TECHNISCHE UNIVERSITT MNCHEN

Lehrstuhl fr Technische Chemie II

Understanding elementary steps in

methanol-to-olefins chemistry

Sebastian Mller

Vollstndiger Abdruck der von der Fakultt fr Chemie der Technischen Universitt Mnchen

zur Erlangung des akademischen Grades eines

Doktors der Naturwissenschaften (Dr. rer. nat.)

genehmigten Dissertation.

Vorsitzender: Univ.-Prof. Dr.-Ing. K.-O. Hinrichsen

Prfer der Dissertation:

1. Univ.-Prof. Dr. J.A. Lercher

2. Univ.-Prof. Dr. K. Khler

Die Dissertation wurde am 15.12.2015 bei der Technischen Universitt Mnchen eingereicht

und durch die Fakultt fr Chemie am 25.01.2016 angenommen.

Fr meine Eltern

und Elisabeth

Acknowledgements

I

Acknowledgements

The success of this thesis is closely related to the help of many people to whom I want to

express my deepest gratitude.

First of all, I would like to thank Prof. Dr. Johannes A. Lercher for giving me the opportunity

to work on this stimulating topic, for excellent scientific discussions and the guidance

throughout the thesis. I enjoyed the freedom of research that I had and the lessons and anecdotes

which Johannes shared with me.

I am very grateful to Dr. Maricruz Sanchez-Sanchez for the excellent collaboration during

the last years. Her support, guidance and trust throughout my PhD thesis as well as numerous

stimulating discussions and all corrections are gratefully acknowledged.

I am also very grateful to my co-worker, Dr. Yue Liu, for being such a great partner. I

appreciated the collaboration a lot and wish him all the best for the future.

I would also like to thank Prof. Dr. Andr C. van Veen for the smooth collaboration we had

at the beginning of my PhD.

Furthermore, I would like to thank the BU Catalysts, Clariant Produkte (Deutschland)

GmbH (former Sd-Chemie AG) for financial support and interesting discussions in the

framework of MuniCat. In particular, I am very thankful to Prof. Dr. Richard Fischer and Dr.

Markus Tonigold for their help.

I am particularly indebted to my predecessor, Dr. Xianyong Sun, who helped me a lot at the

beginning of my PhD and introduced me into the secrets of the 10-fold unit. I also thank my

successor, Jrgen Hajdo, who joined me in the last months of my PhD, giving me new views

on our topic. Moreover, I thank Dr. Muthusamy Vishnuvarthan for help with catalyst

characterization at the beginning of my PhD.

I am very grateful to our technical staff in this group for their strong support. Xaver Hecht

helped me a lot with my setups and technical problems. I also would like to thank our current

and former secretaries, Ulrike Sanwald, Bettina Federmann, Stefanie Seibold, Karen Schulz

and Helen Lemmermhle. Andreas Marx and Martin Neukamm are gratefully acknowledged

as well.

I have to thank several students for their good work: Andreas Schiff, Benedikt Keller, Felix

Reiter, Johanna Wiethaler, Kathrin Arzt, Lorenz Schiegerl, Martin Riedl, Michael Sauer,

Acknowledgements

II

Philipp Buck, Philipp Fritsch, Thomas Steiner, Tobias Bruhm, Tyll Bodden, Vinzenz Luidl and

Wolfgang Strhof.

I am also thankful to Prof. Gary L. Haller for language work on my first paper and several

interesting discussions. Furthermore, I would like to thank Dr. Erika Ember and Dr. Carmen

Hssner for help with EPR measurements.

I would like to thank my colleagues and office mates Peter Hintermeier, Matthias Steib,

Yanzhe Yu, Anastasia Pashigreva, Ferdinand Vogelgsang, Sebastian Eckstein, Andreas

Ehrmeier, Sylvia Albersberger, Martina Braun, Yuanshuai Liu, Daniel Melzer and Eva

Schachtl.

I am deeply grateful to my parents for supporting me in any kind, not only during the past

years but my whole life. I also would like to thank my brother and my sister for all support.

Finally, I want to thank my girlfriend Elisabeth for helping and supporting me during the whole

period of my PhD studies. I am especially grateful to her for always having an open ear and

finding appropriate solutions. My girlfriend and my family always gave me some hope in dark

moments of my PhD.

