Significance of non-isothermal kinetic data - A statistical study

Arrhenius parameters values, in non-isothermal kinetic vaporisation process es for a series of compounds with related structures, have been calculated. This was made using a method of calculation that allows to find the most p robable vaporisation mechanisms. According to this method DTG curves were compared with some theoretical one s reported in literature, whose shape results to be only a function of the mechanisms. In this way the choice of the mathematical functions which can be inserted in the kinetic equations, was influenced by the shape of the DT G plots and other thermal analysis signals thus allowing to choose the most probable mechanisms. The kinetic parameters derived from these mechanisms were compared, using s tatistical analysis, with those obtained from another method of calculation based on 'a priori' vaporisation mechanism chosen for the investigated liq uid-gas transition. The standard deviations of the slope and of the intercept, together with th e standard deviation and the square correlation coefficient (r(2)) of the l inear regression equations related to the mechanisms of the two methods wer e calculated. Student t-test, Fisher F-test, confidence intervals (c.i.) an d residuals values were also given. Statistical analysis shows that the mechanisms obtained with the former met hod (diffusive and geometrical models) and the related Arrhenius parameters result to be more significant (in terms of probability) than the correspon ding quantities of the latter for which a first-order model was chosen.