Oxidative esterification of 1,2-propanediol using gold and gold-palladium supported nanoparticles

The oxidative esterification of 1,2-propanediol to methyl lactate and methyl pyruvate was investigated using gold and gold palladium nanoparticles supported on a variety of supports. Methyl lactate can be used in cosmetics and personal care products, whereas methyl pyruvate is useful in the treatment of diseases of the nervous system. We show that gold-palladium alloy catalysts can be very effective for the oxidative esterification of 1,2-propanediol to methyl lactate and methyl pyruvate. Five supports, titania, carbon, silica, iron oxide and ceria are contrasted. The addition of palladium to gold significantly enhances the activity and retains the high selectivity to methyl lactate using O-2 as oxidant. Using ceria as support a significant improvement in the selectivity to methyl lactate was observed, whereas using silica as support high selectivity to methyl pyruvate was achieved. The use of colloidal methods and the effect of support and Au/Pd molar ratio are discussed.