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Green fire is ubiquitous on the web, and making it is remarkably straightforward - provided you are not led astray, as I was, by ... let's call it poetic license.
Now, after having had a rather disappointing Halloween at chez Green, when I read that a purported "chemistry teacher" found using isopropyl alcohol, rather than methanol, resulted in "a fire that alternated from orange to blue to green" and that it was "pretty cool," I now understand that to mean "after the third whippit, the normal blue and orange flames of the rubbing alcohol looked kind of green. Then I passed out."
The rules of making green fire are as simple as they are inviolate:
1) use methanol
2) add boric acid
The reason for these rules lies in ... chemistry! Here is the chemical equation for the boric acid/methanol reaction:
H3BO3 (boric acid) + 3CH3OH (methanol) --> B(OCH3)3 (trimethyl borate) + H2O (water!)
A very small amount of the boric acid is transformed into the trimethyl borate, but as the flame of methanol burning is a very pale blue, the borate compound easily overwhelms it.
I found that I was dissatisfied with the usual approach of making a puddle of liquid and setting the puddle on fire. First of all, the fuel is used up quickly. Secondly, it's hard to control and makes a big mess. For these reasons, I decided to make a small lamp for my green fire for a more controlled, portable and neater illumination.
For this instructable, you will need the following:
* Methanol (Heet - yellow bottle - is an easy source of this) $2.00
* Boric acid (you can find this in the hardware store as an insecticide, but I ordered it through a pharmacy to ensure that the product was not overly contaminated with unwanted chemicals) $5.00
* lamp wick (small round is easier to work with than large flat variety) $2
* small, "sampler size" jam jar
* an electric drill with a drill bit slightly smaller than the diameter of the wick
* (optional) a small hurricane lamp for a votive candle (I found one for $.50 at a thrift store)
* (optional) the metal holder from a spent votive candle
Safety notes:
Alcohol is flammable, and alcohol vapors are explosive if concentrated and lit. Use good sense. One of the reasons for the small jam jar is that only a small amount of alcohol will spill if the jar is dropped and breaks. Also, try not to get methanol on your skin, as it can be absorbed through the skin, and is not nice. Never drink methanol. It is toxic, and cannot be made "untoxic." Think *permanent blindness*.
Boric acid is fairly innocuous, but inhaling large amounts of it (or swallowing it, or getting it in your eyes, etc) will not feel nice.
Green fire produces a white "smoke" that is actually diboro trioxide. It's (evidently) fairly harmless, but makes a mess. The Spirit Lantern is best used outdoors.
Now, after having had a rather disappointing Halloween at chez Green, when I read that a purported "chemistry teacher" found using isopropyl alcohol, rather than methanol, resulted in "a fire that alternated from orange to blue to green" and that it was "pretty cool," I now understand that to mean "after the third whippit, the normal blue and orange flames of the rubbing alcohol looked kind of green. Then I passed out."
The rules of making green fire are as simple as they are inviolate:
1) use methanol
2) add boric acid
The reason for these rules lies in ... chemistry! Here is the chemical equation for the boric acid/methanol reaction:
H3BO3 (boric acid) + 3CH3OH (methanol) --> B(OCH3)3 (trimethyl borate) + H2O (water!)
A very small amount of the boric acid is transformed into the trimethyl borate, but as the flame of methanol burning is a very pale blue, the borate compound easily overwhelms it.
I found that I was dissatisfied with the usual approach of making a puddle of liquid and setting the puddle on fire. First of all, the fuel is used up quickly. Secondly, it's hard to control and makes a big mess. For these reasons, I decided to make a small lamp for my green fire for a more controlled, portable and neater illumination.
For this instructable, you will need the following:
* Methanol (Heet - yellow bottle - is an easy source of this) $2.00
* Boric acid (you can find this in the hardware store as an insecticide, but I ordered it through a pharmacy to ensure that the product was not overly contaminated with unwanted chemicals) $5.00
* lamp wick (small round is easier to work with than large flat variety) $2
* small, "sampler size" jam jar
* an electric drill with a drill bit slightly smaller than the diameter of the wick
* (optional) a small hurricane lamp for a votive candle (I found one for $.50 at a thrift store)
* (optional) the metal holder from a spent votive candle
Safety notes:
Alcohol is flammable, and alcohol vapors are explosive if concentrated and lit. Use good sense. One of the reasons for the small jam jar is that only a small amount of alcohol will spill if the jar is dropped and breaks. Also, try not to get methanol on your skin, as it can be absorbed through the skin, and is not nice. Never drink methanol. It is toxic, and cannot be made "untoxic." Think *permanent blindness*.
