Analysis of Decisive Structural Parameters and Acidic Property of Zeolites for Gas-Phase Alkylation of Benzene with Ethylene

The effects of the zeolite structure and acidic property on the activity and selectivity in gas-phase alkylation of benzene with ethylene were investigated using TUN, IMF, *SFV and MFI with different structures and Si/Al-2 ratios. The channels of TUN and IMF provide both higher selectivity to ethylation (ethylbenzene and di-ethylbenzene) and lower xylene selectivity compared to MFI with slightly smaller pore diameter in which the pore diffusion limitations are suffered. The activity is mainly controlled by zeolite channel architecture. The higher activity and selectivity are obtained using modified TUN and modified IMF with suitable density of Bronsted acidity in a well-defined channel structure sterically constrained for heavy by-products. It is shown that the activity and selectivity increase with increasing pore diameter of three-dimensional 10 ring channel structure, while the rule is not valid for *SFV.