Mesoxalic acid
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| Surname | Mesoxalic acid | |||||||||||||||||||||
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| Molecular formula | C 3 H 2 O 5 | |||||||||||||||||||||
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| Molar mass | 118.04 g mol −1 | |||||||||||||||||||||
| Physical state |
firmly |
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| Melting point |
113-121 ° C (hydrate) |
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| solubility |
very soluble in water , ethanol and diethyl ether |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||||||||||||||
Mesoxalic acid is both a dicarboxylic acid and a ketocarboxylic acid and easily gives off two protons with the formation of the divalent anion C 3 O 5 2− . With water - as an exception to the Erlenmeyer rule - it forms a stable, isolatable hydrate (2,2-dihydroxymalonic acid); The same applies to their derivatives , such as the esters . Mesoxalic acid has a reducing effect, for example with the Tollensprobe ; their thermal stability is low. When heated, it breaks down, splitting off carbon dioxide ( decarboxylation , to glyoxylic acid ) or carbon monoxide ( decarbonylation , to form oxalic acid ).
Occurrence
Mesoxalic acid is found in various plants, such as sugar beet and alfalfa .
Manufacturing
It can be produced by oxidation of tartronic acid (hydroxymalonic acid) on platinum-bismuth catalysts and air. When glycerol is titrated with aqueous potassium permanganate, it is quantitatively oxidized to mesoxalic acid. ( COD titration by manganometry )
Individual evidence
- ↑ a b c d e Entry on mesoxalic acid. In: Römpp Online . Georg Thieme Verlag, accessed on January 14, 2013.
- ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
- ↑ Hans Beyer, Wolfgang Walter: Textbook of organic chemistry . 18th edition. S. Hirzel Verlag, Stuttgart 1978, ISBN 3-7776-0342-2 , p. 297 .
- ^ P. Fordham, M. Besson, P. Gallezot: "Catalytic oxidation with air of tartronic acid to mesoxalic acid on bismuth-promoted platinum", in: Catal. Lett. , 1997 , 46 (3-4), pp. 195-199; doi : 10.1023 / A: 1019082905366 .
- ↑ In contrast, potassium dichromate oxidizes aqueous glycerine quantitatively to carbon dioxide.