Bromine mediated partial oxidation of ethane over nanostructured zirconia supported metal oxide/bromide

2005-04-01
Yılmaz, Ayşen
Zhou, XP
Lorkovic, IM
Ylmaz, GA
Laverman, L
Weiss, M
Sun, SL
Schaefer, D
Sherman, JH
McFarland, EW
Ford, PC
Stucky, GD
Partial oxidation of ethane to an array of products was achieved through use of bromine/supported metal bromide as redox mediator for oxygen activation. In a two stage flowing fixed bed reactor, ethane bromination (350-450 degrees C) to EtBr and HBr was followed by metathesis of these intermediates with supported cobalt or copper oxides (200-250 degrees C) to produce ethanol (up to 64% selectivity at 45% EtBr conversion), diethyl ether (64% selectivity at 44% conversion), and ethylene (26% selectivity at 68% conversion at 200 degrees C, but conversions and selectivities approaching 100% at temperatures > 300 degrees C) as major products, and butadiene, vinyl bromide, acetaldehyde, ethyl acetate, and acetone as minor products. The supported cobalt and copper bromides thus formed were reoxidized with flowing O-2 to liberate bromine and this cycle was repeated at least three (and as many as fifty) times to establish the reproducibility of both the metathesis product distribution and of the oxide delivery and bromide sequestration capacity of the metal oxide/metal bromide mediators. Different formulations of the supported and unsupported metal oxide/metal bromide were investigated; zirconia or titania-supported Cu and Co oxides prepared from oxalic acid gels showed higher and more reproducible oxide/bromide exchange activity and capacity. These materials' performance is discussed in terms of their morphology, crystallinity, and porosity at different states of bromination in the partial oxidation cycle. (c) 2004 Elsevier Inc. All rights reserved.
MICROPOROUS AND MESOPOROUS MATERIALS

Suggestions

Conducting polymers of decanedioic acid bis-(4-pyrrol-1-yl-phenyl) ester
Çırpan, Ali; Toppare, Levent Kamil (Elsevier BV, 2004-05-15)
A dipyrrolyl monomer was synthesized via the reaction between 4-pyrrol-1-yl phenol and decanedioyl dichloride. The electrochemical behavior of this monomer was studied. Polymerization of decanedioic acid bis-(4-pyrrol-1-yi-phenyl) ester (DAPE) was achieved by chemical and constant current electrolyses methods. Copolymerization of DAPE with thiophene was performed by constant potential electrolysis in acetonitrile-tetrabutylammonium tetrafluoroborate (TBAFB), dichloromethane-TBAFB, solvent-electrolyte couple...
Ruthenium(III) ion-exchanged zeolite Y as highly active and reusable catalyst in decomposition of nitrous oxide to sole nitrogen and oxygen
Curdaneli, Pelin Edinc; Özkar, Saim (Elsevier BV, 2014-09-01)
Ruthenium(III) ion-exchanged zeolite Y, prepared by ion exchange of Ru+3 ions with the extra framework Na+ cations in zeolite Y with a Si/Al ratio of 2.5, is employed to catalyze the decomposition of nitrous oxide to nitrogen and oxygen. Catalytic activity of ruthenium(III) ion-exchanged zeolite Y is studied in the decomposition of nitrous oxide to nitrogen and oxygen depending on the ruthenium loading of zeolite and flow rate of nitrous oxide helium mixture in a continuous flow vertical reactor. The result...
Crystallization of silicalite-1 from clear synthesis solutions: Effect of template concentration on crystallization rate and crystal size
Soydas, B.; Çulfaz Emecen, Pınar Zeynep; Kalıpçılar, Halil; Culfaz, A. (Wiley, 2009-08-01)
Synthesis of silicalite-1 powders and membranes from initially clear solutions with different tetrapropylammonium hydroxide or bromide concentrations was studied. While tetrapropylammonium bromide acts only as template, tetrapropylammonium hydroxide provides both the template and hydroxyl ions to the synthesis medium. The effects of template and hydroxyl ion concentration on the product yield, crystallization rate and crystal size were investigated. Pure and highly crystalline silicalite-1 was obtained with...
Sol-gel synthesis and photocatalytic activity of B and Zr co-doped TiO2
Kapusuz, Derya; PARK, JONGEE; Öztürk, Abdullah (Elsevier BV, 2013-07-01)
Effects of boron (B) and/or zirconium (Zr) doping on photocatalytic activity of sol-gel derived titania (TiO2) powders were investigated. A conventional, non-hydrous sol-gel technique was applied to synthesize the B, Zr doped/co-doped TiO2 powders. Doping was made at molar ratios of Ti/B=1 and Ti/Zr=10. Sol-gel derived xero-gels were calcined at 500 degrees C for 3 h. The crystal chemistry and the morphology of the undoped and B, Zr doped/co-doped TiO2 nanoparticles were investigated using X-ray diffractome...
Conducting polymers of octanoic acid 2-thiophen-3-yl-ethyl ester and their electrochromic properties
CAMURLU, P; Çırpan, Ali; Toppare, Levent Kamil (Elsevier BV, 2005-08-15)
Octanoic acid 2-thiophen-3-yl-ethyl ester was synthesized via the reaction of 3-thiophene ethanol with octanoyl chloride. The resulting monomer was electrochemically homopolymerized in the presence of tetrabutylammonium tetrafluoroborate as the supporting electrolyte, in the acetonitrile/borontrifluoride ethyl ether solvent system. The resulting polymer was characterized using various experimental techniques. Spectroelectrochemistry analysis of the homopolymer reflects electronic transitions at 434, approxi...
Citation Formats
A. Yılmaz et al., “Bromine mediated partial oxidation of ethane over nanostructured zirconia supported metal oxide/bromide,” MICROPOROUS AND MESOPOROUS MATERIALS, pp. 205–214, 2005, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48177.