zooligan (Hive Addict)
10-14-00 20:38
No 60166
      Potassium borohydryde???  Bookmark   

Can it be substituted for sodium borohydride in the synths discussed here at the Hive???

(Chief Bee)
10-14-00 23:22
No 60205
      Re: Potassium borohydryde???  Bookmark   

Yes, if it is substituted in a stoichiometrical amount. The molar weight of KBH4 is higher than for NaBH4.

(Hive Addict)
10-17-00 00:25
No 60663
      Re: Potassium borohydryde???  Bookmark   

Great,  cuz it's about 1/3 the price! 

Will there be any noticeable difference in the workup of any reduction carried out with KBH4 in place of the NaBH4, or is it a completely transparent substitution?

(Stonium's / Changer)
10-17-00 00:51
No 60669
      Re: Potassium borohydryde???  Bookmark   

Solubility of KBH4 might differ somwhat from NaBH4, but for our purposes the differences are negilible (if there are any at all). Reactivity, workup etc. can be considered exactly the same for Na and K variety.
(Hive Addict / Eraser)
10-17-00 02:41
No 60705
      Re: Potassium borohydryde???  Bookmark   


(Hive Bee)
10-17-00 08:42
No 60794
      Re: Potassium borohydryde???  Bookmark   

Yeah, the solubility might be a bit of a problem. Only 0.7% in methanol vs. 16% for sodium borohydride.
(Stonium's / Changer)
10-17-00 11:02
No 60825
      Re: Potassium borohydryde???  Bookmark   

Oooops, it is that low? Didn't know that!
On the other hand, that doesn't necessarily mean it's a disadvantage. The NaBH4 reductive amination needs slow addition of NaBH4 anyway, when you use KBH4 the concentration will be limited by the solubility. Could even be a good thing.
Post your results zooligan.
10-17-00 11:30
No 60829
      Re: Potassium borohydryde???  Bookmark   

Potassium borohydride CAS-Nr.[13762-51-1]

Solub. in water (25 degrees) : 190g/L

Used for preperation of polyfluoro diketones / and for an unusual synthesis of ethers from aliphatic ketones / Reagent for the preperation of many Potassium-indolylborates and their metal complexes.

Sodium borohydride CAS-Nr.[16940-66-2]

Sulub. in water (25 degrees) : 550g/L  (slow decomposition)

Reducing agent for aldehydes, ketones, quinones etc. auxiliary in ther determination of hydride formers by ASS.

The Merck catalogue tells nothing about using KBH4 as a versatile reducing agent, but i need to give it a try since NaBH4 has the toxic symbol and therefore is impossible to obtain (at least for me).

-Le Vogue

Tie to birds together, though they have four wings they cannot fly.
(Hive Bee)
10-28-00 21:05
No 64390
      Re: Potassium borohydryde???  Bookmark   

  Well shit, if you're hell-bent on using K-Borohydride then why not learn how to use it and make it? How can one go about making at least one of his friend's bladder explode into an underwear-stained wet spot, decorated in blood and puss, unless the attack was only permitted on the main-stream brain? Keep it real! See ya!  tongue

  Yes, I said by yourself, alone! Let no one breathe, and no one see the hate you love to show me!
(Hive Addict)
07-02-02 16:20
No 327997
      KBH4 in place of the NaBH4, any results?  Bookmark   

Since this is an old post, has anyone had results to share?

there's a big difference between criticizing your government and criticizing your country