Imperial College London

Prof Jason P. Hallett

Faculty of EngineeringDepartment of Chemical Engineering

Professor of Sustainable Chemical Technology



+44 (0)20 7594 5388j.hallett Website




228bBone BuildingSouth Kensington Campus





Ionic Liquid Based Biorefining: This research aims to establish the core technologies and opportunities in an ionic liquid based biorefinery and identify the key science underpinning this concept. The biorefinery will produce biofuels and chemical feedstock materials from lignocellulosic biomass by first using specially designed ionic liquids to separate the biomass components (lignin, cellulose, hemicelluloses). All aspects of the separations process and several aspects of the conversions (specifically, the initial chemical- and bio-catalytic breakdown steps) are included, particularly important questions related to ionic liquid impact and recovery. The polysaccharides that are separated (cellulose, hemicelluloses) are enzymatically hydrolysed to fermentable sugars, with the impact of residual ionic liquid minimalized through a multi-pronged strategy involving solvent design and novel separations. This requires an investigation into the specific interactions of ionic liquids with the biological catalysts (enzymes, whole cells) vital to bioconversions, utilizing a variety of chemical biology-based tools. 

This is by nature a multi-disciplinary research problem. The underpinning molecular-scale chemical interactions of ionic liquids with biomass, proteins and whole cells will determine the productivity of the biorefinery. The impact of these individual elements on the overall process requires a detailed understanding of both the complex intermolecular interactions driving ionic liquid behavior and an appreciation for how these interactions can impact a chemical process. This places the research firmly at the interface between chemistry and chemical/biomolecular engineering.


Ionic Liquids: Ionic liquids (ILs) are a diverse group of salts that are liquid at ambient temperature.  ILs are polar solvents with varying degrees of hydrogen-bonding ability, negligible vapour pressures under process-relevant conditions and a wide range of tunable solvent properties. ILs have proven highly effective solvents for use in cellulose processing and have recently been demonstrated as effective at lignocellulose pretreatment and biomass fractionation. Anions with high hydrogen-bond basicity, such as chloride or acetate, yield ILs that dissolve cellulose, while bifunctional (protic and hydrogen-bond basic) anions can be employed to de-lignify biomass in partially aqueous ILs. This route simplifies the biorefining process, yielding potential energy savings. While ILs are ideal media for biomass deconstruction, the impact on bioconversions (e.g. biotolerance, IL recyclability) and opportunities for further conversions remain unknown. We explore the fundamental science underlying IL interactions in biocatalytic systems and developing efficient separations for biomass deconstruction and IL recovery. This requires an in-depth knowledge of IL solution behavior and interactions with proteins and cell membranes, the chemistry underlying biomass deconstruction, and the process variables essential to integrated biorefining.

silwood park

Lana, Latiffah, Selina, and Shahrul at the Miscanthus plot at Silwood Park

Deconstruction of biomass using ionic liquids: ILs can effectively pretreat numerous energy crops by separating the components (cellulose, hemicelluloses, lignin). This can be achieved by two main routes: dissolution or de-lignification. We focus on the latter route (the “Ionosolv” process) due to higher water tolerance (reduced energy inputs for biomass or IL drying), better lignin removal, accessible lignin recovery (without destroying the IL) and simplified processing. Our current research in this area focusses on the chemical interactions between ILs and the individual biopolymers leading to better separations, and the impact of the ILs on downstream processing to biofuels and platform chemicals.


cellulase enzyme

Cellulase enzyme attacking cellulose (picture and model from

Enzymatic hydrolysis of cellulose using protein-friendly ILs: The aim of this research is to determine what specific chemical effects ILs have on cellulase hydrolysis activity, then minimize negative impacts through IL design. Little data exists on IL-protein interactions (even less with these ILs), leaving insufficient (and enzyme-specific) data to try and understand molecular interactions between ILs and proteins. This research employs a multi-faceted approach including IL design and synthesis, protein engineering, and ion selection to achieve this aim. The project is collaborative with Dr Karen Polizzi of the Centre for Synthetic Biology and Innovation.

