Potassium carbonate Question

[TATER]

hello, i just had a question about the production method of potassium carbonate. when producing using potassium hydroxides absorbent reaction with CO2. since potassium carbonate is soluble in water do you have to recrystallise the solution after the reaction has taken place?

 

2KOH+CO2->K2CO3+H2O

 

i figured since water is produced you will have to recrystallise it, but i just want to know if the product will precipitate from the solution

and is the carbonation method done by dry ice or by bubbling CO2 through the KOH

thanks,

TATER

[thermonub]

Hey,

I just made a KOH solution and dropped a nice chunk of dry ice in it and then evaporated the water.

 

thermonub

[YT2095]

you can use either method to produce it, but obviously the greater the surface area one or both of the reactants have the better, so if you bubble the CO2 through, use an Airstone to make loots of Tiny bubbles rather than one big one.

 

interestingly the solubility of KOH and K2CO3 are the same in water, it only shifts enough to ppt when you Continue to bubble CO2 gas through and make the Hydrogen carbonate KHCO3.

 

then it shifts from 112g/100ml STP to 33.7g/100ml STP.

 

so if your soln was saturated enough, you would PPT out the Bicarbonate species, but if you want the plain carbonate then you would have to crystalise it.