کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
39135 45807 2015 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Influence of internal diffusion on selective hydrogenation of 4-carboxybenzaldehyde over palladium catalysts supported on carbon nanofiber coated monolith
ترجمه فارسی عنوان
تأثیر انتشار داخلی در هیدروژن انتخابی 4-کربوکسیب بیسنالدئید بر روی کاتالیزورهای پالادیوم بر روی یکپارچه پوشش نانو فایبر کربن
کلمات کلیدی
نانوفیبری کربن، مونولیت، کاتالیست سازنده هیدروژن 4-کاربوکسیبیزنالدئید، انتشار داخلی
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
چکیده انگلیسی


• Pd/CNF/TiO2/monolith highly selective for partial hydrogenation of 4-CBA.
• Superior performance achieved by minimizing internal concentration gradients.
• CNF/TiO2/monolith applied as a fixed bed outperforms slurry catalysts.

In this study, a macro-structured Pd catalyst supported on carbon nanofiber coated on cordierite monolith (Pd/CNF/TiO2/monolith) was employed for hydrogenation of 4-CBA. The effect of mass transfer on the catalyst performance was studied experimentally and the results are described using a simple kinetic model. The results were compared to Pd catalysts supported on activated carbon (Pd/AC) and on carbon nanofibers aggregates (Pd/CNF). Catalytic performance of the Pd/CNF/TiO2/monolith is similar to Pd/CNF and the Pd/AC with particles as small as 50 μm (Pd/AC50), whereas Pd/AC with larger support particles revealed a lower activity per Pd active surface site, due to internal mass transfer limitation. Also the selectivity to the intermediate hydrogenation product (4-HMBA), versus deep hydrogenation to p-TA, is clearly affected by internal mass transfer. Pd/AC with large particles (3000 μm) achieves a maximum yield to the intermediate product of only 35%, whereas all the other catalysts achieve typically 70%. Remarkably, the conversion level at which the maximum yield of the intermediate product is achieved is highest for the Pd/CNF/TiO2/monolith. This advantage is assigned to superior internal mass transfer properties, thanks to high porosity, low tortuosity and short diffusion length of the CNF layer. Clearly, the CNF/TiO2/monolith applied as a fixed bed outperforms slurry phase catalysts, abandoning the need of a filtration section.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Catalysis A: General - Volume 498, 5 June 2015, Pages 222–229
نویسندگان
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