frobet - 14-12-2012 at 10:40
Attempting to find a procedure for converting Potassium Borohydride into Sodium Borohydride. There seems to be a lot of literature on converting
Sodium Borohydride into a number of different Borohydrides, but nothing about turning Potassium back into Sodium Borohydride.
I'm thinking something with NAOH as Potassium Borohydride is made with Aqueous KOH and NABH4.
Sodium Borohydride Digest
thanks,
Attachment: BoronBrown.pdf (419kB)
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DJF90 - 14-12-2012 at 10:56
Using NaOH will never work, clearly. If you consider the known preparation of KBH4 from NaBH4, you'll see why:
NaBH4 + KOH => NaOH + KBH4
The only way you'll ever get your idea to work is if you find a solvent other than water that does not react with the reaction species and allows the
reverse reaction.
garage chemist - 14-12-2012 at 11:03
Why can't you use the KBH4 as it is? Are you sure you really need NaBH4?
frobet - 14-12-2012 at 11:43
Sodium Borohydride has a significantly higher hydrogen Content than KBH4.
That and I have a large amount of KBH4, I'm frustrated I haven't found anything on converting it to NABH4.
DJF90 I know I couldn't complete that reaction using water as a solvent and I don't really think NAOH is the answer but its a place to start.
The Boron Brown Paper attached gives methods of converting KBH into LIBH using Lithium chloride in THF, would THF serve as a possible useful solvent
for the reaction of NABH4 from KBH?
Attachment: BoronBrown.pdf (419kB)
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mr.crow - 14-12-2012 at 12:17
Hydrogen content? You mean per gram? It has the same number of moles of hydrogen, just a higher molecular weight. Unless there is something else going
on.
DJF90 - 14-12-2012 at 12:33
I think you're barking up the wrong tree. Use the KBH4 as is, its a suitable replacement for NaBH4 in almost all cases. Hydrogen density would only
really matter if you're intending on using it for fuel cell purposes.
frobet - 14-12-2012 at 12:55
So are we saying it can't be done?
I thought we would at least get some plausible ideas going...
DJF90 - 14-12-2012 at 13:17
you havent illustrated why KNH4 doesnt suffice, and what it is you're trying to achieve by this metathesis reaction. Do you specifically need NaBH4?
If you think you do, for what purpose? Other members of the forum might be able confirm or clarify whether it is necessary.
Nicodem - 15-12-2012 at 11:23
I seriously doubt that a person who believes the chemical symbol for sodium is "NA" could be competent enough to answer your question regarding a
chemical procedure. If he would have been able to, he would have described the intended use of NaBH4 already in the first post.
chemrox - 15-12-2012 at 23:16
Added to that, why would you want to convert a more expensive borohydride to the cheaper one. KBH4 is soluble in THF. I have a solution for you. I
will trade you 200 grams of NaBH4 for 200 grams of KBH4. Everyone gets what he wants and no losses due to conversions.