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Department of Chemistry, Himachal Pradesh University, Summer Hill, Shimla-171 005, Himachal Pradesh, India E-mail : neerajsharma_univ@yahoo.com Manuscript received 16 April 2009, revised 23 September 2009, accepted 9 November 2009 Thermal behaviour or non-oxovanadium(IV) complexes or composition (VCl2-n(acac)2(OAr1.2)n](where OAr1 = OC6H4C6Hr2; OAr2 = OC6H4C6H5-4; acac = acetylacetonate Jon (CH3COCHCOCH3)-; n = 1 and 2) synthesized by the reaction of VCI2(acac)2 with the sodium salt or the respective phenols has been studied using thermogravimetric (TG) and differential thermal analysis (DTA) techniques. Thermograms Indicate that the complexes undergo decomposition mainly In two steps to yield VO2 as the final product of decomposition. From Initial decomposition temperatures (IDT), the order of thermal stability for complexes has been inferred as VCI(acac)2(OAr1) > V(acac)2(OAr1)2 > VCI(acac)2(OAr2) > V(acac)2(OAr2)2, From the mathematical analysis of TG data, kinetic and thermodynamic parameters viz. energy or activation, frequency factor, order of reaction, entropy or activation etc. at the first and second decomposition states employingCoats-Redfern, Freeman-Carroll and Horowitz-Metzger equations have been evaluated. |
