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Stearin

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Stearin[1]
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
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.008.271Edit this at Wikidata
KEGG
UNII
  • 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,4-53H2,1-3H3☒N
    Key: DCXXMTOCNZCJGO-UHFFFAOYSA-N☒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,4-53H2,1-3H3
    Key: DCXXMTOCNZCJGO-UHFFFAOYSA-N
  • CCCCCCCCCCCCCCCCCC(=O)OCC(COC(=O)CCCCCCCCCCCCCCCCC)OC(=O)CCCCCCCCCCCCCCCCC
Properties
C57H110O6
Molar mass 891.501g·mol−1
Appearance White powder
Odor Odorless
Density 0.862 g/cm3(80 °C)
0.8559 g/cm3(90 °C)[2]
Melting point 54–72.5 °C (129.2–162.5 °F; 327.1–345.6 K)[3]
Insoluble
Solubility Slightly soluble inC6H6,CCl4
Soluble inacetone,CHCl3
Insoluble inEtOH[2]
1.4395 (80 °C)[2]
Structure
Triclinic(β-form)[4]
P1(β-form)[4]
a= 12.0053 Å,b= 51.902 Å,c= 5.445 Å (β-form)[4]
α = 73.752°, β = 100.256°, γ = 117.691°
Thermochemistry
1342.8 J/mol·K (β-form, 272.1 K)
1969.4 J/mol·K (346.5 K)[3][5]
1534.7 J/mol·K (liquid)[5]
−2344 kJ/mol[5]
35806.7 kJ/mol[5]
Hazards
NFPA 704(fire diamond)
[6]
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[6]
Lethal doseor concentration (LD, LC):
2000 mg/kg (rats, oral)[6]
Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa).

Stearin/ˈstɪərɪn/,ortristearin,orglyceryl tristearateis an odourless, white powder. It is atriglyceridederived from three units ofstearic acid.Most triglycerides are derived from at least two and more commonly three differentfatty acids.[7]Like other triglycerides, stearin can crystallise in threepolymorphs.For stearin, these melt at 54 (α-form), 65, and72.5 °C(β-form).[3]

Note thatstearinis 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 aspalm stearin.

Occurrence[edit]

Stearin is obtained from animalfatscreated as a byproduct of processingbeef.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 byinteresterification,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 ofcod liver oilremoved during the chilling process at temperatures below−5 °C.

Uses[edit]

Stearin is used as a hardening agent in the manufacture ofcandlesandsoap.[8]It is mixed with asodium hydroxidesolution in water, creating a reaction which givesglycerinandsodium 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.[clarification needed]

See also[edit]

References[edit]

  1. ^Merck Index,11th Edition,9669.
  2. ^abcLide, David R., ed. (2009).CRC Handbook of Chemistry and Physics(90th ed.).Boca Raton, Florida:CRC Press.ISBN978-1-4200-9084-0.
  3. ^abcCharbonnet, 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.S2CID101805872.
  4. ^abcVan 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.PMID11373397.
  5. ^abcdTristearinin 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. ^abc"MSDS of Stearin Wax"(PDF).swna.us.Sasol Wax North America Corp. Archived fromthe original(PDF)on 2016-03-04.Retrieved2014-06-19.
  7. ^Alfred Thomas (2002). "Fats and Fatty Oils".Ullmann's Encyclopedia of Industrial Chemistry.Weinheim: Wiley-VCH.doi:10.1002/14356007.a10_173.ISBN978-3527306732.
  8. ^Geller, L. W. (1935). "Waxes in the candle industry".Oil & Soap.12(11): 263–265.doi:10.1007/BF02636720.S2CID97117097.
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