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





Prof Jason Hallett received his PhD in Chemical Engineering from the Georgia Institute of Technology. He joined Imperial College, first with a Marshall-Sherfield Postdoctoral Fellowship in Sustainable Chemistry and in 2014 was appointed a Senior Lecturer in the Department of Chemical Engineering, before promotion to Reader in 2016 and Professor in 2018. He has authored over 90 articles and holds 4 patents. His current research interests involve the solvation behaviour of ionic liquids and the use of ionic liquids in the production of lignocellulosic biofuels, sustainable chemical feedstocks, vaccine manufacturing and waste recycling (particularly for metal-contaminated solid materials). This research is supported by both the UKRI and industry.

Prof Hallett currently serves as a core member of the Supergen Bioenergy Hub and the Future Vaccines Manufacturing Research Hub.

He is also co-founder of Lixea, a spin-out company based on the group's ionic liquid biorefinery research. 

PhD opportunities:

We have several opportunities we are currently seeking candidates for


Optimisation of ionic liquid-based biomass processing

Supervisors: Prof Jason Hallett, Dr Agi Brandt-Talbot, Prof Benoit Chachuat

This project will involve optimisation of the application of low-cost ionic liquids to the processing of biomass, used in the production of biofuels and value-added products such as fibres for dissolving pulps (textile and consumer products) and nanocellulose. We are continuing to develop the ionoSolv (BioFlex) process, invented at Imperial College, as a flexible method for the fractionation of biomass into cellulose and lignin product streams. The particular challenge in this PhD project will be to optimize the process parameters during extraction to increase cellulose characteristics (low lignin content, long fibre length) while maintaining key process integration characteristics (downstream water usage and energy consumption). This will enable not only a more efficient process, but a more sustainable approach to chemicals and materials manufacturing. The student will benefit from training in the complementary disciplines of chemistry and chemical engineering, meaning that they will be comfortable with our state-of-the-art biomass processing protocols, but also able to create complex data analysis algorithms and implement them into a process design framework to assess sustainability and profitability. We will also explicitly develop novel high-throughput, rapid analysis protocols for cellulose characteristics. The ionoSolv process is under commercial development by Lixea LTD, an Imperial College spin-out company, and data sharing on process development will continue throughout the project.

Nanocellulosoic materials from waste wood using low-cost ionic liquids
Supervisors: Jason Hallett; Agi Brandt-Talbot
Nanocellulosic Materials (NCMs), cellulose fibers that have at least one dimension that measures less than 100 nm, such as Nano-Crystalline Cellulose (NCCs) and Cellulose NanoFibers (CNFs), is an emerging group of materials that utilise the added functionalities of cellulose when at a nanoscale. NCMs have high aspect ratio and a lower density and higher tensile strength than traditional reinforcement materials, while their Young’s Modulus is comparable. The abundance of hydroxyl surface groups allows for surface modification of the
nanocellulose particles which can impact their dispersibility and ability to form ordered alignments. These are important characteristics for applications such as fillers and reinforcements in composites, for films, hydrogels and emulsions, which can be used in applications such as for packaging, drug delivery, sensors and electronic devices. We have recently proven that ionoSolv cellulose remains in fibre form and the fibre length is shortened, making it potentially an ideal raw material for NCM production.
This project will develop and optimize the production of NCMs using the ionoSolv process followed by total chlorine free bleaching (green oxidation) from waste feedstocks. You will characterize the bleached pulps and final NCMs and correlate the final properties with the starting feedstocks and process conditions, with the goal of optimizing particle size, crystallinity, chemical modifications and adding tailored surface groups. This will produce lowcost, sustainable NCMs, using fewer steps than current processes.

The project is a collaboration with Lixea: 

PhD studentships: The Department of Chemical Engineering is currently accepting applications from outstanding students for our Departmental PhD Studentships (

These are fully funded 42-month positions with a host academic. If you are interested in applying for a scholarship hosted in my lab, please contact me (

Integrated Biorefinery Research:

This area of research focusses on the simultaneous production of both biofuels and chemical feedstocks from renewable resources, such as from lignocellulosic biomass. This involves a range of research areas in my group, including:

Deconstruction of Biomass using Ionic liquids

Enzymatic Biocatalysis in Protein-friendly Ionic Liquids

Bioprocess Development and Scale-up

Other Ionic Liquids Research:

Stabilisation of Therapeutic Proteins

Metal Recovery from Waste Streams

Process, Techno-economic, and Socio-economic Modelling of Ionic Liquid Biorefining

Catalytic Production of Platform Chemicals from Biomass using Ionic Liquids

Interactions of Ionic Liquids with Biopolymers

Recycling Ionic Liquids

Interactions of Ionic Liquids with CO2

Selected Publications

Journal Articles

Mota A, Hallett JP, Kuznetsov ML, et al., 2011, Structural characterization and DFT study of (VO)-O-IV(acac)(2) in imidazolium ionic liquids, Physical Chemistry Chemical Physics, Vol:13, ISSN:1463-9076, Pages:15094-15102

Lui MY, Crowhurst L, Hallett JP, et al., 2011, Salts dissolved in salts: ionic liquid mixtures, Chem. Sci., Vol:2, Pages:1491-1496-1491-1496

Hallett JP, Liotta CL, Ranieri G, et al., 2009, Charge Screening in the S(N)2 Reaction of Charged Electrophiles and Charged Nucleophiles: An Ionic Liquid Effect, Journal of Organic Chemistry, Vol:74, ISSN:0022-3263, Pages:1864-1868

Wells TP, Hallett JP, Williams CK, et al., 2008, Esterification in ionic liquids: The influence of solvent basicity, Journal of Organic Chemistry, Vol:73, ISSN:0022-3263, Pages:5585-5588

Hallett JP, Ford JW, Jones RS, et al., 2008, Hydroformylation catalyst recycle with gas-expanded liquids, Industrial & Engineering Chemistry Research, Vol:47, ISSN:0888-5885, Pages:2585-2589

Ranieri G, Hallett JP, Welton T, 2008, Nucleophilic reactions at cationic centers in ionic liquids and molecular solvents, Industrial & Engineering Chemistry Research, Vol:47, ISSN:0888-5885, Pages:638-644

More Publications