Alternative Solvents 

plants in test tubes, lab equipment, male researcher in lab

The Green Chemistry Centre of Excellence is a world leading research centre which aims to promote the development and implementation of sustainable chemistry and related technologies into new products and processes.

The “Alternative Solvents” technology platform promotes the use of new alternative solvents - supercritical/liquid CO2, bio-based solvents and solvents from food waste - as sustainable and economically attractive alternatives to conventional organic solvents.

Our goal is to develop, apply and promote the implementation of safer, greener and more sustainable solvents into industry. The platform focuses on the use of both supercritical and liquid CO2 and bio-based solvents in a wide range of applications (extraction, fractionation of waxes, chemical reaction, product cleaning, material development, impregnation etc.)

Some of the applications already developed using supercritical or liquid CO2 and bio-based solvents include:

  • Extraction of waxes and botanicals (food, beverage, cosmetic, personal care products)
  • Recovery of liquid crystals from end-of-life electronics
  • Synthesis of aroma molecules using biocatalysts in alternative solvents
  • Use of modelling tools to predict the properties and behaviour of a solvent
  • Use of bio-based solvents for conducting important organic reactions
  • Chromatography in supercritical fluids

Reactions in Alternative Solvents

Traditional heterogeneous catalysts and biocatalytic processes can be performed in supercritical CO2 and bio-based solvents because they offer a number of advantages over the use of conventional solvents including:

  • Lower rates of catalyst poisoning
  • Enhanced stability
  • Better enantioselectivity
  • Simple product and catalyst recovery

Supercritical Fluid Chromatography

The alternative solvent technology platform also operates a state of the art semi-preparative supercritical chromatography system. This system allows one to carry out extractions, reactions and analysis all in the supercritical phase.

Extraction Using Liquid or Supercritical CO2

CO2 is a non-polar solvent that can be used in liquid or supercritical states. Liquid CO2 is significantly less polar than supercritical CO2, and is limited to the extraction of small non-polar molecules. Supercritical CO2 has several distinct advantages over traditional organic solvents in extractions including:

  • Highly tuneable solvent
  • Selective
  • Low surface tension
  • Low viscosity
  • High mass transfer rates
  • Highly efficient solvent
  • Simple product recovery
  • Leaves no solvent residues

 CO2 extractions have been successfully developed to extract:

  • Herbs and spices (food and beverage use)
  • Waxes (cosmetics, personal care products)
  • Oils (neutraceuticals)
  • Pharmaceutical molecules (fractionation)
  • Liquid crystals (end-of-life electronics)

Bio-Based Solvents and Modelling

Solvents from biomass and food waste are viewed as one of the most promising types of alternative solvents:

 Bio-Based Solvent Molecules

A key feature of this work is the use of modelling tools to predict the properties and behaviour of a solvent. The use of such tools allows for the prediction of those solvents offering the most favourable performance for a target application.

Our software modelling tools aid in finding existing alternative solvents but can also design new bio-based solvents that can then be prepared at lab-scale (within GCCE) or at demonstrator scale (at our BDC facilities).


S4 - Sustainable Solvent Selection Service

The GCCE has developed the S4 (Sustainable Solvent Selection Service) concept as a tailor-made service to replace hazardous solvents and to promote benign equivalents:


 Sustainable Solvent Selection Service


Laboratory & pilot plant facilities are available to carry out extractions & fractionation in liquid or supercritical CO2. Supercritical chromatography and reactions systems are also available. To find out more about the use of these technologies in your business or research area contact the GCCE.

Carbonates as Alternative Solvents

Recent estimates by the pharmaceutical and fine chemical industry have suggested solvents account for 80-90% of the total waste produced in a typical batch process. For this reason there has been a large amount of interest in the field of alternative solvents. As it presents the opportunity for the most significant gains, in terms of reducing environmental impact.

Many efforts have investigated the use of neoteric or “new” solvents and solvent technologies, common examples include ionic liquids (IL’s), supercritical CO2 or fluorous solvents. However, these have often been limited to small scale industrial applications or high value products.

There still exists substantial scope for the exchange of volatile organic compounds (VOC) for molecular solvents with favourable environmental, health and safety characteristics. In recent years, organic carbonates (both cyclic and acyclic) have been highlighted as highly promising alternatives to VOCs. Current projects within the GCCE are investigating the use of carbonates as alternative solvents in various synthetic transformations.

Alternative Solvents Brochure (PDF  , 1,399kb)  

Alternative Solvents Group Members

Dr James Sherwood Alternative Solvents Technology Platform Leader
Dr Thomas Attard Postdoctoral Researcher
Fergal Byrne Postdoctoral Researcher
Karima Al-Bulushi Research Student