Modification of SBA-15 mesoporous silica as an active heterogeneous catalyst for the hydroisomerization and hydrocracking of n-heptane

Nisreen S Ali; Ziad T Alismaeel; Hasan Sh Majdi; Hussein G Salih; Mahir A Abdulrahman; Noori M Cata Saady; Talib M Albayati

doi:10.1016/j.heliyon.2022.e09737

Modification of SBA-15 mesoporous silica as an active heterogeneous catalyst for the hydroisomerization and hydrocracking of n-heptane

Heliyon. 2022 Jun 16;8(6):e09737. doi: 10.1016/j.heliyon.2022.e09737. eCollection 2022 Jun.

Authors

Nisreen S Ali¹, Ziad T Alismaeel², Hasan Sh Majdi³, Hussein G Salih⁴, Mahir A Abdulrahman⁴, Noori M Cata Saady⁵, Talib M Albayati⁴

Affiliations

¹ Mustansiriyah University, College of Engineering, Materials Engineering Department Baghdad-Iraq, Iraq.
² Department of Biochemical Engineering, Al-Khwarizmi College of Engineering, University of Baghdad, Al-Jadryah, 47008, Baghdad, Iraq.
³ Department of Chemical Engineering and Petroleum Industries, Al-Mustaqbal University College, Babylon 51001, Iraq.
⁴ Department of Chemical Engineering, University of Technology- Iraq, 52 Alsinaa St., P.O. Box 35010, Baghdad, Iraq.
⁵ Department of Civil Engineering, Memorial University of Newfoundland, St. John's, NL A1B 3X5, Canada.

Abstract

In this study, a mesoporous SBA-15 silica catalyst was prepared and modified with encased 1% platinum (Pt) metal nanoparticles for the hydrocracking and hydroisomerization of n-heptane in a heterogeneous reaction. The textural and structural characteristics of the nanostructured silica, including both encased and non-encased nanoparticles, were measured using small-angle X-ray diffraction (XRD), nitrogen adsorption-desorption porosimetry, Brunauer-Emmett-Teller (BET) surface area analysis, Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Catalytic testing was carried out in a plug-flow reactor under highly controlled operating conditions involving the reactant flow rate, pressure, and temperature. Gas chromatography was used to analyze the species as they left the reactor. The results demonstrated that 1% Pt/SBA-15 has a high n-heptane conversion activity (approximately 85%). Based on the results of this experimental work, there is no selectivity in the SBA-15 catalysts for isomerization products because they are inactive at the relatively low temperature that is essential for hydroisomerization. On the other hand, the SBA-15 catalysts have a considerable selectivity for products that have cracks, owing to their ability to withstand extremely high temperatures (300-400 °C) as well as the availability of Lewis acid sites within the catalyst structure.

Keywords: Catalytic testing; Characterization of SBA-15; Hydroisomerization; Long-chain n-alkanes; Nanoporous materials; Octane number; Platinum catalyst; Platinum precursors; Synthesis of SBA-15; Zeolite.