COMPUTATIONAL MODELING STUDY OF ACYLATION OF PHENOL OVER ZEOLITES TO HYDROXYACETOPHENONES

Ortho- (o-HAP) and para-hydroxyacetophenone (p-HPA) isomers are intermediate compounds for the synthesis of fragrances and pharmaceuticals. In this study, molecular modeling was done to study the acylation of phenol on four potential zeolites, namely, MOR, beta-A, BETAPA, and ZSM-5 catalysts. The grand canonical Monte Carlo method was used, along with the NVT simulation techniques and force field-based calculations to investigate the adsorption, diffusion, and surface reaction, respectively. From this fundamental simulation study, it is concluded that this method can be applied to screen the potential zeolite catalysts. DMol3 was used to carry out the energy minimization and geometrical optimization at various stages by using the density functional theory. An investigation of the comparative sorption, diffusion, and surface binding of all the reacting, product, and intermediate species on these four zeolites was done. Diffusion was studied by making use of the Discover Module, which makes use of molecular dynamics to carry out the calculations. Much more particular properties are studied from the simulation, such as the energy and density distribution of components in silicalite crystal, the diffusivities of each component in the zeolites, the porosity, and accessible surface area of the zeolites, which are difficult to be explained by experiments.