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Author: Subject: Isolation of Boron from Borax (Sodium Tetraborate)
papaya
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[*] posted on 30-9-2013 at 11:50


Well, you could try to do Mg + Na2SiO3 reaction and report back the results if you want the silicate (what about glass+Mg?). I don't know the outcome of course, don't forget that all these boranes, phosphines, silanes are a fire hazard and very toxic.
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bismuthate
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[*] posted on 30-9-2013 at 12:04


i would love to i have some pyrex an mg ribbon that should work
maybe we coulb make boon from glass!




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[*] posted on 30-9-2013 at 12:22


Quote: Originally posted by papaya  
In theory yes I think - see videos on the same channel - with phosphate instead of borax he gets something that when water(or acid) is added releases a gas immediately catching fire - phosphine. (oh - easy way to P2O5 :P )


I hope that latter bit was an attempt at irony: phosphine and diphosphine are very, very toxic, as well as extremely flammable. From Wiki:

NIOSH recommends that the short term respiratory exposure to phosphine gas should not exceed 1 ppm. The Immediately Dangerous to Life or Health level is 50 ppm.

Trying to prepare B2O3 from burning boranes is folly when you can just heat boric acid to full dehydration. Borides aren't that easy to prepare either.




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blogfast25
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[*] posted on 30-9-2013 at 12:28


Quote: Originally posted by papaya  
Well, you could try to do Mg + Na2SiO3 reaction and report back the results if you want the silicate (what about glass+Mg?).


Huh??? Fine sand and an excess Mg powder can be reacted to Mg2Si, magnesium silicide, which when treated with acids like HCl gives a mixture of silanes, mainly monosilane and disilane. There must be numerous Utoobs on Mg2Si and silanes. They do spontaneously combust when in contact with air...

[Edited on 30-9-2013 by blogfast25]




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bismuthate
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[*] posted on 30-9-2013 at 12:28


i want to see if i can make boron from glass as an unusual method.



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[*] posted on 30-9-2013 at 12:32


Quote: Originally posted by bismuthate  
i want to see if i can make boron from glass as an unusual method.


Even borosilicate glass only contains about 15 % B2O3. And glass is a notoriously unreactive substance. Honestly, try and make some B2O3 in the usual way and look up in Brauer's 'Preparative Chemistry' (see library) how to get boron from that.

[Edited on 30-9-2013 by blogfast25]




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bismuthate
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[*] posted on 30-9-2013 at 12:38


i know how you mix B2O3 with mg and ignite it then wash with HCl, but i want to prepare it with a unique method.
lithium reacts with glass and i have some.




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[*] posted on 12-10-2013 at 19:22
Reaction of borax decahydrate with an acid


I am attempting to isolate a sample of boron from borax, and every source I find says that the first step is to react it with some acid. Unfortunately, I am having extreme difficulty coming up with a balanced equation for the reaction of borax decahydrate with an acid. I would like an equation for this reaction using HCl and for using H2SO4, just for reference. I know the decahydrate portion plays a significant role in the reaction, but I just can't figure it out.
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[*] posted on 12-10-2013 at 19:59


This should help :)

http://en.wikipedia.org/wiki/Boric_acid#Preparation




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WGTR
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[*] posted on 12-10-2013 at 20:37


Just a suggestion...boric acid can usually be purchased at the grocery store as "roach killer". It's pretty cheap.
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violet sin
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[*] posted on 12-10-2013 at 20:54


It's fun to mix the boric acid w/ methanol to make green flames :) trimethyl borate. It's not a crazy reaction that goes off by it self, ya have to light it. I have had some in a bottle since Halloween 2 years back. I used the roach powder from Walmart. Cheap fun, but it does burn fairly hot so watch out. I had put some in a beer bottle and once the flame got me. Nothing bad, just missing hair on my hand :) I know that this wasn't the question you were asking but with Halloween coming up, why not mention it. For the methanol I used "HEET", yellow bottle found in auto isle for flushing radiator systems. It's also fairly cheap at Walmart, ~2$ each. I got a couple 4 packs ther and am still using it for various things.

Woulda put in the links to specific items I describe, but I'm outta town working again and only have an iTouch for Internet connectivity, sry.



[Edited on 13-10-2013 by violet sin]
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[*] posted on 12-10-2013 at 20:58


Ah, thanks. I have seen that equation before but I was trying to use an equation balancing applet to confirm it, but I guess it doesn't deal well with hydrates. Also, is the roach killer pure boroc acid? It seems a little unlikely. Now, onto isolating some boron...

I'm trying to see if it is possible with cheap, common household ingredients. First would be to react borax with excess vinegar at elevated temperatures with this equation:

Na2B4O7 • 10H2O + 2C2H4O2 -> 2Na2C2H3O2 + 4H3BO3 + 5H2O

Then, the resultant boric acid is heated to decompose into boric oxide. The boric oxide is then made into a solution and aluminum foil is added:

B2O3 +2Al -> Al2O3 + 2B

I have checked and aluminum is capable of replacing boron in single replacement in an aqueous solution at room temperature.

Now, this procedure has some difficulties. After reacting the borax with vinegar, there will probably be a big pile of a mixture between leftover borax, sodium acetate, and boric acid. I read that if the solution is cooled back down, the boric acid will precipitate leaving the other salts dissolved in water, although I'm not sure of the validity of this statement. Also, the end product will be a solution containing boron and aluminum oxide; how could I separate them?
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violet sin
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[*] posted on 12-10-2013 at 21:12


I have found pure boric acid in CVS and Rightaid stores. Antiseptic wash aid I believe, came as a dry powder with USP(like other things used on people). The roach powder was blue tinged and not pure. But Much cheaper( not the point I understand). The stuff @ CVS was like 7$ for a medium sized pill bottle worth.

