Synergistic catalysis of tandem catalysts of γ-Al2O3 and HZSM-5 for the conversion of 1-naphthol from coal tar to light aromatics

Abstract

High energy consumption, environmental pollution, and poor conversion are major challenges to the efficient utilization of coal tar. Tandem catalysis is considered one of the most promising technologies for the high-value utilization of coal tar. The main challenge for the efficient utilization of coal tar is the low added value and complexity of the products, while tandem catalytic technology is considered as one of the most promising technologies for the high-value utilization of coal tar. It is report here a strategy for the highly selective conversion of 1-naphthol to light aromatics catalyzed by a homemade tandem of macroporous γ-Al2O3 and HZSM-5 catalysts with large specific surface area. We demonstrate that 1-naphthol first undergoes dehydroxylation on γ-Al2O3, and then the naphthalene-dominated intermediates undergo further cracking-selective reactions on the adjacent HZSM-5 bed to produce BTEX. This work was carried out under the loading conditions optimized by machine learning modeling. By adjusting the loading mode, adjusting the mass ratio (bed thickness), optimizing the reaction temperature, enhancing the proximity effect, adjusting the pore structure of HZSM-5, and modifying HZSM-5 with three metals 1Ni-5W-0.2La, the maximum conversion rate of 1-naphthol (R1-naphthol) and the selectivity of light aromatics BTEXN (SBTEXN) reached 67.31 % and 47.43 %, respectively. Additionally, the structure–activity relationship between the physicochemical properties of the catalyst and the SBTEXN, R1-naphthol was also explored. The results of this study can provide a unique reference perspective for the efficient preparation of light aromatic hydrocarbons from phenol-rich coal tar.