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CHEMINFO Record Number: 491
CCOHS Chemical Name: n-Octanoic acid

Caprylic acid
n-Caprylic acid
1-Heptanecarboxylic acid
Octanoic acid
Octic acid
n-Octoic acid
n-Octylic acid
Acide caprylique
Acide octanoïque

Trade Name(s):
Neo-fat 8

CAS Registry Number: 124-07-2
RTECS Number(s): RHO175000
EU EINECS/ELINCS Number: 204-677-5
Chemical Family: Aliphatic carboxylic acid / saturated aliphatic monocarboxylic acid / alkanoic acid / octanoic acid
Molecular Formula: C8-H16-O2
Structural Formula: CH3-CH2-(CH2)4-CH2-C(=O)-OH


Appearance and Odour:
Colourless, oily liquid with a characteristic unpleasant, irritating odour. May solidify to leafy crystals when used or stored below room temperature.(9)

Odour Threshold:
8 ppb (0.008 ppm) (100% recognition) (10)

Warning Properties:
GOOD - detectable by odour at very low concentrations which are unlikely to be harmful.

n-Octanoic acid is one of the eight chemical forms (isomers) of octanoic acid. It is commercially available at 92% purity, with minor amounts of related acids. This CHEMINFO record contains information specific to n- octanoic acid, supplemented by general information for all forms of octanoic acid. Where the information reported is for octanoic acid (isomer unspecified), it has been assumed that the chemical studied was n-octanoic acid. For specific information on 2-ethylhexanoic acid, another isomers of octanoic acid, refer to CHEMINFO record 490.

Uses and Occurrences:
Used as an intermediate for dyes, pharmaceuticals, flavourings and perfumes; used in the manufacture of foods, dental compositions, antiseptics, fungicides, and plasticizers; used in ore separation; used in hydraulic fluids, machining oils, flotation agents, and as a wood preservative.(3,9,11)
n-Octanoic acid is present in some essential oils, many plants, fruits and nuts, milk products including cheeses, wine, beer, grape, plum and pear brandies, rum and whiskey.(1,3)


Colourless, oily liquid with a characteristic unpleasant, irritating odour. May form leafy crystals below room temperature. 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. Can cause permanent eye damage, including blindness, or permanent scarring of the skin.


Effects of Short-Term (Acute) Exposure

n-Octanoic acid does not easily form a vapour. Therefore, significant vapour concentrations are not likely to accumulate at normal temperatures in ventilated areas. Very low vapour concentrations can be detected by smell. Mists can probably cause irritation of the nose, throat and lungs, based on comparison to related carboxylic acids. Symptoms would include nasal irritation, sore throat, coughing, and hoarseness. There is no human or animal information available for n-octanoic acid.

Skin Contact:
n-Octanoic acid is corrosive to skin based on animal information. Corrosive materials are capable of producing severe burns, blisters, ulcers and permanent scarring, depending on the concentration of the solution and the duration of contact.
Application of 0.2 mL of 100% octanoic acid as a powder moistened with water, for 30 minutes to 4 hours, caused skin irritation in 60/69 volunteers.(20) No irritation was observed in humans following application of 1% n-octanoic acid in petrolatum in a closed patch test for 48 hours.(1, unconfirmed) In another study, no redness was observed in any of 10 volunteers following application of 0.5 or 1.0 M solution of n-octanoic acid in propanol for 24 hours, using a patch which prevented evaporation from the skin. Redness was observed in 6-7/10 volunteers after 3 days exposure.(2)

Eye Contact:
n-Octanoic acid is expected to cause serious eye damage, since it is corrosive to the skin. Severe eye irritation was observed in a limited animal study. Direct contact can cause severe eye burns, and permanent injury, including blindness, depending on the concentration of the solutions and duration of contact. Contact with mist or splashes of dilute solutions can probably cause moderate to severe irritation with redness and pain. No human information was located.

n-Octanoic acid is present in low concentrations in many plants, fruits and nuts and is used as a synthetic flavouring agent in foods.(3) Animal information indicates that, in general, acute oral toxicity is low. Corrosive effects such as severe irritation of the mouth, throat and stomach may result following ingestion of concentrated solutions. Permanent damage of the gastrointestinal tract and death could result.
There is no human information available. Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

Repeated or prolonged contact may produce symptoms such as redness, dryness and itching (dermatitis).

Skin Sensitization:
n-Octanoic acid did not produce allergic reactions in a human study.(1, unconfirmed)


There is no human or animal information available.

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 no listing for this chemical.

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

Teratogenicity and Embryotoxicity:
Even in the presence of maternal toxicity, n-octanoic acid did not produce teratogenic or embryotoxic effects in two animal studies. Fetotoxic effects were observed, in the presence of maternal toxicity, in one study. There is no human information available.

