Journal of Catalysis 251 (2007) 21–27 www.elsevier.com/locate/jcat Alkaline-mediated mesoporous mordenite zeolites for acid-catalyzed conversions ✩ Johan C. Groen a,∗ , Tsuneji Sano b , Jacob A. Moulijn a , Javier Pérez-Ramírez c,d a DelftChemTech, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands b Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan c Institute of Chemical Researchof Catalonia (ICIQ), Avinguda Països Catalans 16, 43007 Tarragona, Spain d Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluís Companys 23, 08010 Barcelona, Spain Received 7 June 2007; revised 11 July 2007; accepted 13 July 2007 Available online 24 August 2007 Abstract The preparation of mesoporous mordenite zeolite and its subsequent application in the liquid-phase alkylation of benzene with ethylene is discussed. Mesoporous mordenite was obtained by controlled silicon extraction on alkaline treatment of successfully synthesized high-silica mordenite zeolites with molar Si/Al ratios in the range of 20–30. Besides substantial mesoporosity development, the combined microporous and mesoporous zeolites show preserved Brønsted acidic properties, which are highly attractive when acid-catalyzed reactions are targeted. Catalytic testing of the mesoporous mordenite found superior performance in benzene alkylation due to the unique interplay between improved physical transport in the shortened micropores and the preserved high density of acid sites.  2007 Elsevier Inc. All rights reserved. Keywords: Mesoporous mordenite; Zeolites; Porosity; Desilication; Alkylation; Catalysis 1. Introduction Well-established large-volume hydrocarbon conversions cur- rently used in industry include processes such as catalytic cracking, isomerization, and alkylation [1,2]. In many of these reactions, the traditional liquid acids are progressively substi- tuted with zeolite-based processes [3]. Application of these solid-acid catalysts offers several key advantages. Zeolites are environmentally harmless, noncorrosive, and show ease of sep- aration from the reaction mixture compared with homogeneous catalysts. Moreover, the shape-selective properties of zeolites related to the presence of an ordered microporous network can restrict the formation of undesired products by control of reac- tant or product diffusion as well as the volume available for transition states. But the purely microporous nature of zeo- lites frequently poses transport limitations, particularly when ✩ The research in this paper is documented in European patent application EP07109134.2. * Corresponding author. Fax: +31 15 278 44 52. E-mail address: J.C.Groen@tudelft.nl (J.C. Groen). bulky molecules are involved. This is typically the case in ap- plications in the petroleum, petrochemical, and fine chemical industries. The restricted mass transfer properties frequently result in lower activities and decreased catalyst lifetime due to deactivation [4]. Mordenite, a member of the large-pore zeolite family, con- sists of 12-membered ring (MR) pore channels of 0.67 × 0.70 nm interconnected by 8-MR pores of 0.34 × 0.48 nm [5]. Because the 8-MR channels are too small for most molecules to enter, mordenite is generally considered a one-dimensional pore system, inducing single-file diffusion [6]. Despite this feature, mordenite is widely practiced in industry, particularly for alkylation [7] and (hydro)isomerization [8] reactions. To improve physical transport in the one-dimensional channels, mordenite zeolites are typically subjected to dealumination posttreatments [1,7,9,10]. Although dealumination indeed has proven to generate additional mesoporosity [11], this approach directly affects the acidic properties of the zeolite structure, due to the extraction of aluminum from the zeolite framework. The facilitated transport acquired by the introduction of mesoporos- ity is partially cancelled out by the reduced density of acid 0021-9517/$ – see front matter  2007 Elsevier Inc. All rights reserved. doi:10.1016/j.jcat.2007.07.020