Abbreviations

III

Abbreviations

AHFS Ammonium hexafluorosilicate

BAS Brnsted acid site

CBU Composite building unit

CHA Chabazite

CSTR Continuously operated stirred tank reactor

DICP Dalian Institute of Chemical Physics

DME Dimethyl ether

DMM Dimethoxymethane

DMTO Dimethyl ether or methanol-to-olefin

DSC Differential scanning calorimetry

EFAL Extra-framework aluminum

EPR Electron paramagnetic resonance

FAU Faujasite

FCC Fluid catalytic cracking

HT Hydrogen transfer

I.D. Inner diameter

IR Infrared

IZA International Zeolite Association

LAS Lewis acid site

LDI Laser desorption/ionization

LPG Liquefied petroleum gas

MALDI Matrix-assisted laser desorption/ionization

MFI Mordenite Framework Inverted

MIHT Methanol-induced hydrogen transfer

MOGD Mobil olefins to gasoline and distillate process

MS Mass spectrometry

MTG Methanol to gasoline, methanol-to-gasoline

MTH Methanol to hydrocarbons, methanol-to-hydrocarbons

MTO Methanol to olefins, methanol-to-olefins

Abbreviations

IV

MTP Methanol to propene, methanol-to-propene

NMR Nuclear magnetic resonance

No. Number

OCP Olefin cracking process

OIHT Olefin-induced hydrogen transfer

PFR Plug-flow reactor

RO Reaction order

SAPO Silicoaluminophosphate

STF Syngas to fuels

TGA Thermogravimetric analysis

TIGAS Topse integrated gasoline synthesis

TOF Turnover frequency, time of flight

TOS Time on stream, time-on-stream

TPD Temperature-programmed desorption

TPO Temperature-programmed oxidation

TPSR Temperature-programmed surface reaction

Abstract

V

Abstract

High local methanol concentrations induce the formation of strongly adsorbed oxygen-

containing species on Brnsted acid sites of H-ZSM-5 catalysts in methanol-to-olefins

conversion. These oxygenates cause fast deactivation and are transformed with time on stream

into aromatics remaining attached to Brnsted acid sites. The major pathway leading to

aromatics and paraffins involves the hydrogen transfer reaction from methanol to olefins at

Lewis acid sites, forming formaldehyde and paraffins. Furthermore, formaldehyde is key

compound for first C-C bond and olefins formation, as well as in deactivation.

Hohe lokale Methanolkonzentrationen fhren in der Methanol-zu-Olefin-Umsetzung zur

Bildung stark adsorbierter sauerstoffhaltiger Spezies an Brnsted-Surezentren von H-ZSM-5

Katalysatoren. Diese sauerstoffhaltigen Verbindungen bewirken eine schnelle Deaktivierung

und werden mit der Zeit in Aromaten umgewandelt, die an Brnsted-Surezentren adsorbiert

bleiben. Der wesentliche Pfad zu Aromaten und Paraffinen schliet die

Hydrogentransferreaktion von Methanol zu Olefinen an Lewis-Surezentren ein, wodurch sich

Formaldehyd und Paraffine bilden. Zudem ist Formaldehyd Schlsselkomponente fr die

Bildung der ersten C-C-Bindung und von Olefinen, ebenso wie in der Deaktivierung.

Table of Contents

VI

Table of Contents

Acknowledgements ...............................................................................................I

Abbreviations .................................................................................................... III

Abstract ............................................................................................................... V

Table of Contents............................................................................................... VI

1. Introduction ................................................................................................. 1

1.1 General introduction ....................................................................................... 2

1.2 Catalysts in methanol-to-hydrocarbons (MTH) conversion ....................... 3

1.2.1 Zeolites ................................................................................................................. 4

1.2.1.1 General background .................................................................................................. 4 1.2.1.2 Methods for adjusting the chemical properties of zeolites .................................... 6 1.2.1.3 Structure type Mordenite Framework Inverted (MFI) ......................................... 6

1.3 Mechanistic aspects in MTH reaction ........................................................... 8

1.3.1 Reaction network ................................................................................................ 8

1.3.2 Generation of first hydrocarbon species from methanol/DME ..................... 9

1.3.3 Autocatalysis and hydrocarbon pool mechanism .......................................... 10

1.3.4 Paring and side-chain reaction concepts ........................................................ 13

1.3.5 Dual cycle concept ............................................................................................ 15

1.3.6 Recent insight into the autocatalysis and hydrocarbon pool co