psytech (Newbee)
07-24-03 00:14
No 449338
      ZrCl4/NaBH4  Bookmark   

NaBH4 (1.51 g, 40 mmol) is added to a solution of ZrCl4 (2.39 g, 10 mmol) in THF (35 mL) at room temperature under nitrogen. How necassary is a nitrogen atmosphere? I Have read the MDSD on both, neither is very dangerous.I know often that researchers use in for mmole scale.
(Chief Bee)
07-24-03 06:55
No 449419
      Tips for the preparation of Zirconium Borohydride
(Rated as: good read)

I have experimented with Zr(BH4)4, and it works great without a nitrogen atmosphere. You need to protect the reactants and reaction mixture from atmospheric moisture though, as both ZrCl4 and Zr(BH4)4 decomposes in the presence of water.

Also, watch out when you prepare the ZrCl4 solution in THF, as the dissolution is exothermic, and some THF may splatter if you only add a few milliliters at first, so preferably chill the THF in an ice-bath before adding it to the Zr(BH4)4 and add at least half of the intended amount of solvent in one go. The addition of NaBH4 is also exothermic, and creates foam, so do that too slowly, use good magnetic stirring, and choose a reaction flask large enough as to not get more than 1/3 full with all the initial THF added.
(Active Asperger Archivist)
07-24-03 20:32
No 449579
      Addition speed  Bookmark   

Rhodium, when adding solvent, have you ever had a problem with super-heating? (to the point of being dangerous, not just splattering?) 

I'm assuming good stirring will eliminate any possibility of this being a problem.

Act quickly or not at all.
07-24-03 20:50
No 449582
      Adding the powdered reagents to the solvent...  Bookmark   

Adding the powdered reagents to the solvent solves the problem smile
(Active Asperger Archivist)
07-24-03 20:55
No 449584
      Powder  Bookmark   

Well, that option made sense to me, but the way it was phrased above made me believe that there might be an advantage to that method.

Act quickly or not at all.
(Chief Bee)
07-25-03 05:51
No 449680
      order of addition  Bookmark   

Adding the moisture-sensitive and very dusty solid ZrCl4 will easily suspend particles in the air, as well as expose it to the air for a longer time (depending on your local air humidity this may or may not be a problem). It is also always easier to add liquids to a solid in a flask than the other way around if working with the apparatus sealed from the atmosphere.
(Active Asperger Archivist)
07-27-03 01:12
No 450035
      Duh  Bookmark   

How easily the obvious escapes us.  blush

Act quickly or not at all.
(Hive Bee)
07-27-03 18:21
No 450171
      Hm.. I got 100g Zirconium wet with water (for...  Bookmark   

Hm.. I got 100g Zirconium wet with water (for transportation purposes apparently) for free when buying some other stuff, and I haven't known what to do with it until now. Is it possible to make ZrCl4 out of it without killing yourself? You make it out like it's not so friendly to work with.
(Chief Bee)
07-27-03 22:18
No 450220
      ZrCl4 is preferably bought, not made yourself  Bookmark   

Nope, the synthesis of ZrCl4 is not suitable for the home lab.