Chemical Properties
Acetylacetone (2,4-pentanedione) is a clear or slightly yellowish liquid with a putrid
odor. It is readily soluble in water. It is with other incompatible materials, light, ignition
sources, excess heat, oxidizing agents, strong reducing agents, and strong bases. On
decomposition, acetylacetone releases hazardous products, such as carbon monoxide,
irritating and toxic fumes and gases, and carbon dioxide. Acetylacetone is used in the
production of anticorrosion agents and its peroxide compounds for the radical initiator
application for polymerization. It is used as a chemical intermediate for drugs (such as
sulfamethazine, nicarbazine, vitamin B6, and vitamin K), sulfonylurea herbicides, and
pesticides. It is used as a solvent for cellulose acetate, as an additive in gasoline and
lubricant, as a dryer of paint and varnish. It is used as an indicator for the complexometric
titration of Fe(III), for the modifi cation of guanidino groups and amino groups in
proteins, and in the preparation of metal acetylacetonates for catalyst application.
General Description
A colorless or yellow colored liquid. Less dense than water. Flash point 105°F. Vapors are heavier than air. Used as a solvent in paints and varnishes.
Reactivity Profile
Ketones, such as 2,4-PENTANEDIONE(123-54-6), are reactive with many acids and bases liberating heat and flammable gases (e.g., H2). The amount of heat may be sufficient to start a fire in the unreacted portion of the ketone. Ketones react with reducing agents such as hydrides, alkali metals, and nitrides to produce flammable gas (H2) and heat. Ketones are incompatible with isocyanates, aldehydes, cyanides, peroxides, and anhydrides. They react violently with aldehydes, HNO3, HNO3 + H2O2, and HClO4. May dissolve plastics [USCG, 1999].
Air & Water Reactions
Flammable. Soluble in water.
Health Hazard
Exposures to acetyl acetone cause eye irritation, chemical conjunctivitis, corneal damage,
and skin irritation (harmful if absorbed through the skin). At low concentrations for long
periods, inhalation/dermal absorption of acetyl acetone causes irritation and dermatitis,
cyanosis of the extremities, pulmonary edema, and a burning sensation in the chest.
Ingestion/accidental ingestion in the workplace can result in gastrointestinal irritation,
nausea, vomiting, diarrhea, and CNS depression. Inhalation of high concentrations may
cause CNS effects characterized by nausea, headache, dizziness or suffocation, unconsciousness,
and coma. The target organ of acetyl acetone poisoning has been identifi ed as
the CNS.
Health Hazard
Inhalation causes dizziness, headache, nausea, vomiting and loss of consciousness. Contact with liquid irritates eyes.
Potential Exposure
Acetoacetic acid derivative. 2,4-Pentanedione is used in gasoline and lubricant additives, fungicides, insecticides, and colors manufacture; as a chemical intermediate and in the manufacture of metal chelates
Fire Hazard
Behavior in Fire: Vapor is heavier than air and may travel to a source of ignition and flash back.
First aid
If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit.
Shipping
UN2310 Pentane-2,4-dione, Hazard Class: 3; Labels: 3-Flammable liquid
Incompatibilities
Vapors may form explosive mixture with air. 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. reducing agents; halogens, aliphatic amines; alkanolamines, organic acids; isocyanates. Strong light may cause polymerization.
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.
Application
Acetylacetone, also known as 2,4-pentanedione, is an important commodity chemical and widely used as a fuel additive, as dyeing intermediate, in the fields of metal extraction, metal plating, and resin modification. Hantzsch reaction was used as a derivatizing agent for the assay of compounds having a primary amino group. The reagent was reacted with the primary amino group of the drugs to form a product having color and/or emit fluorescence. This condensation reaction was distinguished by its precision, reproducibility, and analytical cost reduction. FLX contains an aliphatic amino group, in the presence of formaldehyde solution, this amino group can condense with two equivalents of acetylacetone to form dihydropyridine derivative that emits yellow fluorescent product. (Figure1). Under optimized conditions of the reaction, FLX gave highly fluorescent product measured at λem 479 nm using 419 nm as excitation.
Definition
ChEBI: A beta-diketone that is pentane in which the hydrogens at positions 2 and 4 are replaced by oxo groups.
Production Methods
2,4-Pentanedione is produced by thermal or metal-catalyzed rearrangement of isopropenyl acetate(obtained from acetone and ketene):
Isopropenyl acetate vapor is fed at atmospheric pressure through a V2A steel tube with an inner temperature of 520℃. The hot reaction gases are quenched, condensed, and cooled to 20℃, whereby the gaseous byproducts carbon monoxide, carbon dioxide, methane, and ketene are separated. The product is purified by fractional distillation. Other industrially less important processes for the production of 2,4-pentanedione, include the Claisen ester condensation of ethyl acetate with acetone using sodium ethoxide as condensation agent and the acetylation of acetoacetic acid esters with acetic anhydride in the presence of magnesium salts.
Synthesis Reference(s)
Journal of the American Chemical Society, 102, p. 2095, 1980
DOI: 10.1021/ja00526a059Organic Syntheses, Coll. Vol. 3, p. 17, 1955
Purification Methods
Small amounts of acetic acid are removed by shaking with small portions of 2M NaOH until the aqueous phase remains faintly alkaline. The sample, after washing with water, is dried with anhydrous Na2SO4, and distilled through a modified Vigreux column (p 11) Cartledge J Am Chem Soc 73 4416 1951]. An additional purification step is fractional crystallisation from the liquid. Alternatively, there is less loss of acetylacetone if it is dissolved in four volumes of *benzene and the solution is shaken three times with an equal volume of distilled water (to extract acetic acid): the *benzene is then removed by distillation at 43-53o and 20-30mm through a helices-packed column. It is then refluxed over P2O5 (10g/L) and fractionally distilled under reduced pressure. The distillate (sp conductivity 4 x 10-8 ohm-1cm-1) is suitable for polarography [Fujinaga & Lee Talanta 24 395 1977]. To recover used acetylacetone, metal ions are stripped from the solution at pH 1 (using 100mL 0.1M H2SO4/L of acetylacetone). The acetylacetone is then washed with (1:10) ammonia solution (100mL/L) and with distilled water (100mL/L, twice), then treated as above. It complexes with Al, Be, Ca, Cd, Ce , Cu, Fe2+, Fe3+ , Mn, Mg, Ni, Pb and Zn. [Beilstein 1 H 777, 1 I 401, 1 II 831, 1 III 3113, 1 IV 3662.]
Toxics Screening Level
The Initial Threshold Screening Level (ITSL) for 2,4-pentanedione is 25 μg/m3 with
annual averaging time.
