Sublimation kinetic studies of the Zr (tmhd) 4 complex

The thermal behaviour of tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionato) zirconium(iv),[zr(tmhd)4] was investigated by nonisothermal and isothermal thermogravimetric methods in a high pure nitrogen atmosphere. the influence of the heating rate in dynamic measurements (6,8,10,and 12°c/min) on activation energy was also studied. the nonisothermal sublimation activation energy values determined following the procedures of arrhenius,coats and redfern,kissinger,and flynn-wall yielded 76 ± 5,92 ± 2,81 ± 8,and 72 ± 7 kj/mol,respectively,and the isothermal sublimation activation energy was found to be 87 ± 4 kj/mol over the temperature range of 411-462 k. different reaction mechanisms were used to compare with this value. analysis of the experimental results suggested that the actual reaction mechanism was an r n deceleration type. © 2013 t. s. arul jeevan and k. s. nagaraja.