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Chemical Properties

CAS Registry Number: 149-57-5

Selected information from two of the National Library of Medicine's databases: ChemIDPlus2 and HSDB3.

Names 1

  • 2-Ethylhexanoic acid
  • Ethyl Hexanoic Acid, 2-


Chemical Structure for Chemical Abstracts Service Registry Number 149-57-5 from NLM

Synonyms (Sources: NTP,HSDB,RTECS,MESH)2

  • 2-Butylbutanoic acid
  • 2-Ethylcaproic acid
  • 2-Ethylhexanoic acid
  • 2-Ethylhexoic acid
  • 3-10-00-01641 (Beilstein Handbook Reference)
  • 3-Heptanecarboxylic acid
  • BRN 1750468
  • Butylethylacetic acid
  • Ethylhexanoic acid
  • Ethylhexoic acid
  • HSDB 5649
  • Hexanoic acid, 2-ethyl-
  • Kyselina 2-ethylkapronova [Czech]
  • Kyselina heptan-3-karboxylova [Czech]
  • alpha-Ethylcaproic acid

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Other Registry Numbers2

  • 202054-39-5
  • 83829-68-9

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Chemical Properties3

Property Description
Boiling Point
  • 228 deg C
  • Clear liquid
  • None Found
Critical Temperature & Pressure
  • Critical temperature: 615.2 K
Density/Specific Gravity
  • 0.9031 g/cu cm at 25 deg C
Dissociation Constants
  • None Found
Heat Of Combustion
  • None Found
Heat Of Vaporization
  • None Found
Melting Point
  • None Found
Molecular Weight
  • 144.22
  • Mild odor
Other Chemical/Physical Properties
  • Henry's Law constant = 2.8X10-6 atm-cu m/mol at 25 deg C (est)
  • Hydroxyl radical reaction rate constant = 8.18X10-12 cu cm/molec-sec at 25 deg C (est)
Relative Evaporation Rate
  • None Found
  • In water at 20 deg C, 0.2 wt %. /2,000 mg/L/
  • Solubility in water = 1.4 g/L water at 25 deg C.
  • Soluble in ethyl ether, carbon tetrachloride; slightly soluble in ethanol.
Spectral Properties
  • 13C NMR: 317 (Johnson and Jankowski, Carbon-13 NMR Spectra, John Wiley & Sons, New York)
  • 1H NMR: 7293 (Sadtler Research Laboratories Spectral Collection)
  • IR: 4826 (Coblentz Society Spectral Collection)
  • Index of refraction: 1.4241 at 20 deg C/D
  • MASS: 46659 (NIST/EPA/MSDC Mass Spectral Database, 1990 version)
Surface Tension
  • None Found
  • None Found
Vapor Density
  • 5.0 (AIR= 1)
Vapor Pressure
  • 0.03 mm Hg at 20 deg C
  • 7.8 mPa s
log P (octanol-water)
  • log Kow = 2.64
  • None Found

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  • 2-Ethylhexanoic acid is of particular importance in the production of alkyd resins used for baking enamels because of their exceptional stability even at temperatures over 200 deg C and their good weathering and aging stability. ... The acid (2-ethylhexanoic acid) and its derivatives are used in the manufacture of lubricants, detergents, flotation aids, and corrosion inhibitors, as catalysts for polyurethane foaming, for solvent extraction, and for dye granulation ... The lead, cobalt, manganese, and zinc salts are soluble in hydrocarbons. Such solutions serve as drying agents for lacquers and enamels. The iron, nickel, and cobalt salts are used as stabilizers for silicones. The copper salt is a fungicide for marine and other applications. **PEER REVIEWED**
  • Active ingredient of the wood presearvative agent, Sinesto B. /Non-USA use/ **PEER REVIEWED** PubMed Abstract
  • Cosolvent and defoamer in pesticides **PEER REVIEWED**
  • Paint driers; heat stabilizers for PVC **PEER REVIEWED**
  • The acid 2-ethylhexanoic acid) ... /is/ used in the manufacture of lubricants, detergents, flotation aids, and corrosion inhibitors, as catalysts for polyurethane foaming, for solvent extraction, and for dye granulation. **PEER REVIEWED**
  • The metallic salts /of 2-Ethylhexanoic acid/ are used as driers for paints & varnishes and as gelling agents for hydrocarbons. **PEER REVIEWED**

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Notes (Sources: NTP,HSDB,RTECS,MESH)2

  • Wood preservative; 2-ethylhexanoic acid is active ingredient in Sinesto B.

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Superlist Classes2

  • TWA (5 mg/m3, vapor and aerosol, inhalable fraction)

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Links to Additional Information2

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1 Source: the NTP's CEBS database.

2 Source: the National Library of Medicine's ChemIDPlus, 02/28/2017.

3 Source: the National Library of Medicine's Hazardous Substance Database, 02/28/2017.

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