Transcription
Sulfuric acid's corrosive. Ethnosium or ethernet rethane, also flammable. Don't try this at home.
Hello everyone, and today we'll be synthesizing nitroethane from ethanol. So here I have 125 milliliters of anhydrous ethanol and 70 milliliters of sulfuric acid. Our first step in synthesizing nitroethane is to prepare sodium ethyl sulfate. This is done by making ethyl sulfonic acid, which, as you could guess, is made from ethanol and sulfuric acid. Now, if I wasn't so lazy, I would have cooled these mixtures down before adding them together, because the dilution of sulfuric acid gets really hot, and it gets hot enough to boil water. Even so, ethanol—yeah, it's definitely boiling now. I just did the lazy method by just adding a tiny bit of sulfuric acid, swirling it to let it cool down a bit, and the ethanol essentially maintained a light reflux because I let it cool down in between. But yeah, this is not the best way of doing this, but it doesn't really matter. And you can see that, um, yeah, um, it's quite an exothermic reaction. Now, towards the end of addition, because of the sulfuric acid content inside of it, the temperature actually, um, the boiling point raised up quite a lot, so it didn't really boil at the end of addition, and it also went yellow because, of course, it had to go yellow. Pure could be a molecular sieve dust. Anyways, the setup to reflux—well, we're not boiling it technically; we're heating to 80 Celsius. And I couldn't find my stir bar, so I rearranged it to use a mechanical stirrer in the center. Um, this is not really necessary. You want stirring; you can use a stir bar, of course, but, um, you want stirring to help it maintain an even temperature of 80 to 90 Celsius. This is so that you don't heat it up too much and form difficult ether or ethylene gas.
Now this is done after an hour; any longer ends the measuring returns, not really worth it. Now this is going to be neutralized off with an excess of calcium carbonate. Now, the reason we're using calcium carbonate and not any other base is because this mixture contains sulfuric acid, so along with our desired ethyl sulfate, or ethyl sulfonic acid specifically. Now, calcium ethyl sulfate is soluble in water, but calcium sulfate is not. This is our method of separating the sulfate from the ethyl sulfate. And I ran out of calcium carbonate because this requires quite a lot. You could also use calcium hydroxide if you have any of that; I don't, unfortunately. So yeah. Now you can see here it's still acidic; we want this at neutral. And now we can use an excess of calcium carbonate because, one, it's not solvent water, and, two, it won't make it too basic. It's—it's not solvent water; it can't make it any more basic. So, after adding a bunch more calcium carbonate, which I had to prepare because I ran out, like I said, um, we eventually got it to a pH of neutral, which is what we want. And you can see this took quite a lot of calcium carbonate—ridiculous, I know—but, uh, yeah, that's a side effect of this reaction. Frequency neutral, so that's good.
Now this mixture is filtered, and unfortunately the filter paper didn't catch everything, so I had to filter a second time through a sintered glass filter. Um, if you filter it through two pieces of paper, that's probably fine. Now we shall prepare a solution of sodium carbonate in excess, and we're just going to add this until our solution slightly, um, basic, which basically—pH papers green indicator, uh, in universal pH indicator. I don't know; maybe some people are using cabbage juice for indication; I don't know. So yeah, I'm just going to be specific; you'll want it slightly basic. What we're doing here is a metathesis reaction, or double displacement, where we're replacing the calcium in calcium ethyl sulfate—the calcium atom in it—with sodium to form sodium ethyl sulfate, which is solving water, while calcium carbonate is not, which precipitates out as this milk-like mixture. Now this is filtered. I would recommend you to boil this mixture for a little bit actually to coagulate the calcium carbonate, as it's quite fine precipitation. I had to filter a second time to get rid of all of it, or at least most of it. And now, after filtration, we shall wash our calcium carbonate filter cake with—time into water—doesn't pull out any extra. This really doesn't matter too much, but yeah. Now this mixture is boiled down to, um, until crystals start forming, or then I added a bit more water back in because we don't want it to crystallize. Now this mixture is carefully evaporated. I don't have an evaporating dish, so I used a casserole dish. And here's our final powder, which shall now be crushed up and dried. Now we are going to dry this at 100 Celsius for around an hour or so. This is because it contains a slight bit of calcium carbonate, which doesn't really want to dry, and it makes it all clumpy. Now we're going to grind this powder up, and you can see here we have 81.5 grams of sodium ethyl sulfate. I scaled up—nut swamp because on procedure—and now we're going to add this all into a four-neck 250-milliliter round-bottom flask. You don't have to use 4X; you can use 3X, but 4X is ideal because you can both have water addition, um, stirring, a thermometer, and distillation.
