Potassium ferrocyanide
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Chemical formula | {{#Chem:K4(Fe(CN)6)}} |
---|---|
OTP appearance | yellow crystals |
Molar Mass(g/mol) | 368 |
Density(g/cc) | 1.85 |
Melting Point(°C) | decomp |
Solubility in water(g/L) | 289 |
Solubility in ethanol(g/L) | insoluble |
NFPA 704 |
Uses
Other
- Precursor to Prussian blue on WHO LEM
- Production is a relatively safe sink for cyanides
Natural occurrence
- does not occur in nature
Hazards
- "nontoxic"
- Do not heat or acidify, these actions may produce free cyanides.
Production
Synthesis
via nitrogenous biomass
This general process is repeated in many texts including Industrial Chemistry[1] and Manual of Chemical Technology[2]
- Melt 100ubm potassium carbonate in a container devoid of oxygen
- Add 75-400ubm of nitrogenous biomass (feathers, horn, skins, leather, dry blood) directly to the melt
- N.B.: Production of solvated potassium cyanide and potassium sulfate {{#Chem: KCN, K2SO4}}
- Allow to cool
- Mix with water
- Filter
- Recycle residue (or dispose of carefully, it may be toxic)
- Retain filtrate (it contains potassium cyanide, which is very poisonous/toxic)
- Add 10 ubm iron filings to a basic solution
- {{#Chem: 6 KCN + Fe + 2 H2O { OH- = } K4(Fe(CN)6) + 2 KOH + H2 }}
via hydrogen cyanide
- Combine iron (II) chloride and calcium hydroxide in water
- Bubble hydrogen cyanide through the mixture
- {{#Chem: 2 FeCl2(OH)2(H2O)2 + 4 Ca(OH)2 + 12 HCN = 2 Ca2[Fe(CN)6] + 14 H2O + 4 HCl + O2 }}
- Combine with 2 molar equivalents of potassium chloride, precipitating the calcium/sodium salt
- {{#Chem: Ca2[Fe(CN)6] + 2KCl = CaK2[Fe(CN)6(s)]+ CaCl2}}
- Combine with potassium carbonate
- {{#Chem: CaK2[Fe(CN)6](aq) + K2CO3(aq) = K4[Fe(CN)6](aq) + CaCO3(s)}}
- Filter
- Discard residue (calcium carbonate)
- Evaporate filtrate leaving potassium ferrocyanide
Testing
Storage
Disposal
See Also
References
- ↑ Paul, B. H., PhD (1878) "Industrial Chemistry"; pp80.
Longmans, Green & Co
link courtesy Google. - ↑ Von Wagner, Rudolf (1897) "Manual of chemical technology"; pp474-477.
D. Appleton & Co.
link courtesy Hathi Trust.