I made a cyanamide process demonstration, by changing a few parameter, it could be used to make usable cyanamide. Picture added soon.
The cyanamide process was, for a long time the main source of ammonia and nitrogen fixation. The process consisted in heating calcium carbide at 1000
C in a flow of nitrogen. Then the cyanamide was hydrolyzed to ammonia and calcium carbonate.
4g of calcium carbide is ground to a fine powder, and put in a 50ml aluminia crucible. The crucible is heated to yellow heat for 3 minutes. After
cooling, the crucible contain a white part and a carbon black part. The content are poured in 50 ml of cold water. Caution, it is very exothermic.
Ammonia smell can be observed, then, the solution is filtered, and tested with tincture of mercury in the usual way. The test is positive for ammonia.
Notes:
The white part correspond to the first part of the carbide that become hot, as such it is used to remove the oxygen from the crucible, foming carbon
monoxide and calcium carbonate. The black part is the cyanamide, mixed with carbon.
The cyanamide process was, for a long time the main source of ammonia and nitrogen fixation. The process consisted in heating calcium carbide at 1000
C in a flow of nitrogen.
It's also called the Frank–Caro process after its inventors.plante1999 - 6-5-2013 at 08:39
Yes, I forgot to mention it, I should add the picture in a few hours.blogfast25 - 6-5-2013 at 13:26
A nice bit of history in a crucible. Could be interesting to so some quantitative tests on...plante1999 - 6-5-2013 at 14:26
Oh, just a quantitative determination of how much NH3 you obtained.
Looks like you could do with a clay pipe triangle!
[Edited on 7-5-2013 by blogfast25]Rosco Bodine - 7-5-2013 at 12:25
There is also an alternative method for producing pure calcium cyanamide uncontaminated with carbon and at a lower temperature of the red-orange heat
range, which involves pyrolytic decomposition of calcium cyanurate. Some toxic fumes of cyanic acid will be produced as the byproduct during the first
stage of the pyrolysis which should be be done mindful to flare off these fumes or otherwise provide for safe ventilation.
Reaction of nitrous acid and a guanidine salt is a possible cold method which reportedly produces cyanamide in 80% yield. There is some more about
this in the sticky tetrazole thread.
@plante1999 You should edit your picture pixel width to a lower value like 650 because it messes up the text formatting when these large pictures are
attached inline.
