ABSTRACT
VANADIUM AND MOLYBDENUM INCORPORATED MCM-41
CATALYSTS FOR SELECTIVE OXIDATION OF ETHANOL
Gü / ç / bilmez, YeSim
Ph.D., Department of Chemical Engineering
Supervisor : Prof. Dr. Timur Dogu
Co-Supervisor: Prof. Dr. Suna Balci
June 2005, 144 pages
In this study, V-MCM-41, MCM-41 and Mo-MCM-41 catalysts were synthesized by the one-pot alkaline and acidic synthesis methods.
The as-synthesized catalysts were found to have high BET surface areas (430-1450 m2/g), homogeneous pore size distributions (2-4 nm), good crystalline patterns and high metal loading levels (Metal/Si atomic ratio in the solid = 0.01-0.16) as determined by the characterization studies.
MCM-41 and Mo-MCM-41 catalysts were highly active in the selective oxidation of ethanol with conversion levels of 56% and 71%, respectively, at 400oC for an O2/EtOH feed ratio of 0.5. Both catalysts had very high selectivities to acetaldehyde at temperatures below 300oC.
Conversions exceeded 95% with the V-MCM-41 catalyst having a V/Si molar ratio (in the solid) of 0.04 in the temperature range of 300oC-375oC for the O2/EtOH feed ratios of 0.5-2.0. Acetaldehyde selectivities changed between 0.82-1.00 at the temperature range of 150oC-250oC.
Ethylene, which is listed as a minor side product of the selective oxidation of ethanol in literature, was produced with a maximum yield of 0.66 at 400oC at the O2/EtOH feed ratio of 0.5. This yield is higher than the yields obtained in the industrial ethylene production methods such as thermal cracking and oxidative dehydrogenation of ethane. Besides, the feedstock used in this work is a non-petroleum chemical, namely ethanol, which can be produced from sugar and crop wastes by fermentation. Thus, the findings of this study are also proposed as an alternative ethylene production method from a non-petroleum reactant at lower temperatures with higher yields.
Ö / Z
ETANOLÜ / N SEÇ / iCi OKSiDASYONUNDA KULLANILMAK Ü / ZERE VANADYUM VE MOLiBDEN iÇ / EREN MCM-41 KATALiZÖ / RLERiNiN Ü / RETiMi
Gü / ç / bilmez, YeSim
Doktora, Kimya Mü / hendisligi Bö / lü / mü / Tez Yö / neticisi : Prof. Dr. Timur Dogu
Ortak Tez Yö / neticisi: Prof. Dr. Suna Balci
Haziran 2005, 144 sayfa
Bu ç / aliSma kapsaminda, dogrudan sentez metoduyla, alkali ve asit ortamlarinda, V-MCM-41, MCM-41 ve Mo-MCM-41 katalizö / rleri sentezlenmiStir.
Bu Sekilde sentezlenen katalizö / rlerin yü / ksek BET yü / zey alanlarina (430-1450 m2/g), homojen gö / zenek boyutu dagilimlarina (2-4 nm), iyi kristal yapilarina ve yü / ksek metal yü / kleme oranlarina (Metal/Si katidaki molar orani =0.01-0.16) sahip olduklari karakterizasyon ç / aliSmalari sonucunda gö / rü / lmü / Stü / r.
MCM-41 ve Mo-MCM-41 katalizö / rleri etanolü / n seç / ici oksidasyonunda, 400oC& / #8217 / de ve reaktö / r giriSinde 0.5& / #8217 / lik O2/EtOH oraninda, sirasiyla, 56% ve 71% dö / nü / Sü / m seviyeleriyle, yü / ksek aktivite gö / stermiSlerdir.
Her iki katalizö / r de 300oC& / #8217 / nin altinda ç / ok yü / ksek asetaldehit seç / iciligi gö / stermiStir.
Dö / nü / Sü / m degerleri, V/Si katidaki molar orani 0.04 olan V-MCM-41 katalizö / rü / iç / in / 300oC-375oC araliginda ve 0.5-0.2 O2/EtOH reaktö / r giriSi oranlarinda, 95%& / #8217 / i geç / miStir. Asetaldehit seç / icilikleri, 150oC-250oC araliginda, 0.82-1.00 arasinda degiSmiStir.
Literatü / rde, etil alkolü / n seç / ici oksidasyonunda ö / nemsiz bir yan ü / rü / n olarak sö / zü / geç / en etilen, 400oC& / #8217 / de ve 0.5& / #8217 / lik O2/EtOH reaktö / r giriS oraninda 0.66 maksimum verimle ü / retilmiStir. Bu verim degeri isil parç / alanma ve etanin kismi oksidasyonu gibi endü / striyel etilen ü / retim yollariyla elde edilen verimlerden daha yü / ksektir. Ayrica, bu ç / aliSmada kullanilan etanol petrol-bazli olmayan bir hammaddedir ve Seker pancari atiklarindan fermentasyonla ü / retilebilmektedir. Bu sebeple, bu ç / aliSmadaki bulgular, petrol-bazli olmayan bir hammaddeden, daha dü / Sü / k sicaklikta, daha yü / ksek verimle etilen elde etmek iç / in alternatif bir ü / retim metodu olarak da ö / nerilmiStir.
Anahtar Kelimeler: Etilen, Etil alkol, Seç / ici Oksidasyon, MCM-41,
V-MCM-41, Mo-MCM-41, Oksidatif Dihidrojenasyon, Kismi Oksidasyon
Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/3/12606179/index.pdf |
Date | 01 June 2005 |
Creators | Gucbilmez, Yesim |
Contributors | Dogu, Timur |
Publisher | METU |
Source Sets | Middle East Technical Univ. |
Language | English |
Detected Language | English |
Type | Ph.D. Thesis |
Format | text/pdf |
Rights | To liberate the content for public access |
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