On the Mechanism of the Aerobic Oxidation and Dehydrogenation of Alcohols on Palladium and ...

216 Pages·2005·3.18 MB·English

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On the mechanism of the aerobic
oxidation and dehydrogenation
of alcohols on palladium and
platinum
Doctoral Thesis
Author(s):
Keresszegi, Csilla
Publication date:
2005
Permanent link:
https://doi.org/10.3929/ethz-a-004998066
Rights / license:
In Copyright - Non-Commercial Use Permitted
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Diss. ETH No 16008

On the Mechanism of the Aerobic Oxidation
and Dehydrogenation of Alcohols
on Palladium and Platinum

A dissertation submitted to the
Swiss Federal Institute of Technology (ETH) Zurich
for the degree of Doctor of Sciences

presented by

Csilla Keresszegi
Dipl. Chem. University of Szeged (JATE), Hungary
born July 13, 1976
Hungarian citizen

accepted on the recommendation of
Prof. Dr. A. Baiker, examiner
Prof. Dr. R. Prins, co-examiner

2005
“Imagination is more important than knowledge...”
Albert Einstein
Acknowledgment

I owe sincere thanks to the many people who have supported me and encouraged
me to pursue the study of chemistry, particularly during my doctoral studies.
First, I would like to thank my supervisor, Prof. Dr. Alfons Baiker, for
giving me the opportunity to complete doctoral studies in his group. During the
past five years he fulfilled all of my wishes with regard to giving me scientific
freedom, broadening the research topic, providing instrumentation, and
interesting courses. The atmosphere in his group was pleasant and stress-free. I
am grateful to him for the very fast review of my work, his helpful remarks, his
generosity, and his confidence in me. The freedom I had during my doctoral
work made it seem like a great adventure.
I would like to thank my co-examiner, Prof. Dr. Roel Prins, for the careful
and proficient review of my thesis and for his instructive remarks.
I cannot be grateful enough to my Hungarian “daily supervisor”, Dr.
Tamas Mallat, who remained interested in my research and was always ready to
advise me. He was my strongest scientific critic! I had to learn to convince him
and others and also how to stick to my opinion. His friendly and incredible calm
manner helped to get us through some occasional hefty discussions. I am very
grateful to him for correcting my English and for making my manuscripts
“reader-friendly”. His help was especially valuable, because I did not speak
English when I arrived in Zurich.
Many thanks go to Dr. Jan-Dierk Grunwaldt, who made me interested in
XAS and with whom I spent a few night shifts at beamline X1 at HASYLAB. I
acknowledge him for all the XPS and XAS spectra, and data analysis in this
dissertation. Thanks are due to HASYLAB at DESY for providing beamtime and
to the beamline staff for the support during the measurements. Philippe Trüssel
and Max Wohlwend are kindly acknowledged for their valuable support in the
design of the in situ setup. Furthermore, I thank Dr. Frank Krumeich for TEM
and SEM measurements.
vi
I wish to thank Prof. Dr. Thomas Bürgi for teaching me the basic steps in
spectroscopy, for being a jogging mate and for his major contribution to the
SOLA relay race over all the years. He is not only an excellent researcher but also
an outstanding runner!
Lots of thanks go to Dr. Davide Ferri, the expert on ATR–IR
spectroscopy. He shared an office with me, and after leaving the ETH for almost
two years, he returned to our group for the last year of my doctoral work. Lucky
me! We did some great experiments together, and he showed me how to
interpret the IR spectra.
I know that it was sometimes difficult for those directly involved in my
research activities. However, I am glad that finally everyone has profited from the
collaboration and survived the time with me!
I wish to thank Ronny Wirz for sharing an office with me, solving my
computer problems, and especially for making available the IR spectrometer with
his ATR setup. Since his instrument was always in top condition, more than
90 % of my ATR measurements went according to plan. I also thank my two
Italian office mates, Norberto Bonalumi and Marco Piacentini, for the good
atmosphere.
During the past five years, I have met many nice colleagues, most of
whom deserve to be thanked for some reasons. If I were to list them all there
would be more men than women on the list. This is clear, because when I started
my work, there was only one female doctoral candidate in the Baiker group, and
25 male students and scientific staff. To tell the truth, I enjoyed this situation
and made the most of it… Among others, I would like to mention two excellent
Swiss chemical engineers, Dr. Leo Schmid and Dr. Niklaus Künzle, who first
took me hiking and climbing in the mountains, and who organized the group
hiking tours. Moreover, when we moved from the ETH laboratory in the city
centre to the Hönggerberg they taught me how to make proper joints to rebuild
my experimental setup and the fume hood. I cannot mention all the others, but
it was a pleasure to work in this group.
As well as conducting experiments I regularly organised the SOLA relay
race. Sometimes our team was made up only of members of the Baiker group
and three times members of the Prins group joined us to make a “Prince &
Baker” team. Therefore, I thank all my enthusiastic running mates. With runners
like Simon Diezi and Dr. Andy Gisler, I can never fail. Moreover, I thank the
marathon runner, Dr. Gerhard Pirngruber, for providing “half” a group, which
was always in good shape for the competitions. Many thanks go to Dr. Jeroen A.
vii
van Bokhoven and Martin Kuba, not only for their contribution to the SOLA,
but also for regularly taking me with them for indoor climbing.
I would like to acknowledge Dr. Károly Borszéky, for making my arrival
in Zurich so smooth and for helping me to adapt to this completely different
way of life. One would think it would be easy to come to Switzerland from
Hungary. It was not! Not for me. Therefore, thank you, Karcsi, and also for
making me keen on taekwondo.
I also want to say a big “thank-you” to Dr. Katalin Balázsik and Dr.
Mónika Varga for their friendship and support all these years. Furthermore, I am
grateful to the supervisor of my diploma thesis, Prof. Dr. Árpád Molnár, through
whom I became interested in basic research, and who taught me organic
chemistry on a special way, and encouraged me to come to the ETH.
I would like to express my gratitude to my parents and brothers, who
allowed me to go abroad and accepted all of my sudden, hectic decisions. Many
thanks for their patience and for giving me so much freedom.

