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Stearin

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Stearin
Skeletal formula of stearin
Space-filling model of the tristearin molecule
Powder of stearin
Names
Systematic IUPAC name Propane-1,2,3-triyl tri(octadecanoate)
Other names Tristearin; Trioctadecanoin; Glycerol tristearate; Glyceryl tristearate
Identifiers
CAS Number
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.008.271 Edit this at Wikidata
KEGG
PubChem CID
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C57H110O6/c1-4-7-10-13-16-19-22-25-28-31-34-37-40-43-46-49-55(58)61-52-54(63-57(60)51-48-45-42-39-36-33-30-27-24-21-18-15-12-9-6-3)53-62-56(59)50-47-44-41-38-35-32-29-26-23-20-17-14-11-8-5-2/h54H,4-53H2,1-3H3Key: DCXXMTOCNZCJGO-UHFFFAOYSA-N
  • InChI=1S/C57H110O6/c1-4-7-10-13-16-19-22-25-28-31-34-37-40-43-46-49-55(58)61-52-54(63-57(60)51-48-45-42-39-36-33-30-27-24-21-18-15-12-9-6-3)53-62-56(59)50-47-44-41-38-35-32-29-26-23-20-17-14-11-8-5-2/h54H,4-53H2,1-3H3Key: DCXXMTOCNZCJGO-UHFFFAOYSA-N
SMILES
  • CCCCCCCCCCCCCCCCCC(=O)OCC(COC(=O)CCCCCCCCCCCCCCCCC)OC(=O)CCCCCCCCCCCCCCCCC
Properties
Chemical formula C57H110O6
Molar mass 891.501 g·mol
Appearance White powder
Odor Odorless
Density 0.862 g/cm (80 °C)
0.8559 g/cm (90 °C)
Melting point 54–72.5 °C (129.2–162.5 °F; 327.1–345.6 K)
Solubility in water Insoluble
Solubility Slightly soluble in C6H6, CCl4
Soluble in acetone, CHCl3
Insoluble in EtOH
Refractive index (nD) 1.4395 (80 °C)
Structure
Crystal structure Triclinic (β-form)
Space group P1 (β-form)
Lattice constant a = 12.0053 Å, b = 51.902 Å, c = 5.445 Å (β-form)α = 73.752°, β = 100.256°, γ = 117.691°
Thermochemistry
Heat capacity (C) 1342.8 J/mol·K (β-form, 272.1 K)
1969.4 J/mol·K (346.5 K)
Std molar
entropy (S298) 		1534.7 J/mol·K (liquid)
Std enthalpy of
formation (ΔfH298) 		−2344 kJ/mol
Std enthalpy of
combustion (ΔcH298) 		35806.7 kJ/mol
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1 1 0
Flash point ≥ 300 °C (572 °F; 573 K) closed cup
Lethal dose or concentration (LD, LC):
LD50 (median dose) 2000 mg/kg (rats, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). ☒N verify (what is  ?) Infobox references
Chemical compound

Stearin /ˈstɪərɪn/, or tristearin, or glyceryl tristearate is an odourless, white powder. It is a triglyceride derived from three units of stearic acid. Most triglycerides are derived from at least two and more commonly three different fatty acids. Like other triglycerides, stearin can crystallise in three polymorphs. For stearin, these melt at 54 (α-form), 65, and 72.5 °C (β-form).

Note that stearin is also used to mean the solid component of an oil or fat that can be separated into components that melt at higher (the stearin) and lower (the olein) temperatures. This is the usage meant in an example such as palm stearin.

Occurrence

Stearin is obtained from animal fats created as a byproduct of processing beef. It can also be found in tropical plants such as palm. It can be partially purified by dry fractionation by pressing tallow or other fatty mixtures, leading to separation of the higher melting stearin-rich material from the liquid, which is typically enriched in fats derived from oleic acid. It can be obtained by interesterification, again exploiting its higher melting point which allows the higher melting tristearin to be removed from the equilibrated mixture. Stearin is a side product obtained during the extraction of cod liver oil removed during the chilling process at temperatures below −5 °C.

Uses

Stearin is used as a hardening agent in the manufacture of candles and soap. It is mixed with a sodium hydroxide solution in water, creating a reaction which gives glycerin and sodium stearate, the main ingredient in most soap:

C3H5(C18H35O2)3 + 3 NaOH → C3H5(OH)3 + 3 C18H35OONa

Stearin is also added to aluminium flakes to help in the grinding process in making dark aluminium powder.

See also

References

  1. Merck Index, 11th Edition, 9669.
  2. ^ Lide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
  3. ^ Charbonnet, G. H.; Singleton, W. S. (1947). "Thermal properties of fats and oils". Journal of the American Oil Chemists' Society. 24 (5): 140. doi:10.1007/BF02643296. S2CID 101805872.
  4. ^ Van Langevelde, A.; Peschar, R.; Schenk, H. (2001). "Structure of β-trimyristin and β-tristearin from high-resolution X-ray powder diffraction data". Acta Crystallographica Section B. 57 (3): 372–377. doi:10.1107/S0108768100019121. PMID 11373397.
  5. ^ Tristearin in Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD) (retrieved 2014-06-19)
  6. ^ "MSDS of Stearin Wax" (PDF). www.swna.us. Sasol Wax North America Corp. Archived from the original (PDF) on 2016-03-04. Retrieved 2014-06-19.
  7. Alfred Thomas (2002). "Fats and Fatty Oils". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a10_173. ISBN 978-3527306732.
  8. Geller, L. W. (1935). "Waxes in the candle industry". Oil & Soap. 12 (11): 263–265. doi:10.1007/BF02636720. S2CID 97117097.
Types of lipids
General
Geometry
Eicosanoids
Fatty acids
Glycerides
Phospholipids
Sphingolipids
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