High Metal-Acid Balance and Selective Hydrogenation Activity Catalysts for Hydrocracking of 1-Methylnaphthalene to Benzene, Toluene, and Xylene

Hydrocracking of 1-methylnaphthalene to benzene (B), toluene (T), and xylene (X) was performed over a series of bi-functional catalysts (W/Beta) at 420 degrees C and 6 MPa. The reaction results and kinetic study indicated that metal-acid balance (metal-acid interaction and metal-acid ratio) and metal dispersion had a great impact on the cracking, hydrogenation, and selective hydrogenation activity, which directly determine the BTX yield. An inappropriate metal-acid ratio would lead to producing plenty of intermediates or by-products, and poor metal dispersion would result in low hydrogenation activity. However, good metal dispersion usually accompanies the strong metal-acid interaction, which reduces the sulfidation of metal. In this work, a new tungsten precursor, W-complex, was used to prepare the catalysts with good dispersion of metal oxides and high hydrogenation activity. The external surface acidity of zeolite was modified to regulate the metal-acid interaction by forming a layer of SiO2 on acid sites through chemical liquid deposition.