Cheminformatics as a versatile tool in Green and Sustainable Chemistry

In the field of chemoinformatics (or cheminformatics), quantitative structure-activity/property-relationship models (QSA/PR, abbreviated in the following as QSAR) have been developed to predict the activity or property of a chemical. The models can be used to generate data for chemicals assessment of new or existing chemicals and are already used in chemical’s and pharmaceutical’s design. Recently, QSAR models are also applied in the design of less toxic, non-bioaccumulative and environmentally biodegradable chemicals in the context of Benign by Design (4th and 10th principle of green chemistry) since QSAR models are fast and produce no chemical waste compared to experimental testing and reduce animal testing and therefore facilitate to decide which chemical structure is a promising candidate for a benign chemical.

Study on the biotic and abiotic environmental degradation (“Benign by Design”) using ionic liquids as an example.

The example of ionic liquids (ILs) is used to demonstrate the potential and limitations of QSAR models for the development towards green and Sustainable Chemistry. ILs are charged compounds that are composed of an organic cation and an organic or inorganic anion. The ILs were chosen as an example because the combinations of cation and anion in ILs are almost infinite leading to a huge potential to design ILs according to the required properties and functions. Additionally, because of the ionic nature of ILs there are challenges to apply QSARs.

ILs are seen as substitute for volatile organic carbons because of their low vapour pressure and are therefore often called green. Further applications of ILs that are under discussion, such as active pharmaceutical ingredient (API), herbicide, surfactant or antistatic agent in coatings or cleaning agents, will unavoidably release ILs to the environment and makes it impossible to reuse the chemicals in a circular economy.

In order to promote the development towards Sustainable Chemistry and to avoid ILs persisting in the environment or resulting in the generation of transformation products in the environment for these applications ILs have to be designed so that they can fully and fast enough mineralise in the environment (“Benign by Design”) after they have delivered their service and function. Besides no (eco)toxicity, no bioaccumulation, synthesis related issues and resources demands, full mineralisation is an important property to design more sustainable ILs.

© kittirat roekburi/Shutterstock

In a publication “Inventory of biodegradation data of ionic liquids” published in the scientific journal Chemosphere, Ann-Kathrin Amsel, Dr. Oliver Olsson and Prof. Klaus Kümmerer, Director of the ISC3 Research and Education Hub and Professor of Sustainable Chemistry and Material Resources at the Leuphana University, reviewed the state of research of the environmental biodegradability of ILs.
This study is based on a systematic literature review and collected biodegradability data of ILs measured by standardised methods in 109 experimental studies. The collected data was analysed with regard to validity of the data and the environmental biodegradability of ILs. The authors highlight the need for more valid biodegradation data of ILs to increase the availability of reliable data to better compare the data and generate a comprehensive understanding of ILs’ biodegradability.

To allow QSARs for a broader and more convenient application in green chemistry and for Benign by Design a generic workflow is needed. In a scientific publication "Toward application and implementation of in silico tools and workflows within benign by design approaches" in the journal ACS Sustainable Chemistry and Engineering a workflow is proposed that shows how QSAR models, read-across and other in silico methods can be used for the benign design of chemicals and pharmaceuticals. It should help to make faster and better informed decisions in the design process.