Oscilllator
National Hazard
Posts: 659
Registered: 8-10-2012
Location: The aqueous layer
Member Is Offline
Mood: No Mood
|
|
STAB and NaBH4 aquisition or synthesis
where does one obtain sodiumtriacetoxyborohydride OTC? I couldn't find any sources other than chem suppliers like Aldrich.
Edit by Nicodem: This thread was made by splitting the off-topic discussion originating in the Dimethylation of tryptamine via formaldehyde/STAB thread.
[Edited on 8/8/2013 by Nicodem]
|
|
|
Hockeydemon
Hazard to Others
Posts: 218
Registered: 25-2-2013
Member Is Offline
Mood: No Mood
|
|
I found some on Ebay here, but it sure isn't cheap. It's $125 for 25g of the stuff.
|
|
|
hive3
Harmless
Posts: 27
Registered: 3-7-2013
Member Is Offline
Mood: No Mood
|
|
STAB
I Believe the sodiumtriacetoxyborohydride is created in situ from NaBH4 and the acidic acid. You don't have to buy it.
|
|
|
Oscilllator
National Hazard
Posts: 659
Registered: 8-10-2012
Location: The aqueous layer
Member Is Offline
Mood: No Mood
|
|
And where does one obtain NaBH4 from an OTC source? It appears that only sigma and other such suppliers sell NaBH4 and STAB is hardly "dirt cheap"
Edit: Hockeydemon, sigma sells it for 83.50/25 grams and sigma is usually on the more expensive end of the scale, so perhaps a decently cheap supplier
can be found
Edit2: excellent article on various methods of synthesizing sodium borohydride:
http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/review...
[Edited on 5-8-2013 by Oscilllator]
[Edited on 5-8-2013 by Oscilllator]
|
|
|
Crowfjord
Hazard to Others
Posts: 390
Registered: 20-1-2013
Location: Pacific Northwest
Member Is Offline
Mood: Ever so slowly crystallizing...
|
|
Such a question is better suited for the Reagents and Apparatus Aquisision sub-forum. But the question doesn't really need to be asked. A patient and
diligent search will provide the answer. At least two amateur-friendly shops are mentioned in said sub-forum which sell sodium borohydride for an
acceptable price.
|
|
|
zed
International Hazard
Posts: 2283
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
Member Is Offline
Mood: Semi-repentant Sith Lord
|
|
Ball milling anhydrous borates with MgH2 is a documented method of producing NaBH4.
MgH2 is hard to come by, and difficult to handle. CaH2 might be able to achieve the same reduction. Sometimes it is economically priced, and it is
much easier to handle.
|
|
|
Blue Matter
Hazard to Others
Posts: 107
Registered: 20-6-2013
Location: US
Member Is Offline
Mood: Optimus
|
|
http://reagentshop.com/home/366-sodium-borohydride-reagent-5...
I doubt anyone would need 500g but its a good price.
|
|
|
zed
International Hazard
Posts: 2283
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
Member Is Offline
Mood: Semi-repentant Sith Lord
|
|
Recent developments prove that NaBH4 isn't that hard to make. My suggestion that inexpensive CaH2 might be a good starting material might or might
not be valid. As cheap, surplus CaH2 isn't readily available right now, the point is moot.
At any rate, the quick survey of the literature, suggests that procedures utilizing MgH2 or Mg, have been more successful.
These Korean fellows report reasonable yields of NaBH4 from finely ball milling anhydrous NaBO2 with Mg, then heating the mixture under ~50ATM H2 at
500-600 C.
MgH2 is formed in situ, and in conjunction with H2 it reduces NaBO2 to NaBH4.
http://corrosion.kaist.ac.kr/journal/!!thermochemical.pdf
Yeah, you would have to build a suitable pressure vessel. You would need a cylinder of Hydrogen, and the reaction requires a moderate amount of heat.
Still, it's do-able.
[Edited on 7-8-2013 by zed]
|
|
|
Blue Matter
Hazard to Others
Posts: 107
Registered: 20-6-2013
Location: US
Member Is Offline
Mood: Optimus
|
|
What kind of pressure vessel would you need and how would you heat it to 500c? If you heated just about any container to 500c under vacuum wouldn't it
implode?
|
|
|
Bot0nist
International Hazard
Posts: 1559
Registered: 15-2-2011
Location: Right behind you.
