Investigating transition metal formyl complexes for homogeneous syngas conversion
File(s)
Author(s)
Gates, Sarah
Type
Thesis
Abstract
The conversion of synthesis gas, (syngas; a mixture of CO and H2), to liquid fuels has been a process that has been studied for more than a century. Current heterogeneous operating procedures are poorly understood and as such are unselective, requiring costly refining to separate the desired products. It has long been hoped that an alternative homogenous process may allow for the mechanistic insight and understanding to rationally design the conversion of syngas to specific products. This thesis aims to explore the steric and electronic environment of the carbonyl ligand within iron transition metal complexes, as a model for homogenous syngas conversion. Particular attention has been paid to the first step of syngas conversion; hydride transfer to form a formyl complex.
Chapter 1 provides a general overview of the developments to date, in both heterogeneous and homogenous systems for syngas conversion. The use of frustrated Lewis pairs to hydrogenate a carbonyl directly from hydrogen is also discussed in addition to a discussion of the various mechanisms and intermediates present in a homogenous system.
Chapter 2 describes the reduction and subsequent reactivity of the carbonyl complex [Fe(CO)2(Cp*)][BArF24]. Hydrogenation, directly using hydrogen gas in conjunction with FLP systems is discussed.
Chapter 3 describes the use of bisphosphine ligands to impart electron density and stability to transition metal formyl complexes. This work is also discussed in relation to FLP hydrogenation.
Chapter 4 gives an overview of the reactivity of some neutral carbonyl complexes and their reactivity with FLP systems.
Chapter 5 provides an alternative approach for future homogenous transition metal carbonyl reduction chemistry. Some preliminary results are included to support the investigation of such a route for further study.
Chapter 6 details experimental procedures used in this work.
Chapter 1 provides a general overview of the developments to date, in both heterogeneous and homogenous systems for syngas conversion. The use of frustrated Lewis pairs to hydrogenate a carbonyl directly from hydrogen is also discussed in addition to a discussion of the various mechanisms and intermediates present in a homogenous system.
Chapter 2 describes the reduction and subsequent reactivity of the carbonyl complex [Fe(CO)2(Cp*)][BArF24]. Hydrogenation, directly using hydrogen gas in conjunction with FLP systems is discussed.
Chapter 3 describes the use of bisphosphine ligands to impart electron density and stability to transition metal formyl complexes. This work is also discussed in relation to FLP hydrogenation.
Chapter 4 gives an overview of the reactivity of some neutral carbonyl complexes and their reactivity with FLP systems.
Chapter 5 provides an alternative approach for future homogenous transition metal carbonyl reduction chemistry. Some preliminary results are included to support the investigation of such a route for further study.
Chapter 6 details experimental procedures used in this work.
Version
Open Access
Date Issued
2016-05
Date Awarded
2016-08
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Ashley, Andrew
Diez-Gonzalez, Silvia
Sponsor
British Petroleum Company
Publisher Department
Chemistry
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)