• Hafedh Driss

      Articles written in Journal of Chemical Sciences

    • Ammoxidation of 2-methyl pyrazine to 2-cyano pyrazine on MoO3/FePO4 catalysts

      Nagaraju Pasupulety Hafedh Driss Yahia Abobakor Alhamed Abdulrahim Ahmed Alzahrani Muhammad A Daous Lachezar Petrov N Lingaiah P S Sai Prasad

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      The objective of this work is to understand the influence of small amount of Mo=O (1, 3 and 5wt.% MoO3) impregnated on FePO4 and its resultant effect on the acidity was studied for the ammoxidation of 2-methyl pyrazine (2-MP) to 2-cyano pyrazine (2-CP) in the temperature range of 380–420°C. The Mo/FeP catalyst characteristics were evaluated by XRD, HAADF-EDS, TPR and NH3-TPD techniques. Primarily, quartz-type XRD phase was observed for the iron phosphate (FeP). The Mo/FeP exhibits MoO3 and quartztype iron phosphate phase. The interface between Mo particles (20 nm) and FeP was clearly established by HR-TEM in 3Mo/FeP. Furthermore, the average atomic composition revealed by HAADF/EDS for 3Mo/FeP as Fe 30.0%, P 40.0% and Mo 1.6% with Fe/Mo surface XPS ratio 6. The greater 2-CP yield of 68.0% on 3Mo/FeP was attributed to enhanced, moderate acid sites coming from MoO3 and cooperation between Mo and FeP at the interface in terms of oxygen and electron transfer to the reactant (2-MP).

    • Ammonia treated Mo/AC catalysts for CO hydrogenation with improved oxygenates selectivity

      SHARIF F ZAMAN NAGARAJU PASUPULETY ABDULRAHIM A AL-ZAHRANI MUHAMMAD A DAOUS S S AL-SHAHRANI HITOSHI INOKAWA LACHEZAR A PETROV HAFEDH DRISS

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      A series of ammonia treated Mo/Activated Carbon (AC) catalysts were synthesized by wet impregnation method by nominal incorporation of 5, 10 and 15 wt% of molybdenum. The calcined catalysts (500◦C, 4 h, N₂ flow) were subjected to a stepwise ammonia treatment at temperatures from 25 up to 700◦C. This work reports for the first time, ammonia treated different loadings of Mo on DARCO mesoporous activated carbon for CO hydrogenation reaction. These catalysts were tested in the reaction temperature range of 250–325◦C, 7 MPa and 12000/h (GHSV for reactor volume 0.5 mL). At 250◦C, all the catalysts showed total oxygenate selectivity of ∼50%, mainly methanol. At 325◦C, total oxygenate selectivity of 16.5% with 18% CO conversion was obtained on 10Mo-N/AC. The result of alcohol distribution revealed high selectivity to propanol (39%) over methanol (34%) at 325◦C on 10Mo-N/AC which highlights its unique catalytic behavior in CO hydrogenation. Further, 10MoO3/AC catalyst, with no treatment of ammonia, showed only 4% of CO conversion with 96% hydrocarbon selectivity. Only 0.5% of CO conversion was observed on AC itself at 325◦C. The improved oxygenates selectivity on 10Mo-N/AC was associated with Moδ+ sites on AC generated viaammonolysis.

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