Member Is Offline
Mood: Streching my cotyledons.
|
|
Heat a crucible, inside the pressure contianer maybe... I dont know though. Definatly not a reaction I will be attempting. Sounds dangerous for a home
lab...
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
|
|
|
bfesser
Resident Wikipedian
Posts: 2114
Registered: 29-1-2008
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by Blue Matter  | | What kind of pressure vessel would you need and how would you heat it to 500c? If you heated just about any container to 500c under vacuum wouldn't it
implode? |
<a href="http://corrosion.kaist.ac.kr/journal/!!thermochemical.pdf#page=2"
target="_blank"> | Quote: | <strong>2. Experimental methods</strong>
<strong><em>2.1. Setup of reactor</em></strong>
<a>Fig. 1</a> presents a scheme of the homemade system for thermochemical hydride production to induce high temperature and
H<sub>2</sub> pressure in the reactor. The system is composed of inlet gas lines, outlet gas lines, a reactor, furnace, temperature
sensors (located in the reactor inside, reactor outside, and furnace), pressure sensors, a BPR (back pressure regulator), two condensers with cooling
water inlet (CWI) and outlet (CWO), a vacuum pump for removing the remained residual oxygen, and vent lines. In <a>Fig. 1</a>, the reactor
has an internal volume of 100 ml and is constructed of Ni-based alloy (Inconel 600) that has high corrosion
resistance at high temperatures. The upper limit for temperature and H<sub>2</sub> pressure are 700 °C and 70 bar, respectively.
<img src="../scipics/_pdf.png" /> |
</a>
<a href="http://en.wikipedia.org/wiki/Inconel" target="_blank">Inconel™</a> <img src="../scipics/_wiki.png" /> <a
href="http://en.wikipedia.org/wiki/Superalloy" target="_blank">Superalloy</a> <img src="../scipics/_wiki.png" />
<em>"Homemade" my ass!</em>
|
|
|
Blue Matter
Hazard to Others
Posts: 107
Registered: 20-6-2013
Location: US
Member Is Offline
Mood: Optimus
|
|
found it only 100 bucks.
http://www.sigmaaldrich.com/catalog/product/aldrich/z246360?...
|
|
|
Lambda-Eyde
National Hazard
Posts: 860
Registered: 20-11-2008
Location: Norway
Member Is Offline
Mood: Cleaved
|
|
That's a crucible, not a pressure reactor. Which is the expensive part.
This just in: 95,5 % of the world population lives outside the USA
Please drop by our IRC channel: #sciencemadness @ irc.efnet.org
|
|
|
Blue Matter
Hazard to Others
Posts: 107
Registered: 20-6-2013
Location: US
Member Is Offline
Mood: Optimus
|
|
I was thinking you buy the crucible then put into a high temp vacuum oven, could that work?
|
|
|
Oscilllator
National Hazard
Posts: 659
Registered: 8-10-2012
Location: The aqueous layer
Member Is Offline
Mood: No Mood
|
|
Ehhhh, it seems like you guys are overdoing this. I dont think pressure of 50atm are required. I refer you to
http://www.sciencemadness.org/talk/viewthread.php?tid=3151
where bromicAcid has posted a promising procedure, which I shall very roughly outline:
A metal (e.g. magnesium) boride is produced via the reaction between B2O3 and the metal at relatively high temperatures.
This is then hydrolysed to sodium borohydride in a very alkaline solution.
This method is more or less supported in the article I posted earlier, and the only thing that could be a problem to get is the highish temperatures.
I will be trying this method myself once my crucibles arrive 
[Edited on 8-8-2013 by Oscilllator]
|
|
|
Blue Matter
Hazard to Others
Posts: 107
Registered: 20-6-2013
Location: US
Member Is Offline
Mood: Optimus
|
|
What type of crucible did you buy for the reaction a simple silica or graphite one or something more complicated?
|
|
|
Oscilllator
National Hazard
Posts: 659
Registered: 8-10-2012
Location: The aqueous layer
Member Is Offline
Mood: No Mood
|
|
I didn't buy the crucibles specifically for this reaction, in fact I found out about it after I ordered them. They are the cheap n nasty porcelain
ones. I bought 15 of them, but at $1.10 each its no great loss  . I did have a
silica one, but it developed a hole and poured ~150ml of molten copper into my forge 
I don't think that any special crucible is required. Slap a lid on and the atmosphere wont really be able to get in because of positive pressure.
|
|
|
Nicodem
|
Thread Moved
8-8-2013 at 00:56 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
