Thermal decomposition kinetics of ZnII chelates of substituted chalcones

Department of Chemistry, Jawahar Navodaya Vidyalaya, Peddapuram-533 437, India E-mail : mallikarjunkg@yahoo.co.in Fax: 91-8852-243363 Manuscript received 23 April 2004, revised 5 July 2005, accepted 5 August 2005 The thermal decomposition of ZnII complexes of 3-(phenyl)-1-(2'-hydroxynaphthyl)-2-propen-1-one (PHPO), 3-(4-chlorophenyl)-1·(2' -hydroxynaphthyl)-2-propen-1-one (CPHPO), 3·( 4-methoxyphenyl)-1·(2' -hydroxynaphthyl)·2-propen-1-one (MPHPO), 3-(3,4· dimethoxyphenyl).1-(2'·hydroxynaphthyl)·2·propen-1·one (DMPHPO) was studied by thermogravimetry. Mathematical analysis of the data has allowed us to determine various parameters using Freeman-Carroll equation, the integral method using the Coats-Redfern equation and the approximation method using the Horowitz-Metzger equation. The trend of the kinetic parameters was found to be different from that of the thermal stability order. The low values of Z suggest the slow nature of the reaction