Acetylacetone method

The acetylacetone method was proposed as a standard technique for the determination of formaldehyde (VDI 3484, Part 2, 1991) because of its simple handling and high reliability (DIN EN 717-1, 1996). A typical concentration profile of a formaldehyde measurement using the acetylacetone method in a private living room is shown in Fig. 1.2-1. First, the windows in the room were opened for 10-15 min to increase the air exchange rate and to decrease the concentration of pollutants. Sampling started immediately after... 

Several variations of the Feist-Benary reaction furnish substituted furans as products. The following three examples provide synthetically useful alternatives to the standard reaction conditions. One method is based on the reaction of a sulfonium salt with a P-dicarbonyl compound. For example, reaction of acetylacetone (39) with sulfonium salt 38 in the presence of sodium ethoxide yields 81% of trisubstituted furan 40. This strategy provides a flexible method for the preparation of 2,3,4-trisubstituted furans. 

For cobalt phthalocyanines (PcCo, PcCoX), besides the most common method starting with phthalonitrile and cobalt(II) chloride in ethylene glycol, 130-277 279 some other methods have been employed. Other cobalt compounds used are cobalt(II) acetate127 or acetylacetonate.279 Besides using solvents like 2-ethoxyethanol279 and 2-(dimethylamino)ethanol,121 the reaction has also been performed without solvent.137,262 The central metal may exhibit the oxidation states +11 (PcCo) and + III (PcCoX).279... 

Highly active gold catalysts can be prepared by an appropriate selection of preparation methods such as CP, DP, DR, and SG with dimethyl Au(III) acetylacetonate, depending on the kind of support materials and reactions... 

In this paper we report (i) the catalytic activity for SCR of VOx/Zr02 samples prepared by various methods (adsorption from aqueous metavanadate solutions at different pH values, dry impregnation, and adsorption from VO(acetylacetonate)2 in toluene), (ii) sample characterization (nuclearity, dispersion and oxidation state) by means of XPS, ESR and FTIR and (iii) the nature and reactivity of the surface species observed in the presence of the reactant mixture. Catalytic results are here reported in full. Characterization data relevant to the discussion of the catalytic activity will be given, whereas details on the catalysts preparation and... 

VOx/ZrOz samples were prepared by three methods (i) adsorption from a solution of ammonium metavanadate (AV) at pH values from 1 to 4, adjusted by nitric acid, (ii) dry impregnation with AV solutions and (iii) adsorption from a solution of VO(acetylacetonate)2 in toluene. 

V0x/Zr02 catalysts were designated as ZVx(y)pHz, where x gives the analytical vanadium content (weight percent), y specifies the preparation method (a, adsorption, i, impregnation or acac, acetylacetonate) and z the AV solution pH. The V-content was determined by atomic absorption (Varian Spectra AA-30) after the sample had been dissolved in a concentrated (40%) HF solution. 

Over the years, this method has gained considerable attention and many syntheses are based on variations of it, e.g., employing different Fe precursors [279,280] (cf. also Ref [281]) or using hexadecanediol as a solvent for the acetylacetonate (acac) derivatives of both metals [282]. 

In 2000, Sun and co-workers succeeded in synthesis of monodispersed Fe/Pt nanoparticles by the reduction of platinum acetylacetonate and decomposition of Fe(CO)5 in the presence of oleic acid and oleylamine stabilizers [18]. The Fe/Pt nanoparticle composition is readily controlled, and the size is tunable from 3 to 10 nm in diameter with a standard deviation of less than 5%. For practical use, we developed the novel symthetic method of FePt nanoparticles by the polyol reduction of platinum acetylacetonate (Pt(acac)2) and iron acetylacetonate (Fe(acac)3) in the presence of oleic acid and oleylamine stabilizers in di- -octylether [19,20]. The Fe contents in FePt nanoparticles can be tuned from 23 to 67atomic%, and the particle sizes are not significantly affected by the compositions, retaining to be 3.1 nm with a very narrow size distribution, as shown in Figure 6. 

In the early work on the thermolysis of metal complexes for the synthesis of metal nanoparticles, the precursor carbonyl complex of transition metals, e.g., Co2(CO)8, in organic solvent functions as a metal source of nanoparticles and thermally decomposes in the presence of various polymers to afford polymer-protected metal nanoparticles under relatively mild conditions [1-3]. Particle sizes depend on the kind of polymers, ranging from 5 to >100 nm. The particle size distribution sometimes became wide. Other cobalt, iron [4], nickel [5], rhodium, iridium, rutheniuim, osmium, palladium, and platinum nanoparticles stabilized by polymers have been prepared by similar thermolysis procedures. Besides carbonyl complexes, palladium acetate, palladium acetylacetonate, and platinum acetylac-etonate were also used as a precursor complex in organic solvents like methyl-wo-butylketone [6-9]. These results proposed facile preparative method of metal nanoparticles. However, it may be considered that the size-regulated preparation of metal nanoparticles by thermolysis procedure should be conducted under the limited condition. 

