Heterpolyacid catalysts for etherification of isoolefins

Download

index.pdf

Date

2003

Author

Obalı, Zeynep

Metadata

Show full item record

Item Usage Stats

282
views

76
downloads

Due to the water pollution problems created by MTBE, significant research was focused on the production of alternative oxygenates, such as ethyl tert-butyl ether (ETBE), tert-amyl-methyl-ether (TAME) and tert-amyl-ethyl-ether (TAEE) as octane enhancing gasoline blending components. These oxygenates are expected to improve the burning characteristics of gasoline and reduce exhaust emissions of CO and hydrocarbons. Generally, macroreticular acidic resin catalysts (Amberlyst-15) are used for the etherification reactions between C5 iso-olefins (2M1B/2M2B) and alcohols (ethanol/methanol). But in recent years, heteropoly acid compounds are being used in the production of tert-ethers to replace those macroreticular acidic resin catalysts. HPAs are known to be active catalysts for many of homogeneous and heterogeneous acid catalyzed reactions.These compounds have high acidity, high catalytic activity but they are highly soluble in polar solvents such as water,alcohol when they are used in bulk form. In this research, applicability of bulk heteropoly acid (HPA) and its supported form, to the gas-phase etherification reaction of iso-olefin (2-methyl- 2-butene) with ethyl alcohol in a continuous differential reactor was investigated. The heteropoly acid (H3PW12O40.xH2O) was supported on activated carbon, at two different loading levels, by aqueous impregnation technique. After catalyst characterization, kinetic experiments were done in a temperature range between 80°C-97°C with a feed concentration of 30 vol.%2M2B+70 vol.% ethanol. Supported HPA catalysts yielded lower conversion and rate of reaction than the bulk HPA. After that, to make a comparison, same experiments have been carried out with Amberlyst-15 and a different HPA (H3PMo12O40.xH2O) at 90oC. The results showed that, at this temperature, bulk tungstophosphoric acid (H3PW12O40.xH2O) was highly active among the other

Subject Keywords

Octane enhancer, 2M2B, Ethanol, TAEE, Catalyst, Heteropoly acid, Activated carbon, Impregnation technique, Supported heteropoly acid

URI

http://etd.lib.metu.edu.tr/upload/1134923/index.pdf
https://hdl.handle.net/11511/13511

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

The simultaneous production of tert-amyl alcohol and tert-amyl-ethyl ether in a reactive distillation column Varışlı, Dilek; Doğu, Timur; Department of Chemical Engineering (2003) Due to the water pollution problems created by MTBE, significant research was focused on the production of alternative oxygenates, such as tert-amyl- ethyl-ether (TAEE), tert-amyl-methyl-ether (TAME) and higher alcohols as octane enhancing gasoline blending components. Tert-amyl alcohol (TAA) may also be considered as an attractive alternate to MTBE. These oxygenates are expected to improve the burning characteristics of gasoline and reduce exhaust emissions of CO and hydrocarbons. They may be produced by t...
Activated carbon-tungstophosphoric acid catalysts for the synthesis of tert-amyl ethyl ether (TAEE) Obali, Zeynep; Doğu, Timur (2008-05-01) Catalytic activities of bulk tungstophosphoric acid (HPW) and its supported forms on activated carbon were investigated in the vapor phase etherification reaction of isoamylene with ethanol in a continuous flow reactor. Tungstophosphoric acid (H3PW12O40 center dot 11H(2)O) was supported on activated carbon having a surface area of 796 m(2)/g, at two different loading levels (25% and 31%) by aqueous impregnation technique and the kinetic experiments were done in a temperature range between 353 and 370 K. Sup...
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...
Soot and PAH formation in rapeseed oil spray combustion Allouis, Christophe Gerard; Apicella, B.; Barbella, R.; Beretta, F.; Tregrossi, A.; Ciajolo, A. (2002-01-01) The performance of rapeseed oil combustion in regard to organic pollutant production (solid particulate, light hydrocarbons, aldehydes and PAH) was investigated and compared to the performance of a typical heavy fuel oil burned in the same experimental conditions. C1-C6 hydrocarbons were formed in lower amounts in the rapeseed oil flame, but the composition and distribution was found to be very similar for both fuels. Due to the very high-temperature environment typical of stationary combustion a very low p...
HYBRID CATALYTIC COMBUSTION OF METHANE/HYDROGEN MIXTURES Cimino, S.; Allouis, Christophe Gerard; Mancino, G.; Nigro, R. (2014-05-01) Hybrid catalytic combustion technology, which is a staged process comprising a preliminary catalytic partial oxidation (CPO) step followed by a homogeneous flame combustion with interstage heat removal, was tested for the first time with mixtures of methane and hydrogen. Short contact time CPO experiments were run to elucidate the effect of the progressive substitution of methane with H-2 in the fuel feed to the structured catalytic reactor, which was operated under self-sustained conditions at high tempera...

Citation Formats

Z. Obalı, “Heterpolyacid catalysts for etherification of isoolefins,” M.S. - Master of Science, Middle East Technical University, 2003.