The application of infrared spectroscopy to investigate structure/activity relationships in heterogeneously catalysed hydro-deoxygenation reactions

Hydrogenation reactions in chemical manufacturing processes are typically performed using supported metal catalysts. These catalysts are used in large-scale commodity processes such as alkyne hydrogenations, as well as smaller scale fine chemical synthesis as typically encountered in the pharmaceutical and agri-chemical sectors. A "Holy Grail" in heterogeneous catalysis is to develop structure/activity relationships for selective hydrogenation reactions. Here, the goal is to understand how certain structural aspects of finely divided metal particles (dimensions typically 2-20 nm) facilitate access to particular chemical pathways. Such knowledge/awareness then enables reaction profiles to be manipulated via techniques such as selective poisoning of specific sites of the metal crystallites. A major barrier to implementing such catalyst optimisation strategies is the limited number of techniques that can be used to define the morphology (surface structure) of the metal crystallites. One such technique is infrared spectroscopy of chemisorbed probe molecules.

Over the last 10 years the Lennon group have developed the application of infrared spectroscopy (transmission and diffuse-reflectance) to determine the morphology of a series of alumina-supported Pd catalysts that are active for gas phase hydrogenations [1,2]. Catalyst conditioning strategies have then been employed to selectivity "quench" certain active sites. Examples of such work would be the selective hydrogenation of crotonaldehyde [3] and 3-butyne-2-one [4]. The figure on the left is intended to signify how certain 'edge' sites are uniquely active for the hydrogenation of 2-butanone to 2-butanol [4].

The project will be jointly supervised by Professor Lennon and Dr Gibson. It will commence in October 2018 and will utilise a range of high specification FTIR spectrometers to characterise a number of hydro-deoxygenation catalysts. The performance of the catalysts will then be evaluated in specific hydro-deoxygenation reactions of direct relevance to the agri-chemicals and fine chemicals manufacturing industries. Correlations of these two sets of measurements will then enable structure/activity relationships to be proposed. Catalyst modification strategies will be used to favourably influence catalyst selectivity. Regeneration procedures will be adopted for those catalysts exhibiting significant deactivation for continuing time-on-stream. Collectively, the project will provide the student with a sound grounding in the development of industrially relevant heterogeneously catalysed reaction systems, as well as experience in modern catalyst characterisation techniques.

The project is ideally suited to high-calibre graduates in Chemistry, Chemistry and Medicinal Chemistry and/or Chemical Physics. A tax-free stipend of ca. £15,000 p.a. for 3.5 years and the payment of all University fees are provided. Eligibility is restricted to EU citizens only.