And at last:
Dear Davide, Marco, Matteo, Micha, Niels, Norby, Ronny, Simon, and Tomek! It was soooo
great that the day before my submission you looked up one-one of my Chapters quickly to
check whether everything is still complete after all my changes and corrections. Thank you
very much!

Table of Contents

Acknowledgment……………………………………………………………....v
Table of Contents……..……………………...…………………….…...……ix
Summary…………………………………...………………………………..xiii
Zusammenfassung………..……………………………………….………...xvii

Chapter 1 General Introduction………..…………………………………...1
1.1 Heterogeneous Catalytic Oxidation of Alcohols………………………...1
1.2 Supported Pt-Group Metals in Alcohol Oxidation……………………...2
1.2.1 Reaction Mechanism
1.2.2 Reaction Conditions
1.2.3 Catalyst Deactivation
1.2.4 Catalyst Promoters
1.2.5 Application Range of Supported Pt-Group Metals
1.3 In Situ Characterization of Catalysts in Liquid-Phase Reactions….……13
1.3.1 X-ray Absorption Spectroscopy
1.3.2 Attenuated Total Reflection Infrared Spectroscopy
1.4 Scope of the Thesis…………………………………………………….19
References

Chapter 2 Experimental…………………...………………………………27
2.1 Catalysts.………………………………………………………………27
2.2 Methods……………………………………………………………….28
2.2.1 Catalytic Studies in a Batch Reactor
2.2.2 X-ray Absorption Spectroscopy
2.2.3 Infrared Spectroscopy
2.2.4 Analytical Methods
2.2.5 X-ray Photoelectron Spectroscopy
2.2.6 Electron Microscopy
References

