Grinding Chemicals Together in an Effort to be Greener

...In 2011, the mechanochemist Tomislav Friscic and his team used mechanochemical methods to make bismuth subsalicylate, the active ingredient of Pepto-Bismol, by grinding together bismuth oxide and salicylic acid. The method not only does away with solvents, but also uses bismuth oxide, a safe reagent, in lieu of toxic bismuth salts.

In 2013, Dr. Friscic reported a new single-step process to prepare sulfonylguanidines, a family of chemicals used in herbicides and pharmaceuticals, through grinding. His research team at McGill University in Montreal tried to reproduce the process in solution, but failed. New York Times