Green metrics in mechanochemistry

Area of Science:

• Green Chemistry and Sustainable Synthesis
• Mechanochemistry in Organic Transformations

Background:

• Chemistry's societal and economic importance necessitates sustainable practices.
• Alignment with United Nations Sustainable Development Goals (UN SDGs) and the European Green Deal is crucial.
• Traditional solution-based chemistry often has a significant environmental footprint.

Purpose of the Study:

• To review and highlight batch and continuous mechanochemical methods as eco-friendly alternatives for organic synthesis.
• To assess the environmental benefits of mechanochemistry using established green metrics and indicators.
• To demonstrate the superiority of mechanochemical processes over solution-based methods.

Main Methods:

• Review of literature on batch and continuous mechanochemical organic synthesis.
• Application and assessment using green metrics (e.g., atom economy, E-factor, Process Mass Intensity, Eco-scale).
• Utilization of indicators like DOZN tool and Life Cycle Assessment (LCA) studies.

Main Results:

• Mechanochemical methods generally exhibit a lower environmental footprint than solution-based procedures.
• Key advantages include the absence of bulk solvents, precise stoichiometric control, and simplified work-up.
• Successful application demonstrated across diverse organic transformations, including amide bond synthesis, heterocycles, APIs, and polymers.

Conclusions:

• Mechanochemistry presents a superior, sustainable approach to organic synthesis.
• Its adoption promotes environmental well-being and aligns with global sustainability initiatives.
• Reduced solvent usage and enhanced efficiency make mechanochemical processes a key strategy for greener chemistry.