Other Ionic Liquids Research:

Process and Techno-economic Modelling of Ionic Liquid Biorefining (with Prof Nilay Shah, Centre for Process Systems Engineering)

Catalytic Production of Platform Chemicals from Biomass using Ionic Liquids (with Dr George Britovsek, Prof Charlotte Williams and Dr James Wilton-Ely, Department of Chemistry, and Dr Karen Wilson, Cardiff University)

Interactions of Ionic Liquids with Biopolymers (with Dr Paul Fennell and Dr Marcos Millan-Agorio, Department of Chemical Engineering)

Recycling Ionic Liquids

Interactions of Ionic Liquids with Cells

Interactions of Ionic Liquids with CO2 (with Prof Martin Trusler, Dr Paul Fennell, Department of Chemical Engineering, and Dr Niall Mac Dowell, Centre for Environmental Policy)

Current Research Associates:

Dr Agnieszka Brandt, Recycling of ionic liquids during biomass deconstruction.

Dr Alex Brogan, Stabilization of proteins in ionic liquids.

Dr Andreas Brohl, Ionic liquid interactions in biological systems.

Dr Coby Clarke, Design of biologically friendly ionic liquids.

Dr Maria Mota Martinez, Designing ionic liquids for  CO2 capture processes.

Dr Charles Romain, Renewable polymers from lignocellulose.

Current PhD students:

Gilbert De Gregorio (joint with T. Welton), Catalytic transformations of lignin in ionic liquids.

Liyana Ismail (joint with with Prof Tom Welton), Reactivity of biopolymers in acidic ionic liquids.

Paul Corbett (EPSRC-CASE studentship), Application of ionic liquids in fuels, biofuels and lubricants.

Clementine Chambon (joint with P. Fennell), Economical biorefining using ionic liquids.

Vivi Filippousi (Climate-KIC studentship, joint with Prof Donald Craig, J. Wilton-Ely), Platform chemicals from cellulose.

Florence Gschwend (Grantham Institute studentship, joint with P. Fennell), Remediation of CCA-treated waste wood using ionic liquids.

Shaochen Huang (joint with M. Trusler), Thermophysical properties of ionic liquids used for carbon capture.

Bing Tian, Novel hemicellulose extraction techniques.

Lisa Weigand (joint with T. Welton), Ionic liquid biorefining of willow.

Wei-Chien Tu, Celluose valorisation using ionic liquids.

Ollie Levers (joint with Dr Rob Law, Prof. Jon Lloyd), Synthetic Soils.

Meng (Angela) Chen, Valorisation of ionic liquid soluble lignin.

Shah Mostame (joint with P. Fenell, Prof. Geoff Kelsall), Use of ionic liquids in refinery separations.

Francisco Malaret, Biomass processing using ionic liquids.

Current Masters students:

Tianyi Chen, Catalytic valorisation of lignin.

Louis Hennequin, Ionic liquid bioremediation.

Isabella Lei, Recycling PLA using ionic liquids.

Linqian Li, HMF valorisation using ionic liquids.

Shahirah Loqman, Physical properties of ionic liquids used in carbon capture

Sophie Mason, Hemicellulose valorisation in ionic liquid biorefining.

Joseph Ogana, Catalysis in flow.

Harsh Shukla, Process modelling of an ionic liquid biorefinery.

Shubham Singh, Carbon capture with designer ionic liquids.

Clement Tang, Ionic liquid recovery of metals from waste electronics.

Liqing Xu, FDCA from cellulose produced in ionic liquids.


Past PhD students:

Sanan Eminov (joint with J. Wilton-Ely), Catalytic 5-HMF production from cellulose using ionic liquids.

Hazeeq Azman (joint with Prof Tony Cass, J. Wilton-Ely), Enhanced bioremediation with Rhodococcus using ionic liquids.

Latiffah Karim (joint with K. Polizzi), Metagenomic screening of cellulase enzymes for ionic liquid tolerance.

Shahrul SMS Nizan Zahari (joint with T. Welton), Interactions of cellulose with ionic liquids.