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Author: Subject: STAB and NaBH4 aquisition or synthesis
Oscilllator
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[*] posted on 31-7-2013 at 22:13
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]




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Hockeydemon
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[*] posted on 31-7-2013 at 23:40


I found some on Ebay here, but it sure isn't cheap. It's $125 for 25g of the stuff.
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[*] posted on 1-8-2013 at 13:02
STAB


I Believe the sodiumtriacetoxyborohydride is created in situ from NaBH4 and the acidic acid. You don't have to buy it.
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Oscilllator
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[*] posted on 5-8-2013 at 00:29


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]




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[*] posted on 5-8-2013 at 16:18


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.
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[*] posted on 5-8-2013 at 17:48


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.
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[*] posted on 6-8-2013 at 12:43


http://reagentshop.com/home/366-sodium-borohydride-reagent-5...

I doubt anyone would need 500g but its a good price.




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zed
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[*] posted on 7-8-2013 at 10:35


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]
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Blue Matter
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[*] posted on 7-8-2013 at 13:14


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?



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[*] posted on 7-8-2013 at 13:20


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...



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[*] posted on 7-8-2013 at 13:37


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 &deg;C and 70 bar, respectively. <img src="../scipics/_pdf.png" />
</a>
<a href="http://en.wikipedia.org/wiki/Inconel" target="_blank">Inconel&trade;</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>




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[*] posted on 7-8-2013 at 13:52


found it only 100 bucks.

http://www.sigmaaldrich.com/catalog/product/aldrich/z246360?...




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[*] posted on 7-8-2013 at 15:56


That's a crucible, not a pressure reactor. Which is the expensive part.



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[*] posted on 7-8-2013 at 15:58


I was thinking you buy the crucible then put into a high temp vacuum oven, could that work?



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[*] posted on 7-8-2013 at 19:25


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 :cool:

[Edited on 8-8-2013 by Oscilllator]




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[*] posted on 7-8-2013 at 19:54


What type of crucible did you buy for the reaction a simple silica or graphite one or something more complicated?



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[*] posted on 7-8-2013 at 20:08


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 :D. 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.




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