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CHEMINFO Record Number: 413
CCOHS Chemical Name: n-Valeric acid

Butanecarboxylic acid
1-Butanecarboxylic acid
n-Pentanoic acid
Propylacetic acid
Valerianic acid
Valeric acid (non-specific name)
Pentanoic acid (non-specific name)
Acide valerique

CAS Registry Number: 109-52-4
RTECS Number(s): YV6100000
EU EINECS/ELINCS Number: 203-677-2
Chemical Family: Aliphatic carboxylic acid / saturated aliphatic monocarboxylic acid / alkanoic acid / pentanoic acid / valeric acid
Molecular Formula: C5-H10-O2
Structural Formula: CH3-CH2-CH2-CH2-C(=O)-OH


Appearance and Odour:
Clear, colourless liquid, with a characteristic, unpleasant odour, similar to butyric acid.(9,10)

Odour Threshold:
0.62 ppb (0.0026 mg/m3) (low odour threshold) (11); 0.8 ppb (100% recognition) (12)

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

n-Valeric acid is one of four chemical forms (isomers) of valeric acid. It is commercially available as a pure acid. This document reviews the information specific to n-valeric acid. Where the information reported in some studies has been for valeric acid (isomer unspecified), it has been assumed that the chemical studied was n-valeric acid. The composition of valeric acid (mixed isomers) studied in some papers is not known. Valeric acid (mixed isomers) is not available commercially. For information on isovaleric acid or pivalic acid (another isomer), refer to CHEMINFO records 414 or 415, respectively.

Uses and Occurrences:
Used as a chemical intermediate for the production of ester-type lubricants; the manufacture of esters (used as solvents, in flavours and fragrances, and as softeners), and salts (used as rodenticides or fungicides); intermediate for vinyl stabilizers, plasticizers and pharmaceuticals; as a sugarcane ripening agent.(9,10)
Valeric acid is present in a variety of plants, fruits, dairy and meat products.(1)


Clear, colourless liquid, with a characteristic, unpleasant odour, similar to butyric acid. COMBUSTIBLE LIQUID AND VAPOUR. Liquid may accumulate static charge. TOXIC. May be harmful following skin contact. 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

The mist or vapour can cause irritation of the nose, throat and lungs, based on limited animal evidence and physical properties. These effects may be mild to severe depending on the airborne concentration. Symptoms would include nasal irritation, sore throat, coughing, hoarseness and, in extreme exposures, difficulty breathing. No human information is available.

Skin Contact:
n-Valeric acid can probably cause moderate irritation to corrosive injury depending upon the concentration of chemical and the duration of contact, based on animal information. Prolonged exposures or concentrated solutions may cause burns, blistering, tissue destruction (corrosive effects). Permanent scarring could result. There is no human information available.

Eye Contact:
Contact with vapour, mist or splashes of dilute solutions can likely cause redness and pain. Direct contact with concentrated solutions (greater than 5%) can cause corneal burns, based on animal information for the mixed isomers. Permanent injury, including blindness, may occur. There is no human information available.

n-Valeric acid is used as a food additive. Animal information for valeric acids indicates that oral toxicity is moderate. n-Valeric acid is probably a corrosive liquid and ingestion can cause severe irritation or corrosive injury to the mouth, throat and stomach. Permanent injury or death could result.
There is no human information available. Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

There is no animal or human information available. Repeated or prolonged skin contact may cause redness, dryness and itching of the skin (dermatitis).


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:
There is no human information available. n-Valeric acid did not cause developmental effects in one animal study.

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

There is no human or animal information available. n-Valeric acid was mutagenic in one in vitro test.

Toxicologically Synergistic Materials:
There is no information available.

Potential for Accumulation:
n-Valeric acid does not accumulate in the body. In rats, it is rapidly metabolized to acetate and propionate, which are in turn rapidly metabolized and excreted, or used in the production of chemicals required for bodily function.(1)


If symptoms are experienced, 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. As quickly as possible, flush contaminated area with lukewarm, gently flowing water for 20-30 minutes, by the clock. DO NOT INTERRUPT FLUSHING. If necessary, keep emergency vehicle waiting. Under running water, remove contaminated clothing, shoes, and leather goods (e.g., watchbands, belts). If irritation persists, repeat flushing. Transport victim to an emergency care facility immediately. Completely decontaminate clothing, shoes and leather goods before re-use or discard.

