Ball Mills as Catalytic Reactors: Ammonia Synthesis at Room Temperature and Atmospheric Pressure 

The input of mechanical energy is a new way to accelerate chemical reactions or to open up new reaction pathways. Ammonia synthesis normally requires 400-500°C and pressures of 200-300 atm. However, if this reaction is carried out under milling in a ball mill with a suitable catalyst, nitrogen and hydrogen can be converted to ammonia even at room temperature and atmospheric pressure, albeit with substantially lower rates than in the technical process. Mechanocatalytic reactions are not restricted to ammonia synthesis, since we have found a number of other reactions benefitting from milling.