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Dehydration of ethanol over zeolites, silica alumina and alumina: Lewis acidity, Brønsted acidity and confinement effects

Paper ID Volume ID Publish Year Pages File Format Full-Text
39377 45821 2015 13 PDF Available
Title
Dehydration of ethanol over zeolites, silica alumina and alumina: Lewis acidity, Brønsted acidity and confinement effects
Abstract

•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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Keywords
Ethanol dehydration; Zeolites; Silica alumina; Ethylene; Diethyl ether; Coking
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Dehydration of ethanol over zeolites, silica alumina and alumina: Lewis acidity, Brønsted acidity and confinement effects
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 493, 5 March 2015, Pages 77–89
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
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