Turning aspirin pills into mint flavor

methyl salicylate also known as wintergreen is a naturally-occurring oil with a really strong minty odor it can be found in a lot of different plant species and it's often extracted as an essential oil commercially it's mostly used as a flavoring agent in candy or in cream products like bengay to relieve muscle and joint pain to make the wintergreen the easiest thing to start with is aspirin because its structure is really similar they're both derived from the salicylic acid molecule and they've just been esterified in different places to make the conversion I need to make an ester out of the carboxylic acid group marked in red and I need to destroy the other one luckily for me this is quite easy to do and both reactions can be done in a single step by doing the reactions at the same time the reaction isn't as efficient but it's still worth it because it saves a lot of time and materials in terms of the supplies and chemicals I'm going to be using 50 extra-strength aspirin pills methanol and concentrated sulfuric acid because this is edible chem and I want to taste the wintergreen that I make I use only high-grade ACS chemicals and solvents to make sure that I don't have any weird things dissolved into them however considering I'm only going to be tasting a very very small amount even if there is something in there it's really not a big deal anyway to get things started I need to powder eyes all of the pills and to do this I use a coffee grinder of course I could have also just smashed them with a hammer or something but it's just a lot easier this way when it's done I take off the lid and you can see a whole bunch of powder shoot out it's important to avoid breathing this because it's really not healthy for your lungs I pour it out and then I manually scrape off any powder that might be stuck inside and add it to the pile all of the powder is poured into a beaker and on top of it I dump in 190 milliliters of methanol I turn on the stirring and I let it mix for about an hour what I'm trying to do here is dissolve all of the aspirin and behind the binders and the other junk that they include in the pills unfortunately the dye that was used to brand the pills is also soluble in methanol so the solution takes on a very slight pink color anyway at this point it's done and I just need to filter off this insoluble stuff it's pretty easy to do this and I just quickly pass it through a coffee filter some of the particles are too small for the filter to catch so the liquid that passes through is a little bit cloudy this really isn't a problem though and it's not going to affect the reaction after everything passes through the beaker in the filter are both washed with a little bit of methanol then the filter is taken away and I turn on some really strong stirring I start to add the concentrated sulfuric acid and it's very important to do this slowly and carefully adding it generates a lot of heat and it actually causes some of the methanol to boil I'm stirring things here magnetically but it's definitely possible to do it manually you just have to add it a lot slower and be a lot more careful when I finish adding everything I connect a cold water condenser I heat up the methanol using the hot plate and the goal now is to keep it boiling for about 60 minutes any methanol vapor that escapes the flask will be caught by the condenser and dripped back in as I mentioned in the intro there are two reactions going on here one is known as a fishery spherification where methanol reacts with the carboxylic acid to form an ester the other one is a transesterification where the methanol forms an ester with the acetyl group and replaces the salicylic acid overall if both these reactions are done to the same aspirin molecule it will generate our desired wintergreen one important thing to notice about this reaction though is that it's in equilibrium this means that the products can react together to reform the starting materials to try to favor the products though I include a large excess of methanol with so much methanol around the forward reaction should be statistically more likely to happen however the overall efficiency of this process still isn't very high the one hour reflux is eventually done so I take away the hot plate and let it cool a little bit then when it looks like it stopped refluxing I take away the condenser everything's dumped into a beaker and now I have to boil off about 50% of the volume I put it on a medium heat and I set up a fan off screen which really speeds things up when it hits around 100 milliliters I take it off the hot plate while still hot it's transferred to a separatory funnel that has a hundred millilitres of ice-cold water in it the moment it's added a lot of white precipitate falls out of solution and this is just unreacted starting material the wintergreen also separates out and sinks to the bottom but you can't really see it here to really mix things around the separatory funnel is capped and shaken and then it's put back on the stand and I wait for the layers to separate I come back about 20 minutes later and it's kind of hard to see here but there is a lower layer that has four so this lower portion is drained into a small beaker and the rest is dumped off as waste the separatory funnel is washed and the crude wintergreen is re added to get rid of any acid that might remain I wash it with some saturated sodium bicarbonate solution to really mix it up I cap the funnel shake it and vent it but I have to be really careful because a lot of co2 is being generated I wait for about 30 minutes for the layers to separate then I drain off the lower one and I repeat this same washing one last time again I wait for the layers to separate and then the lower one is drained into a vial it's very cloudy and wet with water so to dry it up I add some molecular sieves it's also possible to use another drying agent like magnesium sulfate i swirled it around a little bit but it was still a little bit cloudy so I left it for a couple hours the wintergreen cleared up quite a bit but there was still some solid stuff floating around so to get rid of it I filtered it through some cotton and sea light if no sea lights available it can be replaced with a little bit of magnesium sulfate the stuff that filters through is crystal clear but it's painted slightly yellow the yellow color as well as some other impurities can be removed by distillation but I decided not to do one because I'm just planning to taste it I don't need it to be super pure and it's okay how it is the final yield is 4.85 grams which corresponds to a very low percent yield of only 24 percent if you recall for this prep I did two reactions in one shot but I think if I did them separately the yield would have been closer to 70 percent however it's a lot more work so the decision is really to get a better yield or to save on time anyway now it's time to taste it before I do this though I need to give a warning when wintergreen is ingested it's metabolized to salicylic acid just like aspirin what I have here is equivalent to about 18 doses of regular strength aspirin so it's important to be careful and not eat too much with that warning in place though we can move on to the fun part I'm going to be tasting it directly even though it's going to be super strong and it's not going to taste very good at all but I figure that it might be funny to try so here I have a syringe and I'm going to measure out about half a milliliter which is the equivalent of two regular strength aspirin tablets so it's test so actually quite a bit so I mean it's really minty gets minty er and minty er bloggers in my mouth I mean it's kind of dissipating right now at first it was pretty uncomfortable it actually tasted pretty decent I thought half a mil was going to taste really really bad it actually just I don't know wasn't that bad at all anyway I'm going to be doing something useful with it now instead of just eating it plain and I've decided to make some mint candies which is surprisingly easy to do to make them all they needed some gum paste which is sold as both a powder that needs to be mixed with water or as a premade paste I went with the pre-made one which is more expensive but it saves a lot of time and annoyance the gum paste is basically just a combination of sugar and sodium alginate when it's wet the sodium alginate picks up the water and it forms a gel this holds everything together and lets it be molded like play-doh ed room temperature is pretty thick and tough so you need to mash it around with your hands a little to warm it up and soften it when it feels soft enough I start to add the wintergreen I add only a little bit each time and then I thoroughly mix it in the goal here is to just keep adding it and occasionally tasting it until I get to the mint enos that I want then I lay out some wax paper sprinkle on some powdered sugar and flatten out the paste until I get to the thickness that I want the mint to be now there are a lot of options in theory you could just leave it like this and have one large mint you can cut it up like I did or you can cut out shapes I'm a big fan of the lazy route and just cutting it up using a knife but you can do whatever you want anyway while I'm cutting things up here I feel it's a good time to mention that using wintergreen alone for mints is not the best idea wintergreen alone doesn't have the strongest mint flavor and it wears off pretty quickly to make up for this I added everything that I had into these mints but that's kind of dangerous this really isn't a big batch and it wouldn't be crazy for someone to eat them all in one shot and this can be potentially fatal especially for children it's totally possible that I'm doing things completely wrong here but in my opinion wintergreen should be only added as a flavor and not as the main source of minty Ness if you want really minty stuff you're going to have to add something else anyway when I'm done cutting them they need to be hardened which is done by just letting them sit out to dry after a few days they were much harder but the inside was still a little bit soft I think to fully harden them I'd have to leave them for about a week or I could just make them thinner anyway that's about it for this video let me know in the comments what you guys thought of it and maybe some topics you'd like to see me cover in the future so I really like to hear what you guys have to say and I mean I guess that's about it a big thanks goes out to all of my supporters on patreon anyone who supports me will see my videos 24 hours before I post it to YouTube and they'll also be able to directly con Act me anyone who supports me with five dollars or more will also get their name at the end of the video like you see here [Music]

