Caffine

[Yggdrasil]

I remember extracting caffeine from tea bags in ochem lab. I think we managed to get 40-50mg from three tea bags. My notes say that the theoretical maximum recovery is 2-4% of the weight of the tea leaves. If you want, I can give you a procedure.

[latentheat]

If you want to post a procedure that would be appreciated. I'm assuming with tea you can leave out the defat step with no problems.

 

My only thing with tea.... how significant is theophylline contamination?

[Yggdrasil]

Most of the steps should be doable in a homemade chem lab, though the last step may not be possible in a home lab.

 

The first step is to essentially make tea. Boil water, add the tea bags, and let the hot water extract all the soluble material from the tea leaves. In order to increase the efficiency of extraction, use more water than you normally would to make tea (protocol says 100ml for 2 tea bags) and to brew twice (i.e. boil then soak tea bags, then bring to a boil a second time, and soak the bags a second time).

 

Next, keep on boiling the water to reduce the volume by a little less than half (60ml) Next, add sodium chloride (16g) and calcium hydroxide (3-4 pellets). The salt will improve the efficienty of the extraction (see next step) and the calcium hydroxide will precipitate out the tannates. Calcium acetate may work for this step, though calcium hydroxide will more efficiently deprotonate the tannic acid and caffeine.

 

Next, filter to remove the calcium tannate and collect the filtrate (as it contains the caffeine). Wash the precipitate with 15ml of 1-propanol (isopropanol may be suitable) to disolve any caffeine in the precipitate.

 

Next, let the filtrate cool to RT, then vigorously mix the 1-propanol from the previous step with the filtrate in a separatory funnel or a similar apparatus. Note that if you mix in a closed container, be sure to vent the container frequently as the mixing will release a lot of vapor and increase the pressure inside your container. Since caffeine is more soluble in 1-propanol, it will migrate to the 1-propanol, while the salts and other water-soluble compounds will remain in the aqueous phase. The salt (added earlier) helps to improve the efficiency of the extraction by decreasing the solubility of caffeine in water. After mixing, let the two phases settle, then separate the two layers (aqueous layer should be on the bottom).

 

Repeat the extraction 2 more times with 15ml of new 1-propanol. Pool the 3 1-propanol fractions and dry with an appropriate drying agent (we used anhydrous sodium sulfate).

 

Transfer the dried solution to a new beaker (wash the drying agent with 2ml of 1-propanol to disolve any residual caffeine) and boil off the 1-propanol (of course, do this in a well ventilated area and avoid the 1-propanol fumes).

 

Next, wash the residue 3x with 10ml acetone. The acetone will disolve the caffeine and leave behind any residual salts. Evaporate the acetone, and you have some fairly pure caffeine.

 

If you want to purify it even more, you can put your caffeine into a sublimation aparatus (probably not available if you're doing this at home). Basically it consists of an evacuated flask with a test tube filled with ice hanging from the top. The vacuum inside the flask will allow the caffeine to sublimate at low temperatures, and condense onto the walls of the cold test tube.

 

When I analyzed my product in chem lab, I couldn't say that it was totally pure, and I don't think any of the preliminary steps would remove theophylline. However, the sublimation may remove some of the theophylline contamination. Since chemfinder.com lists caffeine as having a somewhat lower mp than theophylline (238 C v. 272 C), you may be able to remove the theophylline by carefully controlling the temperature you use in the sublimation (I don't know how you would calculate their sublimation temperatures in a vacuum, however).

[latentheat]

Thanks for that. Even easier than an a/b extraction.

[fuhrerkeebs]

Quite caffeine and swith to coca leaves, doesn't last as long, is less jittery..

 

As long as he's not worried about prison, that'd be a fine suggestion. Coca leaves (yes, the leaves) are Schedule II over here in the U.S...

[H2SO4]

what the hell is the point of extracting the caffein from watever? What are you gonna do with it? Just watch it sit there and do nothing? Eat it? (i hope not).

[Nevermore]

what the hell is the point of extracting the caffein from watever? What are you gonna do with it? Just watch it sit there and do nothing? Eat it? (i hope not).

With the caffine removed from, lets say, coffee. You can drink it, but not get the stimulant effects.

[budullewraagh]

not related to the current conversation, one can find anhydrous caffeine sold for $22/lb at http://www.al-chymist.com

[H2SO4]

With the caffine removed from, lets say, coffee. You can drink it, but not get the stimulant effects.

 

 

It sems you have to go through an large process to remove the caffein. When your done, it would be mutilated, nothing like coffee.

[latentheat]

what the hell is the point of extracting the caffein from watever? What are you gonna do with it? Just watch it sit there and do nothing? Eat it? (i hope not).

 

Not every chem experiment has to have an exact purpose. What's the point of tossing sodium into water, it just makes sodium hydroxide, which you can buy anywhere. Same deal. It's a fun thing to do.

 

Given pure reagents were used, why not consume the product...it's no worse than popping a vivarin or stacker 2.

[Nevermore]

It sems you have to go through an large process to remove the caffein. When your done, it would be mutilated, nothing like coffee.

Agreed, but there is enourmous demand for decaf products.

[Yggdrasil]

Not every chem experiment has to have an exact purpose. What's the point of tossing sodium into water' date=' it just makes sodium hydroxide, which you can buy anywhere. Same deal. It's a fun thing to do.

 

Given pure reagents were used, why not consume the product...it's no worse than popping a vivarin or stacker 2.[/quote']

 

I wouldn't recommend consuming any of the caffeine you isolate using this method. Even if pure reagents are used, the reagents themselves (1-propanol, acetone, etc) are still not very good for you.

[akcapr]

i know how to get cafeeine. accoridng to my dad, hoo likes tea, when u set the conc. tea out in like a kettle, and it likes stays there for a few days (after it was boiling at some point before), cafeeine will ppt out of the tea and look like milkish crap at the bottom, and im asssuming as it settles u can collect it. im not even sure its cafeeine, but my dad says it is.

[latentheat]

i know how to get cafeeine. accoridng to my dad, hoo likes tea, when u set the conc. tea out in like a kettle, and it likes stays there for a few days (after it was boiling at some point before), cafeeine will ppt out of the tea and look like milkish crap at the bottom, and im asssuming as it settles u can collect it. im not even sure its cafeeine, but my dad says it is.

 

It probably is partially caffeine, but you won't get it all unless you basify. Some of the caffeine will remain in solution complexed with the organic acids. If you raise the pH really high the caffeine will go freebase and it will all ppt after awhile, because freebase caffeine is only slightly soluble in cool water. The method Yggdrasil posted is based on this idea.

[H2SO4]

is caffein a base?

[Yggdrasil]

The imino group of caffeine is slightly basic, probably with a pKa ~6-8.