Abstract
The conversion of diethyl ether (DEE) to ethene and ethanol was studied at a gas–solid interface over bulk and supported Brønsted solid acid catalysts based on tungsten Keggin heteropoly acids (HPAs) at 130–250 °C and ambient pressure. The yield of ethene increased with increasing reaction temperature and reached 98% at 220–250 °C (WHSV = 2.2 h–1). The most active HPA catalysts were silica-supported H3PW12O40 and H4SiW12O40 and the bulk heteropoly salt Cs2.5H0.5PW12O40. The HPA catalysts outperformed zeolites HZSM-5 and USY reported elsewhere. A correlation between catalyst activity and catalyst acid strength was established, which indicates that Brønsted acid sites play an important role in DEE elimination over HPA catalysts. The results point to the reaction occurring through the consecutive reaction pathway: DEE → C2H4 + EtOH followed by EtOH → C2H4 + H2O, where ethene is both a primary product of DEE elimination and a secondary product via dehydration of the primary product EtOH. Evidence is provided that DEE elimination over bulk HPA and high-loaded HPA/SiO2 catalysts proceeds via the surface-type mechanism.
Highlights
The dehydration of EtOH to ethene and diethyl ether (DEE) is of interest for the production of ethene and DEE from renewable nonpetroleum resources.1−3 Ethene is widely used in the chemical industry,1,2 and DEE is a valuable chemical, aprotic solvent, anesthetic, and green fuel alternative.4CH3CH2OH → CH2=CH2 + H2O (1) (2)(CH3CH2)2O → CH3CH2OH + CH2aCH2 (3)The dehydration of EtOH can be carried out in the gas or liquid phase in the presence of acid catalysts
Metal oxides, zeolites, and heteropoly acids (HPAs) are most often used.5−17 HPAs, having a stronger acidity, are more active in this reaction.14−20 DEE is a key intermediate in the ethanol-to-ethene dehydration.10−13,16 In the presence of an acid catalyst, DEE undergoes elimination to produce ethene and EtOH; the latter, in turn, dehydrates to ethene
We investigate the elimination of DEE to ethene and ethanol in the presence of bulk and supported Brønsted solid acid catalysts based on tungsten Keggin HPAs (HPW and HSiW) at a gas−solid interface in a fixed-bed reactor
Summary
The dehydration of EtOH to ethene (eq 1) and diethyl ether (DEE) (eq 2) is of interest for the production of ethene and DEE from renewable nonpetroleum resources.− Ethene is widely used in the chemical industry, and DEE is a valuable chemical, aprotic solvent, anesthetic, and green fuel alternative.. The ethanol-to-ethene dehydration is suggested to proceed through the bimolecular elimination mechanism E2 This mechanism involves simultaneous cleavage of C−O and C−H bonds in alcohol by a pair of acid and base catalyst sites (Scheme 1).. The acid properties of HPW and HSiW are well documented in the literature (refs 23−28 and references therein) These HPAs have been reported as efficient acid catalysts in a wide range of reactions,− including the dehydration of EtOH.− An HPA catalyst is used in Hummingbird technology for the dehydration of bioethanol to polymer-grade ethene.. We investigate the elimination of DEE to ethene and ethanol in the presence of bulk and supported Brønsted solid acid catalysts based on tungsten Keggin HPAs (HPW and HSiW) at a gas−solid interface in a fixed-bed reactor. We aim to establish a relationship between the turnover activity of HPA catalysts and their acid strength and to gain an insight into the reaction mechanism
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
