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  • 1 Chemistry Department, Faculty of Science, Minia University, 61519 El-Minia, Egypt
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Abstract  

Thermogravimetry, differential thermal analysis, X-ray diffractometry and infrared spectroscopy showed that Ni(CH3COO)2·4H2O decomposes completely at 500°C, giving rise to a mixture of Nio and NiO. The results revealed that the compound undergoes dehydration at 160°C and melts at 310°C. The water thus released hydrolyses surface acetate groups, acetic acid being evolved into the gas phase. At 330°C, the anhydrous acetate is converted into NiCO3, releasing CH3COCH3 into the gas phase. The carbonate subsequently decomposes (at 365°C) to give NiO(s), CO2(g) and CO(g). On further heating up to 373°C, a mixture of Nio and NiO is formed. Other gas-phase products were detected at 400°C, viz. CH4 and (CH3)2CH=CH2, which were formed in surface reactions involving initial gas-phase products. Non-isothermal kinetic parameters (A and ΔE) were calculated on the basis of temperature shifts experienced in the various decomposition processes as a function of heating rate (2–20 deg·min−1).