Eye Contact:
Avoid direct contact with this chemical. Immediately flush the contaminated eye(s) with lukewarm, gently flowing water for 20-30 minutes, by the clock, while 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 or onto the face. 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. Quickly transport victim to an emergency care facility.

First Aid Comments:
Provide general supportive measures (comfort, warmth, rest).
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:
86 deg C (187 deg F) (closed cup) (10); 89 deg C (192 deg F) (closed cup) (13)

Lower Flammable (Explosive) Limit (LFL/LEL):
2.7% (13)

Upper Flammable (Explosive) Limit (UFL/UEL):
7.6% (13)

Autoignition (Ignition) Temperature:
360 deg C (680 deg F) (10); 400 deg C (752 deg F) (14)

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

Sensitivity to Static Charge:
Specific information is not available. By comparison to a related isomer, isovaleric acid, valeric acid may accumulate static charge by flow or agitation.

Combustion and Thermal Decomposition Products:
Incomplete combustion may produce irritating fumes and acrid smoke.

Fire Hazard Summary:
Combustible liquid. Can form explosive mixtures with air at, or above, 86 deg C. During a fire irritating/toxic gases may be formed. Closed containers may rupture violently when exposed to fire or excessive heat for sufficient time.

Extinguishing Media:
Dry chemical powder, carbon dioxide, alcohol foam, polymer foam, water spray or fog.(13)

Fire Fighting Instructions:
Evacuate area and fight fire from a safe distance or protected location. Approach fire from upwind to avoid hazardous vapours and toxic decomposition products.
Closed containers may rupture violently when exposed to heat of fire. If possible, isolate materials not yet involved in the fire, and move containers from fire area if this can be done without risk, and protect personnel. Otherwise, fire-exposed containers or tanks should be cooled by application of hose streams. Application should begin as soon as possible and should concentrate on any unwetted portions of the container. If this is not possible, use unmanned monitor nozzles and immediately evacuate the area.
If a leak or spill has not ignited, use water spray in large quantities to disperse the vapours, protect personnel attempting to stop a leak and to dilute the spill to a nonflammable mixture. Water spray may be used to flush spills away from ignition sources. Solid streams of water may be ineffective and spread material.
For a massive fire in a large area, use unmanned hose holder or monitor nozzles. If this is not possible, withdraw from fire area and allow fire to burn. Stay away from ends of tanks. Withdraw immediately in case of rising sound from venting safety device or any discolouration of tank due to fire.
Valeric 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 clothing (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 - Health: 3 - Short exposure could cause serious temporary or 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.


Molecular Weight: 102.13

Conversion Factor:
1 ppm = 4.17 mg/m3; 1 mg/m3 = 0.240 ppm at 20 deg C (calculated)

Physical State: Liquid
Melting Point: -34 deg C (-29.2 deg F) (1,12,16)
Boiling Point: 186-187 deg C (366.8-368.6 deg F) (1,12,16,17)
Relative Density (Specific Gravity): 0.939-0.942 at 20 deg C (water = 1) (1,13,16,17)
Solubility in Water: Moderately soluble (3.7 mL/100 mL at 16 deg C) (12,17)
Solubility in Other Liquids: Soluble in all proportions in ethanol, chloroform, diethyl ether and other common organic solvents.(1,10)
Coefficient of Oil/Water Distribution (Partition Coefficient): Log P(oct) = 0.99; 1.69 (calculated) (18)
pH Value: 2.92 (0.1 M solution in water) (calculated)
Vapour Density: 3.52 (air = 1) (12)
Vapour Pressure: 0.02 kPa (0.15 mm Hg) at 20 deg C (12)
Saturation Vapour Concentration: Approximately 200 ppm (0.02%) at 20 deg C (calculated)
Evaporation Rate: 0.015 (butyl acetate = 1)
Critical Temperature: 378 deg C (712.4 deg F) (16)