Reproductive Toxicity:
There is no human or animal information available.

Negative results have been obtained in bacteria and yeast. There is no human or animal information available.

Toxicologically Synergistic Materials:
There is no information available.

Potential for Accumulation:
n-Octanoic acid does not accumulate in the body. n-Octanoic acid administered to rats was readily metabolized to carbon dioxide (which was exhaled) and two-carbon fragments, which are incorporated into chemicals required for bodily function, such as long-chain fatty acids.(3)


If symptoms develop, remove source of contamination or have victim move to fresh air. Obtain medical attention immediately.

Skin Contact:
Avoid direct contact with this chemical. Wear chemical protective gloves, if necessary. Quickly blot or brush away excess chemical. Remove contaminated clothing, shoes and leather goods (eg. watchbands, belts). Flush contaminated area with lukewarm, gently flowing water for at least 20-30 minutes, or until the chemical is removed. If irritation persists, repeat flushing. DO NOT INTERRUPT FLUSHING. If necessary keep emergency vehicle waiting. Transport victim to an emergency care facility immediately. Completely decontaminate clothing, shoes and leather goods before re-use or discard.

Eye Contact:
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. DO NOT INTERRUPT FLUSHING. If necessary, keep emergency vehicle waiting. Take care not to rinse contaminated water into the non-affected eye. Quickly transport victim to an emergency care facility.

NEVER give anything by mouth if victim is rapidly losing consciousness, or is unconscious or 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. If milk is available, it may be administered AFTER the water has been given. If vomiting occurs naturally, have victim rinse mouth and repeat administration of water. Obtain medical attention immediately.

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.


Flash Point:
132 deg C (269.6 deg F) (Cleveland open cup) (12)

Lower Flammable (Explosive) Limit (LFL/LEL):
Not available

Upper Flammable (Explosive) Limit (UFL/UEL):
Not available

Autoignition (Ignition) Temperature:
Not available

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

Sensitivity to Static Charge:
Not available

Combustion and Thermal Decomposition Products:
Carbon monoxide and carbon dioxide.(13) 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, polymer foam, alcohol foam, water spray or fog.(13)

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.
n-Octanoic 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.


NFPA - Comments:
NFPA has no listing for this chemical in Codes 49 or 325.


Molecular Weight: 144.21

Conversion Factor:
1 ppm = 5.89 mg/m3; 1 mg/m3 = 0.17 ppm at 25 deg C (calculated)

Physical State: Liquid
Melting Point: 16-16.7 deg C (60.8-62 deg F) (10,11,13,15)
Boiling Point: 237 deg C (458.6 deg F) (10,13); 239.7 deg C (463.5 deg F) (12,15)
Relative Density (Specific Gravity): 0.910 at 20 deg C (water = 1) (10,15)
Solubility in Water: Practically insoluble (68 mg/100 g at 20 deg C) (12,15,16)
Solubility in Other Liquids: Soluble in all proportions in methanol at 20 deg C (12); very soluble in ethanol, chloroform, diethyl ether, carbon disulfide, petroleum ether and glacial acetic acid.(3,16)
Coefficient of Oil/Water Distribution (Partition Coefficient): Log P(oct) = 0.63 (calculated) (17)
pH Value: 3.6 (saturated solution in water (0.068%)) (calculated)
Acidity: Weak acid; pKa = 4.89 (Ka = 1.28 x 10(-5)) at 25 deg C (18)
Viscosity-Dynamic: 5.74 mPa.s (5.74 centipoises) at 20 deg C (15)
Viscosity-Kinematic: 6.31 mm2/m (6.31 centistokes) at 20 deg C (calculated)
Surface Tension: 23.7 mN/m (23.7 dynes/cm) at 70 deg C (15)
Vapour Density: 5 (air = 1) (10)
Vapour Pressure: Extremely low at room temperature; 0.133 kPa (1 mm Hg) at 92.3 deg C (10,18)
Saturation Vapour Concentration: Extremely low at room temperature.
Evaporation Rate: Not available. Probably very low.


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.(13)
BASES (including alkalis, such as sodium hydroxide) - vigorous or violent reaction may occur, yielding heat and pressure.(13)
REDUCING AGENTS (e.g. hydrides such as lithium aluminum hydride) - reaction may be vigorous or violent.(13)

Hazardous Decomposition Products:
None reported

Conditions to Avoid:
Temperatures above 130 deg C, open flames

Corrosivity to Metals:
The closely related acid, isooctanoic acid, is not corrosive to steel, aluminum and type 304 and 316 stainless steels, as well as copper and silicon bronze, provided acid solutions are free of oxidants. Steel and 304 stainless steels are corroded at very high temperatures, while aluminum may be attacked at elevated temperatures. High acid concentrations may severely corrode 304 stainless steels.(19)


LD50 (oral, rat): 10080 mg/kg (4)

LD50 (dermal, rabbit): greater than 5000 mg/kg (1, unconfirmed)

Eye Irritation:

n-Octanoic acid caused severe eye irritation in a limited study.

