Acetylacetone—continued

Epichlorohydrin Elastomers without AGE. Polymerization on a commercial scale is done as either a solution or slurry process at 40—130°C in an aromatic, ahphatic, or ether solvent. Typical solvents are toluene, benzene, heptane, and diethyl ether. Trialkylaluniinum-water and triaLkylaluminum—water—acetylacetone catalysts are employed. A cationic, coordination mechanism is proposed for chain propagation. The product is isolated by steam coagulation. Polymerization is done as a continuous process in which the solvent, catalyst, and monomer are fed to a back-mixed reactor. Pinal product composition of ECH—EO is determined by careful control of the unreacted, or background, monomer in the reactor. In the manufacture of copolymers, the relative reactivity ratios must be considered. The reactivity ratio of EO to ECH has been estimated to be approximately 7 (35—37). 

Under an atmosphere of argon, 50 mL of dry tetrahydrofuran (Note 2) and 23.6 mL (0.16 mol) of freshly distilled 1-octyne (Note 3) are added. The ice/water cooling bath is used to keep the temperature between 15°C and 25°C during the addition. Stirring is continued in the ice bath for 2 hr to control a mildly exothermic reaction then the flask is wrapped in aluminum foil and stirred overnight at room temperature (elapsed time is 18 hr). At this point, 10.9 mL (0.130 mol) of freshly distilled 2-cydopentenone (Note 3) is added and the reaction mixture is chilled in an ice bath for 10 min. To the cooled reaction mixture a total of 3.34 g (0.0130 mol) of vacuum-sublimed (at 180°C), powdered, solid nickel acetylacetonate (Notes 3,4) is added in three portions at 10-min intervals, keeping the temperature of the reaction mixture below 50 C (Notes 5,6). 

After some hours the blue-green compound of copper and acetylacetone is separated by filtration with suction, washed twice with water, transferred directly from the filter funnel to a separating funnel, and, after being covered with ether, decomposed by continuous shaking with 50 c.c. of 42V-sulphuric acid. The ethereal solution is separated and the acid layer is extracted with ether the extract is then combined with the ethereal solution, which is now dried over calcium chloride. After the ether has been removed by distillation the diketone is likewise distilled. The bulk of the material passes over at 125°-140° and, on repeating the distillation, at 135°-140°. The boiling point of the completely pure substance is 139°. Yield 15-20 g. 

To a 20 mL Erlenmeyer flask, 1 mL of 0.15 M Tris-HCl buffer (pH 7.2), 0.1 mL of 0.2 M disodium EDTA, and 0.5 mL of liver homogenate were added. After preincubation for 5 minutes at 37°C, 0.4 mL of 0.5 M glycine was added. Shaking continued for 30 minutes before the reaction was terminated by adding 0.5 mL of 25% trichloroacetic acid. The reaction mixture was centrifuged and the supernate diluted fivefold with distilled water. To 0.1 mL of the supernate, 2.5 mL of distilled water, 0.4 mL of acetylacetone, and 1 mL of 10% formaldehyde solution were added. This mixture was heated for 10 minutes at 100°C and then kept in an ice bath until analysis of 20 fiL by HPLC. Product formed was linear with liver homogenate up to 0.5 mL, and with time up to 60 minutes. 

Sol-gel processes are also suitable for lanthanide oxide formation, as could be shown by the use of Tb(acac)3 and Dy(OBu- )3 in acetylacetone" . Tb203 crack- and pine-hole-free, dense and smooth microstructured buffer layers were produced on nickel tapes by a reel-to-reel continuous sol-gel process. The authors report that the film properties can be strongly influenced by solution components, temperature, time and atmosphere. Nanocrystalline mesoporous dysprosium oxide Dy203 with narrow monomodal pore size distribution can be approached by a combined sol-gel process with a surfactant-assisted templating technique . The spherical Dy203 nanoparticles were formed with aggregations. 

Acetylacetone (acac) and related ) -diketones continue to be extensively used as ligands for transition metal complexes. This section deals with tris(acac) complexes followed by a discussion of the spectra of adducts of bis(acac) complexes. Cramer and Chudyk (75) have studied [Ni(acac)3]2C104. INDO calculations show that the major spin delocalization is into the highest filled ligand orbital which possesses cr-symmetry plus a minor contribution from delocalization into the lowest empty 7i-orbital. This is in contrast to the spin delocalization in Ni(acac)3 and Ni(acac)py2 where the major de-localization is into the highest filled ligand orbital of Ti-symmetry. 

This reaction may continue past the first ligand exchange reaction to completion. When the surface of metal oxide also contains coordinately unsaturated sites, such as on the surface of some aluminas, then another reaction is possible between the volatile metal acetylacetonate and the surface ... 

The Y-AI2O3 support (001-1.5E, Akzo Nobel) was crushed and sieved to a particle size of 0.15-0.3 mm. The support was calcined in a muffle furnace in ambient air for 16 h at 400 (for Ir samples) or 600 °C (for Pt samples). The pretreatment of the support was continued in the ALD reactor for 3 h to remove moisture before the actual runs. Acetylacetone (Hacac, Merck, > 99 %), iridium acetylacetonate (Ir(acac)3, Volatec, > 99 %) and platinum acetylacetonate (Pt(acac)2, Volatec, > 99 %) were used without any further purification. Acetic acid (HAc, Merck, > 99.8 %) was used in the impregnation of a reference sample. 

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