Synthesis of mesoporous high-silica zeolite Y and their catalytic cracking performance

Abstract

Mesoporous high-silica zeolite Y with advantages of improved accessibility of acid sites and mass transport properties is highly desired catalytic materials for oil refinery, fine chemistry and emerging biorefinery. Here, we report the direct synthesis of mesoporous high-silica zeolite Y (named MSY, SiO 2 /Al 2 O 3 ≥ 9.8) and their excellent catalytic cracking performance. The obtained MSY materials are mesoporous single crystals with octahedral morphology, abundant mesoporosity and excellent (hydro)thermal stability. Both the acid concentration and acid strength of H-form MSY are obviously higher than those of commercial ultra-stable Y (USY), which should be attributed to the uniform Al distribution of MSY zeolite. The H-MSY displays an obviously reduced deactivation rate and improved catalytic activity in the cracking reaction of bulky 1,3,5-triisopropylbenzene (TIPB), as compared with its mesoporogen-free counterpart and USY. In addition, H-MSY was investigated as catalyst for the cracking of industrial heavy oil. The MSY-based catalyst (after aging at 800 o C in 100% steam for 17 h) exhibits superior conversion (7.64% increase) and gasoline yield (16.37% increase) than industrial fluid catalytic cracking (FCC) catalyst under the investigated conditions. Mesoporous high-silica zeolite Y with high (hydro)thermal stability has been successfully synthesized, which possesses larger acid concentration and stronger acid strength than USY, and exhibits superior catalytic performance in the cracking of hydrocarbons and industrial heavy oil.