Solid-State Oxidation of Alcohols in Gold-Coated Milling Vessels via Direct Mechanocatalysis

Alcohols are selectively oxidized to their corresponding aldehydes catalytically via mechanochemistry using a gold-coated milling vessel. Superior catalytic efficiency and selectivity was achieved through the meticulous modulation of milling frequency, duration, and media, complemented by controlled heating. Achieving a turnover number (TON) near 8200 and a turnover frequency (TOF) of 0.77 s-1, the system notably surpasses existing alternatives. Utilizing atmospheric oxygen as the primary oxidant facilitated significant yields, with the highest reaching up to 99% for selected substrates. The catalytic reaction indeed occurring on the surface of the vibrating milling ball was confirmed via X-ray photoelectron spectroscopy (XPS). This study highlights the pivotal role of operational parameter optimization in enhancing catalysis, emphasizing the method's sustainability and broad applicability across various alcohol substrates. The findings contribute significantly to green chemistry, offering an efficient, sustainable approach to alcohol oxidation.