مجال التميز | بحثي ودراسي |
البحوث المنشورة | |
البحث (1): | |
عنوان البحث: | Turnover Rate of Metal-Catalyzed Hydroconversion of 2,5-Dimethylfuran: Gas-Phase Versus Liquid-Phase |
رابط إلى البحث: | https://doi.org/10.3390/catal10101171 |
تاريخ النشر: | 12/10/2020 |
موجز عن البحث: | Hydroconversion (hydrogenation and hydrogenolysis) of biomass-derived furanic compounds giving furan ring hydrogenation and ring-cleavage products attracts interest for sustainable production of chemicals and fuels. Here, the hydroconversion of 2,5-dimethylfuran (DMF), chosen as a model furanic compound, was investigated at a gas-solid interface over carbon-supported Pt, Pd, Rh and Ru metal catalysts in a fixed-bed reactor at 70–90 C and ambient pressure. Pt/C was mainly active in ring cleavage of DMF to produce 2-hexanone as the primary product, followed by its hydrogenation to 2-hexanol and hexane. In contrast, Pd/C, Rh/C and Ru/C selectively hydrogenated the furan ring to 2,5-dimethyltetrahydrofuran (DMTHF). The turnover frequency (TOF) of metal sites in the gas-phase DMF hydroconversion was determined from zero-order kinetics in the absence of diffusion limitations. The TOF values decreased in the sequence Pt > Rh > Pd >> Ru, similar to the liquid-phase reaction. The TOF values for the gas-phase reaction were found to be one order of magnitude greater than those for the liquid-phase reaction. This indicates that the gas-phase process is potentially more efficient than the liquid-phase process. TOF values for hydroconversion of ring-saturated furan derivatives, tetrahydrofuran and DMTHF, on Pt/C, were much lower than those for DMF. |
البحث (2): | |
عنوان البحث: | Facile gas-phase hydrodeoxygenation of
2,5-dimethylfuran over bifunctional metal-acid catalyst Pt–Cs2.5H0.5PW12O4 |
رابط إلى البحث: | https://pubs.rsc.org/en/content/articlelanding/2021/CC/D0CC06934E |
تاريخ النشر: | 24/11/2020 |
موجز عن البحث: | 2,5-Dimethylfuran is deoxygenated to n-hexane with 100% yield on a bifunctional Pt/C– Cs2.5H0.5PW12O40 catalyst under very mild conditions (90 8C, 1 bar H2) in a one-step gas-phase process. A proposed mechanism includes a sequence of hydrogenolysis, hydrogenation and dehydration steps occurring on Pt and proton sites of the bifunctional catalyst. |
البحث (3): | |
عنوان البحث: | Hydrodeoxygenation of 2,5-dimethyltetrahydrofuran over bifunctional metal-acid catalyst Pt–Cs2.5H0.5PW12O40 in the gas phase: Kinetics and mechanism |
رابط إلى البحث: | https://doi.org/10.1016/j.mcat.2021.111711 |
تاريخ النشر: | 10/06/2021 |
موجز عن البحث: | Hydrodeoxygenation (HDO) of 2,5-dimethyltetrahydrofuran (DMTHF) was studied at a gas-solid interface in a fixed-bed microreactor in the presence of bifunctional metal-acid catalysts comprising Pt/C and acidic heteropoly salt Cs2.5H0.5PW12O40 (CsPW). The Pt–CsPW catalyst deoxygenated DMTHF to n-hexane with >99% selectivity under mild conditions (90–100 ◦C, ambient pressure) and was much more efficient than monofunctional Pt/C. On the basis of kinetic studies, a mechanism for the HDO of DMTHF over Pt–CsPW was proposed, which includes a sequence of hydrogenolysis, dehydration and hydrogenation steps catalysed by Pt and proton sites of the bifunctional catalyst. The turnover rate of HDO increased with increasing Pt particle size suggesting that the hydrogenolysis of C–O bond in furanic compounds on Pt is a structure-sensitive reaction |
المؤتمرات العلمية | |
المؤتمر (1): | |
عنوان المؤتمر: | 7th EuCheMS Chemistry Congress |
تاريخ الإنعقاد: | 26/08/2018 |
مكان الإنعقاد: | Liverpool, UK |
طبيعة المشاركة: | poster presentation |
عنوان المشاركة: | Hydrogenation and hydrogenolysis of
2,5-dimethylfuran over noble metal catalysts in the gas-phase |
