Crotonaldehyde

Chemical properties

Crotonaldehyde is water-white (turns paleyellow on contact with air) with an irritating, pungent, suffocating odor. The chemical can turn pale yellow when it contacts air. The chemical has a molecular weight of 70.1, a boiling point of 219°F, and a freezing point of -101°F. The vapor pressure is 30mm Hg at 25°C and the specific gravity is 0.87. The lower explosive limit is 2.1% and the upper explosive limit is 15.5%. Crotonaldehyde may be incompatible with caustics, ammonia, strong oxidizers, nitric acid, and amines. It also has the ability to polymerize at high temperatures.

The Uses of Crotonaldehyde

Crotonaldehyde (2-butenal, β-methyl acrolein, propylene aldehyde) is similar in structure to acrolein, as both are α,β-unsaturated aldehydes. This structural similarity leads to similar sensitizing and irritating properties of the two compounds. Crotonaldehyde is used industrially in the preparation of other chemicals (chiefly sorbic acid), flavoring agents, and can form endogenously and in the environment.
Crotonaldehyde is used in the manufacture ofbutyl alcohol, butyraldehyde, and in severalorganic synthesis.

Definition

ChEBI: Crotonaldehyde is an enal consisting of propene having a formyl group at the 1-position.

General Description

Water-white to straw-colored liquid with a pungent, suffocating odor. Used as a chemical intermediate in a variety of industrial processes (surfactants, textiles, paper, fuels, insecticides, leather tanning, etc.). Used in chemical warfare.

Air & Water Reactions

Highly flammable.

Reactivity Profile

Crotonaldehyde is an aldehyde. Crotonaldehyde can react violently with strong oxidizing reagents, e.g., reaction with conc. nitric acid leads to instantaneous ignition [Andrussow, L., Chim. Ind. (Paris), 1961, 86, p. 542]. In contact with strong acids or bases Crotonaldehyde will undergo an exothermic condensation reaction. Reaction with 1,3-butadiene is particularly violent [Greenlee, K. W., Chem. Eng. News, 1948, 26, p. 1985]. Crotonaldehyde may rapidly polymerize with ethyl acetoacetate (Soriano, D.S. et al. 1988. Journal of Chemical Education 65:637.).

Health Hazard

Although slightly less toxic, crotonaldehyde is similar chemically and toxicologically to acrolein, which is rated as extremely toxic. Toxic concentrations for human inhalation have been reported at 12 mg/m3/10 minutes. Irritant dose to human eye is 45 ppm. As with acrolein, vapor exposures cause severe and painful eye irritation, damage to cornea, lacrimation (tearing), irritation of nasal membranes, pulmonary edema (filling of lungs with fluid) and gastrointestinal distress when ingested.

Health Hazard

Crotonaldehyde causes severe irritation ofthe eyes, nose, lungs, and throat. Exposureto a concentration of 12 mg/m³ in air for10 minutes can cause burning of the lungsand throat in humans. The symptoms ofinhalation toxicity in rats were excitement,behavioral change, convulsion, and death.The same symptoms were observed whencrotonaldehyde was administered subcutaneously.
LC50 value, inhalation (rats): 4000 mg/m³/30 minutes
LD50 value, subcutaneous (rats): 140 mg/kg
Crotonaldehyde is less toxic than acroleinor formaldehyde. The toxic symptoms, however,were similar to those of acrolein. Thecis-isomer of crotonaldehyde is mutagenic; itcaused cancer in test animals. Oral administrationof 2660 mg/kg for 2 years producedtumor in the liver in rats. Evidence of carcinogenicityin humans is not yet confirmed.

Fire Hazard

Vapors form explosive mixtures in air or in sewers. Hazardous peroxides and acids emitted when heated to decomposition. Avoid nitric acid. Unstable, avoid oxygen, heat, elevated pressures. Hazardous polymerization may occur. Avoid contact with alkaline materials such as caustic ammonia or amines, or at elevated temperatures.

Safety Profile

Suspected carcinogen. A poison by ingestion, subcutaneous, and intraperitoneal routes. Mutation data reported. A lachrymating material that is very dangerous to the eyes. Human respiratory system irritant by inhalation. Can cause corneal burns and is irritating to the skin. In case of contact, immediately flush the skin or eyes with water for at least 15 minutes and get medlcal attention. See also ALDEHYDES. Dangerous fire hazard when exposed to heat or flame. To fight fire, use alcohol foam, Con, dry chemical. Incompatible with 1,3-butadiene and oxidizing materials. When heated to decomposition it emits acrid smoke and fumes.

Potential Exposure

Crotonaldehyde is used as a warning agent in fuel gases and gas line leaks; as solvent; in Crotonaldehyde 935 chemical warfare; as an intermediate in the manufacture of n-butanol and crotonic and sorbic acids; in resin and rubber antioxidant manufacture; also used as a solvent in mineral oil purification; as an alcohol denaturant.

Shipping

UN1143 Crotonaldehyde or Crotonaldehyde, stabilized, Hazard class: 6.1; Labels: 6.1-Poison Inhalation Hazard, 3-Flammable liquid, Inhalation Hazard Zone B.

Incompatibilities

Vapors may form explosive mixture with air. A strong reducing agent. Readily converted by oxygen to peroxides and acids; heat or contact with alkalis and many other substances may cause polymerization. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, nonoxidizing mineral acids; ammonia, organic amines; aliphatic amines; aromatic amines; 1,3-butadiene, strong bases. Liquid attacks some plastics, rubber, and coatings

Waste Disposal

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed. May be absorbed on vermiculite and burned in open incinerator or dissolved in solvent and sprayed into incinerator