Severe eye injury was observed in rabbits following administration of octanoic acid (isomer unspecified). The exposure caused corneal opacity and redness, which were still present after 72 hours. No further details are available.(5)

Skin Irritation:

n-Octanoic acid is corrosive to the skin.

Severe redness (scored 4/4 at 48 and 72 hours) was observed in rabbits following application of n-octanoic acid for 4 hours, under a patch that partially prevented evaporation. Tissue death (necrosis) was observed in 3/3 rabbits 48 hours after the patch was removed.(6) Moderate to severe irritation was observed following application of n-octanoic acid, to intact or abraded skin for 24 hours, using a patch that prevented evaporation from the skin.(1, unconfirmed) Corrosive effects (necrosis or spotted and/or entire blanching at each site) were observed following application of octanoic acid (isomer unspecified) for 4 hours in another test.(5)

Teratogenicity, Embryotoxicity and/or Fetotoxicity:
No developmental effects were observed in rats following oral administration of 1125 or 1500 mg/kg/day n-octanoic acid for 10 days during pregnancy. Maternal toxicity, as evidenced by deaths and respiratory effects, was observed at both dose levels.(3,7) No embryotoxic or teratogenic effects were observed following oral administration of 2704 mg/kg n-octanoic acid to rats on day 12 of pregnancy. Slight fetotoxicity (a slight reduction in fetal weight) and severe maternal toxicity were observed.(8)


Selected Bibliography:
(1) Opdyke, D.L.J. Monographs on fragrance raw materials: caprylic acid. Food and Cosmetics Toxicology. Vol. 19, no. 1 (Feb. 1981). p. 237-245
(2) Stillman, M.A., et al. Relative irritancy of free fatty acids of different chain length. Contact Dermatitis. Vol. 1 (1975). p. 65-69
(3) 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, 3552-3553
(4) Jenner, P.M., et al. Food flavourings and compounds of related structure. I. Acute oral toxicity. Food and Cosmetics Toxicology. Vol. 2 (1964). p. 327-343
(5) Briggs, G.B., et al. Safety studies on a series of fatty acids. American Industrial Hygiene Association Journal. Vol. 37, no. 4 (Apr. 1976). p. 251-253
(6) Skin irritation and corrosion: reference chemicals data bank. ECETOC technical report number 66. European Centre for Ecotoxicology and Toxicology of Chemicals, Mar. 1995. p. 168
(7) 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
(8) 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
(9) HSDB record for octanoic acid. Last revision date: 96/05/10
(10) Verschueren, K. Handbook of environmental data on organic chemicals. 3rd ed. Van Nostrand Reinhold, 1996. p. 30, 408-410
(11) Riemenschneider, W. Carboxylic acid, aliphatic. In: Ullmann's encyclopedia of industrial chemistry. 5th completely revised ed. Vol. A5. VCH Verlagsgesellschaft, 1985. p. 235-246
(12) Brockmann, R., et al. Fatty acids. In: Ullmann's encyclopedia of industrial chemistry. 5th completely revised ed. Vol. A10. VCH Verlagsgesellschaft, 1985. p. 245-276
(13) The Sigma-Aldrich library of chemical safety data. Ed. II. Vol. 2. Sigma-Aldrich Corporation, 1988. p. 2641B
(14) Forsberg, K., et al. Quick selection guide to chemical protective clothing. 4th ed. Van Nostrand Reinhold, 2002
(15) 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
(16) Budavari, S. ed. The Merck index: an encyclopedia of chemicals, drugs, and biologicals. 12th ed. Merck and Co. Inc., 1996. p. 287
(17) Leo, A., et al. Partition coefficients and their uses. Chemical Reviews. Vol. 71, no. 6 (Dec. 1971). p. 585
(18) Weast, R.C., ed. Handbook of chemistry and physics. 66th ed. CRC Press, 1985-1986. p. C-383, D-162, D-205
(19) Elder, G.B. Corrosion by organic acid. In: Process industries corrosion. National Association of Corrosion Engineers, 1975. p. 247-254
(20) Robinson, M.K., et al. A two-center study of the development of acute irritation responses to fatty acids. American Journal of Contact Dermatitis. Vol. 10, no. 3 (Sept. 1999). p. 136-145

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
Emergency overview 2000-08-01
Acute exposure (ingestion) 2000-08-01
First aid (ingestion) 2000-08-01
Bibliography 2006-04-25
Toxicological info 2007-01-22
Short-term skin contact 2007-01-22
Short-term eye contact 2007-01-22

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