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Lactose

Lactose
Names
IUPAC name
β-D-Galactopyranosyl-(1→4)-D-glucose
Systematic IUPAC name
(2R,3R,4S,5R,6S)-2-(Hydroxymethyl)-6-{[(2R,3S,4R,5R,6R)-4,5,6-trihydroxy-2-(hydroxymethyl)oxan-3-yl]oxy}oxane-3,4,5-triol
Other names
Milk sugar
Lactobiose
4-O-β-D-Galactopyranosyl-D-glucose
Identifiers
3D model (JSmol)
90841
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.509 Edit this at Wikidata
EC Number
  • 200-559-2
342369
KEGG
UNII
  • InChI=1S/C12H22O11/c13-1-3-5(15)6(16)9(19)12(22-3)23-10-4(2-14)21-11(20)8(18)7(10)17/h3-20H,1-2H2/t3-,4-,5+,6+,7-,8-,9-,10-,11-,12+/m1/s1 checkY
    Key: GUBGYTABKSRVRQ-DCSYEGIMSA-N checkY
  • InChI=1/C12H22O11/c13-1-3-5(15)6(16)9(19)12(22-3)23-10-4(2-14)21-11(20)8(18)7(10)17/h3-20H,1-2H2/t3-,4-,5+,6+,7-,8-,9-,10-,11-,12+/m1/s1
    Key: GUBGYTABKSRVRQ-DCSYEGIMBP
  • C([C@@H]1[C@@H]([C@@H]([C@H]([C@@H](O1)O[C@@H]2[C@H](O[C@H]([C@@H]([C@H]2O)O)O)CO)O)O)O)O
Properties
C12H22O11
Molar mass 342.297 g·mol−1
Appearance White solid
Density 1.525 g/cm3
Melting point 252 °C (anhydrous)[1]
202 °C (monohydrate)[1]
195 g/L[2][3]
+55.4° (anhydrous)
+52.3° (monohydrate)
Thermochemistry
5652 kJ/mol, 1351 kcal/mol, 16.5 kJ/g, 3.94 kcal/g
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
0
0
Flash point 357.8 °C (676.0 °F; 631.0 K)[4]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Lactose, or milk sugar, is a disaccharide composed of galactose and glucose and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from lact (gen. lactis), the Latin word for milk, plus the suffix -ose used to name sugars. The compound is a white, water-soluble, non-hygroscopic solid with a mildly sweet taste. It is used in the food industry.[5]

  1. ^ a b Peter M. Collins (2006). Dictionary of Carbohydrates (2nd ed.). Boca Raton: Chapman & Hall/CRC. p. 677. ISBN 978-0-8493-3829-8.
  2. ^ "D-Lactose".
  3. ^ The solubility of lactose in water is 189.049 g at 25 °C, 251.484 g at 40 °C and 372.149 g at 60 °C per kg solution. Its solubility in ethanol is 0.111 g at 40 °C and 0.270 g at 60 °C per kg solution.Machado, José J. B.; Coutinho, João A.; Macedo, Eugénia A. (2001), "Solid–liquid equilibrium of α-lactose in ethanol/water" (PDF), Fluid Phase Equilibria, 173 (1): 121–34, doi:10.1016/S0378-3812(00)00388-5. ds
  4. ^ Sigma Aldrich
  5. ^ Gerrit M. Westhoff; Ben F.M. Kuster; Michiel C. Heslinga; Hendrik Pluim; Marinus Verhage (2014). "Lactose and Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH. pp. 1–9. doi:10.1002/14356007.a15_107.pub2. ISBN 978-3-527-30673-2.

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