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تميز دراسي وبحثي

البحوث المنشورة

البحث (1):

عنوان البحث:

Efficient hydrodeoxygenation of biomass-derived ketones over bifunctional Pt-polyoxometalate catalyst

رابط الوصول:

Link

تاريخ النشر:

May 2012

موجز عن البحث:

Acidic heteropoly salt Cs_2.5H_0.5PW₁₂O₄₀ doped with Pt nanoparticles is a highly active and selective catalyst for one-step hydrogenation of methyl isobutyl and diisobutyl ketones to the corresponding alkanes in the gas phase at 100 °C with 97–99% yield via metal-acid bifunctional catalysis.

البحث (2):

عنوان البحث:

Hydrogenation of methyl isobutyl ketone over bifunctional Pt-zeolite catalyst

رابط الوصول:

Link

تاريخ النشر:

June 2012

موجز عن البحث:

Abstract:

Methyl isobutyl ketone (MIBK) can be viewed as a key intermediate for the conversion of biomass-derived acetone – the by-product of biobutanol production – to transportation fuel. Zeolite H-ZSM-5 doped with Pt nanoparticles was found to be a highly efficient catalyst for gas-phase hydrogenation of MIBK to methylpentanes with >99% yield at 200 °C. The reaction proceeds via bifunctional metal-acid catalysed pathway involving MIBK hydrogenation to 4-methyl-2-pentanol (MP-ol) on metal sites followed by MP-ol dehydration on acid sites to form olefin and finally olefin hydrogenation to 2-methylpentane (2MP) on metal sites, with all three steps occurring on a single catalyst bed. 2MP thus obtained underwent isomerisation over bifunctional Pt/H-ZSM-5 catalyst to give a mixture of 2- and 3-methylpentanes in a ratio of 83:17. The catalyst did not show any deactivation for at least 16 h on stream.

البحث (3):

عنوان البحث:

Deoxygenation of propionic acid on heteropoly acid and bifunctional metal-loaded heteropoly acid catalysts: Reaction pathways and turnover rates

رابط الوصول:

Link

تاريخ النشر:

August 2012

موجز عن البحث:

Abstract:

Reaction pathways of the gas-phase deoxygenation of propionic acid in the presence of heteropoly acid and bifunctional metal-loaded heteropoly acid catalysts were investigated in a fixed-bed reactor at 250–400 °C in flowing H₂ or N₂. Silica-supported H₃PW₁₂O₄₀ (HPW) and bulk acidic salt Cs_2.5H_0.5PW₁₂O₄₀ (CsPW), both in H₂ and in N₂, exhibited ketonisation activity between 250 and 300 °C to yield 3-pentanone, CsPW being more selective than HPW. At 400 °C, HPW and CsPW were active for decarbonylation and decarboxylation of propionic acid to yield ethene and ethane, respectively. Loading Pd or Pt onto CsPW greatly enhanced decarbonylation in flowing H₂ but had little effect in N₂. Similar performance exhibited Pd/SiO₂ and Pt/SiO₂, giving almost 100% selectivity to ethene in H₂. These results are consistent with hydrodeoxygenation of propionic acid on Pd and Pt, suggesting that hydrogenolysis of CC bond plays essential role. In contrast to the Pd and Pt catalysts, Cu catalysts, Cu/CsPW and Cu/SiO₂, were both active in hydrogenation of CO bond to yield propanal and 1-propanol. Turnover rates of propionic acid conversion on metal catalysts followed the order Pd > Pt > Cu for both CsPW-supported and silica-supported metal catalysts.

المؤتمرات العلمية:

المؤتمر (1):

عنوان المؤتمر:

15th International Congress on Catalysis

تاريخ الإنعقاد:

July 2012

بلد ومكان الإنعقاد:

Munich, Germany

طبيعة المشاركة:

Oral presentation

عنوان المشاركة:

Gas-phase deoxygenation and hydrogenation of propionic acid on heteropoly acid catalysts

الملخص

The main pathways of deoxygenation of propionic acid under the conditiones studied involve: (1) ketonisation over heteropoly acid (HPA), (2) decarbonylation over Pd and Pt and (3) hydrogenation over Cu.

From the practical point of view, it may be desirable to produce the ketonisation products with carbon backbone upgrade (C_n → C_2n-1) over CsPW at 250 – 300 ^oC in hydrogen-free system, as well as the C_n hydrogenation products (aldehydes and alcohols) without carbon loss using Cu catalysts. On the other hand, Pd and Pt catalysts possessing high hydrodeoxygenation activity via decarbonylation pathway allow producing the C_n-1 alkenes.

المؤتمر (2):

عنوان المؤتمر:

Saudi International Conference 2011

تاريخ الإنعقاد:

June 2011

بلد ومكان الإنعقاد:

Coventry, UK

طبيعة المشاركة:

Poster

عنوان المشاركة:

Hydrogenation of carboxylic acids over Heteropoly acid catalysts

الملخص

The more stable catalysts based on CsPW retain their primary (Keggin) and secondary structures upon carboxylic acid (hydro)deoxygenation in the gas phase. CsPW is active for acid ketonisation, Cu/CsPW for hydrogenation, whereas Pd/CsPW and Pt/CsPW for decarbonylation. Turnover rates followed the order Pd > Pt > Cu.