123-54-6 Usage
Chemical Description
Acetylacetone is a beta-diketone that can act as a chelating agent, while aromatic aldehydes are organic compounds containing an aldehyde group (-CHO) attached to an aromatic ring.
Chemical Description
Acetylacetone is a beta-diketone used as a ligand in coordination chemistry.
Chemical Description
Acetylacetone is a colorless liquid organic compound with a fruity odor.
Uses
Acetylacetone is used as a chemical intermediate for the production of fungicides, herbicides, pharmaceuticals, and organic synthesis. It serves as a solvent for cellulose acetate, gasoline, and lubricant additives, as well as a desiccant for paints and varnishes. Additionally, it is used as an analysis reagent, an aluminum extraction agent, a catalyst for various chemical reactions, and a metal chelator. It is also used in the preparation of thin films and photocatalysts, and as a reagent for organic synthesis and metal chelation. Furthermore, it is used as a transition metal chelator, an indicator for Fe (III) complex titration, and for modifying guanidine and amino groups in proteins.
Acetone derivatives
Acetylacetone is a derivative of acetone; chemical formula: CH3COCH2COCH3; It is colorless to pale yellow transparent liquid. It is usually the mixture is enol form and keto form which are the tautomers of each other; these two forms are in dynamic equilibrium; enol isomer forms hydrogen bonds inside the molecule; in the mixture, the keto form accounts for about 18% and enol type accounted for 82%. Cool the petroleum ether of their mixture to-78 °C so the enol will be precipitated as a solid and the two forms will be separated with each other. Upon the enol form being returned back to room temperature, the above equilibrium will be restored.
Acetylacetonate have a pleasant odor. It is flammable, and has a relative molecular mass of 100.13. Its relative density is 0.9721 (25 °C). Its melting point is-23.5 °C and boiling point is 140.5 °C or 139 °C (99.458 × 103Pa). Its flash point is 41 °C. The refractive index is 1.4494. It has a vapor pressure of 0.800 × 103Pa (20 °C). (At 20 °C 16.9,80 °C at 34) and is soluble in water, ethanol, benzene, chloroform, ether, acetone, ethyl acetate and acetic acid. It is susceptible to hydrolysis to generate acetic acid and acetone. The molecular structure of the acetylacetone is a saturated diketone structure in which two hydroxyl groups are connected by a methylene group; this form is usually referred to as β-diketone. Acetylacetone is also one of the simplest saturated β-diketones and is a derivative of acetone. It has an active chemical property and can react with ferric chloride aqueous solution to exhibit a dark red color. This product can almost react with the hydroxides, carbonates or acetates of all metals to form a complex with a general formula being (C5H7O2) ? M, wherein M corresponds to the metal element and n is the metal compounds. Most of such compounds are stable, and many of them are soluble in many organic solvents. This product can have reaction with chlorine in the presence of light of with only two ends of methyl hydrogen being replaced by chlorine. When this product is reacted with sodium, it can release hydrogen and generates sodium acetylacetonate. Acetylacetonate have a narcotic effect and can stimulate the skin and mucous membranes; at high concentrations (100 × 10-6 or more), it is easy to produce some symptoms of poisoning such as nausea, headache, and dizziness. Rat oral LD50: 970mg/kg.
Intermediates of organic synthesis
Acetylacetone is an important intermediate for organic synthesis which is widely used in pharmaceutical, perfume, pesticides and other industries.
Acetylacetone is an important raw material in the pharmaceutical industry, such as for the synthesis of 4,6-dimethyl-pyrimidine derivatives. It can also be used as the solvents for cellulose acetate, the drying agent for paints and varnishes, etc., and are also important analytical reagents.
Due to the presence of enol, acetylacetone can form chelate with a variety of metals such as cobalt (II), Co (III), beryllium, aluminum, and chromium, iron (II), copper, nickel, palladium, zinc, indium, tin, zirconium, magnesium, manganese, scandium and thorium; it can also be used as fuel additives and lubricant additives.
Taking advantage of its chelation reaction with many kinds of metals, it can be used as a kind of metal cleaning agent for micropore; It can also used as a catalyst, a resin cross-linking agent, the resin curing accelerator; resins, rubber additives; for the hydroxylation reaction, hydrogenation reaction, isomerized reaction, and the synthesis of low molecular weight unsaturated ketone as well as polymerization and copolymerization of low-carbon olefins; it can also be used as an organic solvent for dissolving cellulose acetate, ink, and paint; it can also used as paint drying agent; it can also be used as the raw materials for preparation of insecticide, fungicide materials, and animals laxatives as well as feed additives; it can also be used as infrared reflective glass, a transparent conductive film (indium salt), a superconducting thin film (indium salt) forming agent; acetylacetone metal complexes has special colors (green copper salts, iron red, purple chromium salt) and is insoluble in water; it can also be used as pharmaceutical raw materials and raw materials for organic synthesis.The above information is edited by the lookchem of Dai Xiongfeng.