Other Physical Properties:
ACIDITY: Weak acid; pKa = 4.82 (Ka = 1.51 x 10(-5)) (16)
VISCOSITY-DYNAMIC: 2.30 mPa.s (2.30 centipoises) at 20 deg C (17)
VISCOSITY-KINEMATIC: 2.45 mm2/s (2.45 centistokes) at 20 deg C (calculated)
CRITICAL PRESSURE: 3810 kPa (37.6 atm) (16)


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)
REACTIVE METALS (e.g. powdered aluminum, zinc) - may produce flammable hydrogen gas.
REDUCING AGENTS (e.g. hydrides such as lithium aluminum hydride) - reaction may be vigorous or violent.(13)
PHOSPHORUS TRICHLORIDE - may form spontaneously flammable phosphine and explode.(19)
POTASSIUM t-BUTOXIDE (solid) - may ignite.(19)

Hazardous Decomposition Products:
None reported

Conditions to Avoid:
Temperatures above 86 deg C, open flames

Corrosivity to Metals:
Based on information for the related acid, butyric acid, valeric acid is probably corrosive to cast iron and lead.(20,21) Valeric acid is not corrosive to steel, aluminum and type 304 and 316 stainless steels, copper and silicon bronze at room temperature. However, steel and copper are corroded at high temperatures, while aluminum may also be attacked at elevated temperatures. High acid concentrations may also severely corrode 304 stainless steels.(21)


LC50 (mouse): 2050 mg/m3 (4-hour exposure); cited as 4100 mg/m3 (2-hour exposure) (assumed aerosol) (2, unconfirmed)

LD50 (oral, mouse): 600 mg/kg (2, unconfirmed)
LD50 (oral, rat): 1060 mg/kg (3); 1900 mg/kg (4) (mixed isomers)

LD50 (dermal, rabbit): 290 mg/kg (4); 660 mg/kg (3) (mixed isomers)

Eye Irritation:

In one test, application of an excess of a 15% solution of valeric acid (mixed isomers) caused severe injury in rabbits (graded 8/10; scored over 5 where 5 is severe injury).(3) In another test, application of in excess of a 5% solution of valeric acid (mixed isomers) caused severe injury in rabbits (graded 9/10; scored over 5 where 5 is severe injury).(4)

Skin Irritation:

Application of 0.01 mL of undiluted valeric acid (mixed isomers) produced tissue death (necrosis) (graded 6/10) in rabbits in two separate tests.(3,4)

Effects of Short-Term (Acute) Exposure:

No rats died after inhaling a saturated vapour concentration (approximately 200 ppm) of valeric acid (mixed isomers) for 8 hours in two separate tests.(3,4)

Effects of Long-Term (Chronic) Exposure:

Lung irritation and inflammation (focal pneumonia, bronchitis and pleurisy) were observed in some rats exposed to 1.7 mg/m3 valeric acid vapour (assumed to be n-valeric acid) for 105 days. Mild liver (fatty degeneration) and kidney effects (for example, glomerulonephritis) were also observed. Similar, but less severe effects were observed at 0.14 mg/m3. No harmful effects were observed following exposure to 0.006 mg/m3.(5) In a similar study, slight changes in the blood were observed in rats exposed to 1.7 mg/m3 or 0.14 mg/m3 valeric acid (assumed to be n- valeric acid) for 3 months. No effects were observed following exposure to 0.006 mg/m3.(6) The statistical significance of these results was not assessed.

