Vanadium And Molybdenum Incorporated Mcm-41 Catalysts For Selective Oxidation Of Ethanol

Description

ABSTRACT



VANADIUM AND MOLYBDENUM INCORPORATED MCM-41
CATALYSTS FOR SELECTIVE OXIDATION OF ETHANOL




G&uuml / &ccedil / 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.


















&Ouml / Z


ETANOL&Uuml / N SE&Ccedil / iCi OKSiDASYONUNDA KULLANILMAK &Uuml / ZERE VANADYUM VE MOLiBDEN i&Ccedil / EREN MCM-41 KATALiZ&Ouml / RLERiNiN &Uuml / RETiMi



G&uuml / &ccedil / bilmez, YeSim
Doktora, Kimya M&uuml / hendisligi B&ouml / l&uuml / m&uuml / Tez Y&ouml / neticisi : Prof. Dr. Timur Dogu
Ortak Tez Y&ouml / neticisi: Prof. Dr. Suna Balci


Haziran 2005, 144 sayfa



Bu &ccedil / aliSma kapsaminda, dogrudan sentez metoduyla, alkali ve asit ortamlarinda, V-MCM-41, MCM-41 ve Mo-MCM-41 kataliz&ouml / rleri sentezlenmiStir.
Bu Sekilde sentezlenen kataliz&ouml / rlerin y&uuml / ksek BET y&uuml / zey alanlarina (430-1450 m2/g), homojen g&ouml / zenek boyutu dagilimlarina (2-4 nm), iyi kristal yapilarina ve y&uuml / ksek metal y&uuml / kleme oranlarina (Metal/Si katidaki molar orani =0.01-0.16) sahip olduklari karakterizasyon &ccedil / aliSmalari sonucunda g&ouml / r&uuml / lm&uuml / St&uuml / r.
MCM-41 ve Mo-MCM-41 kataliz&ouml / rleri etanol&uuml / n se&ccedil / ici oksidasyonunda, 400oC&amp / #8217 / de ve reakt&ouml / r giriSinde 0.5&amp / #8217 / lik O2/EtOH oraninda, sirasiyla, 56% ve 71% d&ouml / n&uuml / S&uuml / m seviyeleriyle, y&uuml / ksek aktivite g&ouml / stermiSlerdir.


Her iki kataliz&ouml / r de 300oC&amp / #8217 / nin altinda &ccedil / ok y&uuml / ksek asetaldehit se&ccedil / iciligi g&ouml / stermiStir.
D&ouml / n&uuml / S&uuml / m degerleri, V/Si katidaki molar orani 0.04 olan V-MCM-41 kataliz&ouml / r&uuml / i&ccedil / in / 300oC-375oC araliginda ve 0.5-0.2 O2/EtOH reakt&ouml / r giriSi oranlarinda, 95%&amp / #8217 / i ge&ccedil / miStir. Asetaldehit se&ccedil / icilikleri, 150oC-250oC araliginda, 0.82-1.00 arasinda degiSmiStir.
Literat&uuml / rde, etil alkol&uuml / n se&ccedil / ici oksidasyonunda &ouml / nemsiz bir yan &uuml / r&uuml / n olarak s&ouml / z&uuml / ge&ccedil / en etilen, 400oC&amp / #8217 / de ve 0.5&amp / #8217 / lik O2/EtOH reakt&ouml / r giriS oraninda 0.66 maksimum verimle &uuml / retilmiStir. Bu verim degeri isil par&ccedil / alanma ve etanin kismi oksidasyonu gibi end&uuml / striyel etilen &uuml / retim yollariyla elde edilen verimlerden daha y&uuml / ksektir. Ayrica, bu &ccedil / aliSmada kullanilan etanol petrol-bazli olmayan bir hammaddedir ve Seker pancari atiklarindan fermentasyonla &uuml / retilebilmektedir. Bu sebeple, bu &ccedil / aliSmadaki bulgular, petrol-bazli olmayan bir hammaddeden, daha d&uuml / S&uuml / k sicaklikta, daha y&uuml / ksek verimle etilen elde etmek i&ccedil / in alternatif bir &uuml / retim metodu olarak da &ouml / nerilmiStir.




Anahtar Kelimeler: Etilen, Etil alkol, Se&ccedil / ici Oksidasyon, MCM-41,
V-MCM-41, Mo-MCM-41, Oksidatif Dihidrojenasyon, Kismi Oksidasyon

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1. http://etd.lib.metu.edu.tr/upload/3/12606179/index.pdf

Tags

QD General (including alchemy) 23743

Additional Fields

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