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SECTION 1. CHEMICAL IDENTIFICATION

CHEMINFO Record Number: 490
CCOHS Chemical Name: 2-Ethylhexanoic acid

Synonyms:
2-Butylbutanoic acid
Butylethylacetic acid
2-EHA
2-Ethylcaproic acid
alpha-Ethylcaproic acid
alpha-Ethylhexanoic acid
2-Ethylhexoic acid
3-Heptanecarboxylic acid
Ethylhexanoic acid (non-specific name)
Acide 2-éthyl caproïque

Chemical Name French: Acide 2-éthyl hexanoïque
Chemical Name Spanish: Acido 2-etilhexanoico
CAS Registry Number: 149-57-5
RTECS Number(s): MO7700000
EU EINECS/ELINCS Number: 205-743-6
Chemical Family: Aliphatic carboxylic acid / saturated aliphatic monocarboxylic acid / alkanoic acid / octanoic acid
Molecular Formula: C8-H16-O2
Structural Formula: CH3-CH2-CH2-CH2-CH(CH2-CH3)-C(=O)-OH

SECTION 2. DESCRIPTION

Appearance and Odour:
Colourless liquid with a characteristic odour.(16)

Odour Threshold:
Not available

Warning Properties:
Insufficient information to evaluate

Composition/Purity:
2-Ethylhexanoic acid is one of the eight isomers of octanoic acid. It can exist in three forms, the d, l and dl forms. It is commercially available in the dl form. For specific information on n-octanoic acid, another isomer, refer to CHEMINFO review of this chemical.

Uses and Occurrences:
Used for the production of alkyd resins used for baking enamels. The metallic salts of 2-ethylhexanoic acid are used as drying agents for paints, varnishes, lacquers and enamels, as gelling agents for hydrocarbons and as silicone stabilizers; the copper salt is used as a marine fungicide. The esters of the acid are used as plasticizers and stabilizers for PVC polymers; peroxides of the acid are catalysts in the production of low-density polyethylene. The acid and its derivatives are also used in the manufacture of lubricants, detergents, flotation aids and corrosion inhibitors, as catalysts for polyurethane foaming, for solvent extraction and for dye granulation; co- solvent and defoamer in pesticides; as a replacement pesticide for pentachlorophenol in the lumber industry.(1,17)


SECTION 3. HAZARDS IDENTIFICATION

EMERGENCY OVERVIEW:
Colourless liquid with a characteristic odour. Can burn if strongly heated. Liquid can float on water and may travel to distant locations and/or spread fire. CORROSIVE to the eyes and skin. May cause blindness and permanent scarring.



POTENTIAL HEALTH EFFECTS

Effects of Short-Term (Acute) Exposure

Inhalation:
2-Ethylhexanoic acid does not easily form a vapour. Therefore, high vapour concentrations are not likely to accumulate at normal temperatures in ventilated areas. Mist and vapour may cause irritation of the nose, throat and lungs, based on information for related carboxylic acids. Symptoms would include nasal irritation, sore throat, coughing, hoarseness and, in extreme exposures, difficulty breathing. No human and only limited animal information is available for 2-ethylhexanoic acid.

Skin Contact:
2-Ethylhexanoic acid is corrosive to the skin, based on animal information. Corrosive materials can cause severe burns, blistering and permanent scarring. There is no human information available.
Based on an animal toxicity value, 2-ethylhexanoic acid can be absorbed through the skin, but significant toxicity is not expected by this route of exposure.

Eye Contact:
2-Ethylhexanoic acid is expected to be corrosive to the eyes, since it is corrosive to the skin. Corrosive materials can cause severe eye injury and permanently impaired vision or blindness could result. One case of corneal injury, followed by prompt healing, has been reported in a worker.(1) Severe eye irritation was observed in one animal study.

Ingestion:
Animal information indicates that oral toxicity is low. There is no human information available. 2-Ethylhexanoic acid is corrosive to the skin and it could cause severe irritation and injury to the mouth, throat and stomach, if ingested. Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

Skin:
Repeated or prolonged skin contact may cause redness, dryness, and itching of the skin (dermatitis).

Carcinogenicity:

There is no human information available. An increase in liver peroxisomes (peroxisome proliferation) was observed in one animal study. In some cases, this observation has been related to later development of liver cancer. However, no conclusions can be drawn based on this very limited information.

The International Agency for Research on Cancer (IARC) has not evaluated the carcinogenicity of this chemical.

The American Conference of Governmental Industrial Hygienists (ACGIH) has not assigned a carcinogenicity designation to this chemical.

