Mellitic acid

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Structural formula
Structural formula of mellitic acid
General
Surname Mellitic acid
other names
  • Benzene hexacarboxylic acid
  • Graphitic acid
  • Honey stinic acid
  • Mellitic acid
Molecular formula C 12 H 6 O 12
Brief description

satin needles

External identifiers / databases
CAS number 517-60-2
EC number 208-243-6
ECHA InfoCard 100.007.495
PubChem 2334
ChemSpider 2244
DrugBank DB01681
Wikidata Q734078
properties
Molar mass 342.16 g mol −1
Physical state

firmly

Melting point

288  ° C

pK s value
  • pK s 1  = 1.40
  • pK s 2  = 2.19
  • pK s 3  = 3.31
  • pK s 4  = 4.78
  • pK s 5  = 5.89
  • pK s 6  = 6.96
solubility

Easily soluble in water and ethanol

safety instructions
GHS labeling of hazardous substances
07 - Warning

Caution

H and P phrases H: 315-319-335
P: 261-305 + 351 + 338
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Mellitic acid ( benzene hexacarboxylic acid , also graphitic acid ) is an acid that was first discovered in 1799 by Martin Heinrich Klaproth in the mineral mellite ( honey stone ), the aluminum salt of the acid.

presentation

Mellitic acid can be made by heating mellite with ammonium carbonate . With an excess of ammonia, the aluminum ions are precipitated as hydroxide and separated; the ammonium salt of mellitic acid remains. The acid can also be produced by the oxidation of pure carbon or hexamethylbenzene , in the cold by alkaline potassium permanganate or by hot concentrated nitric acid.

properties

Mellitic acid crystallizes in fine, silky needles and is soluble in water and ethanol. It is a very stable compound: chlorine, concentrated nitric acid and hydrogen iodide have no decomposing effect. Mellitic acid decomposes by dry distillation into carbon dioxide , water and pyromellitic dianhydride , C 10 H 2 O 6 ; in the presence of lime, it completely decomposes into carbon dioxide and benzene. A reaction of the acid with excess phosphorus pentachloride forms the acid chloride , which crystallizes in needles and melts at 190 ° C.

The high stability of the mellitic acid salts and their property as the end product of the oxidation of polycyclic aromatic hydrocarbons found in the solar system make them possible candidates for organic substances in the Martian soil.

See also

Mellitic anhydride , the anhydride of mellitic acid, which can also be formally understood as an oxide of carbon C 12 O 9 (dodecacarbon nonaoxide).

literature

  • Henry Enfield Roscoe: A Treatise on Chemistry: The chemistry of the hydrocarbons and their derivatives, or Organic chemistry. Appleton, 1889, p. 373 ( limited preview in Google book search).

Individual evidence

  1. ↑ a b c Entry on mellitic acid. In: Römpp Online . Georg Thieme Verlag, accessed on June 19, 2014.
  2. ↑ a b c d e f CRC Handbook of Tables for Organic Compound Identification , Third Edition, 1984, ISBN 0-8493-0303-6 .
  3. ↑ a b Mellitic acid data sheet from Sigma-Aldrich , accessed on April 9, 2011 ( PDF ).
  4. ↑ reactions of the carbon at webelements.com
  5. ↑ SA Benner, KG Devine, LN Matveeva, DH Powell: "The missing organic molecules on Mars", in: Proceedings of the National Academy of Sciences , 2000 , 97  (6), pp. 2425-2430; doi : 10.1073 / pnas.040539497 ; PMID 10706606 .

Web links

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