ملخص المشاركة: | As fossil fuel reserves become depleted, considerable attention is being given to the use of biomass as a sustainable feedstock. Fine chemicals and fuels can be synthesised using furanic compounds such as furfural, 2-methylfuran, 2,5-dimethylfuran, etc., which are a family of cellulosic or hemicellulosic platform compounds. These compounds require upgrading to produce chemicals and fuels. Hydrogenation and hydrogenolysis are effective upgrading processes in the furan chemistry. Hydrotreatment of furanic compounds over Pt, Pd, Ru, Ru, Cu and Co catalysts under relatively mild conditions (90−200 °C, 0.1 MPa) gives ring hydrogenation and ring cleavage products (eq. (1)). In hydrotreatment of 2,5-dimethylfuran (2,5-DMF) over Pt in the liquid phase, ring cleavage is favoured over ring hydrogenation. The aim of this work is to study the hydrogenation and hydrogenolysis of 2,5-DMF over Pt, Pd, Rh and Ru carbon-supported metal catalysts in the gas phase to produce C6 chemicals. The catalysts were characterized by BET, XRD, ICP and CO chemisorption. The reactions were studied using a fixed-bed continuous flow reactor with on-line GC analysis in the temperature range of 70–150 oC and1.6 kPa 2,5- DMF partial pressure using H2 as a carrier gas at ambient pressure. |
المؤتمر (2): | |
عنوان المؤتمر: | 5th Edition of Global Conference on Catalysis, Chemical Engineering and Technology |
تاريخ الإنعقاد: | 16/09/2019 |
مكان الإنعقاد: | London, UK |
طبيعة المشاركة: | poster presentation |
عنوان المشاركة: | Gas-phase Hydrotreatment Reactions of 2,5-Dimethylfuran using Bifunctional Metal-Acid Catalysts |
ملخص المشاركة: | In the last few decades, there has been a growing interest in green chemistry. As fossil fuel reserves become depleted, considerable attention is being given to the use of biomass as a sustainable feedstock. Wide range of chemicals and fuels can be synthesised using furanic compounds which are a family of cellulosic and hemicellulosic platform compounds. These compounds, however, require upgrading (deoxygenation) to produce chemicals and fuels. Bifunctional catalysis is widely used in upgrade strategies to achieve high activity and selectivity. Recently, several groups have focused on the direct ring opening of the aromatic furans. The use of noble metal-based bifunctional catalytic systems can enhance ring opening. The aim of this work is to study the hydrogenation and hydrogenolysis of furan derivatives over bifunctional metal-HPA catalysts containing Pt and Pd together with acidic Keggin heteropoly salt Cs2.5H0.5PW12O40 (CsPW). The reactions were studied using a fixed-bed continuous flow reactor with on-line gas chromatographic (GC) analysis in the temperature range of 60–100 °C and ambient pressure. The catalysts were characterized by BET, ICP, XRD, TEM and H2 chemisorption. It is demonstrated that the bifunctional hydrotreatment pathway is more efficient than the monofunctional metal-catalysed pathway. The Pt/C + CsPW physical mixture, as compared to the impregnated catalyst 1% Pt/CsPW, was found to be a very efficient catalyst for the selective one-step hydrodeoxygenation of 2,5-DMF under mild conditions via the metal-acid bifunctional catalysis, providing almost 100% yield of n-hexane at 90 °C. The reaction did not proceed at all in the absence of Pt or in the presence of CsPW alone. The higher activity of the mixed Pt/C + CsPW catalyst, having Pt and H+ sites far apart, compared to the impregnated Pt/CsPW catalyst with Pt and H+ in close proximity may be explained by catalyst coking, which would affect stronger the Pt/CsPW catalyst. |
المؤتمر (3): | |
عنوان المؤتمر: | Analytical Research Forum 2019 (ARF19) |
تاريخ الإنعقاد: | 25/06/2019 |
مكان الإنعقاد: | London, UK |
طبيعة المشاركة: | poster presentation |
عنوان المشاركة: | Hydrogenation and hydrogenolysis of furan derivatives over noble metal catalysts at the gas-solid interface |
ملخص المشاركة: | Hydrogenation and hydrogenolysis are effective upgrading processes in the furan chemistry. Hydrotreatment of furanic compounds over Pt, Pd, Ru, Ru, Cu and Co catalysts under relatively mild conditions (90−200 °C, 0.1 MPa) gives ring hydrogenation and ring cleavage products. The aim of this work is to study the hydrogenation and hydrogenolysis of 2,5-DMF and 2-MF over Pt, Pd, Rh and Ru carbon-supported metal catalysts in the gas phase to produce value-added chemicals and biofuels. In addition, hydrogenolysis of 2-MF is studied for comparison with DMF. The catalysts were characterized by BET, XRD, ICP and CO chemisorption. The reactions were studied using a fixed-bed continuous flow reactor with on-line GC analysis in the temperature range of 70–150 oC and1.6 kPa 2,5- DMF partial pressure using H2 as a carrier gas at ambient pressure.
