Theoretical Substantiation of the Possibility of Predicting the Catalytic Activity of Carbon Nanotubes in the Diels–Alder Reaction

In the paper we consider the development of an algorithm for predicting the catalytic activity of porous materials based on the concept of transition state shape selectivity (TSSS). We evaluated catalytic activity of single-wall carbon nanotubes (SWCNT) in the Diels–Alder reaction on example of interaction cyclopentadiene with acrylonitrile, maleic anhydride, and piperylene with ethylene. We have viewed the stabilization of transition states (TS) on the surface of nanotubes of various diameters. As a quantitative value of TS stabilization energy, we applied the calculated value of the adsorption energy of TS with frozen structure on SWCNT, which was found using Material Studio 8.0 program. It is shown that the dependence of the adsorption energy on the diameter of the nanotubes has an extremum for all the considered TS, and the maximum adsorption energy is achieved when the TS is placed inside a tube of a certain diameter. Obviously, this diameter can be assumed optimal for achieving the greatest catalytic effect. Depending on the size of the TS of the considered reactions, the optimal diameter of the nanotubes is 9–11 Å. Also, we found, that for the reaction cyclopentadiene with acrylonitrile, the difference between linear dimensions of TS for endo- and exo-isomers formation is noticeable, which suggests the possibility of selective catalysis by SWCNT. Graphical Abstract