Sciencemadness Discussion Board

Bubble CO2 through Ammoium Hydroxide - Make Ammonium BiCarb?

RogueRose - 18-10-2016 at 01:28

If CO2 is bubbled through a solution of ammonium hydroxide, will it produce ammonium bicarb? The temp would be best if kept under 70F - if this process works. The equation for bicarb is NH3 + CO2 + H2O

j_sum1 - 18-10-2016 at 01:38

Research the Solvay process and be amazed!


[Edit]

I did not intend that to sound so flippant. The solvay process is truly genius. The process you have described is one step in it.

[Edited on 18-10-2016 by j_sum1]

AJKOER - 18-10-2016 at 07:30

You could try adding NH3 gas or ammonia water to cold aqueous Mg(HCO3)2. Filter or just let settle out the white Mg(OH)2 precipitate.

2 NH3 + 2 H2O + Mg(HCO3)2 → 2 NH4HCO3 + Mg(OH)2 (s)

I have prepared Mg(HCO3)2 by adding NaHCO3 to cold aqueous MgSO4, and freezing out the Na2SO4. Magnesium bicarbonate is heat sensitive, so if you heat this mix, the product is:

2NaHCO3 + MgSO4 → Na2SO4 + Mg(OH)2 + 2CO2

indicating the decomposition of the magnesium bicarbonate. My experience is also that Mg(HCO3)2 decomposes on standing in a day or so. So use quickly.

[Edit] It is my speculation that the instability of the Mg(HCO3)2 is related to exposure to air or dissolved oxygen (in the water used to dissolve the NaHCO3 or MgSO4), with a small presence of a transition metal like Fe or Mn (or possibly even the Mg itself from photo reactivity of the oxide/hydroxide?), pre-boiling and cooling the distilled water may reduce dissolved oxygen exposure. This may prolong the shelf life of both the magnesium and ammonium bicarbonate (cold storage in any event).

[Edited on 18-10-2016 by AJKOER]