Calcium chloride

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Calcium chloride
Calcium chloride
Hydrophilite.GIF
Identifiers
CAS number 10043-52-4 YesY
22691-02-7 (monohydrate)
10035-04-8 (dihydrate)
25094-02-4 (tetrahydrate)
7774-34-7 (hexahydrate)
PubChem 24854
ChemSpider 23237 YesY
UNII OFM21057LP YesY
EC number 233-140-8
DrugBank DB01164
ChEBI CHEBI:3312 YesY
ChEMBL CHEMBL1200668 N
RTECS number EV9800000
ATC code A12AA07,B05XA07, G04BA03
Jmol-3D images Image 1
Properties
Molecular formula CaCl2
Molar mass 110.98 g/mol (anhydrous)
128.999 g/mol (monohydrate)
147.014 g/mol (dihydrate)
183.045 g/mol (tetrahydrate)
219.08 g/mol (hexahydrate)
Appearance white powder
hygroscopic
Odor odorless
Density 2.15 g/cm3 (anhydrous)
1.835 g/cm3 (dihydrate)
1.83 g/cm3 (tetrahydrate)
1.71 g/cm3 (hexahydrate)
Melting point 772 °C (anhydrous)
260 °C (monohydrate)
176 °C (dihydrate)
45.5 °C (tetrahydrate)
30 °C (hexahydrate)1
Boiling point 1935 °C (anhydrous)
Solubility in water 74.5 g/100mL (20 °C)
59.5 g/100 mL (0 °C)
Solubility soluble in acetone, acetic acid
Acidity (pKa) 8–9 (anhydrous)
6.5–8.0 (hexahydrate)
Refractive index (nD) 1.52
Structure
Crystal structure Orthorhombic (deformed rutile), oP6
trigonal (hexahydrate)
Space group Pnnm, No. 58
Coordination
geometry
octahedral, 6-coordinate
Hazards
MSDS External MSDS
GHS pictograms The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS hazard statements H319, H316, H302
GHS precautionary statements P264, P280, P270, P305+351+338, P337+313, P301+312, P330, P501
EU Index 017-013-00-2
EU classification Irritant (Xi)
R-phrases R36
S-phrases (S2), S22, S24
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
LD50 1000 mg/kg (oral, rat)
Related compounds
Other anions calcium fluoride
calcium bromide
calcium iodide
Other cations Beryllium chloride
Magnesium chloride
Strontium chloride
Barium chloride
Radium chloride
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Calcium chloride, CaCl2, is a salt of calcium and chlorine. It behaves as a typical ionic halide, and is solid at room temperature. Common applications include brine for refrigeration plants, ice and dust control on roads, and desiccation. Because of its hygroscopic nature, anhydrous calcium chloride must be kept in tightly sealed, air-tight containers.

Properties

Calcium chloride can serve as a source of calcium ions in an aqueous solution, as calcium chloride is soluble in water. This property can be useful for displacing ions from solution. For example, phosphate is displaced from solution by calcium:

3 CaCl2 (aq) + 2 K3PO4 (aq) → Ca3(PO4)2 (s) + 6 KCl (aq)

Molten calcium chloride can be electrolysed to give calcium metal and chlorine gas:

CaCl2 (l) → Ca (s) + Cl2 (g)

Calcium chloride has a very high enthalpy change of solution. A considerable temperature rise accompanies its dissolution in water.

The anhydrous salt is deliquescent; it can accumulate enough water in its crystal lattice to form a solution.

Preparation

Calcium chloride can be produced directly from limestone, but large amounts are also produced as a by product of the Solvay process. North American consumption in 2002 was 1,687,000 tons (3.7 billion pounds).2 A Dow Chemical Company manufacturing facility in Michigan houses about 35% of the total U.S. production capacity for calcium chloride.3

Occurrence

Calcium chloride occurs as the rare evaporite minerals sinjarite (dihydrate) and antarcticite (hexahydrate). A related mineral chlorocalcite (potassium calcium chloride, KCaCl3) is also very rare.

