The formolysis and acetolysis of ferrocenylmethyl benzoate are proton catalyzed and accelerated by addition of perchloric acid. Our earlier experiments have shown that at a temperature of about 20 °C addition of a common benzoate ion in formolysis of 3.2 x 10–4 mol dm–3 ferrocenylmethyl benzoate suppresses the formolysis rate only slightly but the formolysis is significantly slower at 40 °C. Such rate lowering is not observed in acetolysis of the same substrate. Decrease of the formolysis rate at increased temperatures (20–40 °C) is most probably caused by the decrease of the hydrogen ion concentration, because the stronger formic acid displaces the weaker benzoic acid from sodium benzoate, thus reducing the formic acid concentration in this acid-catalyzed system. This, however, does not occur in the weaker acetic acid. Besides, the acetolysis rates are equal in the presence of 0.1 and 0.2 mol dm–3 sodium benzoate, while the formolysis rates decrease with the addition of benzoate. The strong temperature dependence of the formolysis rates is probably connected with the formation of formic acid dimers and the temperature dependent hydrogen bonding. Hydrogen bonding and the dimer formation in acetic acid are less pronounced than in formic acid.Formoliza i acetoliza ferocenilmetil benzoata katalizirane su protonima, a ubrzava ih dodatak perklorne kiseline. Naši raniji pokusi pokazali su da na temperaturi od približno 20 °C dodatak zajedničkog iona benzoata u formolizi 3,2 x10–4 mol dm–3 ferocenilmetil benzoata neznatno smanjuje brzinu formolize, dok je na 40 °C formoliza bitno sporija. Takovo smanjenje brzine ne zamjećujemo u acetolizi istog kompleksa. Smanjenje brzine formolize na povišenoj temperaturi (20–40 °C) vrlo je vjerojatno posljedica smanjenja koncentracije vodikovih iona, jer jača mravlja kiselina istiskuje slabiju benzojevu kiselinu iz natrijeva benzoata, što dovodi do smanjenja koncentracije mravlje kiseline u tom kiselinom kataliziranom sustavu. To se me|utim ne doga|a u slabijoj octenoj kiselini. Nadalje, brzine acetolize jednake su u prisutnosti 0,1 i 0,2 mol dm–3 benzoata, dok se brzine formolize smanjuju dodatkom benzoata. Izgleda da je jaka temperaturna ovisnost brzine formolize povezana sa stvaranjem dimera mravlje kiseline pri čemu je dimerizacija jako ovisna o temperaturi. Vodikove veze i stvaranje dimera u octenoj kiselini od manjeg su značaja nego u mravljoj kiselini
