guanidine salts

Guanidine picrate

As you asked about any kind of guanidine salts, I made guanidine picrate from guanidine nitrate and ammonium picrate. But the guanidine nitrate was from another guanidine compound and not form cyanoguanidine, as you probably look for.


↑ Here a picture of the guanidine picrate.

Here you can find the German synthesis-text of guanidine picrate and a description of its properties (a part of LambdaSyn.com).

[Edited on 24-12-2005 by Mephisto]

guanidine

Update :

The reaction of a mixture of calcium hydroxide and cyanuric acid dihydrate and charcoal has been performed and the reaction product is heavily contaminated with graphite formed from the carbon which was not oxidized . So
an alternative method is being contemplated as a cleaner
and probably more efficient synthesis , which would seem
more suitable as a small scale method for calcium cyanamide .

Calcium cyanurate , CaH(OCN)3 is decomposed by high temperature to calcium cyanamide . So it is logical that
simply forming and isolating the calcium cyanurate as a
first step would simplify a small scale synthesis , which
could then be completed by heating the calcium cyanurate
intermediate to high temperature and collecting the residue
of pure calcium cyanamide .

I have done an experiment to produce the calcium cyanurate
which appears to be successful .

16.5 grams ( .1 mole ) cyanuric acid dihydrate was added to
200 ml stirred hot water . 8 grams of NaOH in 50 ml water
was added and the mixture stirred for 15 minutes just barely at the b.p. . Then 11 grams ( .1 mole CaCl2 ) in 50 ml water
was streamed into the mixture with stirring and heating continued for 30 minutes . Theoretically the white precipitate is calcium cyanurate in a supernatant solution of sodium chloride byproduct .

The reactions are :

(HOCN)3 + 2 NaOH + CaCl2 ---> CaH(OCN)3 + 2 NaCl + 2 HOH

After filtering and drying , the calcium cyanurate should
yield calcium cyanamide upon heating to decomposition at red orange heat in the absence of air by the following reactions :

CaH(OCN)3 ---> Ca(OCN)2 + HOCN

Ca(OCN)2 ---> CaC(N)2 + CO2

Here the progress of the first half reaction should be observable by the burning of escaping gases from the loosely sealed container in which the calcium cyanurate is being heated , and it will be the cyanic acid gas which flares
off for this reaction at a lower temperature than the completing second reaction . For the second reaction ,
of course there will be an evolution of carbon dioxide so long as the reaction is proceeding . I think the advantage for
this proposed method , aside from elimination of graphite as a byproduct , is that it involves no gas / solid reactions to
form an intermediate . Such reactions are not generally efficient outside of an industrial process which uses rotary kilns or fluidized bed sorts of apparatus for the reactions and
microfine powders and long reaction times . Those methods are difficult to implement as a lab scale synthesis , where a more straightforward thermal decomposition of an intermediate already formed in advance is much simpler .

Quote: Originally posted by chemoleo

Very interesting reaction, Rosco. It should be fairly easy to do, providing one can raise the mix up to 700 or so deg C. A normal coal fire should do I guess. Anyway, I found a patent that details the production of guanidine nitrate, from calcium cyanamide, and ammoniumnitrate, and water. This one, unlike other related patents, has no danger of detonation, which is definitely a bonus. Temperatures are also quite low, <100 deg C. It's GB507498, see http://v3.espacenet.com/origdoc?DB=EPODOC&IDX=GB507498&a... for details. So quantum, this may be interesting to try in stead. Calcium cyanamide is also contained in certain fertilisers. Should be trivial just to heat the fertiliser with ammonium nitrate and water. Oh, and I found a patent relating to aminoguanidine, which can be obtained straight from calcium cyanamide and hydrazine - not that anyone will be making this I guess. Nonetheless it's interesting to see how many uses calcium cyanamide has!