Catalytic conversion of 2,5-dichlorotoluene over Hβ zeolite, Ag/Hβ and Cu/Hβ catalysts in N2 or H2 atmosphere

Abstract

2,6-Dichlorotoluene (2,6-DCT), 2,4-dichlorotoluene (2,4-DCT), dichlorobenzenes (DCB), and dichloroxylene (DCX) were selectively synthesized through the catalytic conversion of 2,5-dichlorotoluene (2,5-DCT) over Hβ (SiO2/Al2O3 = 25) zeolite, Ag/Hβ, and Cu/Hβ catalysts in a N2 or H2 atmosphere. When Hβ zeolite was used as the catalyst at 310−350 °C in a N2 atmosphere, DCB, 2,6-DCT, 2,4-DCT, and DCX with the selectivities of ca. 28, 15, 17, and 22% were formed as the main products. When the Ag/Hβ catalysts with high Bronsted acid amount catalyzed the conversion of 2,5-DCT, 2,4-DCT with the selectivities of 71.9–83.9% was formed at 310 and 330 °C. The catalytic activities over the Cu/Hβ catalysts were similar to that over the Hβ catalyst. In a H2 atmosphere, the Ag2/Hβ and Cu10/Hβ catalysts favored the 2,5-DCT hydrogenation to DCB with the selectivities of around 40 and 58%, respectively. The acidity and metal type of the catalyst played important roles in the catalytic conversion of 2,5-DCT to chlorinated aromatics.