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CHEMINFO Record Number: 594
CCOHS Chemical Name: Butyric anhydride

Butanoic acid anhydride
Butanoic anhydride
Butyric acid anhydride
n-Butyric acid anhydride
n-Butyric anhydride
Butyryl oxide

Chemical Name French: Anhydride butyrique
CAS Registry Number: 106-31-0
UN/NA Number(s): 2739
RTECS Number(s): ET7090000
Chemical Family: Saturated aliphatic carboxylic acid anhydride / saturated aliphatic monocarboxylic acid anhydride / alkanoic acid anhydride
Molecular Formula: C8-H14-O3
Structural Formula: CH3-CH2-CH2-C(=O)-O-C(=O)-CH2-CH2-CH3


Appearance and Odour:
Water-white or colourless liquid.(3,4)

Odour Threshold:
Not available

Warning Properties:
Information not available for evaluation.

Commercial grade n-butyric anhydride is 98% pure.(3,4)

Uses and Occurrences:
The major use is in the production of cellulose acetate butyrate resins. It is also used to make butyrate esters which are used as flavouring agents, tanning agents, bronchial antispasmodics and perfume scents; and in chemical synthesis.(3,4)


Water-white or colourless liquid. COMBUSTIBLE LIQUID AND VAPOUR. Vapour is probably irritating to the respiratory tract. Severe exposures may cause lung injury--effects may be delayed. May be corrosive to the eyes and skin. May cause permanent eye damage, including blindness, or permanent scarring of the skin.


Effects of Short-Term (Acute) Exposure

Butyric anhydride reacts with moisture in the nose, throat and lungs to form corrosive butyric acid. Therefore, inhalation of vapours or mists can probably result in mild to severe irritation of the nose, throat and lungs. Symptoms would include nose irritation, sore throat, coughing, hoarseness and, in extreme exposures, difficulty breathing. Severe exposures may result in pulmonary edema, a potentially fatal accumulation of fluid in the lungs. Symptoms may include shortness of breath, pain in the chest and difficulty breathing. Symptoms of pulmonary edema may not develop for up to 24 hours after exposure. There is no specific human or animal information available for butyric anhydride.

Skin Contact:
Butyric anhydride reacts with moisture on the skin to form corrosive butyric acid. Therefore, butyric anhydride can likely cause moderate to severe skin irritation depending upon the amount of butyric acid that is formed and the duration of contact. Prolonged exposure to concentrated solutions in water may cause burns, blistering, and tissue destruction (corrosive effects). There is no human or animal information available for butyric anhydride.

Eye Contact:
Butyric anhydride reacts with moisture in the eye to form corrosive butyric acid. Contact with vapour, mist or splashes of dilute solutions of butyric acid can probably cause redness and pain. Contact with concentrated solutions in water can probably cause corneal burns. Permanent eye damage, including blindness, may occur. There is no human or animal information available for butyric anhydride.

Butyric anhydride is low in acute oral toxicity, based on unconfirmed animal information. It reacts with moisture in the throat and stomach to form butyric acid. Butyric acid is corrosive, so ingestion of concentrated solutions of butyric anhydride in water may cause severe irritation or corrosive injury to the mouth and throat. There is no human information available for butyric anhydride. Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

There is no human or animal information available.


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 or animal information available.

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

There is no information available.

Toxicologically Synergistic Materials:
There is no information available.

Potential for Accumulation:
Butyric anhydride probably does not accumulate in the body, based on information for a closely related compound, isobutyric anhydride. It is probably slowly converted to n-butyric acid by water or body fluids. n-Butyric acid does not accumulate in the body. It is rapidly broken down (metabolized) and converted to ketone bodies and acetic acid, which may be excreted in the urine or incorporated into normal processes in the body. Butyrates are normally present in the body.


Remove source of contamination or have victim to fresh air. If breathing is difficult, oxygen may be beneficial if administered by trained personnel, preferably on a doctor's advice. Symptoms of pulmonary edema can be delayed up to 48 hours after exposure. Obtain medical attention immediately.

