Formation of ethyl benzene and styrene by side chain methylation of toluene using different zeolite catalysts [Elektronische Ressource] / Mohamed Hassen Ahmed Abdallah

Mohammed Moudjou

Informations

• Publié par: rheinisch-westfalischen_technischen_hochschule_-rwth-_aachen
• Publié le: 01 janvier 2011
• Nombre de lectures: 27
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Formation of ethyl benzene and styrene by side chain
methylation of toluene using different zeolite catalysts




Von der Fakultät für Mathematik, Informatik und
Naturwissenschaften der RWTH Aachen University zur
Erlangung des akademischen Grades eines Doktors der
Naturwissenschaften genehmigte Dissertation



vorgelegt von


Master - Chem.
Mohamed Hassen Ahmed Abdallah
aus
Aswan - Ägypten

Berichter: Universitätprofessor Dr. Wolfgang F. Hölderich
Universitätprofessor Dr. Wolfgang Stahl

Tag der mündlichen Prüfung: 04.05.2011





Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek online verfügbar.


ACKNOWLEDGEMENT
The work reported here has been carried out at the chair of Chemical Technology and
Heterogeneous Catalyst of the Institute of Fuel Chemistry and Physical Chemistry
Engineering the Faculty of Mathematics, computer science and science, RWTH Aachen
University under supervision of Prof. Dr. Wolfgang F. Hölderich between January 2007 and
October 2010.

First of all, I would like to acknowledge many people for helping me during my doctoral
work.
Words are no real assistance to express my deepest gratitude and thanks to Prof. Dr.
Wolfgang Hölderich, for his generous time and commitment. Throughout my doctoral work
he encouraged me to develop independent way of thinking and research skills. He continually
stimulated my analytical thinking and greatly assisted me with scientific writing.
Many thanks for Prof. Dr. Wolfgang Stahl for his useful notes and suggestion to complete this
dissertation succcefully.
This dissertation would not have been possible without the technical support of the
analytic team. Mrs. E. Biener, Mrs. H. Fickers-Boltz, Mrs. M. Nägler, Mrs. N. Avraham and
Mr. Vaessen are greatly appreciated for the competent support and nice work atmosphere.
I am extremely grateful for the assistance and advices I received from Dr. Michael
Valkenberg and Dr. Bernhard Rusbüldt.
I extend many thanks to all my colleagues and friends, who provided very nice and
friendly atmosphere and supported me with advices and actions.
I extend special thanks to my family who provided me a good atmosphere to study.
I gratefully acknowledge the Ministry of Higher Education, Sector of Egyptian Missions.
Of course, despite all the assistance provided by Prof. Dr. Hölderich and others; I alone
remain responsible for the content of the following, including any errors or omissions, which
may unintentionally remain. Finally, I am very thankful to my parents, my wife and children
for their love, understanding, encouragement and support

Mohamed H. Abdallah




II
Abbreviations used:

BET – Brunauer, Emmett and Teller, surface area and pore size distribution analysis
EB - Ethyl benzene
St – Styrene
TMT – Tetramethyl benzene
TMB – Trim
Xy – Xylenes (o, m and p- Xylene)
GC – Gas Chromatography
GC-MS – Gas Chromatography with Mass Spectrometry analysis
TO – Toluene
ICP-AES – Inductively Coupled Plasma Atomic Emission Spectrophotometry
MeOH – Methanol
GHSV – Gas Hourly Space Velocity
XRD – X-Ray Diffraction analysis
GRT – Gas Residence Time
mol. % mole percent
III
Table of contents