Preparation
1. ethyl acetate and acetone are condensed in the presence of a metallic sodium reaction; after the recovery of ethyl acetate, and the residue was neutralized with acetic acid, further add a solution of copper acetate which will form the green chelate precipitate of cooper acetylacetonate due to the chelation effect of acetylacetone; take out this precipitate and suspended it in diethyl ether, add diluted sulfuric acid for oscillation, after recycling the ether, the residue was separated by distillation to obtain crude acetylacetone, acetylacetone crude was subject to benzene (or ethanol) extraction refining to obtain the refined product.
2. acetyl chloride and acetone can react in an inert solvent in the presence of aluminum chloride to obtain acetylacetone.
3. ketene and acetone can be taken as raw materials and have reaction at 60~70 °C in the presence of sulfuric acid to obtain propylene acetic acid first, after purification, vaporize it at a high temperature (560~570 °C) to obtain acetylacetone after molecular rearrangement.
During this process, the following balance may occur: to get more acetyl acetone, we should minimize the generation of enol as good as possible with a not very high temperature. After obtaining crude acetyl acetone, then vacuum distill for refining.
4. acetone was heated at 700 °C which can directly generate vinyl ketone; acetone is first converted to propylene alcohol; ketones ethylene reacts with propylene alcohol to obtain isopropenyl acetate which can be converted into acetyl acetone at 480~520 °C, then it is further subject to refining and rectification to obtain the fined product. The biggest advantage of this process is that it only needs one raw material-----acetone. Per 1 t product needs 2.55t of raw materials.
The above information is edited by the lookchem of Dai Xiongfeng.
Production methods
It can be produced by adopting different processing routes: reaction between acetone and diketene reaction or condensation between acetic anhydride and acetone or acetone-acetate ethyl condensation. Acetone and diketene reaction is actually using acetone as raw materials, undergoing vinyl ketone, isopropenyl acetate, and then converting into acetylacetone; process is as below: introduce the pre-gasified acetone containing 1/1000 of carbon disulfide into the cracking furnace of 780-800°C, making it generate ketene (or using gasified acetic acid for cracking into ketone in furnace of 700 °C at the presence of triethyl phosphate as the catalyst and ammonia as the stabilizer), ketene is further absorbed by acetone and in the presence of sulfuric acid or acetyl sulfonyl, have it react at 61-71 °C with acetic acid to obtain isopropenyl acetate; after the fractionation for purification, the purity of isopropyl acetate propylene is over 93-95%. Then gasify the isopropenyl acetate, introduce it into the reformer preheated to 560-570 °C to obtain acetyl acetone through molecular rearrangement, condense, and fractionate for purifying the products. Every ton of product consumes about 2700kg of acetone. The condensation process of acetone and ethyl is carried out in the presence of sodium metal. Operation Example 1: add 120ml of refined ethyl acetate and 32 ml of ammonia into a cooling beaker. After the completion of addition of sodium amide, keep shaking the ice-water kept for 24h, have the mixture stand overnight at room temperature. In the following day, add 100g of ice, then join the same quantity of ice-water, for which the aqueous layer was made acidic by adding diluted sulfuric acid. Add saturated solution of copper acetate (produced by dissolving 40g of powdered copper acetate in a certain amount of hot water) to the above solution, so that copper acetylacetone is precipitated in the form of copper salts. If the reaction solution is alkaline, adding a small amount of acetic acid. After 2-3h, filtrate the gray acetylacetone and wash twice with water, directly transfer it into a separating funnel, add ether for constantly shaking while adding 50ml of 4N sulfuric acid to break down it. Take the ether solution for extraction of the acetylacetone within ether acid layer, combined the ether solution in two times, and dry with calcium chloride. The ether was evaporated off with the residue being continued for distillation, collecting the fraction within 125-140 °C and have it subject to refined distillation at 135-140 °C with the yield of 15-20 g and boiling point of 139 °C.
