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Author: Subject: Aminoguanidine bicarbonate from fertilizer

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[*] posted on 24-2-2019 at 02:31
Aminoguanidine bicarbonate from fertilizer

Sup y'all

I've recently tried making aminoguanidine bicarbonate by the CaCN2 + N2H6SO4 method using some impure fertilizer containing CaCN2, Ca(OH)2, carbon and possibly other things. I assumed there were no alkali metal contaminations so wasn't scared of HCN. Now, the process went smoothly and there was no HCN formed. When I filtered off the CaSO4 and Carbon, the filtrate solution was first clear and then very quickly turned yellow with a slight tinge of orange. I acidified this solution down to a ph of 6.5 and then added NaHCO3. Now, after leaving this in the freezer for a day, some very small crystals formed, which I filtered off. They were white but slightly brown. This solid powder melts very easily and leaves a small amount of yellowish orange residue behind.

What could this be?

Is it impure aminoguanidine bicarbonate or something else?

Is it even possible to make aminoguanidine from impure fertilizer?
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National Hazard

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[*] posted on 10-4-2019 at 13:46

Aminoguanidine solutions are indeed yellow, so you may be on to something...

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International Hazard

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[*] posted on 12-4-2019 at 11:13

Aminoguanidine solution is not yellow if its pure; its colourless. This has been discuss in other threads so why not at it to one of them? I suspect you didn't UTFSE. If you had you would have seen that at least 2 members of this community have already reported on this very same preparation. My experience is that the higher purity calcium cyanamide prepared as per the method of Engager gives better results based on yield per unit of hydrazine sulphate than the industrial fertilizer type calcium cyanamide which is only about 50%. While the stuff is very cheap the yield per unit of hydrazine sulphate is less and it is this compound that is difficult to get or make is quantity.

My attempts based on black Perkla prills never gave a yield of better than 17% based on the cyanamide but the yield based on hydrazine sulphate could be improved by simply using less of it! I never tried to optimize the reaction but it looks like you could get away with about 30-40% of the theoretical quantity of hydrazine sulphate without significantly reducing the final yield of guanidine derivative. I now use the cyanamide to prepare dicyandiamide and urea which is a very simple process that can be carried out in large quantities with moderate yield by no expensive or hard to make reactants.
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