Sciencemadness Discussion Board - Borax - Green Flames with Methylated Spirits

Borax - Green Flames with Methylated Spirits

goldensquid2000 - 18-12-2017 at 21:22

First up, I'm just going to put it out there that this is my first post, so soz in advance if I accidentally post in the wrong thread or something else like that (:

So, I want to make some nice green flames for the family in conjunction with the red strontium flames I'm making (it's the whole "red and green" Christmas theme). I've got some borax (aka sodium borate or disodium tetraborate Na2B4O7) that allegedly burns green when prepared properly.

According to my knowledge, the sodium cation in borax causes borax to normally burn yellow when dissolved in water. However, upon adding methanol (CH3OH), trimethyl borate is formed. The prescence of the borate ion turns the flame green during combustion.

Now, I'm having difficulty finding methanol, but I have frequently found methylated spirits being sold in my area. According to what I've searched up, methylated spirits are virtually just 10% methanol and 90% ethanol, so this stuff contains two types of alkanols that should react with borax. My question here is, can methylated spirits be substituted with methanol in mixing borax to produce green flames, or does the ethanol somehow not work?

DraconicAcid - 18-12-2017 at 21:34

I seem to recall that you need to add a bit of sulphuric acid to get the borax/ethanol mixture to work.

j_sum1 - 18-12-2017 at 22:22

You get better results with boric acid than you do with borax. No sodium ion to get in the way.
Making boric acid from borax is quite straightforward: mix up a solution of borax at high temperature to get a nice concentrated solution. Add some concentrated hydrochloric acid and watch your boric acid precipitate out. Filtering it while it is still warm is ok and lessens the liklihood of retaining some crystallised borax (which will occur on cooling.)
Adding this to either methanol or ethanol will work -- you get methyl borate or ethyl borate but both burn green. Using methanol is preferred since there is less carbon to add yellow to the flame.

If you need it, methanol is sold in the US as a Heet product. (I can't remember what its intended use is.

I tried this last year at Christmas. My problem actually was getting somethig strontium based that have a nice continuous flame.

goldensquid2000 - 18-12-2017 at 23:53

Quote: Originally posted by DraconicAcid

I seem to recall that you need to add a bit of sulphuric acid to get the borax/ethanol mixture to work.

Wait, really? The problem is that I live in Australia, where the stuff is heavily regulated. Can any other acids be substituted?

goldensquid2000 - 19-12-2017 at 00:00

Quote: Originally posted by j_sum1

You get better results with boric acid than you do with borax. No sodium ion to get in the way.
Making boric acid from borax is quite straightforward: mix up a solution of borax at high temperature to get a nice concentrated solution. Add some concentrated hydrochloric acid and watch your boric acid precipitate out. Filtering it while it is still warm is ok and lessens the liklihood of retaining some crystallised borax (which will occur on cooling.)
Adding this to either methanol or ethanol will work -- you get methyl borate or ethyl borate but both burn green. Using methanol is preferred since there is less carbon to add yellow to the flame.

If you need it, methanol is sold in the US as a Heet product. (I can't remember what its intended use is.

I tried this last year at Christmas. My problem actually was getting somethig strontium based that have a nice continuous flame.

Thanks for the advice. I'm not too fussy with some yellow in my flame, but the boric acid conversion sounds like an idea to try. Luckily, HCL is available in Oz, so I'll be able to get some. I might use a coffee filter for the boric acid, since regular filter paper is a pain to get here.

With the methanol/ethanol thing, I don't really have much of a choice unfortunately, since methanol is apparently regulated in Oz and not available for commercial use. I don't mind though, since a little yellow will make the flame seem less like Halloween and more happyish

I'm going to try the strontium fire in a few days. I soaked some pine cones in a saturated solution of strontium chloride and I'm going to toss a few in a fire.

j_sum1 - 19-12-2017 at 00:16

I bought 20L of methanol otc from a place that does specialist fuels and oils for performance cars. It is also sold for remote control planes. Shop around hobby stores.

[edit] located in oz.

