at which point, turn the trap to the third bell. After this, let the clear substance dry for 95-97% pure caffeine. The reason why I mention this processes is that, you could extract from five to ten pounds of green coffee at the same time; instead of, the small amounts you were limited to here.
My question is when they use solvents to extract the oils from the coffee beans to make it decaffeinated what's the percentage of solvent that is left in the bean that you're now grinding up and drinking who has that answer I look forward to hear from you bye for now God bless Ken
maybe u can get more by using alcohol to extract, and then leaving the solution in the fridge for say 48 hours. crystals should form in the solution, then u can drain off the liquid and dry the crystals. repeat the process with the remaining liquid to get the last bits out of it.
Separating funnel technique not ideal - you should be opening the tap every time you invert it to equalise the pressure inside and out, otherwise you can get some pretty sudden and unexpected behavior at the end when you open the tap.
@kacperciesla I'll be honest, for whatever reason this was pretty easy. I usually need to do a few more steps to track someone down like get their location and associate data from various internet sources to find them. Use the information at hand first, we have his profile which includes name, google+, education. This most of the time is a good place to start but I got lucky on this one, Ben's name appears pretty unique, we know what he looks like and Google appears to love him
I want to exact caffine, in high amounts, with good yeilds, so i can then turn into tablets for fun and such, is there any methods you can propose that will always give me good yeilds? without being to advanced of a setup? thanks
if you want to make tablets out of it then a solvent extraction is not an option, maybe you could use ethyl acetate, a green solvent, it is still hazardous if consumed but utleast it is not a suspected carcinogen... if you want the cafeine to consume then extraction with supercritical co2 is your way to go but that requires some more complex set up... even though, if you just want to get caffeine then there are a lot of improvments that can be done to this extraction like ading calcium hydroxide to give a basic enviroment to the cafeine so it is less soluble in water (also calcium ions reacts with some of the impurities making them insoluble and leaving them behind by filtration) also sodium chloride should be added befor the solvent since it will decrease the afinity of water to caffeine, and also a temperature of cero degrees celcius would be optimal for the extraction. at the end after the purification by sublimation is done a recrystalisation of cafeine under acetone or ethyl acetate would give you very pure cafein, in the amateur chemist comunity there has been guys that have reported a product of white cafeine powder out of tea employees.oneonta.edu/knauerbr/chem226/226expts/226_expt06_pro.pdf faculty.chemeketa.edu/jcammack/CH241-3B%20Lab/CH241B%20Labs/CH241%205%20Caffeine%20Extraction.pdf
Schatten2712 don't think so mate wikipedia: A mild stimulant found in coffee, tea, and soft drinks, among other sources, caffeine is one of the most widely consumed drugs, noted for its ability to promote wakefulness and provide energy. Caffeine is legal in all countries and jurisdictions, and is in modern times sold in over-the-counter medicines, although historically it was banned (often in the form of coffee) in at least several nations.
Hey. Thanks for this vid! I was looking around for other vids and some guys were using cholroform/DCM. So could I use other nonpolar solvent to extract? Like naphta or maybe heptane? And answering to Tommaso Petrella, Adding NaOH to aqueous layer will mean you turn some of them in freebase form and they will dissolve pretty well and screw up your caffeine ectraxtion... So I think sodium carbonate should be better choice. But that is just me guessing. Havent tested yet. :)
Toluene is commonly used non-polar solvent, but the solution would need to be basified with NaOH first. Toluene seperate ontop of water instead of below like DCM and this methylene chloride mixture, which could prove more difficult to purify than it sounds.
Maybe you could turn it into a chloride salt so the shelf-life would last a long time.
12 лет назад
@bkraz333 Valve? You mean like, making a neat gun for the people who are still alive ;) But seriously, you're projects are like some geek-porn. Keep up the awesome work!
Blonde roast has more caffeine than a dark roast. I don't know shit about chemistry but I wounder if you could take the black goopy tar bit you mentioned. Mix it with pure alcohol filter it. Evaporate it. & repeat the proses until its pure. Or look up the proses to purify & manufacture cocaine. That proses might work well.. Cool video though Oh also check out the method on refining morning glory seeds. I'm sure that would work.