Channel: NileRed

Views: 1,100,319

Rating: 4.9558463 out of 5

Keywords: methyl, salicylate, edible, chem, nile, red, wintergreen, mint, flavor, candy, synthesis, chemistry, science, nilered

Id: 3NN9IUvrKi4

Length: 12min 24sec (744 seconds)

Published: Mon Jul 17 2017

Reddit Comments

[u/AustinThompson]

I think this is a neat idea to try it. I know that he is experienced as a chemist, and I trust that he took as much precautions as possible to prevent contamination such as using fresh unused glassware as much as possible and when not available using thoroughly cleaned glassware, but something in me just does not feel comfortable doing this (tasting) on my own. Regardless, another great informative video.

[u/[deleted]]

Oh my god the comments on that video are so obnoxious. "hey, show us how to make methamphetamine lolooolourolol"

[u/Rocks1nHead]

Love me some NileRed.

[u/TheyreToasted]

Did anyone get worried when they saw he was heating without a bath?

[u/avsfjan]

i think that even when you are as carefull as you can you should never taste/eat anything that you synthesized without proper analysis. simple 1H-NMR, GC and maybe IR. you never know if its actually MeOH free. however, cool video nonetheless.

[u/OldLabRat]

Well, I'm usually a big fan of NileRed's channel, but I would hesitate to do it this way. Seriously perturbed by boiling off methanol without an actual distilling setup - one spark from that fan, and the vapor is going to go blammo.

Of course this method is much faster than mine, I will give it that, he's combined extraction and hydrolysis and esterification into one! Yet we obtain comparable yields, in the end.

When I have students do this, they first extract the aspirins with isopropanol and add water to the filtrate to crystallize it: this avoids any need to breathe dust. I generally have them hydrolyze the product with 20% hydrochloric acid in a sealed Erlenmeyer in a water bath, followed by extensive water washing. This gives us salicylic acid which we can use for other projects. It's a great indicator for ferrous iron, for example.

We do the esterification itself in a water bath, sealed Erlenmeyer, with salicylic acid and a mixture of alcohol (we generally go for the ethyl) containing about 25% sulfuric acid. We use a minimum of alcohol : there's still a massive excess of the stuff, but this has diminishing returns. What really matters here is that there's enough alcohol to completely dissolve the salicylic acid, and enough sulfuric to gobble up all the water. The dehydrating effect of sulfuric acid is what drives the reaction, not so much the excess of alcohol! The added sulfuric actually raises the boiling point enough that we can run the reaction at 70 degrees or so in a stoppered Erlenmeyer. In a water bath, behind a blast shield. Because I am a very, very paranoid individual.

Also, I've found that neutralizing is best done before trying to separate layers: there's no need to actually evaporate alcohol, as you end up with so much sodium sulfate in solution after neutralization that the ester obligingly salts out of the water layer.

Of course, for me, safety is an incredibly high priority: I am working with youth aged 17-19, who do have some understanding of PPE and OSHA but only in the context of vocational trades which aren't much like chemistry.

As far as tasting the stuff: I prefer not to even think about that in the context of reagants that aren't USP or food grade. $$$$$! But we can grind it in a mortar with sugar in a dark room and see the pretty light.