Thermal, Structural and Morphological Characterisation of Freeze-dried Copper(II) Acetate Monohydrate and its Solid Decomposition Products

In the present study the thermal decomposition of a freeze-dried copper(II) acetate monohydrate powder, (CH3COO)2Cu.H2O, (FDCuAcH2O), was analysed by a combination of high-temperature X-ray diffractometry; differential scanning calorimetry and thermogravimetry, up to 700 °C. The structure and morphology of the calcined freeze-dried powders were analysed by scanning electron microscopy and X-ray diffractometry. The results showed that FDAcCuH2O decomposes during heating in two stages: I) (25-225 °C) FDCuAcH2O dehydrates giving rise to copper(II) acetate, (CH3COO)2Cu, (AcCu), and II) (225-525 °C) AcCu decomposes to CuO through complex oxidation reactions of Cu and Cu2O, simultaneously. SEM showed that FDCuAcH2O powder has a scale-like morphology, which is created in the freezing stage and retained after freeze-drying. After calcination at 125 and 225 °C, clusters of elongated tubes (or filaments) compose the resulting powder (AcCu). Subsequent calcination at temperatures above 325 °C resulted in hard clusters of spheroid-like CuO particles.

[1]  A. Apelblat,et al.  Solubilities of magnesium, calcium, barium, cobalt, nickel, copper, and zinc acetates in water fromT = (278.15 to 348.15) K , 1999 .

[2]  A. Burneau,et al.  Infrared and Raman spectra of alkaline-earth and copper(II) acetates in aqueous solutions , 1998 .

[3]  M. Ulla,et al.  Characterization of freeze-dried precursors of La1.85Sr0.15CuO4 , 1996 .

[4]  S. Mansour.  Thermoanalytical investigations of the decomposition course of copper oxysalts , 1995 .

[5]  E. Solomon,et al.  Single crystal morphology of the copper acetate dimers Cu2(CH3COO)4·2H2O and Cu2(CH3COO)4pz , 1995 .

[6]  O. Biest,et al.  Intermediate phases during processing of freeze-dried ybacuo precursors , 1995 .

[7]  William E Lee,et al.  Synthesis and sintering of PLZT powder made by freeze/alcohol drying or gelation of citrate solutions , 1995 .

[8]  M. C. Ball,et al.  The dehydration of copper(II) acetate monohydrate , 1994 .

[9]  Tsuyohito Ito,et al.  Preparation of fine powders for electronic materials by freeze-drying , 1993 .

[10]  S. Dou,et al.  Rapid Formation of the 110 K Phase in BI‐Pb‐Sr‐Ca‐Cu‐O through Freeze‐Drying Powder Processing , 1990 .

[11]  A. Baranowska,et al.  Kinetic parameters of the thermal decomposition of Cu(II) and Zn(II) salts of carboxylic acids , 1984 .

[12]  B. Plunkett,et al.  The thermal decomposition of calcium, sodium, silver and copper(II) acetates , 1974 .

[13]  S. Fletcher,et al.  Refined crystal structure of tetra-µ-acetato-bisaquodicopper(II) , 1973 .

[14]  D. A. Edwards,et al.  Transition metal acetates , 1968 .

[15]  C. Rao,et al.  Infrared spectra and thermal decompositions of metal acetates and dicarboxylates , 1968 .

[16]  J. A. Hill,et al.  Observations on the thermal decomposition of cupric acetate monohydrate , 1961 .

[17]  F. Schoening,et al.  A new type of copper complex as found in the crystal structure of cupric acetate, Cu2(CH3COO)4.2H2O , 1953 .