2-Ethylhexanoic acid

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2-Ethylhexanoic acid
IUPAC name 2-Ethylhexanoic acid
Other names 2-Ethylcaproic acid, 3-heptanecarboxylic acid
Identifiers
CAS number [149-57-5]
Properties
Molar mass 144.21 g/mol
Appearance Colourless oil
Density 0.903 g/cm3, solid
Melting point

-59 °C

Boiling point

228 °C

Solubility in water low
Solubility organic solvents
Hazards
Main hazards flammable
R-phrases 63
S-phrases 36/37
Flash point 230 °F
Autoignition
temperature
371 °C
Related compounds
Related compounds naphthenic acid, valproic acid
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

2-Ethylhexanoic acid is the organic compound with the formula CH3(CH2)3CH(C2H5)CO2H. This carboxylic acid is widely used to prepare metal derivatives that are soluble in nonpolar organic solvents. These lipophilic metal-containing derivatives are used as catalysts in polymerizations. For example, tin 2-ethylhexanoate is used in the production of poly(lactic-co-glycolic acid). The high solubility of these metal complexes is attributable to the long hydrocarbon chain and the presence of a chiral center which leads to mixtures of diastereoisomeric complexes. These metal complexes are often described as salts, when in fact they are not ionic but charge-neutral coordination complexes akin to the better defined, more crystalline acetates.

[edit] Examples of metal ethylhexanoates

  • Hydroxyl aluminium bis(2-ethylhexanoate), used as a thickener.
  • Tin(II) ethylhexanoate (CAS# 301-10-0) as a catalyst for polylactide polymerization.
  • Cobalt(II) ethylhexanoate (CAS# 136-52-7) as a drier for alkyd resins.
  • Nickel(II) ethylhexanoate (CAS# 4454-16-4)

[edit] Health aspects

Some studies showed now subchronic oral toxicity.[1] but as a studiy indicated the teratogenicity of the compound the sources for exposure where evaluated.[2] One major source are the metal derivatives of 2-ethylhexanoic acid, which are widely used as stabilizers for polyvinyl chloride PVC. The other source is the metabolism of bis(2-ethylhexyl) phthalate (DEHP) the two ester bonds are hydrolysed and the resulting 2-ethylhexanol is oxidized in the organism to 2-ethylhexanoic acid. The elevated levels of the compound in even glass jars was due to the diffusion of the compound from the PVC cap into the food. [3]

[edit] References

  1. ^ Juberg DR, David RM, Katz GV, Bernard LG, Gordon DR, Vlaovic MS, Topping DC. (1998). "2-Ethylhexanoic acid: subchronic oral toxicity studies in the rat and mouse.". Food Chem Toxicol. 36 (5): 429–36. 
  2. ^ Ritter, E. J., Scott, W. J. Jr, Randall, J. L. and Ritter, J.M. (1987). "Teratogenicity of di(2-ethylhexyl)phthalate, 2-ethylhexanol, 2-ethylhexanoic acid, and valproic acid, and potentiation by caffeine.". Teratology 35: 41–46. 
  3. ^ S. Elss; L. Grünewald; E. Richling; P. Schreier (2004). "Occurrence of 2-ethylhexanoic acid in foods packed in glass jars". Food Additives & Contaminants 21 (8): 811–814. doi:10.1080/02652030410001732879.