کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
39377 45821 2015 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Dehydration of ethanol over zeolites, silica alumina and alumina: Lewis acidity, Brønsted acidity and confinement effects
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Dehydration of ethanol over zeolites, silica alumina and alumina: Lewis acidity, Brønsted acidity and confinement effects
چکیده انگلیسی


• H-MOR is the most active zeolite in ethanol dehydration at low temperature.
• H-MFI and H-BEA give highest yield to diethyl ether (>70% at 473 K).
• H-FER and H-FAU give stable 99.9% yield to ethylene at 573 K.
• Confinement effects best explain the different behaviours of zeolites.
• Zeolites have more active and different Brønsted sites than silica alumina.

Ethanol dehydration was investigated over commercial H-FER, H-MFI, H-MOR, H-BEA, H-Y and H-USY zeolite samples, and alumina and silica alumina for comparison. The catalysts were characterized using FT-IR spectroscopy of the surface OH groups and of adsorbed CO and pyridine. UV–vis, Raman and TG-DTA were applied to characterize coke, formed more on H-MOR and H-BEA. H-zeolites are definitely more active than silica alumina and alumina on catalyst weight base. The H-MOR sample is the most active but the H-MFI samples with Si/Al2 ratios 280 and 50 show higher reaction rates per Al ion, H-FER and faujasites show highest ethylene yield (99.9% at 573 K). At lower temperature and higher space velocities, diethyl ether is formed with high yield (>70% at 453–473 K on H-BEA and H-MFI (50)). Overconversion of ethylene mainly to aromatics is observed on H-MFI (50). The different behaviour of protonic zeolites can predominantly be explained by confinement effects on the different zeolite cavities.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Catalysis A: General - Volume 493, 5 March 2015, Pages 77–89
نویسندگان
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