The US National Toxicology Program (NTP) has not listed this chemical in its report on carcinogens.

Teratogenicity and Embryotoxicity:
There is no human information available. Developmental effects were observed in animal studies using rats, but the effects were observed in the presence of significant maternal toxicity or maternal toxicity was not assessed, but would be expected at the doses used. Developmental effects were not observed in the offspring of rabbits, even in the presence of significant maternal toxicity.

Reproductive Toxicity:
There is no specific human or animal information available for 2-ethylhexanoic acid. No conclusions can be drawn based on an animal study where the sodium salt of 2-ethylhexanoic acid caused reduced fertility in the presence of other toxicity.

Mutagenicity:
There is no human or animal in vivo information available. Inconclusive results were obtained in one in vitro test using human cells.

Toxicologically Synergistic Materials:
There is no information available.

Potential for Accumulation:
2-Ethylhexanoic acid does not accumulate in the body. It is metabolized to other chemicals and eliminated unchanged or as metabolites. Approximately 72 to 75% of an oral dose given to rats was eliminated in the urine within 24 hours, followed by less than 10% after 24 hours. About 7-12% was excreted in the feces. After dermal application, about 30% was excreted in the urine during the first 24 hours, and an additional 8-17% was eliminated from 24 to 96 hours. Fecal excretion was about 7%.(1)


SECTION 4. FIRST AID MEASURES

Inhalation:
If symptoms are experienced, remove source of contamination or move victim to fresh air and obtain medical attention.

Skin Contact:
Avoid direct contact. Wear chemical protective clothing, if necessary. Quickly and gently blot or brush away excess chemical. Immediately flush contaminated area with lukewarm, gently running water for at least 20-30 minutes, by the clock. If irritation persists, repeat flushing. DO NOT INTERRUPT FLUSHING. If necessary, keep emergency vehicle waiting. Under running water, remove contaminated clothing, shoes and leather goods (e.g. watchbands, belts). Transport victim to an emergency care facility immediately. Discard contaminated clothing, shoes and leather goods.

Eye Contact:
Avoid direct contact. Wear chemical protective gloves, if necessary. Quickly and gently blot or brush away excess chemical. Immediately flush the contaminated eye(s) with lukewarm, gently flowing water for 20-30 minutes, by the clock, holding the eyelid(s) open. Neutral saline solution may be used as soon as it is available. Take care not to rinse contaminated water into the unaffected eye or onto the face. If irritation persists, repeat flushing. Quickly transport victim to an emergency care facility.

Ingestion:
NEVER give anything by mouth if victim is rapidly losing consciousness, is unconscious or is convulsing. Have victim rinse mouth thoroughly with water. DO NOT INDUCE VOMITING. Have victim drink 240 to 300 mL (8 to 10 oz) of water to dilute material in stomach. If milk is available, it may be administered AFTER the water has been given. If vomiting occurs naturally, rinse mouth and repeat administration of water. Quickly transport victim to an emergency facility.

First Aid Comments:
Provide general supportive measures (comfort, warmth, rest).
Consult a doctor and/or the nearest Poison Control Centre for all exposures except minor instances of inhalation or skin contact.
All first aid procedures should be periodically reviewed by a doctor familiar with the material and its conditions of use in the workplace.



SECTION 5. FIRE FIGHTING MEASURES

Flash Point:
114 deg C (237 deg F) (closed cup) (17)

Lower Flammable (Explosive) Limit (LFL/LEL):
0.8% (18); 1.04% at 135 deg C (19)

Upper Flammable (Explosive) Limit (UFL/UEL):
6% (18); 8.64% at 188 deg C (19)

Autoignition (Ignition) Temperature:
320 deg C (608 deg F) (17); 371 deg C (700 deg F) (16,19)

Sensitivity to Mechanical Impact:
Probably not sensitive. Stable material.

Sensitivity to Static Charge:
One source indicates that flow or agitation can cause a build-up of electrostatic charge due to the liquid's low electrical conductivity.(16) However, no specific data was located.

Combustion and Thermal Decomposition Products:
Carbon monoxide, carbon dioxide. Incomplete combustion may produce irritating fumes and acrid smoke.

Fire Hazard Summary:
This material can burn if strongly heated. During a fire, irritating/toxic gases and fumes may be generated. Liquid can float on water and may travel to distant locations and/or spread fire. Closed containers may explode in the heat of the fire.

