Sciencemadness Discussion Board

Borate Spirit Lamps

DalisAndy - 11-9-2015 at 16:10

Hello everyone. Since Halloween is about a month away, I was think about making some borate spirit lamps. For those who don't know borate compound tend to burn green. So I have gather nearly all the required chemicals to make trimethyl borate, triethyl borate, and triisopropanol borate. I was wondering if dissolving a borate in water (or any other) would allow for it to be used in an alcohol lamp? And if not, how could I make a spirit lamp for jack-o-lanterns? Also will the ending boron trioxide just fall to the bottom as a gray powder? And that isn't toxic/harmful. What I have read says no. But I know there are a few of you out there with Ph.D.'s in chemistry

DraconicAcid - 11-9-2015 at 17:25

You cannot dissolve a borate ester in water to any appreciable extent (and it would hydrolyze anyway). You could dissolve it in alcohol, though.

I've poured it on campfires, but never tried it in a burner.

Oscilllator - 11-9-2015 at 20:03

I've dissolved some boric acid in ethanol with some success. The flame is reasonably green to start, but there are problems with boric acid accumulating of the wick due to evaporation of the ethanol. Sodium contamination also tends to colour the flame yellowish, so it isn't completely green.
Perhaps using trimethyl borate or similar would avoid the accumulation problem though.

DalisAndy - 11-9-2015 at 20:41

Quote: Originally posted by Oscilllator  
I've dissolved some boric acid in ethanol with some success. The flame is reasonably green to start, but there are problems with boric acid accumulating of the wick due to evaporation of the ethanol. Sodium contamination also tends to colour the flame yellowish, so it isn't completely green.
Perhaps using trimethyl borate or similar would avoid the accumulation problem though.

Where you attempting to make triethyl borate? Same way as with trimethyl borate btw. You could use borax instead of boric acid

Oscilllator - 11-9-2015 at 21:00

No, I wasn't. I just wanted to make the alcohol burner I used to head test tubes have a pretty flame so I dumped some in as an experiment.

ave369 - 12-9-2015 at 00:11

Not the best fuel for alcohol burners: it soots B2O3.

j_sum1 - 12-9-2015 at 01:01

I believe boric acid dissolves ok in methanol and gives a green flame. I haven't done it. I have mixed boric acid with methylated spirits and burned it in a bowl without a wick. The effect is quite good.

Little_Ghost_again - 12-9-2015 at 02:09

You can get special glass fibre pens for cleaning pcb boards, the pen bit is like very very fine glass strands. I have used these before as wicks and they dont soot up or discolor the flame as much, it might also be worth using cleaned rock wall (the insulation stuff) as a wick. I read somewhere you can clean in conc sulphuric acid to burn off any organics (colourings etc) then was and clean in acetone, I have also used this as wick material but prefer the fibre pens

PHILOU Zrealone - 12-9-2015 at 03:32

Add a little CuCl2 it will enhance the blue/green.

Only CuCl2 saturated ethanol already makes wonders, but use glass fiber wick not a cotton wick (contains Na that polute the colour with yellow-orange). Same process could be used with LiCl for deep red and CaCl2 for pink-orange.

aga - 12-9-2015 at 09:01

The perfect wick is a strand off an old style mop head - the kind that are cotton.

Cheers to arkoma for that tip.