For your plans borax may be fine. Could you buy a small bottle of HCl? 3$ at ACE hardware. I seem to remember seeing some vids on YouTube a while back. Borax was more soluble than boric acis, so when HCl was mixed in the BA precipitated out. Obviously some was still in sol. But who cares.

There were also vids there of people using the thermite rxn with Al powder under a coffee can. They had heated their boric acid to get the oxide, crushed it and mixed in Al. After it was done the guy used acid(again HCl I think) to etch off the crud. And was left with black shiny lumps. I'll see if I can come up with a couple vids for ya, but take a look your self too.

Hope that was a bit more productive of a response
http://m.youtube.com/watch?v=0QBCyOrjR2o
http://m.youtube.com/watch?v=0kbm92a2ltc

[Edited on 13-10-2013 by violet sin]

[Edited on 13-10-2013 by violet sin]
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[*] posted on 12-10-2013 at 23:48


The roach powder that I found was 99% pure. I recrystallized it from hot water a couple of times because I was using it in electroplating (purity is important in that case).

I have a thought question for you. What is being driven off from the boric acid in order to make it into boric oxide?

Also, if you weaken aluminum's tenacious oxide layer (with gallium or mercury), does it react with water?
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weiming1998
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[*] posted on 13-10-2013 at 01:47


When you heat boric acid to make boron trioxide, water vapour is being driven off.

And aluminium indeed reacts with water when its oxide layer is removed with gallium or mercury. This should demonstrate it pretty well.
https://www.youtube.com/watch?v=JasZ8V6LpbQ
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[*] posted on 13-10-2013 at 06:23


Even though pure aluminum will react with water, I still have seen demonstrations of putting aluminum foil in a CuCl2 aqueous solution, yielding copper metal (even though some hydrogen gas was still produced).

Also, how concentrated is the HCl from the hardware store? I know I can also get muriatic acid (HCl) from the local pool store. Would vinegar not just do the same job anyway, just slower? Even if it is only a 5% solution, it should still work if I add enough. I guess I'll try this out and share my results.

[Edited on 13-10-2013 by Upsilon]
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violet sin
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[*] posted on 13-10-2013 at 07:46


Muriatic is fine, that's actually what I meant. The acid has to be strong enough to take the sodium and protonate the weaker acid from borax. Also at only 5% sol you are giving it too much water to dissolve your boric acid product I think. Prob not goin to hit its sol limit and ppt.
Hope it helps, but I literally just woke up so hope I explained it right
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bismuthate
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[*] posted on 13-10-2013 at 07:47


I would not recomend vinegar because it is 95% water which the boric acid can dissolve in, effectively lowering your yield. I belive that concentrated acids are best in this situation. However if your yeild doesn't matter it would work.



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[*] posted on 13-10-2013 at 11:32


Quote: Originally posted by Upsilon  
Even though pure aluminum will react with water, I still have seen demonstrations of putting aluminum foil in a CuCl2 aqueous solution, yielding copper metal (even though some hydrogen gas was still produced).


If boric oxide is simply dehydrated boric acid, then when you add boric oxide back to the water again, does it reform boric acid? And what would happen if you add aluminum to that?

The videos that I have seen so far involve a thermite-type reaction under anhydrous conditions. It would be interesting to see if you can do it in an aqueous solution.
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[*] posted on 13-10-2013 at 12:45


Not sure if this helps, but Rite Aid pharmacies selling over the counter pure boric acid for like $5.00. It was located near the iodine/antiseptics section of the store.

http://shop.riteaid.com/Rite-Aid-Boric-Acid-Powder/dp/B005X7...
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[*] posted on 13-10-2013 at 13:47


There are no Rite Aid stores near me, and I can't seem to find any boric acid on the CVS website. Anyway, as for my experiment so far, I added 150 mL of vinegar to 10g of borax, heated it, and let it sit for a while. I then refrigerated it hoping to see some precipitate, but there was none. Now I just set the solution outside to let the vinegar evaporate to leave a mixture of borax hopefully along with some sodium acetate and boric acid. I'm just going to dump the mixture in some water, dissolve it, toss in some aluminum, and see if any black crystals form.
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bismuthate
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[*] posted on 13-10-2013 at 14:09


There was no percipitate because excess water dissolved the boric acid.
Also aluminuium will not percpitate boron first because the aluminum pssivates and second because if they did react alumminium borate would be formed, not boron.




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[*] posted on 13-10-2013 at 15:39


Quote: Originally posted by bismuthate  
There was no percipitate because excess water dissolved the boric acid.
Also aluminuium will not percpitate boron first because the aluminum pssivates and second because if they did react alumminium borate would be formed, not boron.


Aluminum certainly does have the potential to replace boron, I'll pull up my source if you need me to. Also, would you please show the balanced equation for the formation of aluminum borate? Some may form, but there would still be an ample amount of boron. People usually extract boron from boric oxide by reducing it with magnesium, but aluminum would work just as well.
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bismuthate
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[*] posted on 13-10-2013 at 16:28


I did not say it did form I said that it would form if there was any reaction. However I very well may be wrong. Please do show this reference.
Also yes it is reduced with magnesium but from my experience never while in solution.
ps The equation would be 2Al+2H3BO3==>2AlBO3+3H2 however this reaction does not take place due to passivisation.




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[*] posted on 13-10-2013 at 16:51


I do not have the exact website, however it is a PDF file called "redpot.pdf" at courses.chem.indiana.edu

Edit: Ah, I found it. Here it is: https://www.google.com/url?sa=t&source=web&cd=1&...

Sorry about the huge link, but I'm on a mobile device and I cannot get the exact link, I just have to use the Google search link.

[Edited on 14-10-2013 by Upsilon]
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