Operation Example 2: to a 1500ml round-bottomed beaker, add 25g of sodium metal and 20 ml of diethyl ether, and further add 225 ml of cooled ethyl acetate with coolant. Add 73 mL of acetone upon cooling and stirring constantly, stand at room temperature for 4h, add 400ml of water, the water from the upper ethyl acetate, and the aqueous layer was neutralized with acetic acid, separate the acetylacetone at the upper layer of water layer while the water layer was neutralized by acetate solution, then add cooper acetate solution (dissolve 125 g copper acetate in 1500 mL of water) which will generates green acetylacetone chelate. After standing for 2-3h and the completion of precipitation filtrate it; suspend the precipitate in ether, oscillate with 50 mL of 40% diluted sulfuric acid; dry the ether layer with calcium chloride and evaporate out the diethyl ether; distill the oil-like residue, collecting the fraction in 124-140 °C, distillation again and collect the 139-140 °C fraction. The condensation reaction of acetic anhydride and acetone is catalyzed by boron trifluoride which has a relatively high yield. The refining method of acetylacetone: dissolve about 20 ml of acetylacetone crude product in 80ml of benzene, and then oscillate with an equal volume of distilled water for 3h. Water-soluble acid is assigned into the aqueous phase while acetylacetonate is easily soluble in benzene. The acetylacetone in benzene phase can be directly applied or subject to distilling off the benzene. Material consumption amount: acetone (industrial, water <0.5%) 2553kg/t, fuming sulfuric acid (H2SO4 count) 12kg/t, acetic anhydride (95%) 19kg/t, carbon disulfide (chemically pure) 6kg/t.
The preparation method is using acetone for absorption of the acetyl-keto produced by the cleavage of acetate, in the presence of sulfuric acid or acetyl sulfonyl acetic acid, make it form isopropenyl acetate at 67~71 °C; after isolation and purification, obtain the acetyl acetone at 500~600 °C through molecular rearrangement and finally get the finished product through fractionation and purification.
Toxicity
Moderate toxicity, can stimulate skin and mucous membrane. If the human body stays at 150 ~ 300mg/kg for a long time, it will have symptoms such as headache, nausea, vomiting, vertigo and sensory retardation.
Toxicity grading
Poisoning
Acute toxicity
Oral-rat LD50: 55 mg/kg; Oral-Mouse LD50: 951 mg/kg
Stimulus data
Skin-rabbit 488 mg with mild effect; Eyes-rabbit 20 mg with mild effect;
Flammability and hazard characteristics
Easily flammable in case of fire, heat, and oxidants with burning producing irritating smoke irritation
Storage Characteristics
Treasury: ventilation, low-temperature and dry; store separately from oxidants
Extinguishing agent
Dry, dry sand, carbon dioxide, foam, 1211 fire extinguishing agent
Synthesis Reference(s)
Journal of the American Chemical Society, 102, p. 2095, 1980 DOI: 10.1021/ja00526a059Organic Syntheses, Coll. Vol. 3, p. 17, 1955
Air & Water Reactions
Flammable. Soluble in water.
Reactivity Profile
Ketones, such as 2,4-Pentanedione, 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].
Health Hazard
Inhalation causes dizziness, headache, nausea, vomiting and loss of consciousness. Contact with liquid irritates eyes.
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
Exposure to the vapors of acetyl acetone cancause irritation of the eyes, mucous membrane, and skin. In rabbits 4.76 mg producedsevere eye irritation; the effect on skin wasmild. Other than these, the health hazardsfrom this compound have not been reported.However, based on its structure and the factthat it has two reactive carbonyl groups inthe molecule, this compound should exhibitlow to moderate toxicity at high concentrations, which should be greater than that ofthe C5-monoketones.LD50 value, intraperitoneal (mice): 750mg/kgLD50 value, oral (rats): 1000 mg/kgThere is no report on its carcinogenicity inanimals or humans.
Fire Hazard
Behavior in Fire: Vapor is heavier than air and may travel to a source of ignition and flash back.
Safety Profile
Poison by ingestion and intraperitoneal routes. Moderately toxic by inhalation. A skin and severe eye irritant. Experimental reproductive effects. Mutation data reported. Flammable liquid when exposed to heat or flame. Incompatible with oxidning materials. To fight fire, use alcohol foam, CO2, dry chemical.
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
storage
Acetylacetone should be stored away from heat, sparks, flame, and from sources of ignition.
It should be stored in a tightly sealed container, in a cool, dry, well-ventilated area,
away from incompatible substances.
Shipping
UN2310 Pentane-2,4-dione, Hazard Class: 3; Labels: 3-Flammable liquid
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.]
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.
Precautions
Occupational workers should only use/handle acetyl acetone in a well-ventilated area,
with spark-proof tools and explosion-proof equipment. Workers should not cut, weld,
braze, solder, drill, grind, pressurize, or expose empty containers to heat, sparks, or
flames.
Check Digit Verification of cas no
The CAS Registry Mumber 123-54-6 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 1,2 and 3 respectively; the second part has 2 digits, 5 and 4 respectively.
