| Pages:
1
2
3
..
5 |
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
Isolation of Boron from Borax (Sodium Tetraborate)
would a solution of borax + chlorine make boron oxide because that would be an easy route to elemental boron
<!-- bfesser_edit_tag -->[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: replaced
subject "boron" to reflect topic of merged threads]
[Edited on 14.10.13 by bfesser]
|
|
|
12AX7
Post Harlot
Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline
Mood: informative
|
|
Use HCl, not chlorine.
B(OH)3 will precipitate. It has to be fused to make boron oxide.
Tim
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
i'm not allowed to use heat to decompose it so i was wondering can it react with chlorine?
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
Reacting it with chlorine won't do zilch.
Borax is a (complex) salt of a very weak acid, i.e. boric acid (B(OH)3). When a stronger acid (like HCl) is added to a solution of borax the stronger
acid displaces the weaker one. Simply put:
Borax (solution) + HCl (solution) === > B(OH)3 (oily flakes) + NaCl (solution)
There are plenty recipes for this, use the search facility.
Then filter off the boric acid, wash and dry it. Then, on strong heating, it loses water and forms a glassy mass of B2O3:
2 B(OH)3(s) ==(heat)== > B2O3(s) + 3 H2O(g)
This can be reacted with Al or Mg powder to produce elemental boron. But obtaining pure boron this way isn't easy. See Brauer (library) for a
procedure.
If you're not allowed to use heat, then forget about chemistry: heat is what drives much of it!
[Edited on 29-9-2013 by blogfast25]
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
well i can use heat for short times via alcohol burner and reactions but i can't use a large fire or a stove which is used to decompose boric acid. is
there any other way to make it like a way to make BCl3 or something along the lines of that? (probably not i can't think of a way)
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
An alcohol burner might just be hot enough to slowly dehydrate boric acid. But I'm not sure what temperature is needed for FULL dehydration
(obtaining anhydrous B2O3) Smart use of your burner and correct choice of crucible (copper for instance) could do wonders here.
BCl3 from borax is a hat trick and you'd need to go via B2O3 anyway. It's extremely reactive towards water...
[Edited on 29-9-2013 by blogfast25]
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
i have a idea! i can put the crucible of borax on a Al/MnO2 thermite mixture which will run for quite a while. will that work?
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by bismuthate  | | i have a idea! i can put the crucible of borax on a Al/MnO2 thermite mixture which will run for quite a while. will that work?
|
NO! Thermite mixtures, ESPECIALLY MnO2 thermites, burn far too hot and far too short.
Try this. Use your spirit burner on a 'high' setting (longish wick), with methanol if possible.
Now you'll need some kind of a 'crucible'. A piece of copper sheet would be ideal but if you haven't got any some mild steel sheet cut from a steel
pop can for instance, could work. Fashion it into a concave surface, some 3 x 3 cm maximum. Load a quarter of a teaspoon of the dried boric acid onto
it. Now try and somehow clamp this 'crucible' at the right height above the burner, so you don't have to hold it (which would quickly become tiresome)
and light up the burner. Or try a disused teaspoon (thin metal if possible) as a crucible...
Carefully observe the boric acid: it will probably melt and should start giving off steam. Whether you'll reach high enough temperature to fully
dehydrate it to B2O3 I don't know. It will in any case take time, at least 30 min on full heat.
On p 57 of 'The Golden Book of Chemistry', which you can download here:
http://chemistry.about.com/b/2012/10/01/download-the-golden-...
... is described an experiment that claims to prepare boric oxide from boric acid, with a teaspoon and a spirit burner. But it's not clear to me
whether actual B2O3 or rather one of several intermediates (HBO2 or H2B4O7) is obtained. It's largely a question of heating time, I'm guessing.
[Edited on 29-9-2013 by blogfast25]
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
That would work, but could I silver instead of copper for better conductivity?
|
|
|
elementcollector1
International Hazard
Posts: 2684
Registered: 28-12-2011
Location: The Known Universe
Member Is Offline
Mood: Molten
|
|
Why would you want better conductivity?
