2-Ethylhexanoic acid

2-Ethylhexanoic acid

IUPAC name 2-Ethylhexanoic acid
Other names 2-Ethylcaproic acid; 3-Heptanecarboxylic acid
Identifiers
CAS number	149-57-5^Y
PubChem	8697
ChemSpider	8373^Y
UNII	01MU2J7VVZ^Y
ChEMBL	CHEMBL1162485^Y
Jmol-3D images	Image 1
SMILES O=C(O)C(CC)CCCC
InChI InChI=1S/C8H16O2/c1-3-5-6-7(4-2)8(9)10/h7H,3-6H2,1-2H3,(H,9,10)^Y Key: OBETXYAYXDNJHR-UHFFFAOYSA-N^Y InChI=1/C8H16O2/c1-3-5-6-7(4-2)8(9)10/h7H,3-6H2,1-2H3,(H,9,10) Key: OBETXYAYXDNJHR-UHFFFAOYAO
Properties
Molecular formula	C₈H₁₆O₂
Molar mass	144.21 g mol⁻¹
Appearance	Colorless oil
Density	0.903 g/cm³, solid
Melting point	-59 °C, 214 K, -74 °F
Boiling point	228 °C, 501 K, 442 °F
Solubility in water	Low
Solubility	Soluble in many organic solvents
Hazards
R-phrases	R63
S-phrases	S36/37
Main hazards	Flammable
Flash point	110 °C (230 °F)
Autoignition temperature	371 °C
Related compounds
Related compounds	Naphthenic acid, Valproic acid
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox 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.

Examples of metal ethylhexanoates

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

Health aspects

Some studies showed now subchronic oral toxicity.^[1] but as a study indicated the teratogenicity of the compound the sources for exposure were 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 even in glass jars was due to the diffusion of the compound from the PVC cap into the food. ^[3]

References

^ 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. doi:10.1016/S0278-6915(97)00168-3. PMID 9662418.
^ 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 (1): 41–46. doi:10.1002/tera.1420350107. PMID 3105103.
^ 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. PMID 15370833.