The liquid-phase reduction method was applied to the preparation of the supported catalyst [27]. Virtually, Muramatsu et al. reported the controlled formation of ultrafine Ni particles on hematite particles with different shapes. The Ni particles were selectively deposited on these hematite particles by the liquid-phase reduction with NaBFl4. For the concrete manner, see the following process. Nickel acetylacetonate (Ni(AA)2) and zinc acetylacetonate (Zn(AA)2) were codissolved in 40 ml of 2-propanol with a Zn/Ni ratio of 0-1.0, where the concentration of Ni was 5.0 X lO mol/dm. 0.125 g of Ti02... 

Another particularly convenient preparative method is the reaction of the corresponding gold(l) acetylacetonate complex with the alkyne, which requires no auxiliary base.42 68-71 This reaction is also useful for the simple acetylides (L)AuC=CH.72 The acetylacetonates can be isolated and introduced as the true reagents, or prepared in situ using the corresponding gold(l) halide complex and Tl(acac) (Equations (16) and (17)).73... 

Other methods reported for the determination of beryllium include UV-visible spectrophotometry [80,81,83], gas chromatography (GC) [82], flame atomic absorption spectrometry (AAS) [84-88] and graphite furnace (GF) AAS [89-96]. The ligand acetylacetone (acac) reacts with beryllium to form a beryllium-acac complex, and has been extensively used as an extracting reagent of beryllium. Indeed, the solvent extraction of beryllium as the acety-lacetonate complex in the presence of EDTA has been used as a pretreatment method prior to atomic absorption spectrometry [85-87]. Less than 1 p,g of beryllium can be separated from milligram levels of iron, aluminium, chromium, zinc, copper, manganese, silver, selenium, and uranium by this method. See also Sect. 5.74.9. 

An obvious method to investigate the formation and the nature of the catalytically active nickel species is to study the nature of products formed in the reaction of complexes such as 3 or 4 with substrate olefins. This has been investigated in some detail in the case of the catalytic dimerization of cyclooctene to 1-cyclooctylcyclooctene (17) and dicy-clooctylidene (18) [Eq. (4)] using as catalyst 7r-allylnickel acetylacetonate (11) or 7r-allylnickel bromide (1) activated by ethylaluminum sesquihalide or aluminum bromide (4). In a typical experiment, 11 in chlorobenzene was activated with excess ethylaluminum sesquichloride cyclooctene was then added at 0°C and the catalytic reaction followed by removing... 

An alternate method of proceeding from the hydrazide follows (U.S. Patent 3,085,092). To a solution of 1.4 g (1) in 5.5 ml 1 N HCI, 5 ml water, 5 ml EtOH, add 1 g acetylacetone (2,4 pentanedione), let stand 1 hour at room temperature and neutralize with 5.5 ml 1 N NaOH. Filter off the lysergyl pyrazole (II) and wash with water. Can purify by drying in vacuum at 60° C and recrystallizing from chloroform by the addition of ether. Heat 0.4 g (11) and 2.5 ml DEA at 100° C for 2 hours (or let stand 15 hours at room temperature, evaporate to dryness and heat a few minutes at 100° C in vacuum). Can recrystallize from CHCI3, petroleum ether or as described elsew here here. 

Reaction with chelating agents. Such reactions have been used primarily for partial dealumination of Y zeolites. In 1968, Kerr (8,21) reported the preparation of aluminum-deficient Y zeolites by extraction of aluminum from the framework with EDTA. Using this method, up to about 50 percent of the aluminum atoms was removed from the zeolite in the form of a water soluble chelate, without any appreciable loss in zeolite crystallinity. Later work (22) has shown that about 80 percent of framework aluminum can be removed with EDTA, while the zeolite maintains about 60 to 70 percent of its initial crystallinity. Beaumont and Barthomeuf (23-25) used acetylacetone and several amino-acid-derived chelating agents for the extraction of aluminum from Y zeolites. Dealumination of Y zeolites with tartaric acid has also been reported (26). A mechanism for the removal of framework aluminum by EDTA has been proposed by Kerr (8). It involves the hydrolysis of Si-O-Al bonds, similar to the scheme in Figure 1A, followed by formation of a soluble chelate between cationic, non-framework aluminum and EDTA. 

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