Engineering acid site distribution in hierarchical ZSM-5 microspheres toward high-efficiency benzene-butene alkylation catalysis

The alkylation reaction of benzene with n- butene can not only significantly improve the utilization rate of n- butene, but also solve the shortage problem of phenol and methyl ethyl ketone, and alleviate the surplus problem of acetone. This study demonstrates a strategic approach to engineering hierarchical ZSM-5 zeolites with controlled aluminum distributions for enhanced benzene-butene alkylation catalysis. Through aluminum precursor selection (aluminum isopropoxide, sulfate, and sodium aluminate) coupled with resin-templated synthesis, the framework Al speciation and mesopore architecture in ZSM-5 could be regulated. Advanced characterization revealed that aluminum source chemistry governs Brønsted/Lewis acid ratios, Al spatial positioning (sinusoidal/straight channels), and mesopore volume. The synthetic hierarchical ZSM-5 zeolites exhibited significant difference in catalytic performance toward benzene-butene alkylation, the Al atoms in HZ5-AIP zeolite with the largest pore size mainly in straight and sinusoidal channels, achieving 99 % conversion of n -butene (210 °C, 3 MPa, benzene/butene molar ratio = 5:1, WHSV Bu  = 6 h −1 ).