The working principles of mechanochemistry
5 Ways Mechanochemistry Is Transforming Chemical Manufacturing And Recycling
Mechanochemistry is a branch of chemistry that uses mechanical forces, such as those in ball milling, to drive chemical transformations. It is the oldest form of chemistry known to humanity, dating back to ancient practices such as igniting fires by rubbing stones or preparing food with a mortar and pestle. Mechanochemistry is scalable, with advanced modular systems enabling continuous production at output rates of tonnes per hour, making it viable for industrial operations.
1. Drastic Reduction of Solvent Use
In traditional chemistry, solvents account for about 85% of the process mass, with 50-80% recovered. Despite the widespread availability of infrastructure and well-known safety practices in solution-based chemistry, sticking to tradition isn’t the future. High reagent dilution and large solvent volumes increase reactor sizes and chemical plant costs, driving up capital expenses. Mechanochemistry, however, enables chemical transformations in high-concentration mixtures without dissolving reagents. Although purification is sometimes needed, eliminating solvents in the reaction step significantly reduces overall solvent usage. This cuts capital and operating costs and slashes greenhouse gas emissions by over 70%. Upscaling remains a challenge, but growing industrial success stories boost confidence.
2. Room Temperature and Pressure Conditions
Mechanochemistry excels at mixing and supports high-concentration reaction mixtures without solvent effects. Mechanical energy elevates reagents to higher energy states, lowering activation barriers. As a result, most mechanochemical processes run at room temperature and pressure without the need for heating or pressurisation. In contrast, solution-based processes often require high temperatures and pressures. While impacts and friction generate some heat, it can be managed effectively. Moreover, mechanochemical processes use 5-10 times less energy than solution-based methods, making them well-suited to renewable energy sources such as solar power. Overall, mechanochemistry can reduce operating costs by 30-50%.
3. Faster Chemical Processes
High reagent concentrations and superior mixing make mechanochemical processes faster than traditional methods. While reaction times vary, optimized mechanochemical reactions typically take 30-90 minutes, compared with several hours or days for solution processes. Certain additives can accelerate the process by altering surface energies and local rheology. These changes affect mechanical energy absorption and active-site exposure, thereby boosting efficiency. This cuts operating time by a factor of 2-5, further lowering processing costs.
4. More Selective Processes
Without solvation effects, mechanochemical transformations offer greater selectivity than solution-based methods. This results in higher yields of the desired products and fewer by-products, simplifying purification. Mechanochemistry increases the likelihood of purifying products by recrystallization, avoiding costly procedures. Selectivity can be fine-tuned by adding liquid additives to modify reagent surface energies and stabilize intermediates or transition states.
5. Innovation Potential
Mechanochemistry’s unique principles unlock opportunities to redesign and innovate chemical processes. For example, insoluble reagents such as mineral ores, biomass, or post-consumer waste can be used as starting materials, something impossible in solution-based processes. This expands the chemical reaction space. Mechanical forces also break down solid materials, eliminating the need for pre-processing steps such as particle size reduction. Techniques such as direct mechanocatalysis allow the equipment to act as the catalyst, simplifying separation. You can even combine mechanical energy with light, heat, or electrical potential in photo-, thermo-, and electro-mechanochemistry, creating new materials unavailable through individual methods. Overall, mechanochemistry saves materials, energy, and time while tapping into vast innovation potential.
After decades of academic research, it’s ready to transform the chemical industry.
Mechanochemistry is coming.