Uses

Desiccant

Drying tubes are frequently packed with calcium chloride. Kelp is dried with calcium chloride for use in producing sodium carbonate. Adding solid calcium chloride to liquids can remove dissolved water. Anhydrous calcium chloride has been approved by the FDA as a packaging aid to ensure dryness (CPG 7117.02).4

These hygroscopic properties are also applied to keep a liquid layer on the surface of the roadway, which holds dust down.5

Deicing and freezing point depression

By depressing the freezing point of water, calcium chloride is used to prevent ice formation and to deice. This is particularly useful on road surfaces. Calcium chloride dissolution is exothermic, and the compound is relatively harmless to plants and soil; however, recent observations in Washington state suggest it may be particularly harsh on roadside evergreen trees.6 It is also more effective at lower temperatures than sodium chloride. When distributed for this use, it usually takes the form of small, white balls a few millimeters in diameter, called prills. Solutions of calcium chloride can prevent freezing at temperature as low as −52 °C (−62 °F), making it ideal for filling agricultural implement tires as a liquid ballast, aiding traction in cold climates.7

Source of calcium ions

Calcium chloride is used to increase the water hardness in swimming pools. This reduces the erosion of the concrete in the pool. By Le Chatelier's principle and the common ion effect, increasing the concentration of calcium in the water will reduce the dissolution of calcium compounds essential to the structure of concrete.citation needed

In marine aquariums, calcium chloride is added to introduce bioavailable calcium for calcium carbonate-shelled animals such as mollusks and some cnidarians. Calcium hydroxide (kalkwasser mix) or a calcium reactor can also be used to introduce calcium, however calcium chloride addition is the fastest method and has minimal impact on pH.

Food

As an ingredient, it is listed as a permitted food additive in the European Union for use as a sequestrant and firming agent with the E number E509. It is considered as generally recognized as safe (GRAS) by the U.S. Food and Drug Administration8 and is on the US National Organic Program's National List of Allowed and Prohibited Substances.9 The average intake of calcium chloride as food additives has been estimated to be 160–345 mg/day for individuals.10

As a firming agent, calcium chloride is used in canned vegetables, in firming soybean curds into tofu and in producing a caviar substitute from vegetable or fruit juices.11 It is commonly used as an electrolyte in sports drinks and other beverages, including bottled water. The extremely salty taste of calcium chloride is used to flavor pickles while not increasing the food's sodium content. Calcium chloride's freezing-point depression properties are used to slow the freezing of the caramel in caramel-filled chocolate bars.

In brewing beer, calcium chloride is sometimes used to correct mineral deficiencies in the brewing water. It affects flavor and chemical reactions during the brewing process, and can also affect yeast function during fermentation. Calcium chloride is sometimes added to processed milk to restore the natural balance between calcium and protein in casein for the purposes of making cheeses, such as brie, Pélardon and Stilton. Also, it is frequently added to sliced apples to maintain texture.

Medicine

It is injected to treat internal hydrofluoric acid burns. It can be used to treat magnesium intoxication. Calcium chloride injection may antagonize cardiac toxicity as measured by electrocardiogram. It can help to protect the myocardium from dangerously high levels of serum potassium in hyperkalemia. Calcium chloride can be used to quickly treat calcium channel blocker toxicity, from the side effects of drugs such as diltiazem (Cardizem) — helping avoid potential heart attacks.12

Aqueous calcium chloride is used in genetic transformation of cells by increasing the cell membrane permeability, inducing competence for DNA uptake (allowing DNA fragments to enter the cell more readily).

There are possible side affects of taking calcium chloride orally or intravenously and it is not recommended that you take calcium chloride if you suffer from any of the following conditions:

  • you are allergic (hypersensitive) to calcium salts
  • you are taking medicines for heart problems (e.g. digitalis)
  • you have low calcium levels due to kidney problems
  • you have an excess of calcium present in either your blood or your urine
  • you have breathing problems

Take special care with Calcium Chloride Intravenous Infusion if:

  • you have kidney problems
  • you have heart problems
  • you suffer from an inflammatory disorder known as sarcoidosis 13

Animal sterilization

Calcium chloride dihydrate (20% by weight) dissolved in ethanol (95% ABV) has been used as a sterilant for male animals. The non surgical procedure consists of the injection of the solution into the testes of the animal. Within 1 month, necrosis of testicular tissue results in sterilization.1415

Other

Calcium chloride is used in concrete mixes to help speed up the initial setting, but chloride ions lead to corrosion of steel rebar, so it should not be used in reinforced concrete.16 The anhydrous form of calcium chloride may also be used for this purpose and can provide a measure of the moisture in concrete.17

Calcium chloride is used in swimming pool water as a pH buffer and to adjust the calcium hardness of the water.

