Hilski - 14-5-2007 at 18:28
Are there any reasonable methods for testing the purity of an alkali cyanate? I do not have the resources to perform accurate mp tests,
chromatography, spectrometry or other similar analytical techniques.
After reading the threads about cyanide production and the Prussian blue tests, it got me wondering if such tests existed for cyanates as well.
Thanks
roamingnome - 25-5-2007 at 07:13
last nite i was cooking over the fire and tried to convert 20 grams NaOH with 1.75 molar excess of urea cave man style in a beaker
last time on a smaller scale on a hot plate it went pretty much perfect
but this time inevitablely ash found its way in, and a small contamination discolored the whole mix. post weight indicts incomplete reaction as
well..
to make a long story short have you found any purifing methods to speak of??
------------------------------------------
Studies in qualitative inorganic analysis
The detection of carbonate, hydrogen carbonate, and cyanate
Journal Microchimica Acta
Summary Existing tests for differentiating carbonate and hydrogen carbonate are shown to be unreliable. New tests have been developed which enable
carbonate and hydrogen carbonate to be differentiated readily; cyanate and other anions may also be tested for in the mixture. The recommended tests
are applicable in the presence of other anions.
Preliminary water extraction is done to remove hydrogen carbonates and soluble carbonates and cyanates. The insoluble portion is then treated with
hydrochloric acid; the evolution of carbon dioxide confirms insoluble carbonates or cyanates. The latter are confirmed by making the solution alkaline
and testing for ammonia. Insoluble carbonate is tested for by extracting another portion of the sample with water and treating the residue with acetic
acid. Cyanates do not react under these conditions.
The original water extract is divided into three parts: one portion is treated with hydrochloric acid; the evolution of carbon dioxide indicates that
any of the three ions may be present. A further portion is treated with phenolphthalein. The red colour indicates soluble carbonate. Barium chloride
is added until the colour is discharged; slow evolution of carbon dioxide in the cold or on gently warming indicates the presence of hydrogen
carbonate. The third portion is made alkaline and boiled to expel any ammonia present from ammonium salts. The solution is then acidified, made
alkaline again and then tested for ammonia. A positive test indicates that soluble cyanates are present.
[Edited on 26-5-2007 by roamingnome]