At what temperatures does ammonium carbonate decompose

Ammonium carbonate (NH4)2CO3

   
 


  
White, crystalline
powder
molar mass 96.086 g / mol
  
 

AGW not specified
decomposition +58 ° C  
density 1.6 g / cm3   
Water solubility 
100g H2O dissolve 100 g at 15 ° C
pictogram 
GHS 07
Danger
Hazard classes + category 
Acute toxicity oral 4
HP rates(See note)    
H 302 P 235, 280.3, 301 + 312
disposal keep alkaline, then G 4   
Print a labelGerman nameEnglish name
CAS 506-87-6Ammonium carbonateAmmonium carbonate

Notes for schools: Ammonium carbonate releases ammonia even at room temperature. This process is slowed down when stored in a cool place. Ventilation measures may be required.


properties

Ammonium carbonate is available as a white, crystalline powder. The salt dissolves well in water, the aqueous solution has a slightly alkaline reaction. In acidic solution, for example with carbon dioxide, and in neutral water, hydrogen carbonate and hydroxide ions are formed from ammonium carbonate. The smell of ammonia in dry salt indicates that ammonium carbonate decomposes to ammonium hydrogen carbonate and ammonia even at room temperature:

(NH4)2CO3 NH4HCO3 + NH3

When heated to 58 ° C, the ammonium hydrogen carbonate that is formed at the same time decomposes into ammonia, carbon dioxide and water. This process takes place slowly, even at room temperature, so that a bottle of ammonium carbonate is "empty" after a few years.

NH4HCO3 NH3 + CO2 + H2O
 
 


If you hold a damp universal indicator paper over ammonium carbonate,
this turns blue-green, which indicates the formation of ammonia.


Because of its volatility, the salt is not suitable as a fertilizer. Ammonium carbonate can, however, be used as a leavening agent for leavening dough due to the carbon dioxide generated when heated. So that no ammonia remains in the dough, the Deer horn salt a mixture of ammonium carbonate, ammonium hydrogen carbonate and a little ammonium carbamate NH4OCO (NH2) .


Manufacturing

A production in the laboratory would be possible from the reaction of calcium carbonate with ammonium sulfate in an aqueous solution:

CaCO3 + (NH4)2SO4 CaSO4 + (NH4)2CO3

When carbon dioxide is introduced into ammonia solution, ammonium carbonate is also obtained. In the industrial production of the pure substance, however, precisely calculated mixtures of ammonia, carbon dioxide and water vapor are used. This prevents hydrogen carbonates or carbamates from being formed at the same time. Often even liquid ammonia is used under high pressure:
 
2 NH3 + CO2 + H2O (NH4)2CO3


use

Ammonium carbonate is a component of the deer horn salt for raising agents. The formation of carbon dioxide when heated can be used in the production of foams. Ammonium carbonate is used to generate carbon dioxide in fire extinguishers. It is used as a mordant in textile dyeing. As "smelling salt" it was used to hold an unconscious person under the nose to wake them up.