Fundamental comparison studies on hydrodesulfurization of dibenzothiophenes over CoMo-based carbon and alumina catalysts

Farag, Hamdy; Mochida, Isao; Sakanishi, Kinya

doi:10.1016/s0926-860x(99)00363-4

Cited by 101 publications

(63 citation statements)

References 9 publications

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“…2). These results which are in accordance with previous studies [4,[19][20][21][22][23][24][25][26][27][28][29][30] fit with the generally accepted reaction scheme of the transformation of 46DMDBT (Scheme 1).…”

Section: Transformation Of 46dmdbtsupporting

confidence: 92%

Deep HDS of Diesel Fuel: Inhibiting Effect of Nitrogen Compounds on the Transformation of the Refractory 4,6-Dimethyldibenzothiophene Over a NiMoP/Al2O3 Catalyst

Rabarihoela-Rakotovao

Diehl

Brunet

2008

Catal Lett

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The effect of nitrogen-containing compounds (acridine and 1,4-dimethylcarbazole: 14DMCARB) on the hydrodesulfurization of 4,6-dimethyldibenzothiophene (46DMDBT) was studied on a sulfided NiMoP/Al 2 O 3 catalyst in a fixed bed microreactor (340°C, 40 bar). Both nitrogen-containing compounds inhibited the hydrodesulfurization of 46DMDBT. However, the effect of acridine (a basic compound) and mainly its hydrogenated product (presumably 1,2,3,4,5,6,7,8-octahydroacridine: OHA1) was much more significant than the effect of 14DMCARB (a non-basic compound). In the presence of acridine, the socalled direct desulfurization pathway (DDS) of the HDS of 46DMDBT was less affected than the hydrogenation pathway (HYD) and was even slightly promoted when the partial pressure of acridine increased (after a strong initial inhibition). This was ascribed to a cocatalytic contribution of the nitrogen-containing compound to the C-S bond cleavage. 14DMCARB had the same inhibiting effect on both pathways (DDS and HYD). We also demonstrated that acridine inhibited the transformation of 14DMCARB and can explain why carbazoles are generally the main nitrogen impurities present in gasole after hydrotreatment.

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Section: Transformation Of 46dmdbtsupporting

confidence: 92%

Deep HDS of Diesel Fuel: Inhibiting Effect of Nitrogen Compounds on the Transformation of the Refractory 4,6-Dimethyldibenzothiophene Over a NiMoP/Al2O3 Catalyst

Rabarihoela-Rakotovao

Diehl

Brunet

2008

Catal Lett

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“…The slight deviation from linearity observed at the end of the reaction is attributed to the deactivation of the catalyst by H 2 S accumulated in the reactor. Hydrogen sulfide is known to have an inhibiting effect in the HDS reaction of DBT where the order depends on the partial pressure [29][30][31]. The formation of THDBT is favored at the beginning of the reaction but it declines at the end, showing a behavior like an intermediate compound [3], meanwhile CHB formation suits more a linear fit confirming the known trend of catalysts derived from A-TM for HYD (figure not shown).…”

Section: Catalysts From Mixtures Of A-tm and Ndta-tmsupporting

confidence: 63%

High activity Ni/MoS2 catalysts obtained from alkylthiometalate mixtures for the hydrodesulfurization of dibenzothiophene

et al. 2007

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An efficient method for improving the catalytic properties of unsupported Ni/MoS 2 catalysts is mixing thiometalate precursors applying the appropriate precursors and thermal conditions. High active catalysts for the hydrodesulfurization (HDS) of dibenzothiophene (DBT) are prepared by the controlled decomposition of physical mixtures of Ni(diethylentriamine) 2 MoS 4 (NDTA-TM) and [(Propyl) 4 N)] 2 MoS 4 (TPA-TM). The catalysts with a higher content of NDTA-TM are very active with a high selectivity for the direct desulfurization pathway (DDS) due to the synergistic effect of nickel. In addition the presence of a large amount of carbon may produce single-slabs of nickel promoted carbon containing molybdenum sulfides. The activity enhancement is attributed to an increased number of NiMoS active sites originated by the chemical interaction between the precursors NDTA-TM and TPA-TM during the mixing procedure. Furthermore, the carbon content in the final products is related to the enhancement of the activity and the preference of the DDS pathway. The controlled decomposition of mixtures of NDTA-TM + TPA-TM yields catalysts which are about twofold more active than an industrial NiMo/Al 2 O 3 catalyst. This improvement may be attributed to an intense interaction of the precursors during the synthesis causing a re-dispersion of nickel atoms from NDTA-TM over the surface of carbon containing molybdenum sulfide provided by the precursor TPA-TM, increasing the amount of active sites. The catalysts from mixtures of (NH 4 ) 2 MoS 4 (A-TM) and NDTA-TM behave similarly to the pure precursors.

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“…So, whatever the active phase may be (Mo, W), the presence of Ni as a promoter leads to a considerable increase in the HYD reaction. Further, and in agreement with the thermodynamic restrictions, given that the hydrogenation reaction is exothermic, a decrease in hydrogenation activity is observed with an increase in the reaction temperature for all catalysts (Farag et al, 2000). It is generally accepted that hydrogenation and desulfurization reactions take place on separate active sites (Li et al, 2002).…”

Section: Hds Of Dibenzothiophene (Dbt)supporting

confidence: 76%

Transition Metal Sulfide Catalysts for Petroleum Upgrading – Hydrodesulfurization Reactions

Infantes‐Molina¹,

Romero-Pérez²,

Eliche-Quesada³

et al. 2012

Hydrogenation

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Fundamental comparison studies on hydrodesulfurization of dibenzothiophenes over CoMo-based carbon and alumina catalysts

Cited by 101 publications

References 9 publications

Deep HDS of Diesel Fuel: Inhibiting Effect of Nitrogen Compounds on the Transformation of the Refractory 4,6-Dimethyldibenzothiophene Over a NiMoP/Al2O3 Catalyst

Deep HDS of Diesel Fuel: Inhibiting Effect of Nitrogen Compounds on the Transformation of the Refractory 4,6-Dimethyldibenzothiophene Over a NiMoP/Al2O3 Catalyst

High activity Ni/MoS2 catalysts obtained from alkylthiometalate mixtures for the hydrodesulfurization of dibenzothiophene

Transition Metal Sulfide Catalysts for Petroleum Upgrading – Hydrodesulfurization Reactions

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