Computation-guided descriptor for efficient zeolite catalysts screening in C4 alkylation process

Abstract

Zeolites as the environmentally friendly catalysts for C4 alkylation suffer from rapid deactivation in commercial application. In this work, the intrinsic descriptor (i.e., the i-butane/1-butene ratio in micropores) for catalyst deactivation was proposed by configurational-bias Grand Canonical Monte Carlo (CB-GCMC) calculations. It is found that pore structural topology affects the competitive adsorption between i-butane and 1-butene due to distinct structure of the two adsorbates. The i-butane/1-butene ratios in the pore decreased in the order: BEA > FAU > MOR > MFI. In other words, 3D interconnecting BEA channels formed by 12-membered rings with ordered pore configuration were suggested to have higher i-butane/1-butene ratio, because i-butane has better spatial matching with 12-membered rings on basis of the analysis of the size. Notably, experimental deactivation rate is inversely proportional to calculated i-butane/1-butene ratio inside microproes with good linear correlation. This descriptor for deactivation offers a promising avenue for rational screening of more efficient zeolite catalysts for C4 alkylation.