a computational study on stabilization trends of the adsorption complexes of c1-c4 primary alcohols on modified acidic zeolites

The adsorption complexes and the binding energies of a series of aliphatic alcohols on ti and p-modified acidic zeolites have been studied computationally employing combined quantum mechanics/molecular mechanics (qm/mm) methods suited for large-scale calculation. the investigation has been carried out using an extended 84t cluster model with one hydroxyl brønsted acidic site. this cluster model has been studied employing the hybrid (qm/mm) b3lyp/6‑31+g(d,p):uff method and its counterpart b3lyp‑d3/6‑31+g(d,p):uff level of theory accounting for dispersion forces. the use of the b3lyp-d3 technique has led to a considerable improvement in the b3lyp results, underlining the critical role of the long-range dispersion forces. the modification exhibits higher deprotonation energies and a decreasing acidic character.the modified clusters show a considerable reduction of the order of 3 to 4 kcal/mol in adsorption energy for all alcohol molecules, especially emphasized in the ti-modification in comparison to that of al-zeolite.