1. Introduction………………………………………..……………………………………….1
1.1. Catalysis……………………………………………………………..…………………..1
1.2. Side chain alkylation……………………...……………………..…………………..…..2
1.3. Zeolites……………………………………………………………………………...…...4
1.3.1. HZSM-5, NaX, NaY as well as NaBEA zeolites …..……………………..……....…..5
1.3.2. Application of zeolites…………………..…………………………………....…...…..9
1.4. Reported catalytic systems for the alkylation of toluene …………………...................12
1.5. The reaction mechanism…...…………………………….………………………….....15
1.5.1. The reaction in the presence of acidic catalyst……...………………………...….…..15
1.5.2. Reaction in the presence of basic catalysts……..………………….…………...…....16
2. Alkylation of toluene with methanol over ZSM-5 catalysts……………….…………...20
2.1. Acidity and basicity…..………………………………………….…………………….20
2.1.1. Pure HZSM-5………………………………………………………………………...20
2.1.2. HZSM-5 different metal exchanged….…………...…..………………………….….21
2.1.2.1. Pyridine FT-IR…..………………………………………………………….21
2.1.2.2. NH - TPD analyses………..……………………………………………….............23 3
2.1.2.3. CO - TPD analyses……………………………………………………………...…24 2
2.2. BET analyses……..…………………………………………………………………….25
2.3. ICP AES analyses……………………………………………………………………...26
2.4 Alkylation of toluene with methanol over HZSM-5 catalysts ……...………………….27
2.5. Influence of reaction time on the performance of the catalyst ..…………………….…34
2.6 Effect of different concentrations of NaOH in the treatment HZSM-5………………...35
2.7 Effect of alkali metal addition on HZSM-5 catalyst….………………………………...38
2.7. 1. Impregnation method……………………………………………………………….38
2.7.1.1. Impregnation with RbCl……………………………………………………….......38
2.7.1.2. Impregnation with CsCl…………………………………………………….….......42
2.7.1.3 Relation between catalytic performance and different Rb content on ZSM-5……...46
2.7.1.3.1 Conversion of toluene…………………………………………………………….46
2.7.1.3.2 Selectivity of ethyl benzene……………………………………………………....47
2.7.1.3.3 Selectivity of styrene……………………………………………………………..48
2.7.1.3.4 Selectivities of xylenes……………………………………………………………49
2.7.1.3.5 Selectivity of benzene…..………………………………………………………...50
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2.7.1.4 Relation between catalytic performance and different Cs contents on ZSM-5…….51
2.7.1.4.1 Conversion of toluene……………..…………………………….………………..51
2.7.1.4.2 Selectivity of ethyl benzene…………………...………………………………….52
2.7.1.4.3 Selectivity of styrene…………………………...…………………………………53
2.7.1.4.4 Selectivities of xylenes………………………….………………………………..54
2.7.1.4.5 Selectivity of benzene……………………………..……………………………...55
2.7.2 Effect of different metal ions exchanged on HZSM-5..…………………….…..…....56
2.7.2.1 HZSM-5 treated with 0.025 M NaCl solution…………………...……………........57
2.7.2.2. HZSM-5 treated with 0.025 M KCl solution…..……...…..……………………….58
2.7.2.3. HZSM-5 treated with 0.025 M RbCl solution..………...……………...…………..59
2.7.2.4 HZSM-5 treated with 0.025 M CsCl solution..…………....………..........................60
2.8 Comparison between different alkali metal ion exchanged HZSM-5…...…….………..61
3. Alkylation of toluene with methanol over X- and Y zeolit catalysts….…………...…..64
3.1 X-ray………………………………………………………………………………..…..64
3.2 FTIR investigation of NaY-zeolite catalysts ……………………………………….…..64
3.3 Acidity and Basicity…………………………………………………………………….65
3.4 ICP AES analyses………………….………...…………………………………….…...69
3.5 BET analyses ………………………………….……………………………………….70
3.6 Catalytic activity of X- and Y-zeolite catalysts ………………………………………..71
3.6.1 Comparison between NaY and NaX-zeolite for alkylation reaction………………....71
3.6.2 Influence of the different salts for the ion exchange of NaY-zeolite…...……….……72
+ 3.6.2.1. Effect of different concentrations of Na metal on NaY zeolite……...……………73
+ 3.6.2.2 K ion exchanged NaY zeolite…..…………………………………………….......74
+ 3.6.2.3 Rb ion exchanged NaY zeolite.……..……………………………………………..76
+ 3.6.2.4 Cs ion exchanged NaY zeolite ……..……………………………………………..77
3.7. Effect of different metal ions exchanged NaY zeolite……..………..………………....79
4. Alkylation of toluene with methanol over BEA zeolite catalyst...………… ………......84
4.1 Acidity and Basicity …………………………………………………………………....84
4.1.1 NH -TPD analyses..……………………...………………………………….………..84 3
4.1.2 CO -TPD analyses..…...……………………………………………………………...85 2
4.2 ICP AES analyses……...…………………………..………….………………………..86
4.3 XRD analyses…………………………………………………………………………..86
4.4 Alkylation of toluene over calcined and uncalcined NaBEA…………………………..87
4.5 Comparisons between different calcined and uncalcined NaBEA zeolite……….……..90
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4.6 Effect of different reaction temperatures on alkali metal ion exchanged NaBEA
zeolite…………………………………..……………………………………………….94
4.6.1 NaBEA zeolite treated with 0.025 M KCl solution…………....………………..........95
4.6.2 NaBEA zeolite treated with 0.025 M Rb solution ….…….…………………….........96
4.6.3 NaBEA zeolite treated with 0.025 M CsCl solution..……………….………...….…..97
4.7 Comparison between different alkali metal ion exchange over NaBEA zeolite………..91
5. Conclusions and outlook ………………………………………………………………..101
6. Materials apparatus and experimental ………..………...……………………….........105
6.1 Materials……………………………………….…………………………………….....105
6.2 Preparation of the starting material ………….……………………………….….…….105
6.3 Catalytic reaction…………………………….…………………………………….…..106
6.4 Fixed bed reactor for alkylation reaction….…..………………………………..……...107
6.5 Calculations…..…………………….………………………………………………......109
6.6 Product analyses…..…….………….……………………