Nafion-Incorporated Silicate Structured Nanocomposite Mesoporous Catalysts for Dimethyl Ether Synthesis

Being chemically and thermally stable, Nation resin is considered to be an attractive solid acid catalyst. Although it has high acid strength and the ability to catalyze a wide range of reactions, the catalytic activity of Nation is limited, because of its very low specific surface area. In this study, mesoporous Nafion-silica nanocomposites were developed by following a one-pot acidic hydrothermal synthesis procedure. Synthesized catalysts were determined to have well-dispersed structures with high surface area values (595-792 m(2)/g) and strong Bronsted, as well as Lewis, acid sites. The activities of these novel catalysts were tested in dimethyl ether synthesis from methanol in a flow system. The effects of modifications in the synthesis procedure and Nafion loading showed that the material synthesized from a solution containing a Nafion/silica weight ratio of 0.15 and refluxed with a 2 M sulfuric acid-ethanol (SAE) mixture for surfactant removal was the best catalyst for this reaction. Production of the green transportation fuel alternate dimethyl ether (DME) was achieved with this catalyst at very high yields with almost 100% DME selectivity at >180 degrees C.


Dimethyl Ether Synthesis over Novel Silicotungstic Acid Incorporated Nanostructured Catalysts
Ciftci, Aysegul; VARIŞLI, DİLEK; Doğu, Timur (2010-01-01)
Dimethyl ether (DME), which is an excellent green diesel-fuel alternate with excellent clean burning properties, is synthesized by dehydration of methanol over novel solid acid catalysts, which are synthesized following a direct hydrothermal route and using silicotungstic acid (STA) as the active compound. These mesoporous silicate structured catalysts have surface area values of 108-393 m(2)/g, depending upon their W/Si ratio. These catalysts showed very high methanol dehydration activity and also very hig...
Heteropolyacid Incorporated Bifunctional Core-Shell Catalysts for Dimethyl Ether Synthesis from Carbon Dioxide/Syngas
Core-shell-type catalysts, which are synthesized by encapsulating the Cu-ZnO-Alumina type methanol synthesis catalyst (CZA) by silicotungstic acid (STA)-incorporated mesoporous alumina, were prepared following a hydrothermal route and tested in DME synthesis from syngas and CO2. Activity tests, which were performed in the pressure range of 30-50 bar, and the temperature range of 200-300 degrees C, with different feed compositions (CO2/CO/H-2: 50/-/50, 40/10/50, 25/25/50, 10/40/50) showed that the best-opera...
Vanadium incorporated high surface area MCM-41 catalysts
Gucbilmez, Y; Doğu, Timur; Balci, S (Elsevier BV, 2005-02-28)
High surface area MCM-41 (1452 m(2)/g) and V-MCM-41 materials were synthesized by a direct hydrothermal synthesis method. Characteristic XRD patterns, SEM and AFM photographs indicated no significant change in the morphology of MCM-41 by incorporation of vanadium. XPS and EDS results proved that incorporation of vanadium into the MCM-41 structure was successfully achieved when vanadyl sulfate hydrate was used as the vanadium source. However, use of ammonium vanadate as the vanadium source was not equally su...
Ethylene and acetaldehyde production by selective oxidation of ethanol using mesoporous V-MCM-41 catalysts
Gucbilmez, Yesim; Doğu, Timur; Balci, Suna (2006-05-10)
Vanadium-incorporated MCM-41 type catalytic materials, which were synthesized by a direct hydrothermal synthesis procedure, showed very high activity and high selectivity in the production of ethylene from ethanol in an oxidative process. Ethylene selectivity showed a significant increase with an increase in temperature over 300 degrees C, while relatively high acetaldehyde selectivities were observed at lower temperatures. An ethylene yield value of 0.66 obtained at 400 degrees C with an O-2/ethanol feed r...
DRIFT studies for the reaction and adsorption of alcohols and isobutylene on acidic resin catalysts and the mechanism of ETBE and MTBE synthesis
Doğu, Timur; Aydin, E; Oktar, N; Murtezaoglu, K; Dogu, G (2001-11-14)
Diffuse reflectance FT-IR spectra of methanol and ethanol on Amberlyst 15 and on a synthesized acidic resin catalyst indicate that alcohol molecules are adsorbed by forming hydrogen bridges with the -SO3H sites of the catalyst and among themselves. Some of the alcohol molecules were found to be strongly chemisorbed by dissociation of one or two hydrogen atoms. Isobutylene was also found to be strongly adsorbed by forming a bridged structure between the adsorbed alcohol molecules and the -SO3H groups. DRIFT ...
Citation Formats
A. Ciftci, N. A. Sezgi, and T. Doğu, “Nafion-Incorporated Silicate Structured Nanocomposite Mesoporous Catalysts for Dimethyl Ether Synthesis,” INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, pp. 6753–6762, 2010, Accessed: 00, 2020. [Online]. Available: