Inverse Liquid Chromatography for reaction catalyst monitoring

Lead Research Organisation: Imperial College London
Department Name: Chemical Engineering

Abstract

The objective of the project is to develop a method for the characterisation of catalysts packed Liquid Chromatography (LC) column, whilst chemical reactions are occurring. Such an approach will expand the Inverse liquid chromatography (ILC) work already being carried out in the group. Such investigations for key catalyst properties, such as microporosity and pore size, have been previously reported via Inverse gas chromatography (IGC). However, a large majority of catalytic reactions occur in a liquid medium and therefore, in these circumstances' interactions between catalyst pores and solvent molecules, for example, are not accounted for.
An ILC based approach to catalyst characterisation would effectively allow simultaneous catalyst characterisation and reaction processes to occur. The unique approach would allow the critical relationship between catalyst performance and catalyst properties to be directly investigated.
Currently, the retrosynthesis and reaction monitoring for heterogenous catalysed reactions is both time consuming and inefficient. The main hypothesis of this proposal is that the ILC column would be an ideal reaction space for the analysis of changes in a catalysts physical and chemical properties, following a reaction, as the process allows both facile condition changes (solvent, temperature, pressure, pH, etc.) and tandem catalyst and product analysis. There are novel opportunities for analysing the changes in the physical properties of the catalyst, i.e. changes in pore / active site availability, surface area, site interaction energies and catalytic leeching into the reaction mixture.
The project aims to investigate whether catalytic reactions can be monitored and optimised using an ILC column, and to develop a reliable and repeatable methodology for catalytic reaction analysis and optimisation. It is theorised that this approach will provide an overall picture of catalyst-reaction material interactions during an optimisation process, while also enabling the rapid assessment of reactions involving molecules in which heteroatoms and functional groups may be changed to effect reaction mechanism and rate. This method will provide much needed information regarding the changes that occur on the catalytic surface when the stoichiometry, reactants or reaction conditions are varied. An initial "proof of concept test" would examine what changes in the catalysts physical and chemical properties might be monitored while also looking at other industrially critical phenomena such as catalytic leaching. The intention is that three different heterogenous catalytic systems would be investigated during the research programme. These systems would be chosen based on their industrial importance, academic interest and technical viability from a chromatographic instrumentation perspective. From each system it should be possible to determine different physical and chemical data and gain a complete picture of the ILC retrosynthetic catalyst analysis technique.
The research would be completed within the time frame of three to three and a half years, in addition to attending various seminars and professional skills courses organised by the chemical engineering department and others to develop communication skills and gain an insight into developing research areas.

Publications

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Description Often continuous flow reactions for biomass conversion are diffusion limited, with process being catalysed by cylindrical extrudates of Zeolites, MOFs and ZIFs. In this project a novel method called zero-length column was used and adapted for cylindrical measurements for more accurate determination of diffusion constants. These diffusion constants trend well with those measured by other methods such as PFG-NMR, which has often been an issue in the research space. These diffusion constants were then used to explain the reaction selectivity, activity and catalyst lifetime. Monolithic MIL-88B was synthesised to improve the packing efficiency and decrease pressure drop in columns, for the use of a transfer hydrogenation reaction in biomass conversion.
Exploitation Route Students may be interested in further applications for monolithic MIL-88B and the comparisons of the ZLC method to further diffusion measurement techniques such as Infra-red and neutron scattering. The experimental model created may be used to obtain more accurate diffusion constants for use in reaction engineering and material separations.
Sectors Agriculture, Food and Drink,Chemicals,Environment,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology

 
Description Separation of petrochemicals using novel materials - Shell
First Year Of Impact 2021
Sector Chemicals
 
Title Zero-length column for single packed particles 
Description On a HPLC system using a small column in which the time space is small that that of the diffusion constant, a material is packed and loaded with analyte. This is then swept with pure mobile phase and the desorption curve allows the determination of the diffusion constant. 
Type Of Material Technology assay or reagent 
Year Produced 2021 
Provided To Others? No  
Impact The new model is much more accurate 
 
Title cylindrical model for diffusion in ZLC 
Description this experimental model allows for the application of ZLC to cylindrical particles 
Type Of Material Data analysis technique 
Year Produced 2020 
Provided To Others? No  
Impact Industrial collaboration 
 
Description Shell separation study 
Organisation Shell International Petroleum
Department Shell UK Ltd
Country United Kingdom 
Sector Private 
PI Contribution Shell - provides materials I test materials and compare results, providing data for process scale-up
Collaborator Contribution transfer on materials, association with other research groups in the field.
Impact none yet
Start Year 2021