Sciencemadness Discussion Board

DiLithium TetraBorate

Waffles SS - 30-4-2012 at 08:13

Somebody know how we can make Dilithium tetraborate?Adding Lithium hydroxide to Boric acid should prepare it but i searched in Google and found out maybe this reaction make different componet

LiOH + B(OH)3 = LiBO2 + 2H2O?(like aluminium LiOH + Al(OH)3 = LiAlO2 + 2H20)?
4 B(OH)3 + 2 LiOH = Li2B4O7 + 7 H2O?
B(OH)3 + 3LiOH --> Li3BO3 + 3H2O?
I really confused
I just want to make Dilithium tetra borate(lithium borate)

[Edited on 30-4-2012 by Waffles SS]

kristofvagyok - 30-4-2012 at 09:03

Quote: Originally posted by Waffles SS  
Somebody know how we can make Dilithium tetraborate?


They rarely use LiOH, because it is highly hygroscopic, it could easily form carbonates and other problems...

The use lithium-acetate instead of lithium-hydroxide. It is mixed with boric acid, dried on 100Celsius, calcinated at 1100Celsius for 15 min and melting it for 8hours at 500Celsius under nitrogen atmosphere.

Also there is another method by mixing tributyl-borate and lithium-methoxide in methanol. The title compound will participate from the methanol.

Waffles SS - 30-4-2012 at 09:40

Are you sure?
What will produce if we add Boric acid solution to Lithium Hydroxide solution?

kristofvagyok - 30-4-2012 at 10:09

Quote: Originally posted by Waffles SS  
What will produce if we add Boric acid solution to Lithium Hydroxide solution?


The same, the only porblem with it, that it's harder to measure 1mole of LiOH what could be wet, some parts of it could be carbonated and some other problems.

While with lithium-acetate these problems won't occur.

DJF90 - 30-4-2012 at 14:24

Lithium hydroxide isnt that hygroscopic. The monohydrate is pretty damn stable to be honest, much less hygroscopic than NaOH or KOH, which I find to be deliquescent.

kristofvagyok - 30-4-2012 at 15:52

Quote: Originally posted by DJF90  
Lithium hydroxide isnt that hygroscopic. The monohydrate is pretty damn stable to be honest, much less hygroscopic than NaOH or KOH, which I find to be deliquescent.


I'm just saying this, because we have a large bottle of LiOH in the lab, it is original 50 years old from russia, and it's hard to get out the LiOH from the bottle, and also, it contains some carbonate...

Waffles SS - 30-4-2012 at 21:33

I accept that LiOH is Hygroscopic but i want to use solution of it.I want to react solution of LiOH with Solution of Boric acid.

This is difficult because solubility of Boric acd in water is 50g/L and i should use too much water.

Today i Dissolved 62 gram Boric acid in 2lit of water then i add 126 gram of Lithium hydroxide to it then i checked PH it was 14 !
According to below reaction every mole of Boric acid(62gram) neutralize with 3 mole of Lithium hydroxide(126 gram Mono Hydrate)but i got different result

B(OH)3 + 3LiOH --> Li3BO3 + 3H2O
I dont know i am wrong or not!



[Edited on 1-5-2012 by Waffles SS]

kristofvagyok - 1-5-2012 at 04:47

Quote: Originally posted by Waffles SS  

Today i Dissolved 62 gram Boric acid in 2lit of water then i add 126 gram of Lithium hydroxide to it then i checked PH it was 14 !
According to below reaction every mole of Boric acid(62gram) neutralize with 3 mole of Lithium hydroxide(126 gram Mono Hydrate)but i got different result

B(OH)3 + 3LiOH --> Li3BO3 + 3H2O
I dont know i am wrong or not!
[Edited on 1-5-2012 by Waffles SS]


Li3BO3 has a high solubility in water: 86.4 g/dm3 at 25Celsius and it's a salt of a really weak acid and a strong base, so it's solutions should be basic!

And also: boric acid is a really weak acid, it's pKa-s are:
o-Boric acid (1) 9.14
o-Boric acid (2) 12.74
o-Boric acid (3) 13.80

[Edited on 1-5-2012 by kristofvagyok]

Waffles SS - 1-5-2012 at 05:26

Thank you
Do you know PH of LiBO3 solution?
I searched and found out that heating Boric acid make Pyroboric acid(arround 300c).Can i make Lithium tetra borate by adding pyroboric acid to LiOH solution?
Do you know solubility of pyroboric acid in water?