0   Introduction

 

Agenda 21 calls for “criteria and methodologies for the assessment of environmental impacts and resource requirements throughout the full life cycle of products and processes” (Chapter 4.20) and in numerous chapters it formulates the aims and measures necessary for chemistry to make an important contribution. These aims and measures have to be considered for an assessment of chemical processes and products in regard to their contribution to a sustainable development.

With EATOS a concept for research and training has been developed and incorporated into a software program that now provides the opportunity to carry out, in the laboratory, a simple and rapid juxtaposition and weak-point analysis of syntheses with respect to the utilization of resources and environmental compatibility. The concept is based on an integrated metrics system that is intended to foster the design of the synthesis in an early stage of development. EATOS can be used, among other things, to quantify substances entering the synthesis (raw materials: substrates, solvents, catalysts, auxiliary materials) and substances leaving the synthesis (waste materials: all substances which are not the product proper) in ratio to a mass unit of the product. By means of the mass index S-1 [kg raw materials / kg product] and the environmental factor E [kg waste / kg product] syntheses can be compared with regard to the consumption of raw materials and the generation of waste and thus more resource-effective syntheses can be identified. 

In order to assess and to compare the environmental impact of different reactions, substances can be weighted according to various effect categories with their substance-specific properties, which are then integrated quantitatively into the environmental indices EI_in and EI_out [PEI / kg product] (PEI = potential environmental impact) . This approach gives room for an objectivity that meets holistic requirements. 

This concept can also be applied to complex synthesis sequences.

As an example of the utilization EATOS  has been applied exemplarily to four different protocols of the synthesis of 4methoxyacetophenone, which have been assessed with respect to their utilization of resources and environmental impact. This example demonstrates that the chemical yield, which is typically used by chemists to evaluate the effectiveness of a synthesis, does not offer a sound basis for the selection of the most environmental benign synthesis. 

 

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