Extinguishing Media:
Dry chemical powder, carbon dioxide, alcohol foam, polymer foam, water spray or fog.(19)

Fire Fighting Instructions:
Evacuate area and fight fire from a safe distance or a protected location. Approach fire from upwind to avoid toxic decomposition products.
Water or foam may cause frothing. The frothing may be violent and could endanger personnel close to the fire. However, a water spray or fog that is carefully applied to the surface of the liquid, preferably with a fine spray or fog nozzle, will cause frothing that will blanket and extinguish the fire. In addition, water spray or fog can be used to absorb heat, keep containers cool and protect exposed material. If a leak or spill has not ignited, use water spray to disperse the vapours and protect personnel attempting to stop a leak. Water spray may be used to flush spills away from ignition sources. Solid streams of water may be ineffective and spread material.

Protection of Fire Fighters:
2-Ethylhexanoic acid and its decomposition products may be hazardous to health. Do not enter without wearing specialized protective equipment suitable for the situation. Firefighter's normal protective equipment (Bunker Gear) will not provide adequate protection. Chemical resistant clothing (e.g. chemical splash suit and positive pressure self-contained breathing apparatus (MSHA/NIOSH approved or equivalent) may be necessary.



NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) HAZARD IDENTIFICATION

NFPA - Health: 1 - Exposure would cause significant irritation, but only minor residual injury.
NFPA - Flammability: 1 - Must be preheated before ignition can occur.
NFPA - Instability: 0 - Normally stable, even under fire conditions, and not reactive with water.

SECTION 9. PHYSICAL AND CHEMICAL PROPERTIES

Molecular Weight: 144.21

Conversion Factor:
1 ppm = 5.89 mg/m3; 1 mg/m3 = 0.170 ppm at 25 deg C (calculated)

Physical State: Liquid
Melting Point: -83 deg C (-117.4 deg F) (16)
Boiling Point: 228 deg C (442 deg F) at 100.67 kPa (755 mm Hg) (1,21)
Relative Density (Specific Gravity): 0.908 at 20 deg C (17); 0.903 at 25 deg C (21,22) (water = 1)
Solubility in Water: Slightly soluble (200 mg/100 mL) at 20 deg C (17). Soluble in hot water.(1)
Solubility in Other Liquids: Slightly soluble in ethanol. Soluble in diethyl ether.(1)
Coefficient of Oil/Water Distribution (Partition Coefficient): Not available
pH Value: Not available
Viscosity-Dynamic: 7.73 mPa.s (7.73 centipoises) (17)
Viscosity-Kinematic: 8.5 mm2/m (8.5 centistokes) (calculated)
Vapour Density: 4.98 (air = 1) (19)
Vapour Pressure: Very low at room temperature; 0.004 kPa (0.03 mm Hg) at 20 deg C (1,16)
Saturation Vapour Concentration: Approximately 40 ppm (0.004%) at 20 deg C (calculated)
Evaporation Rate: Not available
Critical Temperature: Not available

SECTION 10. STABILITY AND REACTIVITY

Stability:
Normally stable.

Hazardous Polymerization:
Does not occur.

Incompatibility - Materials to Avoid:

NOTE: Chemical reactions that could result in a hazardous situation (e.g. generation of flammable or toxic chemicals, fire or detonation) are listed here. Many of these reactions can be done safely if specific control measures (e.g. cooling of the reaction) are in place. Although not intended to be complete, an overview of important reactions involving common chemicals is provided to assist in the development of safe work practices.


OXIDIZING AGENTS (e.g. chromium trioxide, nitric acid, peroxides, permanganates) - may react violently or explosively. Increased risk of fire.(16,19)
BASES (including alkalis, such as sodium hydroxide) - vigorous or violent reaction may occur, yielding heat and pressure.(19)
REDUCING AGENTS (e.g. hydrides such as lithium aluminum hydride) - reaction may be vigorous or violent.(19)

Hazardous Decomposition Products:
None reported.

Conditions to Avoid:
Temperatures above 114 deg C, open flames.

Corrosivity to Metals:
2-Ethylhexanoic acid is not corrosive to steel, copper, silicon bronze, aluminum and type 304 and 316 stainless steels at room temperature. However, steel, and 304 stainless steel, to a small extent, are corroded at very high temperatures, while aluminum may also be attacked at elevated temperatures. High acid concentrations may also severely corrode 304 stainless steels.(23)


SECTION 11. TOXICOLOGICAL INFORMATION

LD50 (oral, rat): 3000 mg/kg (2)

LD50 (skin, rabbit): 1260 mg/kg (1, unconfirmed)
LD50 (skin, guinea pig): 5700 mg/kg (cited as 6.3 mL/kg) (2)

Eye Irritation:

2-Ethylhexanoic acid caused severe eye irritation in one study, but is expected to be corrosive based on observations of skin corrosion.

