Bimetallic Dispersed Catalysts Research Articles

Experimental Investigation of Metal-Based Calixarenes as Dispersed Catalyst Precursors for Heavy Oil Hydrocracking

Slurry-phase hydrocracking utilizing metal-containing oil-soluble compounds as precursors of dispersed catalysts is an effective approach for heavy oil upgrading. We propose applying metal-based p-tert-butylcalix[6]arene (TBC[6]s) organic species as dispersed catalyst precursors to enhance catalytic hydrogenation reactions involved in the upgrading of vacuum gas oil (VGO). Co- and Ni-based TBC[6]s were synthesized and characterized by SEM-EDX, ICP, XRD, and FT-IR. The thermogravimetric and calorimetric behaviors of the synthesized complexes, which are key properties of dispersed hydrocracking catalysts, were also explored. The experimental evaluation of the synthesized catalyst precursors show that the synthesized metal-based TBC[6] catalyst precursors improved the catalytic hydrogenation reactions. A co-catalytic system was also investigated by adding a commercial, first-stage hydrocracking supported catalyst in addition to the dispersed catalysts. The naphtha yields increased from 10.7 wt.% for the supported catalyst to 11.7 wt.% and 12 wt.% after adding it along with Ni-TBC[6] and Co-TBC[6], respectively. Mixing the metal-based precursors resulted in elevated yields of liquid products due to the in situ generation of highly active Co–Ni bimetallic dispersed catalysts.

Bimetallic Dispersed Catalysts from Molecular Precursors Containing Mo-Co-S for Coal Liquefaction

This work was undertaken with the goal of exploring novel bimetallic dispersed sulfide catalysts for coal liquefaction. Several heterometallic complexes consisting of two transition metals, Mo and Co, and sulfur in a single molecule were synthesized and tested as precursors of dispersed catalysts for liquefaction of a Montana subbituminous coal (0.5 wt% Mo on dmmf coal). It was found that the structure of the precursors, in particular the ligands to the metal species, affect the activity of the resulting catalyst significantly. Among the M-M'type precursors tested, Mo-Co thiocubane, Mo 2 Co 2 S 4 (Cp) 2 (CO) 2 [Cp = cyclopentadiene], designated as MoCo-TC2, produced in situ the best catalyst

Bimetallic dispersed sulfide catalysts from organometallic clusters for coal liquefaction

Several heterometallic complexes consisting of Mo, Co and sulfur in a single molecule were synthesized and tested as precursors of dispersed catalysts for liquefaction of a subbituminous coal. The structure of the precursors, in particular the type of ligands to the metal species, significantly affects the activity of the bimetallic MoCo sulfide catalysts generated in situ. Among the M-M′ type precursors tested, Mo-Co thiocubane, Mo2Co2S4(Cp)2(CO)2 (Cp = cyclopentadiene), produced the best catalyst.