Genesis of new gas oil HDS catalysts: Study of their liquid phase sulfidation

Hydrodesulfurization‐Supported Catalysts: Effect of the Preparation Method

“…This causes weakening of the interaction between the support and the active component and promoter, facilitating the formation of the active sulfide phase Co-Mo-S [10]. This finding is consistent with the results of the research done by Frizi et al [12,13], i.e., in the presence of a complexing agent the sulfidation of cobalt starts at a higher temperature simultaneously with the sulfidation of molybdenum or after the formation of molybdenum sulfide. Moreover, several researchers reported a beneficial effect of complexing agents such as citric acid (CA), thioglycolic acid (TGA), trans-1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acid (CYDTA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA) on the catalytic activity for HDS [7][8][9][10][11][12][13][14][15].…”

Improvement of HDS catalysts through the modification of the oxidic precursor with 1,5-pentanediol: Gas phase sulfidation and thiophene conversion

“…The improvement of the performances was assigned to the complexation of Mo and Co atoms with TGA, which induces modifications of the amount and morphology of the active phase [7,8]. In the present work we show that the impregnation of a classical CoMo based oxidic precursor with a weak chelating agent such as 1,5-pentanediol in aqueous solution also induces a large improvement in the thiophene HDS conversion.…”

“…The second uptake of H 2 S, which is observed during the loss of C 5 diol, could also be at the origin of this simultaneous sulfidation. It presents two main advantages leading to the best catalytic performances as we discussed in previous papers [7,8]. Firstly, it permits to delay the sulfidation of cobalt and thus to inhibit the formation of Co 9 S 8 allowing to have more Co atoms in the decoration position.…”

“…Among the chelating molecules, EDTA (ethylenediaminetetraacetic acid) [11], En (ethylenediamine) [12,13], CyDTA (cyclohexanediaminetetraacetic acid), NTA (nitrilotriacetic acid), TA (tartaric acid) [5] or saccharose [14] were considered. In our laboratory TGA (thioglycolic acid) [7,8], also described as a sulfiding agent [15], was used to impregnate a commercial CoMo/Al 2 O 3 oxidic precursor. Recently due to its low cost and availability, citric acid has attracted much attention for the preparation of fresh catalysts [4,6,11].…”

New insight in the preparation of alumina supported hydrotreatment oxidic precursors: A molecular approach

“…But in that case, the effect is quite different as this improvement has to be assigned to the modification of the genesis of the active CoMoS phase [43,48,49].…”