Kinetic and Mechanistic Investigation of Asymmetric Organocatalytic Reactions
Author(s)
Zotova, Natalia
Type
Thesis or dissertation
Abstract
The utilisation of the reaction progress kinetic methodology to advance the
mechanistic understanding of the asymmetric proline catalysed aldol and
α-aminoxylation reactions is demonstrated in this work. Mechanistically
meaningful reaction rate laws that describe the catalytic cycles of these
reactions are derived experimentally, using initially the power law driving
force analysis. With the aid of the employed kinetic methodology it is
shown that the processes occurring on the catalytic cycle can be
deconvoluted from the influence of the reactions occurring off the cycle,
and each may be studied separately. It is also shown that the synergetic
efforts of experimental kinetic and spectroscopic studies are capable of
suggesting and ultimately disclosing the role of additives in these reactions
and understanding of catalyst deactivation pathways.
In order to obtain more support towards the kinetically derived mechanistic
implications, kinetic isotope studies of the aldol reaction were performed.
Experimental kinetic data fit to the derived rate model helped to assess and
refine the proposed mechanism of the aldol reaction in a quantitative
manner and consider other factors that potentially may affect the reaction.
The rationalisation of the difference in kinetic behaviour of the aldol and a-
aminoxylation reactions is discussed. The proposed elucidation is also
supported by reaction simulations performed using COPASI simulation
software.
mechanistic understanding of the asymmetric proline catalysed aldol and
α-aminoxylation reactions is demonstrated in this work. Mechanistically
meaningful reaction rate laws that describe the catalytic cycles of these
reactions are derived experimentally, using initially the power law driving
force analysis. With the aid of the employed kinetic methodology it is
shown that the processes occurring on the catalytic cycle can be
deconvoluted from the influence of the reactions occurring off the cycle,
and each may be studied separately. It is also shown that the synergetic
efforts of experimental kinetic and spectroscopic studies are capable of
suggesting and ultimately disclosing the role of additives in these reactions
and understanding of catalyst deactivation pathways.
In order to obtain more support towards the kinetically derived mechanistic
implications, kinetic isotope studies of the aldol reaction were performed.
Experimental kinetic data fit to the derived rate model helped to assess and
refine the proposed mechanism of the aldol reaction in a quantitative
manner and consider other factors that potentially may affect the reaction.
The rationalisation of the difference in kinetic behaviour of the aldol and a-
aminoxylation reactions is discussed. The proposed elucidation is also
supported by reaction simulations performed using COPASI simulation
software.
Date Issued
2008-06
Date Awarded
2008-08
Advisor
Blackmond, Donna
Creator
Zotova, Natalia
Publisher Department
Chemical Engineering and Chemical Technology
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)