1-hexene isomerization over bimetallic M-Mo-ZSM-5 (M: Fe, Co, Ni) zeolite catalysts: Effects of transition metals addition on the catalytic performance

• DOI: 10.1016/j.joei.2019.06.009
• Publication Date: 2019-06-25T17:06:35Z
• Authors: Andrii Kostyniuk; David Key; Masikana Mdleleni
• Keywords: 01 natural sciences; 7. Clean energy; 0104 chemical sciences

Abstract The aim of this study is to investigate the promotional effect of Fe–Mo, Co–Mo, and Ni–Mo bimetallic additives on the activity and stability of H-ZSM-5 zeolite for isomerization of 1-hexene. The catalysts were synthesized by wet-impregnation method and characterized by XRD, FTIR, BET, ICP-AES, HRSEM-EDS, HRTEM, H2-TPR, NH3-TPD, and pyridine-DRIFT analysis. The isomerization of 1-hexene was carried out in a micro-scale system under the conditions: T = 250 °C, P = 4.0 MPa, FR = 0.1 ml/min, WHSV = 1 h−1. The conversion of 1-hexene over the 4 g bed of catalyst was in the range of 95–97% after 74 h time-on-stream with cis-3-hexene and cis-2-hexene as the principal products. It was shown that the appearance of the new strong Lewis acid sites, decreases the ratio of Bronsted/Lewis acid sites. Increase of the weak Lewis acid sites in the 2.5 wt%Ni2.5 wt%Mo-ZSM-5 catalyst facilitated the isomerization of 1-hexene and showed higher C6 olefin selectivity (48.4 mol%), research octane number (99.7), and bromine number (148.3) than other studied catalysts.