In the α-olefin isomerization reaction, the reaction is slightly exothermic, but the reactor temperature decreases

This phenomenon can be explained by the following two reasons: 1. The temperature drop is caused by the exothermic reaction that occurs during the isomerization of the reactants. Although the reaction is slightly exothermic, its rate is relatively fast; this allows most of the heat released to be carried away as the reactants pass through the catalyst bed, thereby reducing the temperature of the catalyst bed. Since the faster the reaction rate, the shorter the time the reactants spend in the catalyst bed, and thus more energy is released as heat; therefore, the temperature of the catalyst bed at the reactor inlet is higher, while the temperature at the outlet is lower. 2. The temperature drop in the reactor may be caused by the mass transfer process of the reactants. Mass transfer occurs as the reactants pass through the catalyst bed, that is, the mass transfer process between the reactants and the catalyst. This mass transfer process requires energy, which leads to a decrease in temperature. Since the mass transfer process occurs from the inlet to the outlet, the temperature distribution in the reactor decreases gradually from the inlet to the outlet. Regardless of the explanation, it illustrates the phenomenon of the reactor temperature distribution decreasing gradually from the inlet to the outlet. .

Due to its low heat of reaction and fast reaction rate, the reaction is complete only in the upper part of the bed, resulting in no reaction heat in the lower layers; subsequently, heat and mass transfer, as explained above, lead to a low outlet temperature.