Calculate Digit Verification of CAS Registry Number 123-54:
(5*1)+(4*2)+(3*3)+(2*5)+(1*4)=36
36 % 10 = 6
So 123-54-6 is a valid CAS Registry Number.
InChI:InChI=1/C5H8O2/c1-4(6)3-5(2)7/h3,6H,1-2H3/b4-3-
123-54-6Relevant articles and documents
Determination of cysteine and glutathione based on the inhibition of the dinuclear Cu(II)-catalyzed luminol-H2O2 chemiluminescence reaction
Chaichi, Mohammad Javad,Ehsani, Mahjoobeh,Khajvand, Tahereh,Golchoubian, Hamid,Rezaee, Ehsan
, p. 405 - 410 (2014)
The catalyzed luminol chemiluminescent reaction has received a great amount of attention because of its high sensitivity and low background signal which make the reaction an attractive analytical chemistry tool. The present study, introduces the beneficial catalytic effects of dinuclear Cu(II) complex [Cu 2L2(TAE)]X2, where TAE = tetraacetylethane; L = N,N'-dibenzylethylenediamine and X = ClO4 on the luminol chemiluminescent reaction as a novel probe for the determination of glutathione (GSH) and L-cysteine (CySH) in human serum and urine. The [Cu2L 2(TAE)]X2 has exhibited highly efficient catalytic activity of luminol CL as an artificial peroxidase model at pH as low as 7.5 in water in the presence of H2O2×GSH and CySH can induce a sharp decrease in CL intensity from the [Cu2L 2(TAE)]X2-catalyzed luminol system. Under the selected experimental conditions, a linear relationship was obtained between the CL intensity and the concentrations of GSH and CySH in the range of 1.0 × 10-7-1.0 × 10-4 M, with detection limits (S/N = 3) of 2.7 × 10-8 and 6.8 × 10-8 M and RSD 4.2% (n = 7) for GSH and CySH, respectively.
The Reactions of Zinc(II) with 1,3-Diketones in Aqueous Solution. Catalysis by Cacodylic Acid during Complex Formation
Hynes, Michael J.,Mooney, Marie T.,Moloney, Ann
, p. 313 - 318 (1993)
The reactions of zinc(II) with three 1,3-diketones have been investigated in aqueous solution at 25 deg C and an ionic strength of 0.5 mol dm-3 NaClO4.The catalytic effect of cacodylic acid on the reactions of zinc(II) with pentane-2,4-dione has been demonstrated.In addition, the effect of cacodylic acid on the hydrolysis of the nickel(II) and copper(II) triglycine complexes has been investigated.
One-pot diastereoselective synthesis of functionalized 4,5-dihydropyrroles by reactions of arylglyoxals, β-dicarbonyl compounds, and aromatic amines
Kolos, Nadezhda N.,Karpan, Sergey A.,Omelchenko, Irina V.,Chechina, Natal’ya V.,Yaremenko, Feodor G.
, p. 827 - 833 (2019)
[Figure not available: see fulltext.] A multicomponent reaction of arylglyoxal hydrates, acetylacetone or acetoacetic ester, aniline or its 3(4)-substituted analogs in 1:1:2 ratio occurred upon stirring in methanol, giving 4-arylamino-5-hydroxypyrroline derivatives containing 4,5-dihydroxypyrrolines as impurities.
Adsorption and Decomposition of Isopropyl Alcohol over Zinc Oxide. Infrared and Kinetic Study
Koga, Osamu,Onishi, Takaharu,Tamaru, Kenzi
, p. 19 - 29 (1980)
The adsorption of isopropyl alcohol and acetone on zinc oxide was studied by an infrared technique which revealed that isopropyl alcohol is dissociatively adsorbed at room temperature to form zinc alcoholate and hydroxyl group on the surface, while the adsorption of acetone takes place in its enolic form.When adsorbed isopropyl alcohol was heated to 363 K, the zinc alcoholate species changed gradually to acetone adsorbed in its enolic form, which further desorbed at higher temperatures as acetone, being replaced by the attacking isopropyl alcohol.The behaviour of the adsorbed species during decomposition of isopropyl alcohol on zinc oxide was studied in more detail, leading to the overall reaction mechanism described by eqn (V).
THERMAL REARRANGEMENT OF DIENOLESTERS. SEQUENTIAL SIGMATROPIC REARRANGEMENT AND INTERMOLECULAR DIELS-ALDER CYCLOADDITION OF 1-METHYLENE-2-METHYL-2-PROPENYL HEX-5-ENOATE
Shea, K. J.,Wada, E.
