Mucic acid

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Structural formula
Structure of mucic acid
General
Surname Mucic acid
other names
  • (2 R , 3 S , 4 R , 5 S ) -2,3,4,5-tetrahydroxyadipic acid
  • (2 R , 3 S , 4 R , 5 S ) -2,3,4,5-tetrahydroxyhexane-1,6-diacid
  • D- galactaric acid ( IUPAC )
  • Mucic acid
  • Galactaric acid
  • Galactosaccharic acid
  • Lactic acid (obsolete)
  • meso- galactaric acid (obsolete)
Molecular formula C 6 H 10 O 8
Brief description

colorless, almost odorless crystals

External identifiers / databases
CAS number 526-99-8
EC number 208-404-0
ECHA InfoCard 100.007.641
PubChem 3037582
Wikidata Q424916
properties
Molar mass 210.14 g mol −1
Physical state

firmly

density

0.4 g cm −3 (bulk density)

Melting point
  • 220–225 ° C (decomposition)
  • 255 ° C (decomposition)
solubility

poor in water (3.3 g l −1 at 14 ° C)

safety instructions
GHS labeling of hazardous substances
no GHS pictograms
H and P phrases H: no H-phrases
P: no P-phrases
Toxicological data

8000 mg kg −1 ( LD 50 ,  mouse ,  oral )

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Mucic , even mucic or galactaric called, is one of the poly hydroxy - dicarboxylic acids . It belongs to the sugar dicarboxylic acids ( aldaric acids ). It shows no optical activity ; mucic acid is epimeric to glucaric acid . Their salts and esters are called galactarates or mucates .

history

Mucic acid was discovered in 1780 by Carl Wilhelm Scheele in the oxidation of lactose by nitric acid . The mucic acid was later examined more closely by Liebig and Pelouze . The origin of the name comes from the name for galactose (mucous sugar) as it occurs in mucous membranes.

Extraction and presentation

Mucic acid is formed during the oxidation of certain carbohydrates such as lactose , galactose or galacturonic acid ( botrytis acid ).

To illustrate (by way of example) 25 g of galactose in 300 ml of 25% nitric acid are evaporated to approx. 50 ml in a water bath. After cooling, the pasty mass is stirred up with 50 ml of water. After one hour, the supernatant can then be suctioned off and about 15 g of mucic acid are obtained.

properties

Dry distillation ( pyrolysis ) of mucic acid gives 2-furancarboxylic acid ( pyrocucic acid ).

use

Mucus acid can in baking powder and effervescent tablets the tartaric acid replaced.

Biological importance

Mucic acid can in wine by the gray mold Botrytis cinerea are formed where they as calcium salt a Calciummucat forms mentioned, white precipitate.

Individual evidence

  1. ^ Friedrich Albrecht Carl Gren , Christian Friedrich Bucholz : Grundriß der Chemie. First part, 4th edition, Hallisches Waisenhaus, 1818, p. 579.
  2. ^ Gerhard Kempter : Study library: Organic-chemical internship. 7th edition, Springer, 1978, ISBN 978-3-528-33540-3 , p. 147.
  3. ↑ a b c d e data sheet mucic acid (PDF) from Merck , accessed on January 18, 2011.
  4. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 97th edition. (Internet version: 2016), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-280.
  5. ↑ a b c data sheet Mucic acid, 97% from Sigma-Aldrich , accessed on February 26, 2013 ( PDF ).
  6. ^ Gattermann, Wieland: The practice of the organic chemist. 43rd edition, De Gruyter Verlag, 1982, ISBN 3-11-006654-8 .

literature