Cupric acetylacetonate: Preparartion and Applications

Cupric acetylacetonate (Cu(acac)₂), also known as copper(II) acetylacetonate, is a compound coordination with the chemical formula C₁₀H₁₄CuO₄. It is characterized by a copper atom coordinated to two acetylacetonate ligands in a square planar geometry. This compound is widely used in various industrial and chemical applications due to its unique properties and versatility.[1]

Preparation of Cupric acetylacetonate

Preparation of Cupric acetylacetonate; Put the above-prepared high-activity copper salt into the reaction kettle, and add appropriate amount of acetylacetone and organic solvent to the reaction kettle, then set the temperature in the reaction kettle to 30°C, and heat and ultrasonically shake at this temperature for 2h ; After the reaction is completed, the organic solvent and excess acetylacetone are recovered by distillation recovery method, and then the remaining mixed components in the reaction kettle are taken out and placed in a glass container containing an ethanol solution for recrystallization After the crystals are completely precipitated, they are subjected to suction filtration to obtain the finished Cupric acetylacetonate. In the preparation process of the copper salt raw material, the complexing agent is citric acid or soluble citrate; and the ratio of the amount of copper ion to citrate ion is 1:0.15. In the preparation process of the copper salt raw material, the frequency of ultrasonic mixing is 20kHz, and the power of ultrasonic is 500W. During the preparation process of the copper salt raw material, the drying temperature in the constant temperature drying box is set to 50°C. In the preparation process of the highly active copper salt, the mass ratio of naphthene, metal lithium, copper salt raw materials and myristaldehyde is 1:0.15:1.8:0.85. In the preparation process of Cupric acetylacetonate, the mass ratio of the highly active copper salt to acetylacetone is 1:1.85. In the preparation process of Cupric acetylacetonate, chloroform is selected as the organic solvent, and the ratio of acetylacetone to its amount is 0.16 g/mL. During the preparation process of Cupric acetylacetonate, the frequency of the ultrasonic oscillation is 32 kHz and the power is 600 W. In the preparation process of Cupric acetylacetonate, the concentration of the ethanol solution is 90%, and the usage amount is twice that of the organic solvent. The Cupric acetylacetonate prepared by the invention is used as an organic synthesis catalyst, resin crosslinking agent and curing accelerator, rubber additive and fuel oil additive.[2]

Synthesis of Nanoparticles via Cupric acetylacetonate

Experimental data on the synthesis of crystalline Cu, Cu2O, and CuO nanoparticles obtained earlier by the vapor-phase decomposition of copper(II) acetylacetonate (Cupric acetylacetonate) were systematized and generalized. Studies were performed using a laminar flow reactor at atmospheric pressure within the ranges of precusor partial vapor pressure Pprec = 0.06–44 Pa and reactor temperature from 432 to 1216°C. The decomposition of Cupric acetylacetonate was studied in an inert nitrogen atmosphere and in the presence of various reagents (water vapors, H2, O2, and CO). The composition of synthesized particles varied from pure copper to its oxides (Cu2O and CuO) depending on experimental conditions and used reagents. A semi-empirical kinetic model was proposed for describing the product dynamics. The hypothesis on the predominant role of copper dimers in a particle's growth was stated. It was established that the composition of products is determined by the surface reactions on growing particles and is dependent on the ratio between the concentrations of the gaseous reagents. Calculated phase diagrams of the products of Cupric acetylacetonate decomposition in the presence of various reagents were in good agreement with experimental data. The proposed method of construction of the phase diagram of decom position products can be employed for other systems. It was established that, upon the Cupric acetylacetonate decomposition in the presence of CO, carbon nano-onions were formed in addition to copper nanoparticles.[3]

Since carbon monoxide and oxygen did not react with a solid precursor, they were employed for the saturation of flow with precursor vapors in the saturator. In order to check the possibility of reaction between water vapors and precursor, we used vessel filled with water to bubble the gas at room temperature. The reagent was usually added to the unit independently of the flow of Cupric acetylacetonate vapors through the tube made of stainless steel (wall thickness of 1 mm) with an inner diameter of 11 mm. The flows were mixed and heated in the furnace. The use of removable cartridge with precursor made it possible to determine the pressure of Cupric acetylacetonate vapors in reactor. The vapor pressure was calculated by the known gas flow rate and variation in cartridge mass after some time interval. Thus, the temperature and the composition of vapor–gas phase were successfully controlled during experiments.

In order to study the influence of reducing media on the Cupric acetylacetonate decomposition and characteristics of forming particles, we added the mixture of nitrogen and hydrogen in 93.0/7.0 molar ratio. The studies were performed in the range of nitrogen–hydrogen flow rates from 80 to 1980 cm3 /min (usually, at 330 cm3 /min) and at 432, 596, and 705°C. As a result, we obtained the ultrafine copper particles with sizes of 3–10 nm. The phase of copper oxide was not detected by X-ray diffraction and electron diffraction performed in the transmission electron microscope. This turned out to be the only advantage of using hydrogen together with pure nitrogen. One should note that the behavior of a system slightly differed from the behavior upon the Cupric acetylacetonate decomposition in the inert nitrogen atmosphere: the presence of hydrogen did not affect the rate (more exactly, the completeness) of precursor decomposition at low temperatures. The results of TGA performed at = 80 cm3 /min and 432°C demonstrated incomplete (47%) decomposition of precursor. An increase in the flow rate leads to an increase in the fraction of undecomposed precursor due to a decrease in its residence time in the reactor hot zone. The complete precursor decomposition occurs at 596°C, as in the Cupric acetylacetonate–N2 system. Thus, we will not consider in detail the Cupric acetylacetonate–H2–N2 system, because the only important role of hydrogen can be reduced to the protection of copper particles from the oxidation by the decomposition products that, in principle, was self-evident.

References

[1] R. Garriga, V. Pessey, F. Weill, B. Chevalier, J. Etourneau, F. CansellKinetic study of chemical transformation in supercritical media of bis(hexafluoroacetylacetonate)copper (II) hydrate, The Journal of Supercritical Fluids, 20 (2001), pp. 55-63

[2] CN112142584A Copper acetylacetonate and preparation method thereof

[3] S. Yoda Decomposition of metal acetylacetonate in supercritical carbon dioxide, Proc. Int. Symp. Supercrit. Fluid, 2006 (2006), pp. 2-29

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