Ethylhexanoic Acid, Octoic Acid,  2-Ethylhexanoic Acid, 2-EHA, 149-57-5

Ethylhexanoic Acid, Octoic Acid,  2-Ethylhexanoic Acid, 2-EHA, 149-57-5

2-ETHYLHEXANOIC ACID (2-EHA)

1. PRODUCT DEFINITION AND CHEMICAL IDENTITY

Note: Do not confuse 2-ethylhexanoic acid with caprylic acid (n-octanoic acid, C8:0). 2-EHA is a branched-chain isomer with distinctly different physical and chemical properties.

2. PHYSICAL AND CHEMICAL PROPERTIES

3. FUNCTIONAL PROPERTIES

• Metal salt precursor: Reacts with metal oxides, hydroxides, or carbonates to form metal 2-ethylhexanoates. These salts are widely used as driers, catalysts, and stabilizers.

• Excellent low-temperature fluidity: The branched structure imparts very low pour points to its esters, making it valuable for synthetic lubricants.

• High hydrolytic stability: Esters of 2-EHA are more resistant to hydrolysis than linear fatty acid esters.

• Good solvency: Miscible with many organic solvents (xylene, toluene, mineral spirits, alcohols, ketones) but only sparingly soluble in water.

• Corrosion potential: As an acid, can be corrosive to certain metals; neutralized salts are non-corrosive.

4. ALTERNATIVE NAMES AND SYNONYMS

• 2-Ethylhexanoic acid

• 2-EHA

• 2-Ethylcaproic acid (historic)

• Ethylhexanoic acid

• Branched octanoic acid

• (Mistakenly called) Octoic acid – not correct, as that properly refers to caprylic acid (linear C8:0).

5. SECTORAL APPLICATIONS, USAGE RATES, AND EXAMPLE FORMULATIONS

Example Formulations (stoichiometric bases):

• Cobalt Drier (10% Co metal):

  • Cobalt acetate tetrahydrate + 2-EHA → Cobalt 2-ethylhexanoate + acetic acid.

  • Typical usage: 0.05–0.5% Co metal on paint binder weight.

• Calcium/Zinc PVC Stabilizer:

  • Calcium hydroxide / zinc oxide + 2-EHA → Calcium and zinc 2-ethylhexanoates + water.

  • Used as a secondary stabilizer in flexible PVC at 3–5 phr.

• Polyol Ester (POE) Refrigeration Lubricant:

  • 2-EHA + Pentaerythritol (or TMP) → POE + water (acid-catalyzed esterification).

  • Provides lubricity with R134a, R410A refrigerants.

• Bismuth Polyurethane Catalyst:

  • Bismuth nitrate + 2-EHA → Bismuth 2-ethylhexanoate + nitric acid.

  • Used at 0.01–0.1 phr in 2K PU coatings and elastomers.

6. ALTERNATIVES AND COMPARISON

7. REGULATORY STATUS AND SAFETY

• GHS Classification (CLP Regulation):

  • Signal word: Danger

  • Hazard statements:

    • H315: Causes skin irritation.

    • H318: Causes serious eye damage.

  • Precautionary statements: P264, P280, P302+P352, P305+P351+P338, P310, P332+P313, P362.

• Transport Classification: Not classified as dangerous goods for transport (but check local regulations).

• Environmental:

  • Readily biodegradable (OECD 301).

  • Moderate toxicity to aquatic life.

  • Do not allow to enter drains or watercourses.

• Storage: Keep in tightly closed containers in a cool, dry, well-ventilated place (<40 °C), away from direct sunlight and incompatible materials (strong bases, strong oxidisers, reactive metals). Stainless steel (316) or HDPE containers are recommended.

• Personal Protection: Wear chemical-resistant gloves (e.g., butyl rubber) and safety goggles. In case of skin or eye contact, rinse immediately with plenty of water. If eye irritation persists, seek medical attention.

• Certifications: The product is registered under EU REACH (05-2116281979-31-0000) and listed on TSCA (US), K-REACH (Korea), etc. Ask your supplier for specific compliance documents.

8. FREQUENTLY ASKED QUESTIONS

Q1. Is 2-EHA the same as caprylic acid?
No. Caprylic acid (n-octanoic acid, C8:0) is a straight-chain molecule. 2-EHA is a branched isomer. Their chemical and physical properties (e.g., melting point: 16 °C for caprylic acid vs. −8 °C for 2-EHA) are different.

Q2. Can 2-EHA be used in food contact applications?
Generally, no. 2-EHA is not a direct food additive. Some of its salts (e.g., calcium 2-ethylhexanoate) may have very limited indirect food contact approval under specific regulations, but this must be verified per application.

Q3. Which metals can form salts with 2-EHA?
Almost all: Li, Na, K, Ca, Mg, Ba, Zn, Co, Mn, Zr, Bi, Sn, Cu, Fe, Al, Ni, Ce (rare earth). The most common are Co (driers), Ca/Zn (PVC), Bi/Zn (PU), K/Na (emulsifiers).

Q4. What is the shelf life of 2-EHA?
Under proper storage conditions (closed container, dry, 10–30 °C), minimum 24 months. After opening, it is recommended to use within 6–12 months.

Q5. In which solvents is 2-EHA soluble?
It is miscible with alcohols, xylene, toluene, mineral spirits, acetone, ethyl acetate, and most organic solvents. It has low water solubility (~1.4 g/L).

Q6. Does the high flash point (113 °C) mean it is non-hazardous?
No. Although the flash point is relatively high, the liquid causes severe eye damage and skin irritation. Vapour generated when heated may also be irritating.

Q7. Is there a natural or green alternative?
Partially. Linear fatty acids such as oleic acid from vegetable oils can replace 2-EHA in some applications, but performance differs significantly. The branched structure, which gives low pour points, is difficult to obtain from natural renewable sources economically.

Q8. What types of packaging are used?
25 kg plastic jerrycans, 200 kg plastic/steel drums, 1000 kg IBCs, and bulk tankers. Stainless steel or high-density polyethylene is recommended; avoid galvanised steel or copper-based alloys.

Q9. Is REACH registration available?
Yes, 2-EHA (149-57-5) is fully REACH registered. Request the compliance certificate from your supplier.

Q10. What influences the price of 2-EHA?
Purity (≥99% vs. 98%), packaging size, raw material costs (propylene, syngas), and transportation (not classed as dangerous goods, but still an acid).

9. QUICK REFERENCE TABLE