Single reactions rate function rules

Below are listed general rules on the form of the reaction rate function (M. Boudart, Kinetics of Chemical Processes, Butterworth-Heinemann, 1991, pp. 13-16). The rules are of an approximate nature but are sufficiently general that exceptions to them usually reveal something of interest. It must be stressed that the utility of these rules is their applicabdity to many single reactions. 

Currently, there are numerous empirical functions of the adsorption-desorption reactions kinetics proposed for various specific conditions. As a rule, the adsorption rate is considered to be a linear function of the number of active centres on the surface of the mineral. The simplest is the single-reaction model, which assumes that the exchange is caused by the interaction of a single component i with active centres of a single type surface, is subject to the first order reactions and its rate may be presented by the following equation... 

These decreased yields (due to the unstable intermediate getting lost so to speak, in the pore structure) can be quantitatively calculated as follows Consider a single pore of radius r and length L as in Section V. At the mouth of this pore let the concentration of A be A" and let the concentration of B be B°. The reactant A will diffuse into the pore and after a certain number of collisions with the pore wall will react to form B. The concentration of A within the pore will ruled by eq. (31) Section V. For first order reaction the solution for A as a function of distance from the pore mouth will be given by eq. (32), since the fact that is an unstable intermediate in no way affects the rate of reaction of A. The concentration of B within the pore is ruled by a steady-state equation analogous to (31), except that the right hand side contains a term for the formation of B from A ... 

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