Calcium cyanamide

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Calcium cyanamide
Names
IUPAC name
Calcium cyanamide
Other names
Cyanamide calcium salt
Lime Nitrogen
Nitrolime
UN 1403
Properties
CaCN2
Molar mass 80.102 g/mol
Appearance White solid (Often gray or black from impurities)
Odor Odorless
Density 2.29 g/cm3
Melting point 1,340 °C (2,440 °F; 1,610 K)
Boiling point Sublimes
Reacts
Solubility Insoluble in organic solvents
Thermochemistry
-351.6 kJ/mol
Hazards
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Related compounds
Related compounds
Calcium carbide
Cyanamide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Calcium cyanamide is an inorganic compound with the formula CaCN2, widely used as fertilizer in agriculture.

Properties

Chemical

Hydrolysis of CaCN2 will yield cyanamide, as well as ammonia.

CaCN2 + H2O + CO2 → CaCO3 + H2NCN
CaCN2 + 3 H2O → 2 NH3 + CaCO3

Fusing calcium cyanamide with sodium carbonate will give sodium cyanide.

CaCN2 + Na2CO3 + 2C → 2 NaCN + CaO + 2 CO

Physical

Calcium cyanamide is a white (gray or black if impure) solid, which reacts with water.

Availability

Calcium cyanamide is sold as fertilizer. In some places it's hard to find.

It can also be bought from chemical suppliers.

Preparation

A common route to calcium cyanamide involves heating a mixture of calcium oxide and urea at 120-350 °C which gives calcium cyanate, followed by calcination at 7-900 °C to give calcium cyanamide.[2]

3 CO(NH2)2 → 3 HOCN + NH3
CaO + 2 HOCN → Ca(OCN)2 + H2O
Ca(OCN)2 → CaCN2 + CO2

Calcium cyanamide is obtained industrially by heating calcium carbide powder at 1,000 °C, usually in an electric furnace, while injecting nitrogen gas over the hot carbide, which is recirculated. The reaction takes several hours for completion.

Another route involves heating calcium cyanide with nitrogen gas at 600 °C for at least one hour.[3]

Reducing calcium nitride with carbon at 800-900 °C in a nitrogen atmosphere will also give calcium cyanamide.[4]

Reacting ammonia with calcium carbonate above 600 °C is another route.[5][6]

Since calcium cyanamide reacts with oxygen at high temperatures, all of these routes must be done in low of oxygen environment, and an inert gas is used.

Projects

Handling

Safety

Calcium cyanamide is harmful and should be handled with care.

It is known to cause alcohol intolerance, before or after the consumption of alcohol.

Storage

In closed containers, away from moisture.

Disposal

Can be dumped in the ground.

References

  1. Franck, H. H.; Hochwald, F.; Zeitschrift fuer Elektrochemie; vol. 31; (1925); p. 581 - 590
  2. https://www.youtube.com/watch?v=S-SOjfZ_yS4
  3. Franck, H.; Heimann, H.; Angewandte Chemie; vol. 44; (1931); p. 372 - 378
  4. Krase, H. J.; Jee, J. Y.; Journal of the American Chemical Society; vol. 46; (1924); p. 1358 - 1366
  5. Franklin; Journal of the American Chemical Society; vol. 44; (1922); p. 504
  6. Patent; Caro; Frank; DE467479; Fortschr. Teerfarbenfabr. Verw. Industriezweige; vol. 16; p. 283

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