Boric acid is fairly innocuous, but inhaling large amounts of it (or swallowing it, or getting it in your eyes, etc) will not feel nice.
Green fire produces a white "smoke" that is actually diboro trioxide. It's (evidently) fairly harmless, but makes a mess. The Spirit Lantern is best used outdoors.
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Signing UpStep 1Step 1: Make Green Fire!
In a jar, bowl or other receptacle, add 1 teaspoon of boric acid and pour roughly a quarter cup of methanol. Agitate, stir or shake this mixture, as applicable to your container-type, until the boric acid is largely dissolved (see third picture). As you can probably guess from the measurements, this is not an exact, stoichiometric ratio. That's okay. We're not all "chemistry teachers."
Now, cover your proto-green fire, and set it aside. Do NOT light up a cigarette to relax after mixing. Do not taunt green fire!
Let's make the lantern.
Now, cover your proto-green fire, and set it aside. Do NOT light up a cigarette to relax after mixing. Do not taunt green fire!
Let's make the lantern.
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H3BO3 (boric acid) + 3CH3OH (methanol) --> B(OCH3)3 (trimethyl borate) + 3H2O (water!)
Also, on one of the later pages, I write that you should use sandpaper to remove pain. I sincerely apologize for this misinformation. No amount of sanding will take away the pain. However, it can be helpful in removing paint. Again, the editor function is preventing me from correcting this typo.
Search "boric acid" reproductive toxicity in Google
Maybe you should try Ethanol.
The same doesn't hold true about the boric acid and you may realize years later.
Also, you comments about flame colour reasons leave a bit to be desired. For more info about flame atomic excitation and colour emission go to http://en.wikipedia.org/wiki/Flame_test.
You comment that your candle gives too much B2O3. Add less, the amount that will give a really strong colour(high molar extinction) is about a teaspoon (5g) per cup (250ml), any more is just dangerous and wasteful.
Source: I'm not a chemistry teacher, I'm a chemistry professor!
http://www.deltaindustrial.com/MSDS/FuelsLubesAntifreeze/HeetAntifreeze.pdf
The products of combustion for methanol and ethanol are the same: CO2 and water, possibly a small amount of CO. Unburned alcohol vapors should be minimal. Still, it's always better to be safe than sorry, which is why I recommended that this lamp be used outside.
I don't believe that I addressed the reason why the fire is green at all, so I would imagine that my non-existent comments leave everything to be desired.
If you want a nice green (boron-shade) flame, borax is not the way to go. The sodium component of borax, which emits a yellow color in flame tests, tends to outshine the green of the boron. Since we're quoting Wikipedia, here's the opinion shown there regarding the use of borax in pyrotechnics:
http://en.wikipedia.org/wiki/Borax
Regarding the wastefulness of my boric acid use: I would be far more concerned about someone drinking the methanol in the mixture than drinking the boric acid in the mixture. That's why I recommend that one not drink it.
Last but not least, the LD50 (median lethal dose) for boric acid is considered to be 5g/kg body weight (Merck index, via Wikipedia). The LD50 for borax is considered to be 4.5g/kg body weight. For reference, the LD50 of table salt is 3g/kilogram. Therefore, in order of toxicity, from least to greatest, we have: boric acid, borax, table salt.
In the long term will harm you just breathing near the candle which is something much less intuitive. And yes, you won't die the same week or even notice for years, which doesn't mean that you didn't get hurt.
For reference, table salt won't damage your reproductive capacity, boric acid and its decomposition subproducts will. And you won't notice.
Probably you know that boric acid in methanol is burnt for a few seconds to use as flux when brazing silver jewlery as I do as a hobby and even when is considered safe there is plenty of warnings in these products about the boric acid toxicity. (The methanol is way much more toxic if you drink it, so no, they are not expecting you to drink it)
Boric acid also was used in the food industry in minute quantities as sea food preservative until the middle of the last century when was banned for that use due to its toxicity.
I just won't use regularly a candle with boric acid indoors. It's too cool that I've done it too many times before knowing about it. Better safe than sorry.
Thanks for pointing out this information. It allows people to make informed decisions about the level of risk they choose to accept.
green fire! awesome.
RE Mint: I'm no biochemist (or chemist for that matter) but I would be a little leary of adding other chemicals to the mix. Mint oil may very well react with the trimethylborate, and while such a reaction could be harmless, it could also be very nasty. Many essential oils are methyl variants. I personally wouldn't mess with it. My two cents.