[Edited on 19-12-2017 by j_sum1]

AngelEyes - 19-12-2017 at 02:21

Biodiesel suppliers is where I buy my methanol.
Also, lithium salts burn red too...can you source lithium chloride? Burns a decent red in methanol. I never had much success with strontium.

Sulaiman - 19-12-2017 at 06:12

To get a nice green flame I used Boric Acid and Methanol,
ethanol (methylated spirits) gives a slight yellow tinge to the flame, as does borax (sodium borate).
Also, if using a wick, it must be clean and trimmed to avoid yellow from carbon soot.

Melgar - 19-12-2017 at 09:01

Even the smallest trace of sodium will overwhelm the green tint with yellow. You really should look harder for boric acid. It's often sold as a low-toxicity anti-cockroach powder. Check the labels, and look for "100% boric acid".

To get the green color, you need to form borate esters, so you need to remove water somehow. Sulfuric acid is one option, but it'll interfere with the flame in many cases. So try mixing methylated spirits (denatured alcohol) with boric acid and silica gel, then shaking the mixture periodically. You can get silica gel by cutting open desiccant packs, and some places sell it as well.

If propylene glycol is easy to get, I've had very good luck mixing that with boric acid, although you have to give it some time to form the borate ester (about a day or so). It burns with an emerald-green flame, and burns more slowly than methanol does.

[Edited on 12/19/17 by Melgar]

Rhodanide - 19-12-2017 at 10:17

Quote: Originally posted by goldensquid2000

First up, I'm just going to put it out there that this is my first post, so soz in advance if I accidentally post in the wrong thread or something else like that (:

So, I want to make some nice green flames for the family in conjunction with the red strontium flames I'm making (it's the whole "red and green" Christmas theme). I've got some borax (aka sodium borate or disodium tetraborate Na2B4O7) that allegedly burns green when prepared properly.

According to my knowledge, the sodium cation in borax causes borax to normally burn yellow when dissolved in water. However, upon adding methanol (CH3OH), trimethyl borate is formed. The prescence of the borate ion turns the flame green during combustion.

Now, I'm having difficulty finding methanol, but I have frequently found methylated spirits being sold in my area. According to what I've searched up, methylated spirits are virtually just 10% methanol and 90% ethanol, so this stuff contains two types of alkanols that should react with borax. My question here is, can methylated spirits be substituted with methanol in mixing borax to produce green flames, or does the ethanol somehow not work?

Methanol is easily available in not only vehicle parts stores such as Napa and/or VIP, as well as being readily available at most gas stations!
It's in a bright yellow plastic bottle, usually located near to other vehicle fluids. It's small, and has a base about 3 or so inches wide, with a thin tapering neck about 2 centimeters wide, of a circular shape. It goes under the brand name "Heet" gas line antifreeze and water remover. It's usually right next to an identical RED bottle, which for this purpose is NOT what you want. The red bottle contains ISOPROPANOL, and the yellow one contains METHANOL, which is the one you want. Hope this helps, I'll also slide in a picture of the bottle below, if that helps you more. (NOTE: Since I now see that you're in Australia, availability for you may be different. Regardless, check both hardware stores, auto part stores, and maybe even gas stations.)

Right! Now the Boric acid. You don't want to use the Borax, as the Sodium contained in it will overwhelm the Boron's green color with it's bright yellow hue. You need Boric acid! You can find it most reliably in any hardware store which carries it. You may need to do some research, as I guess you're in Australia and I'm in the US, so your stores and the availability of products are likely different. It's most commonly sold as a cockroach killer, and comes in the form of a fine white powder. Container types may vary where you live, but they should all say the same thing. Check it's ingredients first, of course! I've left an example picture of the kind that they sell near me.
Best of luck, and Happy Holidays!
-R/T

download.jpg - 9kB

[Edited on 19-12-2017 by Tetra]

[Edited on 19-12-2017 by Tetra]

Chemetix - 19-12-2017 at 11:19

Look for water softener in pool shops, check the labels but you will find some that are 100% boric acid. I'm in Aus btw.