Promoter role of octahedral Co (and Ni) in modified Co(Ni)Mo-Al2O3 catalysts for hydrodesulfurization reactions

Morales, Alfredo Martin; Agudelo, M.M. Ramírez de

doi:10.1016/s0166-9834(00)81449-9

Cited by 63 publications

(7 citation statements)

References 10 publications

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“…Phosphorus loading to NiMo catalysts promoted a slight decrease in the Mo/Al ratio, suggesting a high stacking degree of Mo . A linear increase between the P/Al ratio and the phosphorus content was observed, suggesting that phosphorus is well dispersed over the alumina surface. , …”

Section: Resultsmentioning

confidence: 89%

Effects of Phosphorus Content on Simultaneous Ultradeep HDS and HDN Reactions over NiMoP/Alumina Catalysts

Mello

Braggio

Magalhães

et al. 2017

Ind. Eng. Chem. Res.

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The effects of phosphorus content on competitive hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and hydrodenitrogenation (HDN) of quinoline (Q) over NiMo catalysts were evaluated. Reactions were carried out in a trickle-bed high-pressure flow microreactor. HDS of 4,6-DMDBT was strongly inhibited at Q concentrations of 90 ppmw N, mostly hydrogenation (HYD) route in HDS, suggesting that 4,6-DMDBT and Q compete for the same hydrogenation active sites, which was confirmed by the products’ distribution in HDN reactions. Morphology and nature of active sites promoted by phosphorus addition led to different activity performance on competitive HDS and HDN reactions, as evidenced by TOF values. At low concentrations of Q, promoted catalysts maintained activity for both HDS and HDN. High Q levels (above 90 ppmw N) decreased HDS and HDN activity due to stronger inhibition of catalysts. The addition of 1 wt % of phosphorus showed superior activity, attributed to a combination of better dispersed NiMoS active sites and Brønsted acidity.

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Section: Resultsmentioning

confidence: 89%

Effects of Phosphorus Content on Simultaneous Ultradeep HDS and HDN Reactions over NiMoP/Alumina Catalysts

Mello

Braggio

Magalhães

et al. 2017

Ind. Eng. Chem. Res.

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“…In addition, the increased proportion of octahedral Co 2+ (as also observed by UV-vis, Figure 6) in the corresponding oxidic solid could be beneficial as that species is considered a precursor of cobalt that could efficiently form the highly active "CoMoS" phase during catalyst activation by sulfiding (see Section 3.3. HDS Reaction Test) [58]. A linear relationship between Co (Oh)…”

Section: Hds Reaction Testmentioning

confidence: 99%

Dibenzothiophene Hydrodesulfurization over P-CoMo on Sol-Gel Alumina Modified by La Addition. Effect of Rare-Earth Content

et al. 2019

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Alumina-lanthana (La at 1, 3, or 5 wt%) supports were prepared by sol-gel from Al alkoxide sol where La(NO3)3 was added. Annealed (550 °C) xerogels were characterized by N2 physisorption, thermal analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy- energy dispersive spectroscopy (SEM-EDS), CO2-adsorption studied in IR region, Raman and ultraviolet-vis (UV-vis) spectroscopies. The texture of amorphous binary matrices of high La dispersion was adequate to applications in catalysts for middle distillates hydrodesulfurization (HDS). Generally, the amount and strength of surface basic sites increased with La content in solids. Mo (at 2.8 at. nm−2) and Co (at Co/(Co+Mo) = 0.3) were deposited over carriers by one-pot simultaneous impregnation in the presence of PO43− (P2O5/(NiO+MoO3) = 0.2 mass ratio). Calcined (400 °C) Co-Mo-P impregnated precursors had decreased basicity as to that of corresponding carriers, suggesting strong La-deposited species interaction. As La content in carriers increased Mo=O Raman stretching vibrations shifted to lower wave-numbers (949 to 935 cm−1) suggesting octahedral molybdates coordination change to tetrahedral. Although La at the lowest concentration (1 wt%) enhanced dibenzothiophene, HDS (~38% higher as to the Al2O3-supported formulation) desulfurization was significantly diminished at augmented content. Presence of hardly sulfidable tetrahedral Mo originated during impregnation at basic conditions in pores of La-modified carriers seemed to dictate observed behavior. Rare earth content in formulations enhanced selectivity to biphenyl.

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“…In the literature there are a large number of studies on the effect of P on NiMo/Al 2 O 3 catalysts using sulfur containing model molecules (thiophene, benzothiophene, 4.6 dimethyl dibenzothiophene, etc.) [1][2][3][4][5][6][7][8][9][10][11][12][13]. These studies have shown that phosphorus has different effects, such as: (a) Improves the stability of impregnating solutions helping the dispersion of the metals on the support [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…Some patents claim that P incorporation increases hydrodesulfurization (HDS), hydrodenitrogenation (HDN), hydrodemetallization (HDM) and improves hydrocracking [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Hydrodesulfurization and hydrocracking of Maya crude with P-modified NiMo/Al2O3 catalysts

Rayo

Ramı́rez

Torres–Mancera

et al. 2012

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Promoter role of octahedral Co (and Ni) in modified Co(Ni)Mo-Al2O3 catalysts for hydrodesulfurization reactions

Cited by 63 publications

References 10 publications

Effects of Phosphorus Content on Simultaneous Ultradeep HDS and HDN Reactions over NiMoP/Alumina Catalysts

Effects of Phosphorus Content on Simultaneous Ultradeep HDS and HDN Reactions over NiMoP/Alumina Catalysts

Dibenzothiophene Hydrodesulfurization over P-CoMo on Sol-Gel Alumina Modified by La Addition. Effect of Rare-Earth Content

Hydrodesulfurization and hydrocracking of Maya crude with P-modified NiMo/Al2O3 catalysts

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