Calcium hypochlorite: Difference between revisions
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{{Compound|chemf=Ca(OCl)2 | {{Compound|chemf=Ca(OCl)2 | ||
|mm=142.98|density=2.35|mp=100|sol_aq= | |mm=142.98|density=2.35|mp=100|sol_aq=210 | ||
|group=salts | |group=salts | ||
|stp_p=powder|stp_q=white/grey | |stp_p=powder|stp_q=white/grey|nfpa_h=3|nfpa_r=1|nfpa_o=OX}} | ||
|nfpa_h=3|nfpa_r=1|nfpa_o=OX}} | |||
Calcium hypochlorite is the simplest hypochlorite to produce and isolate. | Calcium hypochlorite is the simplest hypochlorite to produce and isolate. | ||
==Uses== | ==Uses== | ||
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* Can substitute for [[sodium hypochlorite]] in the production of [[trichloromethane]] | * Can substitute for [[sodium hypochlorite]] in the production of [[trichloromethane]] | ||
==Natural occurrence== | ==Natural occurrence== | ||
Calcium hypochlorite does not appear naturally | Calcium hypochlorite '''does not''' appear naturally | ||
==Hazards== | ==Hazards== | ||
Toxic and irritating | Toxic and irritating |
Latest revision as of 16:15, 19 July 2019
Chemical formula | Ca(OCl)2 |
---|---|
OTP appearance | white/grey powder |
Molar Mass(g/mol) | 142.98 |
Density(g/cc) | 2.35 |
Melting Point(°C) | 100 |
Solubility in water(g/L) | 210 |
NFPA 704 |
Calcium hypochlorite is the simplest hypochlorite to produce and isolate.
Uses
Justification Questioned
Other
- Disinfecting and cleansing
- Feedstock for sodium hypochlorite
- Can substitute for sodium hypochlorite in the production of trichloromethane
Natural occurrence
Calcium hypochlorite does not appear naturally
Hazards
Toxic and irritating
Production
Synthesis
Combined hydroxides
- Gather 37ubm calcium hydroxide
- Gather 40ubm sodium hydroxide
- Gather 80ubm chlorine gas
- Prepare a saturated solution of the hydroxides
- Bubble (and recirculate) the chlorine through the hydroxides
- Ca(OH)2(aq) + 2 NaOH(aq) + Cl2(g) → Ca(OCl)2(s) + 2 NaCl(aq) + 2 H2O
In the absence of sodium hydroxide, a mixture of calcium hypochlorite and calcium chloride is produced. This mixture is difficult to separate, and the -chloride attracts water from the air which decomposes the -hypochlorite. Removal of the calcium chloride is required to stabilize the bleach.
Separating the sodium chloride from the calcium hypochlorite can be accomplished by gravity separation of a dense slurry of well-over-saturated solution rich with with crystals of both products. Agitating the slurry in a tall cylindrical container will gravitically sort the salt crystals (which are larger and denser) from the hypochlorite crystals (which are smaller and lighter).
- Evaporate the mother liquor until it forms a cloudy crystal-rich supersaturated slurry
- Fill a tall cylindrical container with the slurry
- Agitate the solution steadily, allowing gravity to separate the crystals
- Decant the slurry into three parts: the top 30%-40%, the bottom 30-40%, and the remainder (the mother liquor and "middle" slurry)
- Filter the top 30-40%
- Return the filtrate to the mother liquor
- Dry the residue completely. This is the hypochlorite cake
- Wash the hypochlorite cake with a small amount of distilled water
- Filter
- Return the filtrate to the mother liquor
- Dry the residue completely. This is the refined hypochlorite
- Filter the bottom 30-40%
- Return the filtrate to the mother liquor
- Dry the residue completely. This is the salt cake
- Wash the salt cake with a small amount of distilled water
- Filter
- Return the filtrate to the mother liquor
- The residue is primarily salt with some toxic impurities. It is not safe for consumption. Discard or retain for other purposes.
This process can be repeated until there is no more mother liquor to evaporate. The salt cake will contain primarily sodium chloride. The hypochlorite cake will contain primarily calcium hypochlorite.
References
See Also
- Sodium hypochlorite
- US patent 1713669 "Manufacture of calcium hypochlorite"
Link courtesy Google