If you mean heat conductivity, I think you'd want less, not more: More heat conductivity will mean more heat is dispersed to the atmosphere.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
|
|
|
papaya
National Hazard
Posts: 615
Registered: 4-4-2013
Member Is Offline
Mood: reactive
|
|
Look at this
https://www.youtube.com/watch?v=3IAv6Ohjuh8
It may be that one of the products is boron (I'm not sure).
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
What was that? (I only speak English, sorry)
Also, could i burn a pile of Mg ribon to provide heat?
|
|
|
violet sin
International Hazard
Posts: 1475
Registered: 2-9-2012
Location: Daydreaming of uraninite...
Member Is Offline
Mood: Good
|
|
I don't know that every one has these available, but the little stainless steel condiment cups are great for stuff like this. I went to a near by
wall-mart and got 2 four packs of em for 97cents each. practically disposable at that cost.
http://www.walmart.com/ip/Mainstays-Condiment-Cups/14964954
work great for me
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
Thanks for the tip. Also, kind of off topic but i went to Stop and Shop and i saw 100ml pyrex custard cups and they would make great beakers for small
experiments.
|
|
|
bfesser
Resident Wikipedian
Posts: 2114
Registered: 29-1-2008
Member Is Offline
Mood: No Mood
|
|
Beware that new "Pyrex" cookware isn't borosilicate, and therefore prone to thermal shock induced shattering.
|
|
|
Tdep
National Hazard
Posts: 516
Registered: 31-1-2013
Location: Laser broken since Feb 2020 lol
Member Is Offline
Mood: PhD is done! It isn't good but it's over lol
|
|
Is there any distinguishing way to tell if glassware is borosilicate or not? Does it have to be labelled as such or is your only clue when it shatters
under heat shock?
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
i wasn't suggesting usin pyrex for this reaction, i was just mentioning somthing i saw at the store. sorry for the confusion.
|
|
|
bfesser
Resident Wikipedian
Posts: 2114
Registered: 29-1-2008
Member Is Offline
Mood: No Mood
|
|
The cookware issue was discussed a few years ago in <a href="viewthread.php?tid=12170">several topics</a>.
[Edited on 30.9.13 by bfesser]
|
|
|
papaya
National Hazard
Posts: 615
Registered: 4-4-2013
Member Is Offline
Mood: reactive
|
|
It is a mixture of borax + magnalum, a non-standard thermite, I suppose the boron (or some borides) may be on of the products (another is sodium as
you can see it afterburning in video).
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
thats interesting if i mix borides with HCl i get boran which i can burn to get B2O3 right?
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by elementcollector1 | Why would you want better conductivity?
If you mean heat conductivity, I think you'd want less, not more: More heat conductivity will mean more heat is dispersed to the atmosphere.
|
No. The highest temperature of a material in a rudimentary crucible (all other things being equal) is obtained with the highest heat conductivity
crucible material and the thinnest crucible wall thickness. That's basic heat transfer science. There's no getting around that.
[Edited on 30-9-2013 by blogfast25]
|
|
|
papaya
National Hazard
Posts: 615
Registered: 4-4-2013
Member Is Offline
Mood: reactive
|
|
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  )
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
that sounds awesome shame i don't have any phosphates
would this work with silicates? just out of curiosity.
|
|
|
papaya
National Hazard
Posts: 615
Registered: 4-4-2013
Member Is Offline
Mood: reactive
|
|
search for SiO2 + Al + S thermite. Btw. there's an entire discipline in material synthesis (mostly ceramics) called SHS
https://en.wikipedia.org/wiki/Self-propagating_high-temperat...
|
|
|
bismuthate
National Hazard
Posts: 803
Registered: 28-9-2013
Location: the island of stability
Member Is Offline
Mood: self reacting
|
|
actualy i was talking about silicates mixed with aluminum. (I have already seen many videos about sand thermite) hovever i found that link very
interesting. maybe i'll use one of those reactions soon.
[Edited on 30-9-2013 by bismuthate]
|
|
|
| Pages:
1
2
3
..
5 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
