Implementing objectives of sustainability into ionic liquids research and development

Abstract

This paper proposes the ECO (ecological and economic optimisation) method to accompany and optimise early stage development work in chemical research and development (R&D) regarding the principles of ecological and economic sustainability. The ECO method is a screening tool that uses a simplified life cycle assessment (SLCA) approach, in combination with an optimisation procedure. All life cycle stages from the production of reactants, solvents etc., synthesis and work-up, recycling and disposal are considered within this methodology. They are evaluated regarding three main objectives: the factors for energy demand (EF), risks concerning human health and environment (EHF) and costs (CF). During each process step, a variation of process parameters (e.g.T, t, c, n : n, solvent, reactant alternatives) will be compared using an outranking algorithm, in order to find the most efficient combinations. At this stage, all objectives will be assessed with respect to an input-benefit ratio. Using this approach, the search for sustainable chemical compounds, synthesis pathways, or processes can already be applied during the R&D stage. This will be demonstrated on the example of ionic liquids, which may have a remarkable potential to improve a wide range of chemical syntheses. Thus, their application may lead to environmental and cost improvements, when compared to commonly used volatile organic solvents. However, the preparation and work-up of ionic liquids are presently not environmentally benign. The application of the ECO method to ionic liquids R&D can help to overcome this problem.