Application of 0.02 mL of undiluted 2-ethylhexanoic acid caused severe injury in rabbits (grade 5/10; scored over 5 where 5 is severe injury).(3)

Skin Irritation:

2-Ethylhexanoic acid is corrosive to the skin.

Application of 0.5 mL 2-ethylhexanoic acid for 4 hours produced slight necrosis of the skin in 5/6 rabbits. By 48 hours, scabs had formed in all 5 animals.(26) In another study, mild irritation was observed following application of 450 mg in rabbits.(4, unconfirmed) No further details are available.

Effects of Short-Term (Acute) Exposure:

Inhalation:
No rats died following exposure to the saturated vapour (approximately 40 ppm) of 2-ethylhexanoic acid for 8 hours.(2)

Ingestion:
Minor liver changes (enzyme effects) were observed after 3 days in mice fed 1% 2-ethylhexanoic acid in the diet.(5) An increase in liver weight was observed in rats fed 2% in the diet for 3 weeks.(6) Minor changes in the level of fats in the blood (hypolipidemic effect) were observed in rats fed 2% 2-ethylhexanoic acid for 3 weeks.(7) These minor effects at relatively high dietary levels indicate a low oral toxicity for this acid.

Carcinogenicity:
An increase in liver peroxisomes (peroxisome proliferation) was observed in rats fed 2% 2-ethylhexanoic acid for 3 weeks.(6) This type of effect has been associated with liver carcinogenesis in other cases. However, no conclusions can be drawn from this single observation following short-term administration.

Teratogenicity, Embryotoxicity and/or Fetotoxicity:
There is insufficient information available to conclude that 2-ethylhexanoic acid causes developmental toxicity in the absence of maternal toxicity.
Studies with 2-ethylhexanoic acid have shown embryotoxicity, teratogenicity and fetotoxicity in rats at doses that either caused significant maternal toxicity (10,11,12,13) or for which maternal toxicity was not evaluated (9,14), but would have been expected at the doses used. No developmental effects were observed in the offspring of rabbits, despite the presence of significant maternal toxicity.(13) Two studies with the sodium salt of 2-ethylhexanoic acid (8,25) have shown teratogenic effects in the absence of maternal toxicity. However, it is not possible to conclude that 2-ethylhexanoic acid itself would have caused these effects in the absence of maternal toxicity.

Reproductive Toxicity:
There is insufficient information available to draw conclusions about the potential reproductive toxicity of 2-ethylhexanoic acid.
The sodium salt of 2-ethylhexanoic acid produced reduced fertility in rats that were showing other signs of toxicity (reduced liquid consumption and body weight).(25)


