As can be seen in Fig. 6, the reaction rates reasonably follow
the Arrhenius law in the temperature range studied (10–40 ◦C):
k1 = k0exp
−Ea
RT
(6)
As expected [22], the value of the activation energy Ea is
quite low: Ea =22±2 kJmol−1. Since the photoactivation process is irrelevant to thermal activation, the activation energy
found is only apparent. Its (slightly) positive value indicates that
temperature concerns the desorption of first step intermediates
in the medium [19]. This measured value might be exaggerated
because of the effect of naphthalene volatilization, which
accelerates when temperature increases.