(458a) Catalytic Dehydration of Methyl Lactate: Selectivity Control

Catalytic dehydration of lactic acid and its esters is a promising approach to renewably produce acrylic acid and its esters, which are currently produced via the oxidation of petroleum-derived propylene. Molecular level understanding of pathways for the desired dehydration and undesired decarbonylation reactions on NaY has been achieved via a combination of reactivity and in-situ transmission FTIR spectroscopic investigations. Brønsted acid sites generated via the ion exchange between adsorbed methyl lactate and Na⁺ cations in NaY, with the assistance of water, have been identified as the primary active sites for the dehydration pathway.  The key branching point between the dehydration and decarbonylation pathways has been identified as the dissociation of methyl lactate on NaY to form adsorbed sodium lactate and methyl groups. The mechanistic understanding gained will enable rational design of catalysts for selective dehydration of methyl lactate.