SECTION 16. OTHER INFORMATION

Selected Bibliography:
(1) Katz, G.V., et al. Aliphatic carboxylic acids. In: Patty's industrial hygiene and toxicology. 4th ed. Edited by G.D. Clayton et al. Vol. II. Toxicology. Part E. John Wiley and Sons, 1994. p. 3523-3527, 3529, 3553-3558
(2) Smyth, Jr., H.F., et al. The place of the range finding test in the industrial toxicology laboratory. Journal of Industrial Hygiene and Toxicology. Vol. 26 (Oct. 1944). p. 269-273
(3) Carpenter, C.P., et al. Chemical burns of the rabbit cornea. American Journal of Ophthalmology. Vol. 29 (1946). p. 1363-1372
(4) RTECS record for hexanoic acid, 2-ethyl-. Last updated: 9610
(5) Lundgren, B., et al. Characterization of the induction of cytosolic and microsomal epoxide hydrolases by 2-ethylhexanoic acid in mouse liver. Drug Metabolism and Disposition: the biological fate of chemicals. Vol. 15, no. 1 (Jan./Feb. 1987). p. 114-121
(6) Moody, D.E., et al. Hepatic peroxisome (microbody) proliferation in rats fed plasticizers and related compounds. Toxicology and Applied Pharmacology. Vol. 45 (1978). p. 497-504
(7) Moody, D.E., et al. Serum triglyceride and cholesterol contents in male rats receiving diets containing plasticizers and analogues of the ester 2- ethylhexanol. Toxicology Letters. Vol. 10, no. 4 (1982). p. 379-383
(8) Pennanen, S., et al. The developmental toxicity of 2-ethylhexanoic acid in Wistar rats. Fundamental and Applied Toxicology. Vol. 19, no. 4 (Nov. 1992). p. 505-511
(9) Ritter, E.J., et al. Teratogenicity of di(2-ethylhexyl) phthalate, 2-ethylhexanol, 2-ethylhexanoic acid, and valproic acid, and potentiation by caffeine. Teratology. Vol. 35, no. 1 (Feb. 1987). p. 41-46
(10) Narotsky, M.G., et al. Structure-activity relationships for the developmental effects of aliphatic acids in rats. [Abstract]. Teratology. Vol. 39 (1989). p. 470
(11) Narotsky, M.G., et al. Continued evaluation of structure-activity relationships in the developmental effects of aliphatic acids in rats. [Abstract]. Teratology. Vol. 43, no. 5 (May 1991). p. 433
(12) Narotsky, M.G., et al. Developmental toxicity and structure-activity relationships of aliphatic acids, including dose-response assessment of valproic acid in mice and rats. Fundamental and Applied Toxicology. Vol. 22, no. 2 (Feb. 1994). p. 251-265
(13) Hendrickx, A.G., et al. Assessment of the developmental toxicity of 2-ethylhexanoic acid in rats and rabbits. Fundamental and Applied Toxicology. Vol. 20 (1993). p. 199-209
(14) Scott, Jr., W.J., et al. Pharmacokinetic determinants of embryotoxicity in rats associated with organic acids. Environmental Health Perspectives. Vol. 102, suppl. 11 (Dec. 1994). p. 97-101
(15) Sipi, P., et al. Sister-chromatid exchanges induced by vinyl esters and respective carboxylic acids in cultured human lymphocytes. Mutation Research. Vol. 279 (1992). p. 75-82
(16) Chemical safety sheets: working safely with hazardous chemicals. Kluwer Academic Publishers, 1991. p. 415
(17) Riemenschneider, W. Carboxylic acid, aliphatic. In: Ullmann's encyclopedia of industrial chemistry. 5th completely revised ed. Vol. A 5. VCH Verlagsgesellschaft, 1985. p. 235-246
(18) Fire protection guide to hazardous materials. 13th ed. Edited by A.B. Spencer, et al. National Fire Protection Association, 2002. NFPA 325
(19) The Sigma-Aldrich library of chemical safety data. Ed II. Vol. 1. Sigma-Aldrich Corporation, 1988. p. 1619B
(20) Forsberg, K., et al. Quick selection guide to chemical protective clothing. 4th ed. Van Nostrand Reinhold, 2002
(21) Weast, R.C., ed. Handbook of chemistry and physics. 66th ed. CRC Press, 1985-1986. p. C-306
(22) Bagby, M.O. Carboxylic acids: survey. In: Kirk-Othmer encyclopedia of chemical technology. 4th ed. Vol. 5. John Wiley and Sons, 1993. p. 147-168
(23) Elder, G.B. Corrosion by organic acid. In: Process industries corrosion. National Association of Corrosion Engineers, 1975. p. 247-254
(24) European Communities. Commission Directive 96/54/EC. July 30, 1996
(25) Pennanen, S., et al. Effects of 2-ethylhexanoic acid on reproduction and postnatal development in Wistar rats. Fundamental and Applied Toxicology. Vol. 21, no. 2 (1993). p. 204-212
(26) Initial submission: Dermal corrosivity test of 2-ethylhexanoic acid in rabbits with cover letter dated 09/28/92. Eastman Kodak Co. Date produced: Feb. 28, 1986. EPA/OTS 88-920009066. NTIS/OTS0555383.

Information on chemicals reviewed in the CHEMINFO database is drawn from a number of publicly available sources. A list of general references used to compile CHEMINFO records is available in the database Help.


Review/Preparation Date: 1997-08-25

Revision Indicators:
Resistance of materials 1998-04-01
EU Classification 1998-11-01
EU Risk 1998-11-01
EU Safety 1998-11-01
TLV Comments 2001-03-01
TLV-TWA 2002-06-03
Teratogenicity/embryotoxicity 2003-11-11
Reproductive toxicity 2003-11-11
OSHA hazcom 2003-11-11
WHMIS disclosure list 2003-11-11
First aid inhalation 2003-11-11
Engineering controls 2003-11-14
Handling 2003-11-14
Storage 2003-11-14
Short-term skin contact 2005-01-19
Short-term eye contact 2005-01-19
Short-term ingestion 2005-01-19
Bibliography 2005-01-19
Toxicological info 2005-01-19
WHMIS detailed classification 2005-01-19
WHMIS proposed classification 2005-01-19
WHMIS health effects 2005-01-19
Emergency overview 2005-01-19
First aid skin 2005-01-19
First aid eye 2005-01-19
First aid ingestion 2005-01-19
Handling 2005-03-29



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