Bifunctional Silicotungstic Acid and Tungstophosphoric Acid Impregnated Cu-Zn-Al & Cu-Zn-Zr Catalysts for Dimethyl Ether Synthesis from Syngas

Date

2020-09-01

Author

Karaman, Birce Pekmezci
OKTAR, NURAY
DOĞU, GÜLŞEN
Doğu, Timur

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

271
views

0
downloads

In the present study, a set of methanol synthesis catalysts with different Cu/Zn/Al or Cu/Zn/Zr molar ratios were synthesized by a co-precipitation method. Silicotungstic acid and tungstophosphoric acid were impregnated into these materials to synthesize new bifunctional catalytic materials to be used in direct synthesis of dimethyl ether (DME) from syngas. In the case of methanol production, synthesized Cu/Zn/Al catalysts exhibited quite high methanol selectivity, reaching to approximately 87%. These results indicated that the dispersion of copper particles profoundly affected the selectivity of methanol. Direct synthesis of DME was investigated in the presence of heteropoly acid impregnated copper-based novel hybrid type bifunctional catalysts. Results revealed that product distributions were strongly influenced by the reaction temperature, pressure, heteropoly acid content, and type. Results proved that silicotungstic acid (STA) impregnated bifunctional catalysts showed much better catalytic performance than the tungstophosphoric acid (TPA) impregnated ones in DME synthesis from syngas. Very high dimethyl ether selectivity values were achieved in direct synthesis of dimethyl ether over the 25%, and 30% STA impregnated methanol synthesis catalysts, at 275 degrees C and 50 bar. DME selectivity presented an increasing trend due to the increase in heteropoly acid content over methanol synthesis catalysts. The silicotungstic acid incorporated (30%) Cu/Zn/Al catalyst, having a composition of 6/3/1 (30STA@CZA:631), showed the highest CO conversion and DME selectivity. However, coke formation over this catalyst was much more than the catalyst containing 25% STA. This is mainly due to the higher Bronsted acidity of 30STA@CZA:631 than 25STA@CZA:631. Low coke formation, together with quite high DME selectivity values achieved with 25STA@CZA:631, is a worthy distinction of this catalyst for the direct synthesis of DME from synthesis gas.

URI

https://hdl.handle.net/11511/31571

Journal

CATALYSIS LETTERS

DOI

https://doi.org/10.1007/s10562-020-03171-6

Collections

Graduate School of Natural and Applied Sciences, Article

Suggestions

OpenMETU
Core

Asymmetric aldol addition of alpha-azido ketones to ethyl pyruvate mediated by a cinchona-based bifunctional urea catalyst Okumus, Seda; Tanyeli, Cihangir; Demir, Ayhan Sıtkı (Elsevier BV, 2014-07-30) The first asymmetric synthesis of ethyl 4-aryl-3-azido-2-hydroxy-2-methyl-4-oxobutanoates via a cinchona organocatalyst induced aldol addition of alpha-azido ketones to ethyl pyruvate has been developed. The coupling reaction under optimized conditions was carried out to furnish tetrafunctionalized synthons with enantioselectivities of up to 91:9 and enriched diastereoselectivities of up to 95:5 (syn:anti).
Multipurpose acetic acid functionalized carbazole derivatives: Synthesis, electrochemical properties and electrochromic device applications Özdemir Hacıoğlu, Şerife; YİĞİT, DENİZ; Akbey, Tuba E.; UDUM, YASEMİN; GÜLLÜ, MUSTAFA; DEPCİ, TOLGA; Toppare, Levent Kamil (2022-03-01) In this study, synthesis of two multifunctional acetic acid functionalized carbazole bearing monomers; 243,6-bis(2,3-dihydrothieno [3,4-b] [1,4]dioxin-5-yl)-9H-carbazol-9-yl)acetic acid (Ml) and 3,6-dithien-2-yl-9H car bazol-9-ylaceticacid (M2) via Stille cross-coupling reaction was reported. Obtained monomers were electro-chemically polymerized in 0.1 M TBAPF(6)/DCM/ACN (5:95, v:v) solution and characterized in terms of electrochemical, spectroelectrochemical and electrochromic switching behaviors. When po...
Asymmetric synthesis of 1,4-amino alcohol ligands with a norbornene backbone for use in the asymmetric diethylzinc addition to benzaldehyde Tanyeli, Cihangir (Elsevier BV, 2005-06-06) The asymmetric synthesis of cis-1,4-amino alcohols with a norbornene backbone was performed starting with (2S,3R)(-)-cis-hemiester 2 (98% ee). Chemoselective amination with NH4OH and HMPTA followed by LAH reduction afforded 5 and 7. respectively. Amido ester 6 was transformed into chiral ligand 9 with Grignard reaction followed by LAH reduction. The chiral ligands 5. 7. and 9 were subjected to asymmetric diethylzinc addition to examine their effectiveness as chiral catalysts. Among these, c chiral ligand 7 ...
Enantioselective synthesis of 2-(2-arylcyclopropyl)glycines: Conformationally restricted homophenylalanine analogs Demir, Ayhan Sıtkı; Sesenoglu, O; Ulku, D; Arici, C (Wiley, 2004-01-01) Starting from simple aromatic aldehydes and acetylfuran, (E)-1-(furan-2-yl)-3-arylprop-2-en-1-ones (2) were synthesized in high yields. Cyclopropanation of the C=C bond with trimethylsulfoxonium iodide (Me3SO+I-) furnished (furan-2-yl)(2-arylcyclopropyl)methanones 3 in 90-97% yields. Selective conversion of cyclopropyl ketones to their (E)- and (Z)-oxime ethers 5 and oxazaborolidine-catalyzed stercoselective reduction of the C-N bond followed by separation of the formed diastereoisomers, furnished (2-arylcy...
Polybenzimidazole based nanocomposite membranes with enhanced proton conductivity for high temperature PEM fuel cells Ozdemir, Yagmur; Uregen, Nurhan; DEVRİM, YILSER (2017-01-26) In this study, phosphoric acid doped PBI nanocomposite membranes were prepared by dispersion of various amounts of inorganic nanoparticles in PBI polymer followed by phosphoric acid (H3PO4) doping for high temperature proton exchange membrane fuel cells (HT-PEMFC). All of the PBI composite membranes were cast from the same FBI polymer with the same molecular weight. Titanium dioxide (TiO2), silicon dioxide (SiO2) and inorganic proton conductor zirconium phosphate (ZrP) were used as inorganic fillers. The PB...

Citation Formats

B. P. Karaman, N. OKTAR, G. DOĞU, and T. Doğu, “Bifunctional Silicotungstic Acid and Tungstophosphoric Acid Impregnated Cu-Zn-Al & Cu-Zn-Zr Catalysts for Dimethyl Ether Synthesis from Syngas,” CATALYSIS LETTERS, pp. 2744–2761, 2020, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/31571.