Abstract

OVIEDO, Edwin; LINARES, Carlos F.  and  BRUNEI, Sylvette. CoMo sulfide catalysts supported on calcined (MeFeAl) tertiary hydrotalcites (Me²⁺: Co²⁺, Ni²⁺, Mg²⁺ and Zn²⁺) for being used in the dibenzothiophene hydrodesulfurization reaction. Rev. ion [online]. 2023, vol.36, n.2, pp.46-62.  Epub Oct 22, 2024. ISSN 0120-100X.  https://doi.org/10.18273/revion.v36n2-2023004.

Five tertiary hydrotalcites containing Fe3+ and Al3+ (M3+) as trivalent cations, and Mg2+, Co2+, Ni2+ or Zn2+ (M2+) as divalent cations were synthesized. A [M+3/(M3++M2+)] ratio of 0.22 and a [Fe3+/Al3+] ratio of 0.66 were kept for all synthesis with exception of a MgFeAl hydrotalcite whose [Fe3+/Al3+] ratio was duplicated to 1.32. The mixed oxides from these hydrotalcytes were used as supports of the active phase (Mo) promoting with Co. As-synthesized hydrotalcites, supports and their catalytic precursors were characterized by techniques such as chemical analysis by X-ray fluorescence, surface measurements, X-ray diffraction (XRD), CO2 temperature programmed desorption (CO2-TPD), elemental analysis (S and C) and high-resolution transmission electron microscopy (HRTEM). All catalytic precursors were tested in the reactions of dibenzothiophene hydrodesulfurization, showing the following order of activity: CoMo/ γ -Al2O3 > CoMo/MgFeAl(0.66)> CoMo/MgFeAl(1.32)> CoMo/CoFeAl> CoMo/NiFeAl> CoMo/ZnFeAl, The catalytic activity and selectivity towards the formation of hydrogenation products over direct desulfurization (HID/DSD) increased as the basicity of the catalyst increased. These results were associated to (f M ) Mo fraction and the nature of supports. It is important to mention that the catalysts: CoMo/MgFeAl(0.66) and CoMo/MgFeAl(1.32) showed the highest selectivity towards the hydrogenation route compared to the reference catalyst (CoMo/y-Al2O3). Additionally, the activity of the CoMo/MgFeAL(0.66) catalyst towards the HID pathway was the highest, even exceeding the activity of CoMo/y-Al2O3.

Keywords : Hydrotalcite; Hydrodesulfurization; Dibenzothiophene; Hydrotreating; Sulfide catalyst.

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