, p. 1523 - 1526 (1982)
The high temperature thermal rearrangement of the title dienol ester is reported.Its reactions entail a acyl shift followed by intramolecular Diels-Alder cycloaddition of the resulting β-diketone.
Acid induced acetylacetonato replacement in biscyclometalated iridium(III) complexes
Li, Yanfang,Liu, Yang,Zhou, Ming
, p. 3807 - 3816 (2012)
Biscyclometalated iridium(III) complexes with an ancillary acetylacetone ligand, Ir(L)2(acac), (L = 2-(benzo[b]thiophen-2-yl)pyridine (btp), 1-phenylisoquinoline (piq), 2-phenylbenzothiazole (bt), 2-phenylpyridine (ppy), acac = deprotonated acetylacetone), demonstrate spectroscopic changes in their UV-Vis absorption and luminescent emission under acidic conditions. Such changes were found to be the same as those observed when certain mercury salts exist in the systems. Because some iridium(III) complexes have sulfur-containing ligands (i.e., btp and bt), a question was then raised as for whether or not the spectroscopic changes are associated with the specific affinity of Hg 2+ to the sulfur atom. Extensive studies performed in this work unambiguously proved that the observed spectroscopic changes were solely the results of the acid induced departure of acac and the follow-up coordination of solvent acetonitrile to the iridium(III) center and that the generally anticipated Hg2+-S affinity and its effect on the photophysical properties of iridium(III) luminophores did not play a role. The Royal Society of Chemistry 2012.
Modulation of tautomeric equilibria by ionic clusters. Acetylacetone in solutions of lithium perchlorate-diethyl ether
Pocker,Spyridis, Greg T.
, p. 10373 - 10380 (2002)
Acetylacetone (2,4-pentanedione, 1) is a molecule whose tautomeric forms are in dynamic equilibrium. Concentrated salt solutions in nonaqueous solvents exert a remarkable influence on the keto-enol ratio of this β-diketone. The keto content of 1 increases from 5% in pure diethyl ether to 84.5% in a 4.14 M lithium perchlorate-diethyl ether (LPDE) solution, a nearly 17-fold increase. The equilibrium expression, K = [keto]/[enol] = kf/kr, exhibits a linear dependence on [LiCIO4], with the formal order of participation of lithium ion in the equilibrium being 1.0. A kinetic analysis reveals that kf is independent of LPDE concentration, whereas kr displays an inverse dependence on salt concentration, indicating preferential coordination of the keto tautomer with Li+. Although 1 exits as the enol in water only to the extent of 16%, the addition of lithium perchlorate further reduces this figure. In an aqueous 4.02 M LiCIO4 solution, acetylacetone enol accounts for only 4.6% of the total amount of 2,4-pentanedione present. It has also been found that acetylacetone itself is an excellent solvent for LiCIO4 as well as for NaCIO4 with solutions containing up to 7.5 M LiCIO4 attainable. The enol content of 1 decreases dramatically from 81% to 7.4% on going from the neat liquid to a solution of 6.39 M LiCIO4 in acetylacetone.
Keto-enol tautomerism as a polarity indicator in ionic liquids
Earle, Martyn J.,Engel, Brian S.,Seddon, Kenneth R.
, p. 149 - 150 (2004)
The keto-enol tautomeric equilibrium for pentane-2,4-diode has been explored in several ionic liquids and these data have been used to give an indication of their polarities in the ground state. The results suggest higher apparent polarities than have been previously indicated by the use of solvatochromatic dyes.
Origin of the activity of hydrogenation catalysts based on palladium complexes and primary phosphines
Belykh,Goremyka,Shmidt
, p. 770 - 774 (2004)
The activity of the catalytic system based on palladium bisacetylacetonate and phenylphosphine in hydrogenation catalysis was studied.
The rates and mechanism of hydrolysis reactions of some metal acetylacetonates
Pearson, Ralph G.,Moore, John W.
, p. 1528 - 1532 (1966)
Rates of hydrolysis of acetylacetone complexes of oxovanadium(IV) and beryllium(II) have been measured using a stopped-flow technique. In aqueous solution at 25° VO(acac)2 decomposes in two steps with the second ring being removed 150 times slower than the first. Both rings were removed from Be(acac)2 at the same rate. The hydrogen ion dependence of the rates indicates that the special chelate mechanism, in which H+ traps a half-bonded intermediate, is a general one for hydrolysis of acetylacetonates. The behavior of hydrolysis rates upon addition of nucleophilic reagents is consistent with the interpretation that direct nucleophilic attack on the metal ion does not occur. The vanadyl complex, however, can add a sixth group which influences the rate of dissociation.