It is demonstrated that the ring cleavage of DMF in the gas phase, like in the liquid phase, occurs by direct hydrogenolysis of furan ring, resulting in parallel formation of 2-hexanone and DMTHF. In the reaction with Pt/C, the selectivity to ring cleavage products increased with increasing reaction temperature, giving up to 74% selectivity to 2-hexanol at 100% conversion of 2,5-DMF at 90°C. No significant deactivation was observed during 20 h run, indicating that the catalyst remained relatively stable. Overall, findings from the current research indicate that platinum catalysts are the most promising in terms of the production of linear products from 2,5-DMF. The reactivity of furanic compounds towards ring hydrogenolysis across the C-O bond over Pt sharply decreases in the order DMF >> 2-MF, in line with decreasing the electron density on the ring. |
المؤتمر (4): | |
عنوان المؤتمر: | 5th UK Catalysis Conference 2019
(UKCC 2019) |
تاريخ الإنعقاد: | 09/01/2019 |
مكان الإنعقاد: | Holywell Park, Loughborough, UK |
طبيعة المشاركة: | poster presentation |
عنوان المشاركة: | Conversion of 2,5-dimethylfuran into 2-hexanol under mild conditions using carbon-supported noble metal catalysts in the gas phase |
ملخص المشاركة: | The conversion of biomass-derived furanic compounds to chemicals has attracted significant interest in the green chemistry research. Hydrotreatment reactions are effective upgrading processes in the furan chemistry. Previous studies have shown that the hydrogenation of 2,5-dimethylfuran (DMF) over Pt catalyst in the liquid phase favours ring cleavage over ring hydrogenation. Here, we looked at the selective hydrogenation of DMF using noble metals catalysts (Pt, Pd, Ru and Ru) supported on carbon in the gas phase. The activity of catalysts was studied varying the key reaction parameters such as catalyst loading, contact time, temperature, H2 and DMF pressure. |
المؤتمر (5): | |
عنوان المؤتمر: | 7th UK Catalysis Conference 2021 (UKCC 2021) |
تاريخ الإنعقاد: | 06/01/2021 |
مكان الإنعقاد: | Holywell Park, Loughborough, UK |
طبيعة المشاركة: | poster presentation |
عنوان المشاركة: | Hydrodeoxygenation of 2,5-dimethyltetrahydrofuran over bifunctional metal-acid catalyst Pt–Cs2.5H0.5PW12O40 in the gas phase: Kinetics and mechanism |
ملخص المشاركة: | Catalytic hydrodeoxygenation is an effective strategy for achieving controlled transformation of biomass-derived furanic compounds to produce value-added products and fuels. Hydrodeoxygenation (HDO) of 2,5-dimethyltetrahydrofuran (DMTHF) was studied at a gas-solid interface in a fixed-bed microreactor in the presence of bifunctional metal-acid catalysts comprising Pt/C and acidic heteropoly salt Cs2.5H0.5PW12O40 (CsPW). The effect of different Pt particle sizes and Brønsted acid co-catalyst on the HDO of 2,5-DMTHF over bifunctional Pt-acid catalyst were investigated. Kinetics was studied under differential conditions (conversion ≤ 20%).
We demonstrate that the Pt–CsPW catalyst deoxygenated DMTHF to n-hexane with >99% selectivity under mild conditions (90–100 ºC, ambient pressure) and was much more efficient than monofunctional Pt/C. Kinetic results have consistent with a Langmuir-Hinshelwood mechanism involving adsorption of DMTHF and H2 on Pt sites followed by a sequence of hydrogenolysis, dehydration, and hydrogenation steps catalysed by Pt and proton sites of the bifunctional catalyst. The turnover rate of HDO increased with increasing Pt particle size suggesting that the hydrogenolysis of C–O bond in furanic compounds on Pt is a structure-sensitive reaction. It was also indicated that the acid strength of the co-catalyst has a significant impact on HDO efficiency than the acid site density. These results clearly show that for the efficient HDO of DMTHF both Pt and H+ sites are required. |
المرفقات
- https://uksacb.org/wp-content/uploads/Certificate-of-conference-6-01-2021.pdf
- https://uksacb.org/wp-content/uploads/Certificate-of-conference-09-01-2019.pdf
- https://uksacb.org/wp-content/uploads/Certificate-of-conference-16-09-2019.pdf
- https://uksacb.org/wp-content/uploads/Certificate-of-conference-25-06-2019.pdf
- https://uksacb.org/wp-content/uploads/Certificate-of-conference-26-08-2018.pdf
- https://uksacb.org/wp-content/uploads/Confirmation-Conference-09-01-2019.pdf
- https://uksacb.org/wp-content/uploads/Confirmation-Conference-16-09-2019.pdf
- https://uksacb.org/wp-content/uploads/Confirmation-Conference-25-06-2019.pdf
- https://uksacb.org/wp-content/uploads/Hanan-Althikrallah-paper-1.pdf
- https://uksacb.org/wp-content/uploads/Hanan-Althikrallah-paper-2.pdf
- https://uksacb.org/wp-content/uploads/Hanan-Althikrallah-paper-3.pdf