Chapter 3 Transfer Dehydrogenation of Alcohols.………………………..37
3.1 Introduction…………………………………………………………...37
3.2 Experimental…………………………………………………………..38
x
3.2.1 Materials
3.2.2 Methods
3.3 Results…………………………………………………………………39
3.3.1 Influence of Catalysts and Reaction Conditions
3.3.2 Scope and Limitations of the Pd–Cyclohexene System
3.4 Discussion……………………………………………………………..46
3.5 Conclusion…………………………………………………………….48
References

Chapter 4 On the Role of Oxygen in Alcohol Oxidation……..…………...51
4.1 Introduction…………………………………………………………...51
4.2 Experimental…………………………………………………………..52
4.2.1 Materials
4.2.2 Catalytic Studies
4.2.3 ATR–IR Spectroscopy
4.3 Results…………………………………………………………………54
4.3.1 Reaction Network
4.3.2 Catalytic Dehydrogenation and Oxidation of Cinnamyl Alcohol
4.3.3 ATR–IR Spectroscopy
4.4 Discussion……………………………………………………………..62
4.4.1 Oxidative Removal of Degradation Products
4.4.2 Generalization of the Observations
4.5 Conclusions……………………………………………………………66
References

Chapter 5 Oxidation of Cinnamyl Alcohol over Pd/Al O Studied
2 3
by XAS………………………………………………………….71
5.1 Introduction…………………………………………………………...71
5.2 Experimental…………………………………………………………..72
5.2.1 Materials
5.2.2 Alcohol Dehydrogenation in the EXAFS cell
5.2.3 Alcohol Dehydrogenation in a Slurry Reactor
5.2.4 EXAFS Analysis
5.3 Results and Discussion………………………………………………...73
5.3.1 Catalyst Reduction during Dehydrogenation
5.3.2 Oxidation State of Pd during Oxidative Dehydrogenation
5.4 Conclusions……………………………………………………………78
References

Chapter 6 Alcohol Oxidation over Bi-Promoted Pd: A Preliminary Study..81
6.1 Introduction…………………………………………………………...81
6.2 Experimental…………………………………………………………..82
Table of Contents xi
6.3 Results and Discussion………………………………………………...83
6.4 Conclusion…………………………………………………………….87
References

In Situ
Chapter 7 Oxidation State of Bi–Pd/Al O Studied by XAS…....…89
2 3
7.1 Introduction…………………………………………………………...89
7.2 Experimental…………………………………………………………..90
7.2.1 Materials
7.2.2 Catalytic Studies in a Slurry Reactor
7.2.3 Catalytic Studies in the EXAFS Cell
7.2.4 X-ray Absorption Spectroscopy
7.2.5 X-ray Photoelectron Spectroscopy
7.3 Results and Discussion………………………………………………...93
7.3.1 Choice of Catalysts and Reaction Conditions
7.3.2 Investigation of Pd/Al O during Alcohol Oxidation
2 3
7.3.3 Structure of the Bimetallic Catalyst
7.3.4 Investigation of Bi–Pd/Al O during Alcohol Oxidation
2 3
7.3.5 Implication to the Reaction Mechanism over Bi-Promoted Pd
7.4 Conclusions………………………………………………………..…110
References

Chapter 8 A Simple Discrimination of the Promoter Effect……………..115
8.1 Introduction………………………………………………………….115
8.2 Experimental…………………………………………………………116
8.2.1 Materials
8.2.2 Methods for Catalyst Characterization
8.2.3 Alcohol Dehydrogenation
8.2.4 Catalytic Hydrogenation
8.3 Results………………………………………………………………..119
8.3.1 Catalyst Characterization
8.3.2 Alcohol Dehydrogenation: Preliminary Screening
8.3.3 Dehydrogenation of 1-Phenylethanol
8.3.4 Dehydrogenation of 2-Octanol
8.3.5 Dehydrogenation of Cinnamyl Alcohol
8.4 Discussion……………………………………………………………130
8.5 Conclusions…………………………………………………………..132
References

Chapter 9 Surface Reactions Studied by ATR–IR. Part 1:
Oxidation of Benzyl Alcohol……………....………………….137
9.1 Introduction………………………………………………………….137
9.2 Experimental…………………………………………………………139