Skin Contact:
Avoid direct contact. Wear chemical protective clothing, if necessary. Quickly and gently blot away excess chemical. Remove contaminated clothing, shoes and leather goods (e.g. watchbands, belts). Flush contaminated area with large volumes of lukewarm, gently flowing water for 20-30 minutes, by the clock. If irritation persists, repeat flushing. Obtain medical attention immediately. Completely decontaminate clothing, shoes or leather goods before re-use or discard.

Eye Contact:
Avoid direct contact. Wear chemical protective gloves, if necessary. Quickly and gently blot away excess 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. If irritation persists, repeat flushing. Take care not to rinse contaminated water into the unaffected eye or onto the face. Obtain medical attention immediately.

NEVER give anything by mouth if the 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 the 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. 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.
Some recommendations in the above sections may be considered medical acts in some jurisdictions. These recommendations should be reviewed with a doctor and appropriate delegation of authority obtained, as required.
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:
82 deg C (180 deg F) (closed cup) (3,6); also reported as 87.7 deg C (190 deg F) (closed cup) (4)

Lower Flammable (Explosive) Limit (LFL/LEL):
0.9% (6)

Upper Flammable (Explosive) Limit (UFL/UEL):
5.8% (6)

Autoignition (Ignition) Temperature:
279 deg C (535 deg F) (3,6)

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

Sensitivity to Static Charge:
No information is available.

Combustion and Thermal Decomposition Products:
Corrosive butyric acid, acrid smoke and other toxic, irritating fumes of unburned anhydride and products of incomplete combustion.

Fire Hazard Summary:
Combustible liquid. Can form explosive mixtures with air, at or above, 82 deg C. During a fire irritating/toxic gases may be formed. Water reacts slowly with butyric anhydride at normal temperatures, but more rapidly and violently under fire conditions, to form corrosive butyric acid and give off heat. The reaction is hazardous in a confined space, since an explosion can result. Closed containers may rupture violently when exposed to fire or excessive heat for sufficient time.

Extinguishing Media:
Carbon dioxide, dry chemical powder or appropriate foam.(1) Special "alcohol resistant fire-fighting foams" are recommended for use with any polar flammable liquid. Water is also an effective extinguishing agent, but must be used in flooding quantities to completely solubilize the anhydride and fully absorb the heat of reaction. Fire fighting foam manufacturers should be consulted for recommendations regarding types of foams and application rates.

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. DO NOT get water into butyric anhydride containers. If it is not possible to cool the containers, 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. Dike fire control water for appropriate disposal.
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, but be aware that flying material from ruptured tanks may travel in any direction. Withdraw immediately in case of rising sound from venting safety device or any discolouration of tank due to fire.

Protection of Fire Fighters:
Butyric anhydride is hazardous to health and forms hazardous decomposition products. 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 protective 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: 2 - Must be moderately heated or exposed to relatively high ambient temperatures before ignition can occur.
NFPA - Instability: 1 - Normally stable, but can become unstable at elevated temperatures and pressures, or may react vigorously, but non-violently with water.


Molecular Weight: 158.20

Conversion Factor:
1 ppm = 6.46 mg/m3; 1 mg/m3 = 0.155 ppm at 25 deg C (calculated)

Physical State: Liquid
Melting Point: -66 to -75 deg C (-87 to -103 deg F) (7)
Boiling Point: 199.5 deg C (391 deg F) (4,7)
Relative Density (Specific Gravity): 0.967 at 20 deg C (water = 1) (7,8)
Solubility in Water: Decomposes to form butyric acid.(4)
Solubility in Other Liquids: Soluble in ethanol (decomposes to form ethyl butyrate) and diethyl ether.(7)
Coefficient of Oil/Water Distribution (Partition Coefficient): Not applicable (reacts)
pH Value: Not applicable. Reacts with water to form acidic solutions.
Viscosity-Dynamic: 1.615 mPa.s (1.615 centipoise) at 20 deg C; 1.486 mPa.s (1.486 centipoise) at 25 deg C (5)
Viscosity-Kinematic: 1.670 mm2/s (1.670 centistokes) at 20 deg C (calculated)
Surface Tension: 28.93 mN/m (28.93 dynes/cm) at 20 deg C; 28.44 mN/m (28.44 dynes/cm) at 25 deg C (5,7)
Vapour Density: 5.4 (air = 1) (6)
Vapour Pressure: 0.027 kPa (0.2 mm Hg)(3) or 0.04 kPa (0.30 mm Hg)(4) at 20 deg C
Saturation Vapour Concentration: Approximately 260 ppm (0.03%) or 400 ppm (0.04%) at 20 deg C (calculated)
Evaporation Rate: Not available

Other Physical Properties:
DIELECTRIC CONSTANT: 12.8 at 20 deg C (7)


Decomposes in the presence of moist air or water to form butyric acid.(4)

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.

