Haruka - 16-1-2015 at 19:50
I'm going to prepare potassium cyanate for school and I have several questions about why should be used some things in the process to prepare it.. I
hope you all can help me!
1) I have this reaction: 2NH4NCO+ K2CO3---- 2NH3+ CO3+ 2KNCO+ H2O
I found that I can replace to its equivalent bicarbonate (KHCO3) and it would be more advantageous.. Why?
2) Then, when I get the KOCN I have to purified the mix... I would explain you how we are going to do this:
"..The crude cyanate is ground in the crucible and placed in a beaker. It is then mixed with an equal volume of water. The solution is made alkaline
with a few drops of KOH. Once alkaline the mixture is stirred at 50C until only a small amount of solids remain undissolved. The solution is then
quickly filtered at the pump to remove the solids. 50 ml of 95% ethanol is added to the filtrate and then cooled by ice. After the solution reaches
its coldest temperature and the cyanate has precipitated. The crystals are filtered at the pump and washed with ice cold ethanol.."
My questions are: Why I have to make alkaline the solution? What would happen If I do not make an alkaline environment? and Why the ethanol have to be
cold??
I'm sorry for the long of the post..! 
Zombie - 16-1-2015 at 23:56
I'm not smart enough to completely answer your question but I do have a partial answer.
Since you freeze precipitated your crystals they are not truly formed. They were forced. If they do not form with slow cooling at room temperature
then perhaps you have the wrong solvent.
The "ice cold ethanol" is used to maintain that forced environment so your crystals do not re-liquefy.
I have found crystals formed in this way have to be kept refrigerated to maintain a crystalline form.
The crystallization I do requires a solvent that when brought down to, and stored at room temp begins the formation, and it may take 2-3 days for
complete separation, and crystallization but my product remains stable, and has a higher purity than anything I have freeze precipitated.
I am unfamiliar with what you are working with so I an simply sharing what general information I have gained
Hopefully someone more qualified can help you out with a better method, solvent, or explanation.
Eli25 - 2-7-2015 at 22:50
Hi. Please help me.
I need to produce Potassium Cyanate.
I react Urea with Potassium Hydroxide.....I have read that the temperature should be about 240°C....I do it...the reactants melts above 100 °C then
by heating more they get solid again...and little by little it gets black!!! I don't know how long should I wait till reactin is complete and how I
can purify the product and gain white Potassium cyanate!!!!!
Has anyone done this reaction and gained pure white potassium cyan ate?
aga - 3-7-2015 at 07:07
Where did you read that the temperature should be 240 C ?
Do you have a reference for the procedure ?
Edit:
try google and hey presto :
http://www.sciencemadness.org/talk/viewthread.php?tid=17361
[Edited on 3-7-2015 by aga]