Calcium stearate

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Calcium stearate
Calcium stearate.png
Identifiers
CAS number 1592-23-0 YesY
PubChem 15324
ChemSpider 14587 YesY
UNII 776XM7047L YesY
ChEMBL CHEMBL2106092 N
Jmol-3D images Image 1
Properties
Molecular formula C36H70CaO4
Molar mass 607.02 g mol−1
Appearance white to yellowish-white powder
Density 1.08 g/cm3
Melting point 155 °C (311 °F; 428 K)
Solubility in water 0.004 g/100 mL (15 °C)
Solubility soluble in hot pyridine
slightly soluble in oil
insoluble in alcohol, ether
Hazards
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
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 stearate is carboxylate of calcium that is found in some lubricants and surfactants. It is a white waxy powder.[1]

Production and occurrence[edit]

Calcium stearate is produced by heating stearic acid, a fatty acid, and calcium oxide:

2 C17H35COOH + CaO → (C17H35COO)2Ca + H2O

It is also the main component of soap scum, a white solid that forms when soap is mixed with hard water.[2] Unlike soaps containing sodium and potassium, calcium stearate is insoluble in water and does not lather well.[citation needed] Commercially it is sold as a 50% dispersion in water or as a spray dried powder. As a food additive it is known by the generic E number E470.

Applications[edit]

  • Calcium stearate is used as a flow agent in powders including some foods (such as Smarties), a surface conditioner in hard candies such as Sprees, a waterproofing agent for fabrics, a lubricant in pencils and crayons.
  • The concrete industry uses calcium stearate for efflorescence control of cementitious products used in the production of concrete masonry units i.e. paver and block, as well as waterproofing.[3]
  • In paper production, calcium stearate is used as a lubricant to provide good gloss, preventing dusting and fold cracking in paper and paperboard making.[4]
  • In plastics, it can act as an acid scavenger or neutralizer at concentrations up to 1000ppm, a lubricant and a release agent. It may be used in plastic colorant concentrates to improve pigment wetting. In rigid PVC, it can accelerate fusion, improve flow, and reduce die swell.
  • Applications in the personal care and pharmaceutical industry include tablet mold release, anti-tack agent, and gelling agent.
  • Calcium stearate is a component in some types of defoamers.

References[edit]

  1. ^ Angelo Nora, Alfred Szczepanek, Gunther Koenen “Metallic Soaps” in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a16_361
  2. ^ Hermann Weingärtner, "Water" in Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. doi:10.1002/14356007.a28_001
  3. ^ Preventing Efflorescence, Portland Cement Association
  4. ^ US 5527383