WATER - reacts to form corrosive butyric acid and heat.(1,4)
STRONG OXIDIZING MATERIALS (e.g. chromic trioxide, hypochlorous acid, nitric acid, perchlorates, peroxides or potassium permanganate) - can react rapidly and violently with a risk of fire and/or explosion.(1)
STRONG ALKALIS or CAUSTICS (e.g. sodium or potassium hydroxide) or BASES (e.g. 2-aminoethanol or ethylenediamine) - may react violently with spattering, accompanied by a temperature and pressure rise.(1)
STRONG REDUCING AGENTS (e.g. hydrogen iodide, lithium aluminum hydride or sodium borohydride) - may react vigorously or violently. Increased risk of fire.(1)
ALCOHOLS (e.g. methanol or ethanol) - react to form butyl esters and heat.(1)

Hazardous Decomposition Products:
Corrosive butyric acid.

Conditions to Avoid:
Temperatures above 82 deg C and moisture.

Corrosivity to Metals:
Pure and moisture-free butyric anhydride is not corrosive to cast iron, steel, stainless steels, copper, bronze, nickel and its alloys, aluminum, tantalum, titanium, lead and silver.(9) In the presence of moisture, butyric anhydride forms butyric acid which is corrosive to carbon steel, cast iron, bronze, admiralty brass and lead.(9,10) Aluminum and stainless steels (e.g. types 316 and 20 Cb 3) are resistant at room temperature, but aluminum and some stainless steels may be attacked at elevated temperatures.(10,11)


LD50 (oral, rat): 8790 mg/kg (2, unconfirmed)


Selected Bibliography:
(1) The Sigma-Aldrich library of chemical safety data. Ed. II. Vol. 1. Sigma-Aldrich Corporation, 1988. p. 655D
(2) National Institute for Occupational Safety and Health (NIOSH). Butyric Anhydride. Last updated: 1997-04. In: Registry of Toxic Effects of Chemical Substances (RTECS(R)). [CD-ROM]. Canadian Centre for Occupational Health and Safety (CCOHS). Issue: 2004-1. Also available from World Wide Web: <>
(3) Center for Chemical Hazard Assessment, Syracuse Research Corporation. Butyric anhydride. In: Information profiles on potential occupational hazards: organic anhydrides. SRC TR 81-635. 2nd draft. National Institute for Occupational Safety and Health, Feb. 1982. p. 33-35
(4) Lewis, Sr., R.J., ed. Butyric anhydride. Hawley's condensed chemical dictionary. [CD-ROM]. 14th ed. John Wiley and Sons, Inc., 2002
(5) Riddick, J.A., et al. Organic solvents: physical properties and methods of purification. 4th ed. Techniques of organic chemistry. Vol. II. John Wiley and Sons, 1986. p. 383
(6) Fire protection guide to hazardous materials. 13th ed. Edited by A.B. Spencer, et al. National Fire Protection Association, 2002. NFPA 325
(7) Dean, J.A. Lange's handbook of chemistry. 15th ed. McGraw-Hill, Inc., 1999. p. 1.135, 5.91, 5.108
(8) Lide, D.R., ed. Handbook of chemistry and physics. [CD-ROM]. Chapman and Hall/CRCnetBASE, 1999
(9) Corrosion data survey: metals section. 6th ed. National Association of Corrosion Engineers, 1985. p. 26-5 to 27-5, 26-4 to 27-4
(10) Schweitzer, P.A. Corrosion resistance tables: metals, nonmetals, coatings, mortars, plastics, elastomers and linings, and fabrics. 4th ed. Part A, A-D. Marcel Dekker, Inc., 1995. p. 557-696
(11) Elder, G.B. Corrosion by organic acid. In: Process industries corrosion. National Association of Corrosion Engineers, 1975. p. 247-254

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: 2004-09-27

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