Mucic acid

• Mucic
• Galactaric
• 2,3,4,5- tetrahydroxyadipic acid

Colorless, almost odorless, crystalline powder

Fixed

0.4 g · cm -3 ( bulk density )

220-255 ° C ( decomposition)

Poorly in water ( 3.3 g · l -1 at 14 ° C)

8000 mg · kg -1 ( LD50, mouse, oral)

Template: Infobox chemical / molecular formula search available

Mucic acid, also known as mucic or galactaric, one of the dicarboxylic acids. It shows no optical activity. Mucic acid is epimeric to glucaric acid.

History

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

Production and representation

Mucic acid obtained by the oxidation of certain carbohydrates such as lactose, galactose or galacturonic acid ( Botrytissäure ).

To represent (for example) 25 g galactose in 300 ml of 25 % nitric acid are evaporated in a water bath to about 50 ml. After cooling, the slurry is stirred with 50 ml of water. After an hour you can then aspirate the supernatant and so gives about 15 g of mucic acid.

Properties

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

Use

Mucic acid can replace tartaric acid in baking powder and effervescent tablets.

Biological Significance

Mucic acid can be formed in wine by the gray mold Botrytis cinerea, where it forms a Calciummucat as the calcium salt called white precipitate.