Calcium chloride is included as an additive in plastics and in fire extinguishers, in wastewater treatment as a drainage aid, in blast furnaces as an additive to control scaffolding (clumping and adhesion of materials that prevent the furnace charge from descending), and in fabric softener as a thinner.

The exothermic dissolution of calcium chloride is used in self-heating cans and heating pads.

In the oil industry, calcium chloride is used to increase the density of solids-free brines. It is also used to provide inhibition of swelling clays in the water phase of invert emulsion drilling fluids.

CaCl2 acts as flux material (decreasing melting point) in the Davy process for the industrial production of Sodium metal, through the electrolysis of molten NaCl.

Calcium chloride is also an ingredient used in ceramic slipware. It suspends clay particles so that they float within the solution making it easier to use in a variety of slipcasting techniques.

Hazards

Calcium chloride can act as an irritant by desiccating moist skin. Solid calcium chloride dissolves exothermically, and burns can result in the mouth and esophagus if it is ingested. Ingestion of concentrated solutions or solid products may cause gastrointestinal irritation or ulceration.18

Other possible side effects of taking calcium chloride include:

  • A chalky taste in the mouth
  • Hot flushes
  • Lowered blood pressure
  • Loss of appetite
  • Feeling sick (nausea)
  • Being sick (vomiting)
  • Constipation
  • Stomach pain
  • Feeling weak
  • Mental disturbances
  • Extreme thirst
  • Passing a large amount of urine
  • Bone pain
  • Calcium deposits in the kidney
  • Kidney stones
  • Irregular heart beat
  • Coma

Any of these may be a sign of overly high calcium blood levels (hypercalcemia).19

Calcium chloride salts also tend to contain a small amount of metals, especially aluminum. Over time these metals can accumulate in the body and have a toxic effect.

See also

References

  1. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  2. ^ Calcium Chloride SIDS Initial Assessment Profile, UNEP Publications, SIAM 15, Boston, 22–25 October 2002, page 11.
  3. ^ Calcium Chloride Chemical Profile, The Innovation Group, www.the-innovation-group.com, printed 9 September 2005.
  4. ^ "CPG 7117.02". FDA Compliance Articles. US Food and Drug Administration. March 1995. Retrieved 3 December 2007. 
  5. ^ "Dust: Don't Eat It! Control It!". Road Management & Engineering Journal. US Roads (TranSafety Inc.). 1 June 1998. Retrieved 9 August 2006. 
  6. ^ "De-icer damaging thousands of trees on mountain passes". The Seattle Times. 19 March 2008. Retrieved 18 March 2008. 
  7. ^ "Agricultural Tire Hydroinflation". www.firestoneag.com. Firestone Tires. December 2007. Retrieved 3 December 2007. 
  8. ^ 21 CFR § 184.1193
  9. ^ 7 CFR § 205.602
  10. ^ Calcium Chloride SIDS Initial Assessment Profile, UNEP Publications, SIAM 15, Boston, 22–25 October 2002, pp. 13–14.
  11. ^ "Apple Caviar Technique". StarChefs Studio. StarChefs.com. April 2004. Retrieved 9 August 2006. 
  12. ^ "Calcium chloride Prescribing Information". Hospira, Inc. November 2009. Retrieved 10 June 2011. 
  13. ^ http://www.drugs.com/pro/calcium-chloride.html | title = Calcium Chloride Intravenous Infusion
  14. ^ Koger, Nov 1977, "Calcium Chloride, Practical Necrotizing Agent", Journal of the American Association of Bovine Practitioners (USA), (Nov 1977), v. 12, p. 118–119
  15. ^ Jana, K.; Samanta, P. K. "Clinical evaluation of non-surgical sterilization of male cats with single intra-testicular injection of calcium chloride". BMC Vet Res. doi:10.1186/1746-6148-7-39. PMID 21774835. 
  16. ^ "Accelerating Concrete Set Time". Federal Highway Administration. 1 June 1999. Retrieved 16 January 2007. 
  17. ^ National Research Council (U.S.). Building Research Institute (1962). Adhesives in Building: Selection and Field Application; Pressure-sensitive Tapes. National Academy of Science-National Research Council. pp. 24–5. 
  18. ^ "Product Safety Assessment (PSA): Calcium Chloride". Dow Chemical Company. 2 May 2006. 
  19. ^ url = http://www.drugs.com/pro/calcium-chloride.html | title = Calcium Chloride Possible Side Affects

External links








Creative Commons License