Kinetic analysis on the non-isothermal dehydration by integral master-plots method and TG-FTIR study of zinc acetate dihydrate

The thermal decomposition of Zn(AC)(2)center dot 2H(2)O has been studied by TG-DTA/DSC at the heating rate of 2, 3, 4,5, 10 and 20 degrees C min(-1) from ambient temperature to 350 degrees C in static air and flowing N-2, respectively. The TG-DTA/DSC experiments show both the decompositions under the two different atmospheres go through two well-defined steps: release of crystal water and subsequent decomposition of anhydrous zinc acetate into zinc oxide. Kinetic analysis was performed by using an integral composite procedure, which includes an integral isoconversional method and an integral master-plots method. The results of integral isoconversional method at various heating rates suggest that in both atmospheres the dehydration (0.3 < alpha < 0.9) followed simplex kinetic mechanism which can be described by an Avrami-Erofeev (A(1.5)) model. The evolved gas of non-isothermal decomposition of Zn(AC)(2)center dot 2H(2)O in flowing N-2 was measured by TG coupled with Fourier transform infrared spectroscopy (FTIR). During 60-120 degrees C water was firstly detected. And in the range of 175-390 degrees C acetic acid, acetone and carbon dioxide were detected. (C) 2008 Published by Elsevier B.V.