Design of an MWW Zeolite Catalyst for Linear Alkylbenzene Synthesis with Improved Catalytic Stability

Abstract

The effect of micro-meso hierarchical porosity on the catalytic performance of MWW zeolites during linear alkylbenzene (LAB) synthesis was studied. The catalytic active sites of the MWW zeolite during LAB synthesis are identified as the acid sites located on the external surface cage (EC-12) and the internal supercage (C10-12). The catalytic stability of MCM-22 obtained from the optimum preparation protocol could be improved by increasing the number of EC-12 cages as well as increasing the S-meso and pore volume. The catalytic activity of ITQ-2 by delamination for LAB synthesis is mainly attributed to the acid site located at surface cage EC-12. The ITQ-2 sample subjected to the optimum delamination procedure exhibited very strong stability even in benzene lean LAB feed or 0.1% octadiene-containing LAB feed. Alternatively, the pillared MCM-36 zeolite increases the C10-12 supercage and mesoporous surface area, enabling MCM-36 to catalyse a lower LAB product selectivity with formation of more di-alkylate by-products with a similar LAB isomer selectivity.