Now we're going to measure out our 60 grams of sodium nitrite and also add that into the flask along with 5 grams of sodium carbonate as a catalyst. It usually uses potassium carbonate, but both work fine. Now the powder is mixed together, and it's set up with this apparatus. We have water addition, um, thermometer, a string in the center, and distillation on the side neck, which—in distillation—I had to rearrange off a Claisen adapter due to foaming issues. We add enough water to form a slurry, and we turn on heating to maintain temperature between 110 to 120 Celsius, and we just distill—that's really it. And you can see here foaming issue, like I said, so I had to rearrange it for a longer path with a Claisen adapter. Alternatively, if you have acetyl alcohol or some other similar anti-foaming agent or photo flow, you can add a tiny bit of that into it, which will prevent the foaming. But yeah, I went with this lazy method because I am lazy. I did try putting some lotion in which has acetyl alcohol, but it didn't really do much because it's not that pure acetyl alcohol. So yeah. And now you can see here we have a distillate, and this is slightly yellow. There's also quite, um, irritating, weird-smelling gas coming off this one, so I had to do this under the fume hood, and that's probably acetaldehyde or something. Anyways, here you can see that our distillation's done, which is indicated by the mixture in the flask changing completely. This is now sodium sulfate and time we have, um, sodium carbonate.
Now we take our distillate and add it into a separatory funnel to separate our nitroethane, which is orange because, of course, it is. This is a destructive distillation, so our product, um, at first is not going to be super pure; we're going to have to work it up quite a lot. So here's our nitroethane, which I separated off and saved into a beaker. Now our aqueous layer, um, we're going to have to add a bunch of salt into it, so yeah. And the salt that I added in excess of it, because of course I did. Now this is extracted with 30 milliliters of diethyl ether. If you have dichloromethane, that would also work; any solvent that boils at a low temperature and does not form an azeotrope with nitroethane will work. I had diethyl ether; that's why. Dichloromethane is quite difficult for me to get here, and I still don't have any. Anyways, this is extracted; don't forget to vent it, of course, for safety, so you don't over-pressure it. And yeah, we let this separate, and we drain off the aqueous layer; we discard that; we don't need that anymore. And we save the upper ether layer, which contains our nitroethane. Now you could extract this a few more times with diethyl ether, but no point really. Now, diethyl ether layer is added to our nitroethane as well, and this is dried. I use calcium chloride because—a random magnesium sulfate when I filmed this—I hate calcium chloride; it takes so much effort to try to use it to dry something; it's just not worth it. Get magnesium sulfate, seriously. Look at this; I have to dry it, then I have to decant it, and I have to add more calcium chloride because calcium chloride only has two waters of hydration; that's so stupid. And then I had to wash the calcium chloride because it has so much of its stuff stuck to it with more diethyl ether. This is so useless; get magnesium sulfate or sodium sulfate. Anyways, rant over. Now our ether—dried ether layer—is added into a 100-milliliter flask, and our ether is distilled off, and then, um, after like the volume is down a bit, I transfer into a 15-milliliter flask and wash the 100ml flask with a bit of ether, and this is so we don't lose as much product to physical losses, and is distilled further. Then I had to vacuum distill the nitroethane because my heating mantle—it's meant for Soxhlet extractors; I've made it myself—it doesn't reach high temperatures, so I had to distill under vacuum. They've had a good heating mantle, of course; you could just like just crank it up and distill it at atmospheric pressure or use an oil bath; I don't know. I hate oil baths though, so I didn't do that. But anyways, yeah, um, you can see here we have our nitroethane; it's still not as pure, but it's good enough for chemistry. And I had some nitroethane previously attempting this reaction, so I added that in as well. So yeah, there's our nitroethane, and then I rinsed out the flask of it because nitroethane is quite oily, and, um, yeah, although it's probably not going to recover much, might as well do it; no point in not doing it. And then I evaporate the ether off in air, and here's our nitroethane—wonderful. Now the pure stuff is supposed to smell fruity, but mine has still a burnt smell to it, very slightly; that's from decomposition products. Is our diethyl ether? Can now be purified up further, and you need me knocking it over. Now, um, before you do this though, I'd recommend you to clean up some activated charcoal first. Um, nitromethane is known to react very violently with sodium hydroxide, so I don't know what nitroethane will do with sodium metal, so yeah. Um, yeah, this part's a bit sketchy; nothing blew up though, but, uh, yeah, that's how you make nitroethane from ethanol, and, um, I hope you enjoyed this video. Subscribe if you want to see some more epic content. I'm working on a couple things right now; this is just some old footage I'm editing up, so yeah. There's quite a lot of stuff I want to share with you guys, and, um, join the Discord; join it; join it; it's not active enough, please. Um, yeah, that's it. [Music] Oh yeah. [Music] We could leave the light songs. [Music]