Chromium acetylacetonate determination

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. 

The tris and bis complexes of acetylacetone (2,4-pentanedione) (167) with chromium(III) have been known for many years (168,169).739 The tris compound is generally prepared by the reaction of an aqueous suspension of anhydrous chromium(III) chloride with acetylacetone, in the presence of urea.740 Recently a novel, efficient synthesis of tris(acetylacetonato)chromium-(III) from Cr03 in acetylacetone has been reported.741 The crystal structure of the tris complex has been determined.744 A large anisotropic motion was observed for one of the chelate rings, attributed to thermal motion, rather than a slight disorder in the molecular packing. 

Addition of a paramagnetic relaxation agent enables quantitative determination of carbons by C NMR. This technique has been applied to a series of phenylindoles using chromium(lll) acetylacetonate (Cr(acac)3) as the relaxation reagent <1996M111>. 

In series C of Figure 90, the silica alone was again calcined at 500-950 °C. This time, however, Cr(III) acetylacetonate in toluene was added by impregnation, to avoid major rehydroxylation of the silica surface. The sample was then dried and given a second calcination step only at 500 °C. This time, the polymers were found to have LCB levels very similar to that observed in series A. Thus, it is the state of silica dehydroxylation, and the degree of coalescence, that determine LCB levels. The data from series C show that it is not necessary for the chromium to experience a high... 

Chromium(III) acetylacetonate is a red-violet, crystalline material (d = 1.34,4 m.p. 216°).3 It boils at ca. 340°1 to form a green vapor2 but sublimes even at 100°. Molecular-weight determinations in such solvents as amyl benzoate show that the compound is not associated. 

Speciation of chromium (histidine/acetic acid acetate buffer/EDTA °), mercury (borate/MeOH), tin (pyridine/CTAB), lead (SDS/p-CD), arsenic (borate, phosphate or phosphate/borate, " phosphate/TTAB, phosphate andphosphate/TTAB ), sulfur (phosphate/TTAB/ACN), and selenium (histidine/acetic acid, SDS/p-CD ) by CE methods have been reported. Other examples include the analysis of beryllium (as an acetylacetone complex) in digested airborne dust and the determination of Fe(II)-, Cu(I)-, Ni(ll)-, Pd(II)-, and Pt(II)-cyano complexes and nitrate from leaching solutions of automobile catalytic converters. ... 

Ferric acetylacetonate catalyst, H2S determination Cadmium sulfate catalyst, halogenation Chromium fluoride (ic) catalyst, high temp. polyester premix compounds... 

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