Teratogenicity, Embryotoxicity and/or Fetotoxicity:
No developmental effects were observed in rats following oral administration of 75 or 100 mg/kg valeric acid (assumed to be n- valeric acid) for 10 days during pregnancy. Maternal toxicity, as evidenced by respiratory effects, was observed at both exposure levels.(1,7)


Selected Bibliography:
(1) Katz, G.V., et al. Aliphatic carboxylic acids. In: Patty's industrial hygiene and toxicology. 4th edition. Edited by G.D. Clayton et al. Volume II. Toxicology. Part E. John Wiley and Sons, 1994. p. 3523-3527, 3528, 3543-3544
(2) Izmerov, N.F., et al. Toxicometric parameters of industrial toxic chemicals under single exposure. Centre of International Projects, GKNT, 1982. p. 119
(3) Smyth, H.F, Jr., et al. Range-finding toxicity data: list VI. American Industrial Hygiene Association Journal. Vol. 23 (March-April, 1962). p. 95-107
(4) Smyth, H.F., Jr., et al. Range-finding toxicity data: list VII. American Industrial Hygiene Association Journal. Vol. 30, no. 5 (1969). p. 470-476
(5) Sergeev, A.N., et al. Effect of low concentrations of synthetic fatty acids on experimental animals (pathomorphological investigations). Gigiena i Sanitariya Vol. 35, nos 7,8,9 (1970). (English Translation: Hygiene and Sanitation. Vol. 35, nos 7,8,9 (1970))
(6) Dubrovskaya, F.I., et al. Effect of low concentrations of valeric acid vapor on experimental animals. Hygiene and Sanitation. Vol. 31, no. 8 (September, 1966). p. 193-196
(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) Furmanski, P., et al. Function of the glyoxylate-condensing enzymes. 1. Growth of Escherichia coli on n-valeric acid. Journal of Bacteriology. Vol. 94, no. 4 (1967). p. 1075-1081
(9) HSDB record for pentanoic acid. Last revision date: 96/01/29
(10) Riemenschneider, W. Carboxylic acid, aliphatic. In: Ullmann's encyclopedia of industrial chemistry. 5th completely revised edition. Vol. A 5. VCH Verlagsgesellschaft, 1985. p. 235-246
(11) Ruth, J.H. Odor thresholds and irritation levels of several chemical substances: a review. American Industrial Hygiene Association Journal. Vol. 47 (March, 1986). p. A-142 to A-151
(12) Verschueren, K. Handbook of environmental data on organic chemicals. 3rd edition. Van Nostrand Reinhold, 1996. p. 30, 1880-1881
(13) The Sigma-Aldrich library of chemical safety data. Edition II. Volume 2. Sigma-Aldrich Corporation, 1988. p. 3585C
(14) Fire protection guide to hazardous materials. 13th ed. Edited by A.B. Spencer, et al. National Fire Protection Association, 2002. NFPA 325
(15) Forsberg, K., et al. Quick selection guide to chemical protective clothing. 3rd edition. Van Nostrand Reinhold, 1997
(16) Weast, R.C., ed. Handbook of chemistry and physics. 66th edition. CRC Press, 1985-1986. p. C-543, D-162, D-200, F-63
(17) Bagby, M.O. Carboxylic acids: survey. In: Kirk-Othmer encyclopedia of chemical technology. 4th edition. Volume 5. John Wiley and Sons, 1993. p. 147-168
(18) Leo, A., et al. Partition coefficients and their uses. Chemical Reviews. Vol. 71, no. 6 (December, 1971). p. 567
(19) Urben, P.G., ed. Bretherick's handbook of reactive chemical hazards. 5th edition. Volume 1. Butterworth-Heinemann Ltd., 1995. p. 567, 1350
(20) Corrosion data survey: metals section. 6th edition. National Association of Corrosion Engineers, 1985. p. 153-9
(21) Elder, G.B. Corrosion by organic acid. In: Process industries corrosion. National Association of Corrosion Engineers, 1975. p. 247-254
(22) European Communities (EC). Commission Directive 2000/32/EC. May 19, 2000

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: 1997-04-30

Revision Indicators:
Resistance of materials 1998-04-01
Bibliography 2002-02-08
EU Class 2000-04-01
EU Risk 2000-04-01
EU Safety 2000-04-01
Emergency overview 2000-08-01
Acute exposure (ingestion) 2000-08-01
First aid (ingestion) 2000-08-01
Bibliography 2003-04-16
NFPA (health) 2003-04-16

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